United States
            Environmental Protection
            Agency
            Office of Research and
            Development
            Washington, DC 20460
EPA/600/R-92/175
October 1992
vvEPA
Opportunities for Pollution
Prevention Research to
Support the 33/50 Program

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                                      EPA/GOO/R-92/175
                                      October 1992
OPPORTUNITIES FOR POLLUTION PREVENTION RESEARCH
           TO SUPPORT THE 33/50 PROGRAM
                        by
                      Battelle
                Columbus, Ohio 43210

                 Work Assignment 06
             EPA Contract No. 68-CO-0003
                 EPA Project Officer

                   Paul M. Randall
            Waste Minimization, Destruction
            and Disposal Research Division
     RISK REDUCTION ENGINEERING LABORATORY
       OFFICE OF RESEARCH AND DEVELOPMENT
      U.S. ENVIRONMENTAL PROTECTION AGENCY
               CINCINNATI, OHIO 45268
                                      Printed on Recycled Paper

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                                NOTICE
This review of research needs  summarizes  information  collected from U.S.
Environmental Protection Agency programs, peer reviewed journals, industry
experts, vendor data, and other sources.  A variety of potential candidate source
reduction  and recovery/recycling methods are described.   This  document  is
intended as advisory guidance in identifying research needs for reducing pollution.

Publication of this document does not signify that the contents necessarily reflect
the views and policies of the U.S. Environmental Protection Agency, nor does
mention of trade names or commercial  products constitute endorsement or
recommendation for use. Compliance with environmental and occupational safety
and health laws is the responsibility  of each individual business and  is not the
focus of this document.

This effort has been funded wholly or in part by the United States Environmental
Protection Agency under Contract No. 68-CO-0003, Work Assignment 06. It has
been subjected to the Agency's peer review and administrative review, and it has
been approved for publication as an EPA document.

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                              FOREWORD
Today's rapidly developing and changing technologies and industrial products and
practices frequently carry with them the increased generation of materials that, if
improperly dealt with, can threaten both  public health and the environment. The
U.S. Environmental Protection  Agency  (EPA) is charged  by  Congress with
protecting the Nation's land,  air, and water resources.  Under a mandate of
national environmental laws, the agency strives to formulate and implement actions
leading to a compatible balance between human activities and the ability of natural
systems to support and  nurture life.  These laws direct  the EPA to  perform
research to define our  environmental problems, measure the impacts, and search
for solutions.

The  Risk  Reduction   Engineering  Laboratory  is  responsible for planning,
implementing, and managing research, development, and demonstration programs
to provide an  authoritative, defensible engineering basis in support of the policies,
programs, and regulations of the EPA with respect to drinking water, wastewater,
pesticides, toxic substances, solid and hazardous wastes, and Superfund-related
activities. This publication is one of the products of that research and provides a
vital communication link between the researcher and the user community.

This report reviews common industrial uses and emerging future approaches to
reducing waste of the chemical groups  identified  in the "33/50 Program."  The
Branch  is charged with defining, evaluating, and  advancing the  technology for
implementing the national pollution prevention program.  It also provides technical
assistance  to other sections of the  Agency  for  the purpose  of  reducing  or
eliminating pollution hazards.
                             E. Timothy Oppelt, Director
                             Risk Reduction Engineering Laboratory

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                               ABSTRACT
The  intent of this effort was to provide guidance  information for the  Pollution
Prevention Research Branch in planning its research program.  This document
compiles information on'existing  pollution prevention  methods and identifies
research needs.  It helps  define areas for research to increase application  of
existing methods and create new approaches for  source reduction and recov-
ery/recycling of the 17 chemical groups targeted  in the 33/50  Program.  The
emphasis is  on source reduction,  but  recovery/recycling methods are  also
considered.

A functional approach is used to identify and organize research areas for each  of
the 17 targeted chemical groups. The sources and production characteristics and
rates are briefly  summarized.   Then  pollution prevention opportunities  and
supporting research needs are discussed for the major industrial and consumer
applications of the targeted chemical groups.  The opportunities and research
needs are presented in both narrative and tabular formats.

This report was submitted in  partial fulfillment of  Contract 68-CO-0003, Work
Assignment 06, under the sponsorship  of the U.S. Environmental Protection
Agency.  This report covers a period from September 1991 to February 1992, and
work was completed as of June 1992.
                                   IV

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                                   CONTENTS
Notice ..	..	.		  ii

Foreword	'.	;	Hi

Abstract 		iv

Tables	 viii

Acknowledgments	ix


1  Introduction	  1

      Background	  1
            Pollution Prevention Act of 1990 .	  1
            Source Reduction	  1
            What Is the 33/50 Program?	  2
            What Is Pollution Prevention?	  3
            Major 33/50 Program Goals	  3
            What Are the Target Chemicals?	  3
            The 33/50 Program Signals a New Approach	  4
            What Is EPA Asking Companies to Do?	  4
            How to Get More Information	  5
            Toxic Release Inventory Database	  5
      Objective	  6
      Potential Users of This Document	  6
      References for the Introduction	  11


2  Cadmium Pollution Prevention Research Needs for the 33/50 Program  	  12

      Sources and Production Characteristics and Rates  	  12
      Pollution Prevention Opportunities and Supporting Research Needs	  15
            Electrical Applications  .	  15
            Coating and Plating	  15
            Pigments  .	  16
            Plastics and Synthetic Products	  16
            Alloys  .	  17
            Catalysts	  17
            Other Uses	  18
      References for Cadmium  	  18

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3  Chromium and Nickel Pollution Prevention Research Needs for the
   33/50 Program	  19

      Sources and Production Characteristics and Rates	 .   19
      Pollution Prevention Opportunities and Supporting Research Needs  	  26
             Plating for Hardness and Corrosion Resistance	, .	  26
             Plating for Appearance	  29
             Surface Etching, Preparation, and Cleaning 	  30
             Alloying	, . .	  31
             Water Treatment Chemicals	  31
             Refractories  	'....-.... i....  32
             Catalysts	  32
             Wood Treatment and Preservation	  32
             Pigments and Oxides	-.34
             Battery Manufacture	  35
             Leather Tanning  	  35
      References for Chromium and Nickel	  36


4  Cyanide Pollution Prevention Research Needs for the 33/50 Program  	  38

      Sources and Production Characteristics and Rates 	  38
      Pollution Prevention Opportunities and Supporting Research Needs  	  39
             Electroplating 	;	  39
             Mining and Ore Processing	  41
             Primary Metals 	  41
             Treatment Processes .		  41
             Chemical Intermediates and Polymers	  44
      References for Cyanide	  44


5  Lead Pollution  Prevention Research Needs for the 33/50 Program	  46
                                i
      Sources and Production Characteristics and Rates 	  46
      Pollution Prevention Opportunities and Supporting Research Needs  	  51
             Emissions from Primary  Lead Smelting	  51
             Alloys	  52
             Storage Batteries  	  56
             Catalysts	  57
             Electrical  Components	  58
             Paints and Pigments	  59
             Plastics and Rubber .'	  60
             Ceramics and Glasses	  61
             Specialty Uses  	  61
      References for Lead	  63
                                         VI

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6  Mercury Pollution Prevention Research Needs for the 33/50 Program  .........  66

      Sources and Production Characteristics and Rates	  66
      Pollution Prevention Opportunities and  Supporting Research Needs	  70
             Batteries	  70
             Catalysts	-.	 . . .	  71
             Chlorine and Caustic Soda	  72
             Switching Devices and Control Instruments	  72
             Electrical Lamps	  73
             Fungicides	'.	  73
      References for Mercury	  74


7  Pollution Prevention Research Needs for Eleven TRI Organic
   Chemical Groups	  75

      Sources and Production Characteristics and Rates	  75
      Pollution Prevention Opportunities and  Supporting Research Needs	  88
             Paint Stripping	  88
             Solvent Gleaning/Degreasing	  90
             Solvent for Coatings   	. . . .	  93
             Dry Cleaning  ................. .	;......  94
             Blending Components in Gasolines	  95
             Emissions from Petroleum Refining and Related Industries . . .	  95
             Emissions from Primary Metal Smelting and Refining	  96
             Solvents for Printing Processes	  97
             Solvents for Rubber and Miscellaneous Plastic Manufacturing 	  98
             Chemical Manufacturing	 . . .	  98
      References for Eleven TRI Organic Chemical Groups  ....". '.	  99
                                       VII

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                              TABLES


TABLE 1. PROPERTIES OF THE TRI TARGET CHEMICALS				  7

TABLE 2. REPORTED RELEASES FOR EACH CHEMICAL BY
        RELEASE/TRANSFER PATH	  9

TABLE 3. RELEASES AND TRANSFERS OF THE TRI CHEMICALS
        BY INDUSTRY	• • •	• • • •	 10

TABLE 4. CADMIUM POLLUTION PREVENTION RESEARCH NEEDS	 13

TABLE 5. CHROMIUM AND NICKEL POLLUTION PREVENTION
        RESEARCH NEEDS	 20

TABLE 6. CYANIDE POLLUTION PREVENTION RESEARCH NEEDS	 40

TABLE 7. LEAD POLLUTION PREVENTION RESEARCH NEEDS	 47

TABLE 8. MERCURY POLLUTION PREVENTION RESEARCH  NEEDS	 . 68

TABLE 9. ELEVEN ORGANIC CHEMICALS POLLUTION PREVENTION
        RESEARCH NEEDS I	 79
                                 VIII

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                         ACKNOWLEDGMENTS
This report was prepared under the direction and coordination of Paul Randall of
the U.S. Environmental Protection Agency, Office of Research and Development,
Risk Reduction Engineering Laboratory, Pollution Prevention Research Branch, in
Cincinnati, Ohio.

Contributions were also made by Harry Freeman, Ivars Licis, S. Garry Howell, and
Hugh  Durham  of the U.S.  EPA's Office of Research and Development.  Also,
contributions were made by David Hindin of the U.S, EPA's Office of Prevention,
Pesticides, and Toxic  Substances;  Robert  Pojasek  and David  Allen of  the
American institute of Pollution Prevention.

This report was compiled and prepared by Battelle (under Contract No. 68-CO-
0003, Work Assignment 06) under the direction of Bob Olfenbuttel for the U.S.
Environmental  Protection Agency Office of Research and Development.
                                   IX

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                                 1  INTRODUCTION
BACKGROUND

Pollution Prevention Act of 1990

       Prior to passage of the Pollution Prevention Act of 1990 (PPA) in November 1990,
       U.S. environmental protection regulations generally focused on treatment and
       disposal  of polluting materials rather than reduction at the source.  The PPA
       established prevention of pollution at the source as a national policy.
             1.

             2.

             3.

             4.


Source Reduction
Industry is encouraged to prevent or reduce pollution at the
source wherever feasible.
Unpreventable pollution should be recycled in an environ-
mentally safe manner when feasible.
When  pollutants cannot be  prevented  or recycled,  they
should be treated.
As a last resort, pollutants would be disposed of or other-
wise released into the environment.
       Source reduction, as defined by the Act, means any practice that

             "reduces the amount of any hazardous substance, pollutant  or
             contaminant entering any waste stream or otherwise released into
             the environment (including fugitive emissions) prior to recycling,
             treatment or disposal: and which  reduces the hazards to public
             health and the environment  associated with the release  of such
             substances, pollutants, or contaminants."  (U.S. EPA, 1991 a)

       The EPA is empowered by the PPA to establish a program for the EPA to promote
       source reduction.  According to the PPA, the EPA will:

             1.     Facilitate  adoption of  source reduction techniques by busi-
                    nesses and other federal agencies.
             2.     Establish  standard methods for measuring source reduction.
             3.     Determine effect of regulations on source reduction.
             4.     Find opportunities to use federal procurement to encourage
                    source reduction.
             5.     Improve  public access to data  collected  under federal
                    environmental statutes.

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 INTRODUCTION
              6.      Implement a training program on source reduction opportu-
                     nities, model source reduction auditing procedures, a source
                     reduction clearinghouse, and an annual award program.

 What Is the 33/50 Program?

       The 33/50  Program is EPA's voluntary pollution prevention  initiative to reduce
       national pollution releases and off-site transfers of 17 toxic chemicals by 33% by
       the end of 1992 and by 50% by the end of 1995.  EPA is asking companies to
       examine their  own industrial processes to identify and implement cost-effective
       pollution prevention practices for these chemicals.  Company participation in the
       33/50 Program is completely  voluntary.  The Program aims, through voluntary
       pollution prevention activities, to reduce releases and off-site transfers of a
       targeted set of 17 chemicals from a national total of 1.4 billion pounds in 1988 to
       700  million pounds by 1995, a 50%  overall reduction.  The Toxics  Release
       Inventory  (TRI)  (established  by federal law,  the Emergency  Planning  and
       Community Right-to-Know Act of 1986) will be used to track these reductions using
       1988 data as a baseline.  As required by the Pollution Prevention Act of 1990, TRI
       industrial reporting requirements were to be expanded, beginning in calendar year
       1991, to include information on pollution prevention.

       EPA announced the 33/50 Program in February 1991 when  EPA Administrator
       William K.  Reilly asked 600  U.S. companies to reduce their releases of these 17
       toxic chemicals.   EPA contacted these 600 companies first  because TRI data
       indicated that these companies were the largest dischargers to the environment
       of these chemicals. EPA is also contacting thousands of additional companies that
       release these 17 chemicals and requesting their voluntary participation in the 33/50
       Program. All companies are encouraged to participate in the 33/50 Program (even
       if they do not receive a letter from EPA inviting them to participate).

       While EPA is seeking to reduce aggregate national environmental  releases of
       these 17 chemicals by 50% by 1995, individual  companies are encouraged to
       develop their own reduction goals to contribute to this national effort. EPA also
       encourages companies to reduce releases of other TRI chemicals and to extend
       these reductions to their facilities outside the United States. For those companies
       that have not yet  made a commitment to participate,  EPA encourages them to
       participate  in this  national  pollution prevention initiative.  EPA will  periodically
       recognize those companies that commit to reduce their releases and transfers of
       the targeted chemicals, and will publicly recognize the pollution prevention success
       companies achieve. (U.S. EPA, 1991b; U.S. EPA, 1992)

What Is Pollution Prevention?

       The overall goal of the 33/50 Program is to promote the benefits  of pollution
       prevention while obtaining measurable reductions in pollution. Pollution prevention

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                                                                       INTRODUCTION
       is the use of materials, processes,  or practices that reduce or eliminate the
       creation of pollutants or wastes.

       Pollution prevention should be considered the first step in a hierarchy of options
       for reducing the generation of pollution. The next step in the hierarchy is responsi-
       ble recycling  of any wastes that cannot be reduced or eliminated at the source.
       Wastes that cannot be recycled should be treated in accordance with environmen-
       tal standards. Finally, any wastes that remain after treatment should be disposed
       of safely.                                    .

       EPA is promoting pollution prevention because it is often the most cost-effective
       option to reduce pollution, and the environmental and health risks associated with
       pollution.  Pollution prevention is often cost effective  because it may reduce raw
       material losses; reduce reliance on expensive "end-of-pipe" treatment technologies
       and disposal  practices; conserve energy, water, chemicals, and other inputs; and
       reduce the potential liability associated with waste generation. Pollution prevention
       is environmentally desirable for these very same reasons: pollution itself is reduced
       at the source while resources are conserved.

Major 33/50 Program Goals

       The 33/50 Program has three basic goals.  First, EPA is aiming to reduce national
       aggregate environmental releases of the 17 target chemicals from 1988 levels by
       33% by the  end  of 1992 and by 50% by the end  of 1995.  Second, EPA  is
       encouraging  companies to use pollution prevention practices (rather than end-of-
       pipe treatment) to achieve these reductions.  Third, EPA hopes that this Program
       will  help foster a pollution prevention  ethic in American business whereby
       companies routinely analyze all their operations to reduce or eliminate  pollution
       before it is created.

What Are the Target Chemicals?
       The 17 chemical groups are:

             Benzene
             Cadmium & Cadmium Compounds
             Carbon Tetrachloride
             Chloroform
             Chromium & Chromium Compounds
             Cyanide & Cyanide Compounds
             Lead & Lead Compounds
             Mercury & Mercury Compounds
             Methylene Chloride
Methyl Ethyl Ketone
Methyl Isobutyl Ketone
Nickel & Nickel Compounds
Tetrachloroethylene
Toluene
1,1,1-Trichloroethane
Trichloroethylene
Xylenes

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INTRODUCTION
       These chemicals were selected from the Toxics Release Inventory (TRI). The TRI
       is a computerized database containing public information on the annual releases
       and transfers of approximately 300 toxic chemicals reported by U.S. manufacturing
       facilities to EPA and the States.  Since 1987 federal law has required facilities to
       report the amount of  both  routine and accidental releases of the 300 listed
       chemicals to  the  air,  water, and soil,  and the amount contained in wastes
       transferred off-site.
       The chemicals listed above were selected for the 33/50 Program because:

              1.     They are produced in large quantities and subsequently
                    released into the environment in  large quantities.
              2.     They are generally identified as toxic or hazardous pollut-
                    ants; thus there may be significant environmental and health
                    benefits from reducing their releases to the environment.
              3.     The is the potential to reduce releases  of these chemicals
                    through  pollution prevention.

The 33/50 Program Signals a New Approach

       The  33/50 Program  complements  EPA's traditional  command  and control
       approach. The key attributes of this new approach are:

       National  in Scope.  Success will be measured according to whether reductions
       have been achieved nationwide, rather than for each company or facility.  The
       reductions also will be looked at as an aggregate — total releases of all chemicals
       rather than for each one.

       Voluntary.  Companies are free to decide if and how to participate in the program
       by: a) committing to meet their own specified reduction goals; and b) making good
       faith voluntary efforts to identify and implement cost-effective prevention measures.
       Any steps taken to reduce targeted toxics will not be enforceable,  unless these
       activities are otherwise required by law or regulation.

       Multi-Media.  The reduction goals apply to total releases and  off-site transfers to
       air, land, and water.

       Prevention-Oriented.  EPA's objective is to encourage these  reductions through
       pollution prevention. However, companies are encouraged to participate in  the
       33/50 Program even if all of their reductions are not achieved through prevention.

What Is EPA Asking Companies to Do?

       EPA is contacting thousands of companies to provide them with information on the
       33/50 Program and to solicit their participation.  Each company is being asked to
       examine its processes to identify and implement cost-effective pollution prevention

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                                                                       INTRODUCTION
      practices that will reduce or eliminate releases of the 17 chemicals.  In addition,
      companies are being asked to  submit  a letter to  EPA  publicly  stating  their
      reduction goals and how they plan to achieve them.  All companies wishing to
      .participate  in the 33/50  Program and receive official public recognition of their
      (Commitments are encouraged to  supply EPA with information  on their reduction
      goals.                   ,

How to Get More Information

      Guidance on how a company can participate in the 33/50 Program is available
      upon request. For copies of this commitment guidance and other 33/50 Program
      documents, fax your request to the TSCA Assistance Service at (202) 554-5803.
      For more information on the 33/50 Program, contact the TSCA Hotline at (202)
      554-1404, (8:30 am.to 4:00 pm).

      Information on pollution  prevention (and the 33/50 Program) is available through
      the  Pollution  Prevention Information Exchange System (PIES), a free computer
      bulletin board associated with EPA's Pollution  Prevention Information  Clearing-
      house. To learn how to use the Clearinghouse and the PIES, call (703) 821-4800.
      To access the  PIES using a PC, a  modem, and communications software, call
      (703) 506-1025 (set your communications software to no parity, 8 data bits, and
      1  stop bit).

Toxic Release Inventory Database

      The computerized Toxic Release Inventory (TRl) database was established to
      track toxic releases by the Emergency Planning and Community Right-to-Know Act
      of 1986. The TRl contains public  information on the annual releases and transfers
      of approximately 300 toxic chemical groups.  US. manufacturing facilities report
      on these chemical groups to the  EPA and the states. The law requires reporting
      of both routine and accidental releases of these 300 chemical groups to the air,
      water,  and soil,  and  the  amount contained in wastes transferred to off-site
      locations.  The TRl includes the  17 chemical groups selected for the 33/50
      . Program based on these reasons:                                         ;

              1.     They are produced, and  subsequently released, in large
                    quantities. Collectively, more than 6,000 parent companies
                    reported  1.4 billion pounds of releases or off-site transfers
                    of these 17 chemical groups in  1988.
              2.     Because  they are generally identified as toxic or hazardous
                    pollutants, significant environmental and health benefits may
                    accrue from reducing their releases to the environment.
              3.     Their releases potentially may be reduced through pollution
                    prevention.

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INTRODUCTION
       The PPA requires facilities that report releases for the TRI to report on pollution
       prevention and recycling. Information would include quantity entering the waste
       stream, percentage change from the previous year, source reduction practices,
       and changes in production from the previous year.

       The 17 priority chemical groups are listed in Table 1.  The chemicals are chiefly
       heavy metals, chlorinated  organic compounds,  and nonchlorinated  solvents.
       These high-priority chemicals are of the greatest concern to the EPA's air, water,
       land, and toxic chemical control programs. The EPA sought a way to reduce their
       serious known health and environmental effects and to limit their exposure.

       To help focus the discussion of pollution prevention  research needs for the 17
       chemical  groups,  releases  and transfers reported  in the 1988 TRI  data are
       summarized in Tables 2 and 3.  Table 2 shows the  reported  releases for each
       chemical  by release/transfer path.  Table  3  details  releases and transfers by
       industry. The 50 industries, identified by the four-digit Standard Industrial Category
       (SIC), for each chemical are grouped by two-digit SIC.  All other four-digit SICs are
       grouped as others.
OBJECTIVE
       This document compiles information on existing and emerging source reduction
       and recovery/recycling methods for each of the 17 priority chemicals targeted in
       the 33/50 Program. It provides an overview of many common uses of the priority
       chemicals and potential methods for reducing waste of the chemicals.  Based on
       these uses  and waste reduction methods, research needs are identified.  The
       research  needs describe functional requirements for research to expand the
       application  of existing  methods or to  foster  rapid development of emerging
       methods.

       This document  provides a  preliminary review  of a broad  range of  candidate
       methods. It is intended to focus development and screening of new ideas and to
       facilitate planning for research projects in source reduction and recovery/recycling.
       Selection of research opportunities is concerned  with the efficient allocation of
       money, skills,  equipment, and facilities  to projects. Careful selection of  projects
       is essential to efficient use of limited  resources.  Research  efforts should be
       focused on projects that give a significant reduction of the target chemicals and
       have a  reasonable probability of success.

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                                                                      INTRODUCTION
POTENTIAL USERS OF THIS DOCUMENT

      This document broadly scopes the functional requirements of research needed to
      develop source reduction methods for the priority chemicals. The document is
      intended for those in charge of 33/50 Program application, for R&D and process
      development personnel at companies where releases or off-site transfers of the 17
      priority chemical groups take place, and for researchers and process development
      personnel at other companies doing independent research on source reduction
      technologies, and on recovery and recycling operations.

      The purpose of this document is to present interesting and stimulating challenges
      leading to new ideas for research in  the development of new methods for source
      reduction and recovery/recycling.

      Although examples  are used to  clarify the discussion, the definition of research
      needs describes the functions needed without reference to a specific approach.
      Specifications of the research needs are, as much as possible, stated as functions
      to avoid  limiting creativity in developing new ideas. There is also an  attempt to
      make the statement of research needs sufficiently general to ensure the resulting
      technologies have  wide  application and to  avoid projects requiring a large
      component of proprietary intellectual property.
REFERENCES FOR THE INTRODUCTION

       Perry, J.H., and C.H. Chilton.  1963.  Chemical Engineers' Handbook, 4th ed.,
       McGraw-Hill, New York.

       U.S.  EPA.  1991 a.   Pollution Prevention Act of  1990.   Office of Pollution
       Prevention, Washington, DC, March.

       U.S.  EPA.  1991b.   The 33/50 Program:  Forging an Alliance for Pollution
       Prevention (2nd ed.).   Special Projects  Office,  Office of Toxic Substances,
       Washington, DC, July.

       U.S. EPA. 1992. EPA's 33/50 Program Second Progress Report, JS-7Q2A, Office
       of Pollution Prevention and Toxics, February.

       Verschueren, K. 1983. Handbook of Environmental Data on Organic Chemicals,
       2nd ed. Van Nostrand Reinhold, Co.
                                         11

-------
2
                CADMIUM POLLUTION PREVENTION RESEARCH NEEDS
                             FOR THE 33/50 PROGRAM
SOURCES AND PRODUCTION
CHARACTERISTICS AND RATES

      Cadmium (chemical symbol Cd) is a Group II-B element in the Periodic Table and
      exhibits a +11 oxidation state in  almost all of its compounds.  Pure cadmium
      compounds are rarely found in nature, although occurrences of greenockite, CdS,
      and otavite, CdCO3, are known.  The main sources of cadmium are sulfide ores
      of lead, zinc,  and copper, from which cadmium  is recovered as a by-product of
      production of these ores.  Because  cadmium is produced as  a  by-product of
      sulfide ore refining, reducing  cadmium consumption may not directly  affect
      cadmium production rates. However, reducing cadmium use will avoid distribution
      of cadmium throughout the environment and should, therefore, be pursued.

      Cadmium is obtained  in vapor form when roasting sulfide ores, and as a sludge
      from zinc sulfate purification. Pure cadmium metal is silver-white, tinged with blue,
      and lustrous.  Cadmium is often converted to  its oxide, CdO, where it is a more
      convenient starting material for synthesis of other compounds.

      Of the estimated 4,080 tons of cadmium consumption in 1990, the U.S. Bureau of
      Mines (1991)  has approximated apparent consumption patterns as follows:
                   batteries
                   coating and plating
                   pigments
                   plastics and synthetic products
                   alloys and other uses
                                            40%
                                            25%
                                            13%
                                            12%
                                            10%'
      Cadmium and its compounds are highly toxic. Most poisoning cases have been
      reported to be due from inhalation of fumes or dusts. Fumes are formed at high
      temperatures by such industrial processes as welding and brazing, and they may
      be released from incinerators that are unequipped with pollution  control devices.
      Cadmium is immediately dangerous to human health upon exposure to 1 mg/m3
      over an 8-h period (Chizikov, 1966) and is lethal in air concentrations of 6 mg/m3
      over an 8-h  period  (Barrett and Card, 1947).   Cadmium causes a range of
      systemic effects, for example, kidney and lung damage.  Some shellfish tend to
      concentrate cadmium and it causes chronic effects in many aquatic organisms.

      A variety of cadmium applications and potential approaches for reducing waste are
      summarized in Table 4 and are outlined in the text following the table.
                                        12

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ESEARCH NEEDS
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                                                                            CADMIUM
POLLUTION PREVENTION OPPORTUNITIES
AND SUPPORTING RESEARCH NEEDS

Electrical Applications

      . Cadmium hydroxide is used as the active anode material in rechargeable silver-
       cadmium and nickel-cadmium batteries.  Silver-cadmium oxide material is used to
       make  electrical  contacts,  cadmium  chalcogenide electroluminescent  and
       photoconductive devices, as well as phosphors and several types of semiconduc-
       tors.   Cadmium  arsenides, antimonides, and phosphides  are used  in  many
       electronic devices and semiconductors.  A minor use of cadmium sulfide is in the
       manufacture of photovoltaic solar cells.
Replace cadmium hydroxide in Ag-Cd and
Ni-Cd batteries. Alternative materials may be
available for battery anodes.
Research needs.   Research  is  needed to
determine the performance requirements for
rechargeable and high-performance batteries
and to identify test methods to measure perfor-
mance with respect to those standards. Then
candidate materials can  be identified  and
tested as alternatives.
Coating and Plating
       Cadmium is used in plating because it has properties that are superior to those of
       other coatings for some applications.  It is used to plate fasteners to help ensure
       that the parts pass  torque-tolerance tests, which simulate the action of a power
       wrench tightening a nut on a bolt. The nut should tighten quickly under the proper
       applied torque and  hold securely thereafter.  Cadmium is a soft metal and has
       natural lubricity, which give it good torque properties.  It also has good corrosion
       resistance and meets salt-spray tests used in the automotive industry. In the past,
       numerous military specifications have required the use of cadmium.

       The  major  cadmium  complex used in electroplating is cadmium  cyanide,
       Cd(CN)4~2;  other plating salts include  cadmium  sulfate,  sulfamate,  chloride,
       fluoroborate, and pyrophosphate. Cadmium borates are used with a fluoroborate
       process for electrodeposition of cadmium in high-strength steels.  Cadmium oxide
       is used in electroplating baths, dissolved in  excess sodium cyanide.  Cadmium
       suifate is  used in electrodeposition of cadmium.
Eliminate cyanide pollution from-cadmium
plating. Traditionally, most cadmium plating is
done using cyanide because  of its excellent
throwing  power.  Other plating solutions are
being tried that do not contain  cyanide  and
offer high cathode efficiency at high  current
Research needs. Research is needed to test
and evaluate the characteristics of cadmium
plating performed without cyanide.
                                         15

-------
CADMIUM
density.  These baths contain  metallic salts
such as  neutral sulfates, acid  sulfates, and
acid fluoroborates.  Non-cyanide  baths  are
often   preferred   for  cadmium  plating   of
quenched and tempered high strength steels
because  less  hydrogen is  generated, thus
lessening the danger of embrittlement. Ajax
Metal Processing  in Detroit plates  a large
number of parts using a proprietary non-cya-
nide method.

Use an alternative to cadmium plating, such
as  ion vapor deposition  (IVD)  aluminum.
IVD aluminum has recently been used as a
substitute for cadmium plating in aircraft parts
because of its excellent corrosion  resistance                              ;
and because it meets or  exceeds  most of
cadmium's performance features  (Holmes et       -    •
al.,  1989; Rizzietal., 1986).

Pigments

       Cadmium sulfide, cadmium sulfoselenide, and lithopone pigments are used to
       produce a  range of colors, including yellow, orange, red, and maroon.  These1 '
       colorants are sometimes used in plastics, paints,  rubber, paper, glass, inks, and
       ceramic glazes, although pigment applications are being reduced.
Research needs.   Research is needed  to
verify that IVD aluminum can be used in place
of cadmium plating  for commercial, applica-
tions.                           ;I
Use nonhazardous materials for pigment.
Alternative  nonhazardous materials may be
available for coloration.
Minimize use of cadmium pigments. It may
be possible to reduce the amount of cadmium
compounds used on a coating material.
Plastics and Synthetic Products
Research needs.   Research is needed  to
determine the  performance  requirements for
cadmium  pigments  and  to  find alternative:
substances that are nonhazardous.

Research needs.   Research is needed  to
determine the  performance  requirements for
cadmium pigments and to  find methods  of
improving performance without adding more
cadmium pigment.
       Organocadmium salts are used as heat and light stabilizers in  some plastics,
       particularly PVC, to retard discoloration. Cadmium salts of organic acids are used
       together with barium soaps to produce stabilizers for plastics.
                                         16

-------
                                                                             CADMIUM
um in stabilizers would account for a large sav-
ings  in cadmium usage.
                                            that can be  substituted  for  cadmium  com-
                                            pounds to  prevent PVC and  other polymers
                                            from discoloring.
Alloys
       Cadmium oxide is used in the manufacture of silver alloys.
                                            Research  needs.  Research is needed  to
                                            examine the properties of pure metals and
                                            alloys in order to determine  if  they may be
                                            adapted for use in place of silver-alloys'. /

                                            Research  needs.  Research is needed  to
                                            examine the  properties of plastics and com-
                                            posites  in order to determine if they may be
                                            adapted for use in place of silver-alloys.
Use a non-silver alloy. Non-silver alloys may
be used to fabricate products that do not spe-
cifically require silver's physical properties to
perform their functions.

Use a  plastic or composite alternative.
Products that do not require silver's electrical
or physical properties to perform their functions
may be  fabricated instead  from  plastic or
composite materials. Substitutions of this sort
may be possible in low-temperature applica-
tions, such as decorative cast materials.

Optimize traditional alloying operations.  If
cadmium cannot be avoided,  improvements
can be developed to reduce waste in tradition-
al operations.

Recover or recycle  cadmium in alloying
process.  Develop methods to remove impu-
rities  in  cadmium-alloys  used for  casting,
plating, or other processes, to extend lifetime
of the melt. For example, ion-specific separa-
tion methods  may be  needed to allow repro-
cessing.

Catalysts

      Cadmium dialkyls and many inorganic cadmium  salts are  used as catalysts,
      particularly for organic polymerization reactions.  Cadmium carbonate is used as
      a  catalyst in the production of other cadmium compounds. Cadmium tungstate is
      an industrial catalyst.
                                            Research needs. Areas of need may exist to
                                            decrease  waste  and  improve  recycling  in
                                            traditional processing operations.
                                            Research  needs.  Research is  needed  to
                                            improve the performance of separation, tech-
                                            nology. Ion-specific techniques may be used
                                            in this  regard.
Change synthesis path to avoid the need of
a catalyst or use a nonhazardous catalyst.
Different combinations of chemical feedstocks
                                            Research needs:  Research is  needed  to
                                            determine the requirements for specific reac-
                                            tions and to  identify test methods to measure
                                            the purity, yield, and other requirements. Then
                                          17

-------
CADMIUM
Different combinations of chemical feedstocks
may allow preparations of the desired product
without the need for a catalyst.
Other Uses
tions and to identify test methods to measure
the purity, yield, and other requirements. Then
candidate reaction paths can be identified and
tested  as  alternatives for paths  requiring
cadmium compounds as catalysts.
       Cadmium chloride is used in photography, dying and cloth printing, special mirrors,
       and lubricants. Cadmium nitrate is used in photographic emulsions.

Eliminate  cadmium  from  miscellaneous   Research needs. Research is needed to fully
uses.  Find alternative materials with similar   understand the  role of cadmium  in  these
performance features as cadmium for substitu-   various uses in order to find viable alternatives,
tion into product or process.
REFERENCES FOR CADMIUM

       Barrett, H.M., and B.Y. Card.  1947. J. Ind. Hyg. Toxicol.29: 286.

       Chizikov, D.M.  1966. Cadmium, trans. D.E. Hayler, Pergamon Press, Oxford, p.
       17.

       Holmes, V.L, D.E. Muehlberger, and JJ. Reilly.  1989.  The Substitution of IVD
       Aluminum for Cadmium.  U.S. Air Force, Final Report, ESL-TR-88-75,

       Humphreys,  P.G.  1989. "New Line Plates Non-Cyanide Cadmium."  Products
       Finishing, May, pp. 80-90.

       Kirk, R., and  D. Othmer (Eds.).  1979. Encyclopedia of Chemical Technology, 3rd
       ed., Vol. 7, John Wiley & Sons, New York,  NY.

       Licis, Ivars J.,  Herbert  S. Skovronek,  and Marvin Drabkin.  1991.   Industrial
       Pollution Prevention Opportunities of the  1990s.  EPA/600/8-91/052, Task 0-9,
       Contract 68-C8-0062. Risk Reduction Engineering Laboratory, U.S. Environmental
       Protection Agency, Cincinnati, Ohio, August.

       Nelson, K.E., 1990.  "Use These Ideas to Cut Waste." Hydrocarbon Processing.
       March.

       Rizzi, KW., NJ. Spiliotes, and K.F. Blurton. 1986. "New Zinc Electroplate Fights
       Both Wear and Corrosion." Metal Progress, February, pp. 51-55.

       U.S. Bureau  of Mines. 1991.  Mineral Commodity Summaries.
                                          18

-------
         CHROMIUM AND NICKEL POLLUTION PREVENTION RESEARCH NEEDS
                             FOR THE 33/50 PROGRAM
SOURCES AND PRODUCTION
CHARACTERISTICS AND RATES

      Chromium is a naturally occurring hard, brittle, steel-gray metal. It is produced
      from chromite ores.  Chromium has a wide  range of  uses in three primary
      consumption groups. The metal is a major constituent in stainless steel and other
      specialty ferrous  and nonferrous alloys.   Of the  418,924 tons of chromium
      ferroalloys, metal, and other chromium-containing metals used in 1988, stainless
      steel accounted for 80% of the reported consumption.  Manufacture of refractory
      bricks to line metallurgical furnaces used 88,750 tons of chromite in 1988.  The
      chemical industry consumed  chromite for manufacturing  sodium bichromate,
      chromic acid, and pigments (BOM Cr, 1988).  Chromium chemicals, such as
      chromic acid, are frequently used in metal plating applications.

      Nickel is a naturally occurring malleable, silvery metal.  Nickel ores occur mainly
      as sulfides or oxides, with sulfides accounting for about two-thirds of the world's
      supply.  The reported consumption of nickel in 1988 was 195,758 tons.  Nickel,
      like chromium, is a major constituent of austenitic stainless steels. Stainless steel
      accounted for 40% of the reported nickel consumption in  1988.  Nonferrous and
      superalloys accounted for another 31% of nickel consumption.  Electroplating was
      the next largest nickel use at  17% (BOM  Ni, 1988).  Nickel  is also  used as a
      catalyst and in batteries, pigments, and specialty ceramics.

      A  variety of chromium and nickel applications and potential  approaches for
      reducing waste are summarized in Table 5 and are outlined in the text following
      the table.
                                        19

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CHROMIUM AND NICKEL
POLLUTION PFtEVENTION OPPORTUNITIES
AND SUPPORTING RESEARCH NEEDS

Plating for Hardness and Corrosion Resistance

       Hard chromium plating is used to provide a working surface for a part. Chromium
       plating is the standard method for improving the hardness; smoothness; chemical
       inertness; or resistance to wear, abrasion, galling, or high temperatures for a wide
       variety of substrates.  Typical applications are  cylinder  liners and pistons for
       internal  combustion engines, cylinders  and  rams  for hydraulic pistons, and
       extrusion equipment in plastic making (Guffie, 1986).  Hard chromium plating will
       continue to  be needed for specific applications, but alternatives are available for
       many of chromium's traditional applications.  Design engineers will be required to
       be more selective in specifying hard chromium plating by exploring alternative
       technologies.

       The hard chromium  plating is electrolytically applied onto the substrate from an
       aqueous solution of chromic  acid and sulfuric acid.  The  most common form of
       chromium in the plating  baths is hexavalent chromic acid.  Chromium metal is
       deposited on the substrate by a complex  six-electron reduction of hexavalent
       chromium.  The reduction reaction is catalyzed by the sulfuric acid.  Plating from
       a hexavalent bath reliably  produces a bright chromium plating.  However, the
       current efficiency, the quantity of chromium deposited per unit of  electric energy
       used, the throwing power, and the ability to produce a uniform coating over a large
       area are low.  Hydrogen produced by the plating operation can migrate into the
       metal substrate  and embrittle it.   The use of  hexavalent  chromium  involves
       operator exposure to chromic acid — a toxic material — and  requires treatment and
       disposal of chromium waste.

       The most commonly sought property for engineering nickel coatings is  corrosion
       resistance.  However, nickel plating also provides wear resistance,  solderability,
       magnetism, and other properties needed in specific applications. Nickel plating is
       applied to protect chemical, pulp and paper, and other similar process equipment
       that must survive in corrosive environments.  Nickel  is frequently used  as an
       undercoat for chromium plating where the chromium provides a hard bright surface
       and the nickel gives good  corrosion resistance.   Nickel plating is also used to
       salvage worn, corroded, or incorrectly machined parts.

       Nickel plating involves deposition of a layer of  nickel  on a substrate.  During
       deposition  of nickel  metal on the cathode, the nickel anode dissolves.  Direct
       current flows through a solution of  nickel salts to drive the  reaction.  Nickel is
       present in the solution  as divalent ions that are converted to nickel metal  at the
       cathode.  The nickel in the bath is  replenished by dissolution  of the anode, so
       nickel plating can typically operate for long periods without interruption.  Anode
       efficiency for nickel plating is typically  100%, whereas the cathode efficiency is
                                          26

-------
                                                                CHROMIUM AND NICKEL
       slightly lower. As a result, the nickel concentration in the bath increases with use,
       and periodic adjustments to the bath concentration are required. Chloride, sulfate,
       sulfamate, and fluoroborate are the, most common nickel salts used in the plating
       baths.   Nickel coatings for engineering purposes are  usually  prepared from
       solutions that deposit pure nickel.
Use an alternative substrate that does not
need chromium or nickel plating. It may be
possible to  use an alternative substrate to
provide sufficient hardness or corrosion resis-
tance.   For  example, advanced ceramic and
composite  materials  have  been tested as
replacements for metal parts in internal  com-
bustion engines.
Use nonaqueous plating for chromium or
nickel pollution prevention.  If an alternative
substrate is not available, it may be possible to
produce a coating with the necessary proper-
ties  without plating from an aqueous bath.
Hard coatings can be applied by physical va-
por deposition (PVD).  For example, titanium
nitride is used as a coating to improve the
wear resistance of cutting tools.

PVD coatings are applied in a vacuum cham-
ber. A cleaned piece of substrate material is
placed in a heated vacuum chamber.  A gas
plasma or electric arc heats and vaporizes the
metal that is  to be plated onto  the substrate.
The vaporized metal ions are deposited onto
the substrate  as  a thin hard film (Gresham,
1991).

Plate with a less hazardous metal. Aqueous
electroplating  with less hazardous  metals is
another approach to  reducing use of  hard
chromium or nickel plating.  The electroplating
operation  is conceptually the same as chro-
mium  or nickel  plating but, of course,  uses
different bath  composition and plating condi-
tions such as voltage  and  current.  Possible
alternatives   include   nickel-tungsten-silicon
Research needs.  Research is needed to de-
termine the performance requirements for hard
chromium or nickel plating in specific applica-
tions and to identify test methods to measure
the performance with respect to those stan-
dards. Then candidate substrate materials can
be identified and tested as alternatives for hard
chromium or nickel plating in specific applica-
tions.

Research needs. PVD coatings are generally
harder and thinner than electrolytically deposit-
ed coatings.  The  major research need is to
develop PVD coatings that give  the required
hardness  and coiating  thickness, as well as
other  required performance characteristics,
uniformly over a large complex part.
 Research needs. The major research need is
 to  develop replacements  for  chromium or
 nickel  that give the  required hardness  and
 coating thickness, as well  as other required
 performance characteristics, at a reasonable
 cost.  Given  the generally low current  effi-
 ciency, deposition rate, and throwing power of
 hexavalent chromium plating, it is  likely  that
 alternative  plating systems  will give similar or
 better  production rates.
                                           27

-------
 CHROMIUM AND NICKEL
 carbide plating (Schiffelbein, 1991) and molyb-
 denum plating (Groshart, 1989).

 Replace hexavalent chromium with trivalent
 chromium  plating.  There is  a continuing
 trend in the chromium plating industry toward
 replacing hexavalent chromium baths with tri-
 valent  chromium  baths,  although  trivalent
 plating is used mainly for appearance coatings
 rather than for hard coatings.  The chromium
 chemicals used in trivalent plating  are more
 expensive than those  used  in hexavalent
 plating. Some of the higher cost can be offset
 by the  higher current  efficiency and  better
 throwing power of the trivalent process, as well
 as by selection of additives and process opti-
 mization to reduce costs.

 Another impediment to  wider acceptance of
 trivalent  chromium is the  color and  finish
 achieved.  Trivalent chrome gives a  "gray"
 satin nickel appearance that is acceptable in
 many applications.  While appearance should
 not be a major concern in most hardness and
 corrosion  resistance applications, many cus-
 tomers prefer the "blue" finish typical of hard
 chromium plating from a hexavalent bath.

 The anodes in trivalent chromium baths must
 be immersed  in a non-chromium electrolyte
 solution held in a semipermeable membrane
 shield in  the  tank.  The  shielding  prevents
 formation  of  hexavalent  chromium at  the
 anode. The shield  occupies space in the bath
that could otherwise  be  used  for plating
throughput (PsF, 1988).

Optimize  traditional plating operations.  If
nickel  or  hexavalent chromium  cannot be
avoided, improvements can be developed to
reduce waste in traditional nickel or hexavalent
chromium plating operations (PsF, 1988).
 Research needs. Research is needed to op-
 timize trivalent chromium plating and expand
 its range of  application.  The  major area of
 concern  is  to  develop trivalent  chromium
 plating methods that produce a coating with
 similar thickness,  hardness,   and  color  to
 hexavalent chromium plating. Methods to opti-
 mize the trivalent plating bath composition and
 operation to  reduce costs  are needed.  Im-
 proved designs to  minimize the  volume re-
 quired for electrode shielding are needed.
Research needs.  Areas for research leading
to improved  plating operations include  (1.)
using conductivity controls  to minimize rinsing
water use, (2) studying bath viscosity/temper-
ature relations to optimize rates for solution
draining  from parts,  and  (3)  studying  the
mixing effects to optimize  plating tank agita-
tion.
                                          28

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                                                                CHROMIUM AND NICKEL
Recover or recycle plating solutions and
rinse baths.  Plating paths can be processed
for  reuse to decrease waste.   Traditional
separation processes can be used to recycle
rinsing solutions or other baths  that are no
longer usable because of dilution but are not
contaminated  with  undesirable  impurities.
However, the concentration or pH of the solu-
tions  may lead to challenges in equipment
design or operation.  If the solution is contami-
nated with impurities,  more advanced ion-
specific  separation  methods are  needed to
allow reprocessing.
Plating for Appearance
Research needs.  To expand the use of cur-
rent separation methods such as evaporation,
reverse osmosis, or ion exchange for process-
ing spent plating solutions, research is needed
to improve  performance with  high-salt-con-
centration,  low-pH solutions (Walker et  al.,
1990).

To extend the useful life of contaminated plat-
ing solutions,  new  ion-specific  separation
methods need to be developed.   Advanced
selective ion separation methods to consider
include advanced ion exchange resins, crown
ethers, or membranes.
       Chromium plating is applied in some cases mainly to improve the appearance of
       the part. The plating solutions and procedures for appearance plating are similar
       to those for hard chromium plating. However, the operating  conditions such as
       plating current and  voltage are different.

       Like chromium,  some nickel plating has a mainly decorative function.  Nickel
       plating appears on many commonly used items such as pins, paper clips, scissors,
       keys,  and  fasteners.   Solutions  used for appearance  nickel  plating have
       compositions similar to baths used for functional plating.  However, baths used for
       appearance plating  contain organic agents to modify the growth of the coating to
       control the surface  finish of the nickel deposit.

       Similar pollution prevention and  recovery/recycling  options are  available for
       appearance  plating.  For example, plated parts  could be replaced by brushed
       aluminum parts to eliminate the need for plating, a less hazardous metal could be
       applied to reduce the potential for pollution, or refractive plastics coatings could be
       used to eliminate metal plating. Because the appearance plating baths are similar,
       optimization  and the  bath recovery and recycling approaches for functional
       chromium  and nickel  plating will also apply. Appearance chromium and nickel
       coatings have lower wear resistance, corrosion protection, and thermal resistance
       requirements, so additional options are available for chromium and nickel replace-
       ment in appearance applications.
Use a non-chromium or non-nickel appear-
ance coating. Because of the reduced perfor-
mance requirements for appearance coatings,
organic coatings such as refractive plastic or
powder coatings can be acceptable.
Research needs.  Research is needed to de-
termine the  performance  requirements for
appearance chromium  or  nickel  plating in
specific applications and to identify test meth-
ods to measure the performance with respect
                                          29

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CHROMIUM AND NICKEL
                                             to those standards.  Then candidate coatings
                                             can be identified and tested as alternatives for
                                             appearance chromium or nickel plating in spe-
                                             cific applications.
Surface Etching, Preparation, and Cleaning
       Hexavalent chromium in the form of chromic acid is an inexpensive but powerful
       oxidizing solution. The  oxidizing power of chromic acid solutions leads to a wide
       variety of industrial applications for cleaning and preparing surfaces.

                    Chromic acid deoxidizing/desmutting — chromic acid is
                    used to remove the natural metal oxide and other surface
                    contaminants to prepare a surface for plating, painting, or
                    other surface treatment.

                    Chromic acid etch — chromic acid  roughens surfaces to
                    improve coating adhesion.

                    Chromic acid anodize — anodizing is a process for treating
                    aluminum to give a highly corrosion-resistant coating that
                    offers  an excellent  surface  for  bonding  and  painting.
                    Anodizing uses electrochemical  methods to form  a thin
                    aluminum oxide surface layer that contains chromium ions.

                    Sealing  — Sodium dichromate  as  a sealant enhances
                    fatigue   properties  by  anodizing  and   by  depositing
                    oxydichromate onto the anodized layers.

                    Chemical film — chromate  solutions can be  used to
                    chemically deposit a thin film to prepare metal surfaces for
                    subsequent painting (Evanoff, 1990).
Use alternative etchant for silicon wafer
testing.  Chromic acid is used to etch silicon
wafers to reveal flaws in the crystal structure.
The silicon wafers are the starting material for
semiconductor circuits, so minute flaws must
be reliably detected.  Alternatives to  chromic
acid etching solutions are being developed and
tested (Dickens and Cannon, 1991).

Use alternative oxidizing agents to prepare
metal surfaces for coating or other  use.
Chromate solutions are used in a wide variety
Research needs. Research is needed to ide-
ntify solutions that will provide adequate etch-
ing speed, give sufficient etching to meet or
exceed  current flaw detection requirements,
and be  compatible  with the final use of  the
silicon wafer.
Research needs. Surface preparation alterna-
tive  methods  to  treatment  with  hexavalent
chromium need to be developed.  The alterna-
                                          30

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of surface cleaning and pretreating processes.
Several different formulations have been tested
as alternatives to chromate solutions for sur-
face  preparation  in  a  specific  application
{Bibber,  1991; Carrillo et ai., 1991; Stewart,
1991).
                                                                CHROMIUM AND NICKEL
lives must provide a surface layer with corro-
sion resistance,  paint  adhesion properties,
impact resistance, and  other anodic  coating
properties equal to those provided by chromate
treatments.
Alloying
       Chromium and nickel are common alloying additions in both nonferrous alloys such
       as chromium in Stellite™  or nickel in Inconel™ and in ferrous  alloys such as
       chrome and stainless steels. The addition of chromium and/or nickel increases the
       corrosion resistance and durability of the alloys.
Use non-chromium, non-nickel metal alloy
or use a nonmetal alternative.   It may  be
possible to develop other alloying agents to
give the required wear, heat, or  corrosion
resistance. In lower temperature applications,
it may  be possible to use plastic or composite
materials to replace chromium or nickel alloys.
However, considerable effort by the nuclear
industry searching for a replacement for Stel-
lite™ has  met with limited  success.   The
manufacture of plastics and composites may
generate organic solvent waste.

Increase recycle of  high  performance  al-
loys. High alloy steels and superalloys are not
are readily recycled as mild  steels.  The alloy-
ing agents essentially become impurities in the
steel making  process  when the alloys  are
recycled.  It  may be  possible by  increasing
waste segregation and/or operating in smaller
batches to increase the recycle of  high per-
formance alloys.

Water  Treatment Chemicals
Research needs.  Research is needed to de-
termine the  performance  requirements for
alloys in specific  applications and to identify
test methods to measure the performance with
respect to those standards. Then candidates
can be identified and tested as alternatives for
chromium and  nickel alloys in specific appli-
cations.
Research needs.  Research is needed to de-
termine the  performance  requirements for
recycled alloys in specific applications and to
identify test methods to measure the perfor-
mance with respect to those standards. Then
candidates can  be identified and tested as
alternatives for chromium and nickel alloys in
specific applications.
       Chromate salts, in combination with phosphate salts or other chemicals, are very
       effective for control of corrosion in low- and medium-temperature cooling water
       systems.  These cooling systems typically contain several metals such as iron,
       steel, brass, copper, or aluminum.  The range of properties of the materials of
       construction  greatly complicates formulation  of  an  effective corrosion-control
       additive package.  Chromate-based additive packages have proven to be very
                                          31

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CHROMIUM AND NICKEL
       stable and  reliable for  corrosion control in  multimetal cooling water systems.
       Because of environmental concerns about chromate releases, many vendors are
       developing effective non-chromate cooling water treatment additive packages.
Expand  use  of  non-chromium treatment
chemicals.  A variety of non-chromium addi-
tive packages are available and in  use for
specific applications.
Refractories
Research needs.  Research is needed to op-
timize  and demonstrate  available corrosion
control  additive  packages  in  mixed metal
cooling systems under a wide range of pH and
oxidation/reduction potential  conditions  and
high heat flux.
       Chromium is used in ceramic refractories for furnace lining materials that can resist
       high temperatures.  Chromic oxide has very low solubility in molten glass, so
       chromic oxide bricks are used to line glass-making furnaces.
Use non-chromium refractories.  It may be
possible to develop refractory materials that do
not rely  on chromium additives to increase
temperature resistance.
Research needs.  Research is needed to de-
termine the  performance  requirements for
refractories in specific applications and to iden-
tify test methods to measure the performance
with  respect to those standards. Then candi-
date refractories can be identified and tested
as alternatives for chromium-containing refrac-
tories in specific applications.
Catalysts
       Nickel and chromium are used as catalysts in many industrial applications. Nickel
       catalysts find extensive application in the food processing industry for hydrogena-
       tion of edible and inedible oils.  Nickel and chromium are essential in several steps
       in ammonia manufacture. Nickel catalysts are used in the primary and secondary
       reforming and methanation in ammonia production.  Chromium catalysts are used
       in the high-temperature shift reaction in ammonia production.  Combined nickel-
       chromium  catalysts allow selective hydrogenation of olefins for use in ethylene
       manufacture.  Nickel  catalysts are also used for methanation of fuel gas in the
       petrochemical industry. Chromic oxide catalyzes hydrogenation-dehydrogenation
       reactions.  Unlike metal oxides, chromic oxide will catalyze hydrogenation of both
       the C=O and C=C double bonds. Chromic oxide or various chromate salts can be
       used to catalyze the  production of alcohols;  dehydrogenation of alcohols; or
       hydrogenation of esters, aldehydes, and ketones.
Change synthesis path to avoid the need
for a  catalyst.   Different  combinations of
chemical feedstocks may allow preparation of
Research needs.  Research is needed to de-
termine the requirements for specific reactions
and to  identify test methods to measure the
                                          32

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                                                                 CHROMIUM AND NJCKEL
the desired product without the  need for a
catalyst.
Optimize the system to reduce catalyst use.
Improved reactor design  or  control  can im-
prove yields and reduce the need for catalysts.
The classic continuous-stirred tank reactor may
not be  the  best choice.   Staged plug flow
reactors can give better  control of  reaction
conditions (Licis et al., 1991;  Nelson, 1990).
Guard beds could be used to  remove poisons
before  the  reacting mixture  is  sent to the
catalyst process.
Improve reaction yield with  the catalyst.
Design  of  the  catalyst and  its support will
significantly affect the yield and product mix of
the reaction and the resistance of the catalyst
to poisoning.  Changes in the formulation of
the catalyst; how it is made; or its size, shape,
porosity, and  other  physical properties  can
improve the performance of the  reaction or
increase catalyst life (Licis et al.,  1991)  and
(Nelson, 1990).

Use a nonhazardous catalyst.   It may be
possible to identify alternative  catalysts  that
give the same  performance as chromium or
nickel without increasing cost.
Recycle catalysts.  Thermal and other regen-
eration  techniques  are  available to remove
poisons or otherwise process spent catalysts
for reuse.
purity, yield, and other requirements.   Then
candidate reaction paths can be identified and
tested  as  alternatives for  paths  requiring
chromium or nickel-containing catalysts.

Research needs.  Research is needed to opti-
mize  catalyst performance with specific reac-
tions  includes determining reaction  kinetics,
developing  optimum  reactor designs,  and
developing improved measurement and control
systems.    Research  is  needed to identify
materials for guard beds  to protect catalysts
from  poisons that degrade  catalyst perfor-
mance. The guard bed material would need to
be  compatible with the  process materials,
remove the poisons, and have  low  environ-
mental impact.

Research  needs.   Research is needed to
reduce the use of chromium or nickel catalysts
by  improving catalyst  performance  includes
identifying  and validating improved  catalyst
support matrices and developing catalysts with
improved selectivity.
Research needs.  Research is needed to de-
termine the requirements for specific reactions
and to identify  test methods  to measure the
purity,  yield,  and other requirements.  Then
candidate  nonhazardous  catalysts  can  be
identified and tested as alternatives for chromi-
um- or nickel-containing catalysts.

Research needs.  Research is needed to de-
termine the requirements for specific catalyst
recycle applications and to  identify test meth-
ods to measure the purity, yield, and other
requirements. Then candidate catalyst recycle
treatments  can be identified and tested  as
alternatives to extend the life of chromium- or
nickel-containing catalysts.
                                          33

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CHROMIUM AND NICKEL
Wood Treatment and Preservation

      The wood preserving industry has been through several material changes to
      continue to provide durable wood products while reducing the hazards of treatment
      chemicals.  The industry shifted from creosote to pentachlorophenol and most
      recently to chromated copper arsenate (CCA) for wood treatment.
Replace CCA as chemical  treatment  for
wood preserving. Although an improvement
over earlier wood preservatives,  CCA  still
presents environmental concerns.   Develop-
ment  of  alternative treatments is  desirable.
One candidate is copper naphthenate (Licis et
al., 1991).

Pigments and Oxides
Research needs. Research is needed to de-
termine  the performance  requirements for
wood preservatives and to identify test  met-
hods to measure the performance with respect
to those standards.  Then  candidate' preser-
vatives can be identified and tested as alterna-
tives for CCA.
       Chromates are used to produce a wide  range of yellow, orange, and  green
       pigments. Zinc and strontium chromate pigments are used as corrosion-inhibiting
       priming coat under other paints. An expanding market for chromium oxide is as
       a component in the magnetic media in high-performance recording materials.

       Black and green nickel oxides are used in the ceramic industry.  Nickel oxide is
       added to ceramic formulations for  porcelain enameling of steel  to  improve
       adhesion. Nickel oxides are also used in specialty ceramics such as nickel-zinc
       ferrites for magnets and nickel silicides for high-temperature electrical conductors.
       Various nickel  compounds  are used  to color ceramic  glazes.   Organic  nickel
       compounds are used as dyes.
Do not use a pigment or oxide.  Methods
may be available to avoid the need for chromi-
um or nickel pigments or oxides.
Use  nonhazardous  pigment  or  oxide.
Alternative  nonhazardous materials  may be
available.
Research needs. Research is needed to de-
termine the  performance  requirements for
chromium or nickel pigments or oxides and to
identify test methods to  measure the perfor-
mance with respect to those standards. Then
candidate materials can be  identified  and
tested as alternatives for chromium and nickel
pigments and oxides.

Research needs. Research is needed to de-
termine the  performance  requirements for
chromium or nickel pigments or oxides and to
identify test methods to  measure the perfor-
mance with respect to those standards. Then
candidate materials can be  identified  and
                                         34

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Minimize  use of chromium  or nickel pig-
ment or oxide.  There may be ways to mini-
mize the use of chromium or nickel pigment.
Use non-chromium oxide recording media.
Metal powder-based magnetic recording mate-
rial is available; however, its  use is limited by
cost and problems with oxidation on the media.

Avoid  the  use  of  chromium  recording
media.   Methods such  as  laser disk data
storage  are  available  and could reduce the
reliance on magnetic media for data storage.

Battery Manufacture
                                                               CHROMIUM AND NJCKEL
tested as alternatives for chromium and nickel
pigments and oxides.

Research needs. Research is needed to de-
termine the  performance  requirements  for
chromium or nickel pigments or oxides and to
identify test methods to measure the perfor-
mance with respect to those standards. Then
candidate materials  can  be identified  and
tested as alternatives for chromium and nickel
pigments and oxides.

Research needs.   Research is needed to
develop and validate methods to reduce cost
and increase the corrosion resistance of metal
powder magnetic recording media.

Research needs.   Research is needed to
develop  methods to  reduce the  cost  and
increase the flexibility of optical data recording
systems.
       Porous electrodes made from nickel powder are used in rechargeable and high-
       performance batteries and fuel cells. Nickel-cadmium rechargeable batteries are
       used in many applications because they allow many discharge/charge cycles, have
       a long shelf life, and can be recharged quickly.
Replace nickel-based  batteries and fuel
cells. Alternative materials may be available
for battery and fuel cell applications.
Research needs. Research is needed to de-
termine the  performance  requirements  for
rechargeable and high-performance batteries
and to identify test methods to measure perfor-
mance with respect to those standards. Then
candidate  materials  can  be  identified  and
tested as alternatives for nickel.
Leather Tanning
      Tanning processes treat hides and skins  to improve flexibility,  durability, and
      resistance to microbial attack, producing leather that is useful for commercial
      applications.  Chromium tanning gives a stable hide fiber which resists microbial
      attack and high temperatures. Chromium tanning is usually done in a single bath.
      In the single bath process, hides that have been soaked in an acidic solution of pH
      3  are immersed into  a solution of trivalent chromium salt, typically  chromium
                                         35

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CHROMIUM AND NICKEL
       sulfate. After the chromium salt penetrates into the hide, the pH is raised to cause
       the chromium to react with proteins in the hide.
Use a less hazardous tanning agent. Vege-
table, aldehyde, and oil tanning can be used
for limited applications but chromium tanning is
still the most common process.   The main
advantages  or  chromium  tanning are  high
processing speed, low cost, minimum discolor-
ing, and good preservation qualities. It may be
possible to improve vegetable or oil tanning to
provide increased strength, acceptable color,
and improved resistance to microbial attack.
Research needs.   Research is needed to
develop non-chromium tanning processes that
give acceptable quality  leather and  good
preservative properties.
REFERENCES FOR CHROMIUM AND NICKEL

       Bibber, John W. 1991.  "Sanchem-CC: A Chrome-Free Aluminum Pretreatment
       System." In: Sixth Annual Aerospace Hazardous Waste Minimization Conference.
       Boeing, Seattle, Washington, June 25-27.

       Bureau of Mines  (BOM Cr).   1988.  Chromium  Minerals  Yearbook.   U.S.
       Department of the  Interior.

       Bureau of Mines (BOM Ni). 1988. Nickel Minerals Yearbook.  U.S. Department
       of the Interior.

       Carrillo, G., J.  Mnich, and R. Werley.  1991. "Sulfuric/Boric Acid Anodize as an
       Alternative to Chromic Acid Anodize." In:  Sixth Annual Aerospace Hazardous
       Waste Minimization Conference.  Boeing, Seattle, Washington, June 25-27.

       Dickens, Paul  S., and Paul M. Cannon.  1991.  "Reducing Chromium Waste in
       Silicon Wafer Production."  Hazmat World.  4(9): 50-52.

       Evanoff, S.P.  1990. "Hazardous Waste Reduction in the Aerospace  Industry."
       Chemical Engineering Progress.  April, pp. 51-52.

       Gresham, Robert M. 1991. "Physical Vapor Deposition Surface Treatments as
       an Environmentally Friendly Alternative to Hard Chrome Plating." In: Sixth Annual
       Aerospace  Hazardous  Waste Minimization  Conference.    Boeing,  Seattle,
       Washington, June 25-27.

       Groshart, Earl.  1989.  "Molybdenum — A Corrosion Inhibitor."  Metal Finishing,
       87(1), January.
                                         36

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                                                        CHROMIUM AND N1CKEL
Guffie, Robert K.  1986.  "Hard Chrome Plating."  Products Finishing,  51(2),
November.

Licis,  Ivars J., Herbert S. Skovronek, and Marvin Drabkin.   1991.   Industrial
Pollution Prevention Opportunities of the 1990s.  EPA/600/8-91/052, Task 0-9,
Contract 68-C8-0062. Risk Reduction Engineering Laboratory, U.S. Environmental
Protection Agency, Cincinnati, Ohio, August.

Nelson, K.E., 1990.  "Use These Ideas to Cut Waste." Hydrocarbon Processing,
March.

PsF, Products Finishing. 1988. "Turn to Trivalent." Products Finishing, October.

Schiffelbein, Daniel V.  1991.  "Evaluation of Ni-W-SiC Plating as Replacement for
Chromium Plating."  In: Sixth Annual Aerospace Hazardous Waste Minimization
Conference.  Boeing, Seattle, Washington, June 25-27.

Stewart,  Thomas G.   1991.   "Non-Chromated Desmutter Prior to Penetrant
Inspection  of Aluminum."   In:  Sixth  Annual Aerospace Hazardous  Waste
Minimization Conference. Boeing, Seattle, Washington, June 25-27.

Walker, Jr., J.F., J.H.  Wilson, and  C.H. Brown,  Jr.   1990.  "Minimization of
Chromium-Contaminated Wastewater at a Plating Facility in the  Eastern  United
States."  Environmental Progress, 9(3); August.
                                   37

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                 CYANIDE POLLUTION PREVENTION RESEARCH NEEDS
                              FOR THE 33/50 PROGRAM
SOURCES AND PRODUCTION
CHARACTERISTICS AND RATES

      The name "cyanide" refers broadly to any molecule or ion that contains the
      carbon-nitrogen triple-bonded group -CsN. This includes, for example:

                    Hydrogen cyanide (hydrocyanic acid, prussic acid, formoni-
                    trile), HCN, which is a colorless, poisonous, low-viscosity
                    liquid (melting point, or mp, -13.24°C; boiling point, or bp,
                    25.70°C).  Hydrogen cyanide is a weak acid (pKd=8.89 at
                    18°C) and is not normally corrosive, with two exceptions:
                    aqueous  solutions  can cause  trans-crystalline   stress-
                    cracking of carbon steels, and aqueous solutions containing
                    HCN and sulfuric acid as a stabilizer severely corrode steel
                    above 40°C and stainless steels above 80°C (Kirk and Oth-
                    mer, 1979).
                    Alkali metal and alkaline earth cyanides are usually white,
                    ionic, crystalline  powders. Sodium cyanide, NaCN, is often
                    called white cyanide. It is stable in water as an anhydrous
                    salt above 34.7°C and  as a dihydrate below 34.7°C.  The
                    solubility of NaCN-2H2O is 45 g (NaCN)/100 g solution, and
                    decreases markedly with  decreasing  temperature.   In
                    aqueous solutions of NaCN, the cyanide ion is considered
                    free, i.e., it does not completely form ion pairs with sodium
                    ions. Free cyanide is quite toxic.
                    Cyanide also forms strong complexes with iron, such  as
                    ferrocyanide and ferricyanide. Strongly complexed cyanides
                    are  resistant to  breakdown and are low in toxicity.

      Hydrogen cyanide  enters the human body by inhalation, skin absorption, or orally.
      It is described as having the odor of bitter almonds, but one of five people cannot
      sense this odor, causing it to be all the more dangerous to them.  Major uses of
      HCN  are acrylonitrile, other nitriles, acrylates for plastics, and intermediates, such
      as  for production of NaCN.  Other products are ferrocyanides, chelating agents,
      optical laundry bleaches, and Pharmaceuticals.  Hydrogen cyanide is encountered
      as  an industrial waste through the  production of HCN  and when other cyanide
      compounds are acidified.

      Sodium and potassium cyanides are the only important alkali metal cyanides.  As
      toxins, they behave similarly to HCN when taken  orally or through the skin.  They
                                         38

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                                                                               CYANIDE
       can evolve HCN if exposed to moisture, such as in humid air.  Sodium cyanide is
       used  for gold  and silver metallurgical extraction, Pharmaceuticals, vitamins,
       plastics, ferrocyanides, and for electroplating of copper, zinc, cadmium, gold, and
       silver.  Potassium cyanide is  used in electroplating, and together with NaCN in
       nitriding steel, refining platinum, and in metal coloring processes. Calcium cyanide
       is the only alkaline earth metal cyanide used commercially.  It is largely used in
       ore refining, for extraction and flotation, in the production of ferrocyanides for case
       hardening of steel, and also as a fumigant, rodenticide, and insecticide. See Table
       6 for cyanide's pollution prevention needs.

       Metal cyanides  used commercially include nickel cyanide, which is used as a
       brightener in plating of other metals, and silver cyanide and zinc cyanide, which
       are used, respectively, in silver and zinc plating.  In the plating  process, these
       metals form complex cyanides, such as ferrocyanide and ferricyanide complexes
       with iron.  Although these complexes are less toxic,  they are also resistant to
       removal by treatment processes, and are decomposed by ultraviolet light, so that
       there  is a possibility of  generating HCN in waste streams  containing cyanide
       complexes discharged by industry. Another waste source of cyanide is from spent
       pot liners used in aluminum refining.

       Certain organic  cyanides, called nitriles, are used as  intermediates in chemical
       products and as a copolymer in plastics such  as acrylonitrile/butadiene/styrene.
       The organic cyanide intermediates are not nearly as  toxic as the  inorganic
       cyanides.
POLLUTION PREVENTION OPPORTUNITIES
AND SUPPORTING RESEARCH NEEDS

Electroplating

       Cyanide waste generated in  metal finishing comes primarily from copper, zinc,
       cadmium, silver, and gold plating, where large amounts of sodium and potassium
       cyanides and smaller amounts of metal cyanides are used. A considerable volume
       of wastewater is produced in the finishing industry. This waste usually contains
       dilute cyanide (10 to 770 ppm) from rinsing.

       Due to process changes that do not use cyanide baths and the increasing use of
       cyanide recovery systems, cyanide waste is  expected to decline greatly  in the
       future.
                                          39

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Use alternatives to cyanide in plating pro-
cesses.  Sodium cyanide is considered to be
a  multipurpose  ingredient in many  plating
operations, but is especially  important when
plating the more noble  metals.   However,
many alternatives are now being investigated
for pollution control.
                                                                              CYANIDE
                                             Research needs.   Research  is  needed to
                                             develop  non-cyanide  processes  that  can
                                             provide  acceptable  performance  features.
                                             Some examples of systems being studied are
                                             acid fluoroborate in cadmium plating, copper
                                             pyrophosphate or copper sulfate in  copper
                                             plating,  gold  sulfite in gold and  gold alloy
                                             plating,  silver succinimide and silver sulfite/
                                             thiosulfate in silver plating, and acid chloride
                                             and alkaline noncyanide  zinc baths for zinc
                                             plating.
Mining and Ore Processing
       Sodium  and calcium cyanides  are  used as  a flotation depression  agent in
       processing of copper, lead, and zinc ores.  Cyanide complexing agents are used
       to extract silver and gold from ores.  Cyanide  is discharged with effluent water
       from mill tailings, which are usually untreated.
Find flotation modifiers and extractants to
replace cyanide chemicals in ore process-
Ing.   It may be possible to extract copper,
lead, and zinc from their ores by a  process
that does not involve the use of cyanide.

Primary Metals
                                             Research needs. Research is needed to find
                                             alternative methods to provide flotation depres-
                                             sion  or extraction characteristics of cyanide
                                             salts in ore separation.
       Considerable amounts of cyanide are generated in steel production from coking
       operations and from carryover into blast furnace dust and sludges.  Additionally,
       cyanide waste  is generated in cold finishing of steel. In the aluminum industry,
       cyanides are generated in the process conversion  of cryolite to aluminum metal.
                                             Research  needs.   Research  is needed to
                                             control  the escape of HCN gases  in coking
                                             operations.
Control release of cyanide in coking opera-
tions.  Although recovery of HCN from coke-
oven gases received little  attention  in  past
decades, environmental controls have spurred
new research  and development in this  area
(Ger. Pat., 1974).

Treatment Processes
      A large number of treatment processes  have been  developed  for cyanide
      treatment and destruction. Some of the known processes are as follows (Conner,
      1990):
                                          41

-------
CYANIDE
                    Electrolytic oxidation (U.S. Pat., 1972)
                    Chemical oxidation (FMC Corp., 1975; Asturquimica, 1975;
                    Zievers et al., 1968)
                    Chemical reaction                         •....',
                    Acidification followed by HCN destruction ("Cyan-Cat") (Jola,
                    1976)
                    Evaporative recovery
                    Incineration or catalytic oxidation
                    Gamma irradiation
                    Reverse osmosis or electrodialysis (recovery)
                    Carbon absorption                                 .
                    Carbon bed catalytic destruction
                    Foam separation
                    Waste-plus-waste (Qttinger et al., 1973)    .          , >;,
                    Freeze-out (recovery)                           .,,„'..,.
                    "Kastone" process (ES&T, 1971).
                    Nascent oxygen
                    Solvent extraction (recovery)
                    Aeration
                    Polymerization (U.S. Pat. 3,505,217)
                    Starch process (U.S. Pat. 3,697,421)
Improve electrolytic treatment process.  A
considerable amount of research was done on
anodic oxidation processes in the 1950s and
1960s. However, the effluent from this kind of
treatment usually contains up to 10  ppm free
cyanide and therefore must be given a follow-
up treatment, such as by alkaline chlorination.
This problem has made electrolytic  oxidation
uneconomical for dilute solutions.

A modification of this process has been pro-
posed by Shockcor (1972,  see U.S.  Patent
3,692,661), in which the  space between the
anode and cathode is filled with carbon cylin-
ders or spheres which act like a semiconductor
bed to improve the conductivity of dilute solu-
tions.

Improve chemical oxidation treatment pro-
cess.  The main problem is that although the
reaction of cyanide to cyanate (which is about
1000 times less toxic) is fast, further  oxidation
of cyanate to carbon dioxide and nitrogen is
Research needs.  Research is  needed  to
improve the  electrolytic process  to  convert
more cyanide to cyanate and to decrease the
costs associated with chlorination.
Research needs.  Research is  needed  to
improve the oxidation kinetics of  cyanide  to
cyanate, such as by using a catalyst or other
means.
                                          42

-------
                                                                             CYANIDE
quite slow. Also, chemical oxidation of com-
plex metal cyanides is very slow because of
their stability, so that the reactions may take
hours to weeks to approach completion.  In the
Kastone process, organic glycolic compounds
are formed that  may require biological  treat-
ment  before  discharge.   Furthermore, the
presence of any oxidizable organic species will
consume the oxidant and will be more costly.

Improve nonoxidation  chemical treatment
process.  A variety of cyanide reactions can
convert cyanide  to less toxic substances or
even commercially valuable compounds. One
is  the waste-plus-water method,  in  which
ferrous sulfate waste at  high pH is used to
convert cyanide to ferrocyanide.

Organic polymerization, such as the reaction of
cyanide with aldehydes at elevated tempera-
tures to form nitriles and then hydrolyzed to
amino acids, which are biodegradable. Starch
conversion syrup has been used to produce a
nontoxic reaction product.

Improve acidification  treatment  process.
This process works by acidifying concentrated
cyanide wastes  with a strong  acid, such  as
sulfuric acid, to decompose free and complex
cyanides into other metal salts and HCN. The
HCN is then stripped from solution in a desorp-
tion tower and catalytically oxidized in a ther-
mal reactor to produce carbon dioxide, nitro-
gen, and  water  vapor (the  "Cyan-Cat" pro-
cess).   The disadvantages  are  high capital
cost, inherent dangers of producing HCN gas,
and that dilute cyanide is left in solution, which
must  be removed by  some other method.
Advantages  are  that little  auxiliary fuel  is
needed because the exothermic combustion of
HCN provides almost all of the heat necessary
for combustion (350 to 400°C).
Research needs.   Research  is  needed to
convert ferrocyanide products  of  the waste-
plus-water process  to stable,  nontoxic sub-
stances.

Research is  needed to improve the efficiency
and economics of the organic polymerization
methods.
Research needs.   Research  is  needed to
improve the  efficiency of the "Cyan-Cat" pro-
cess so that a greater fraction of cyanide is
converted, and to  investigate  the safety of
operations in which HCN is handled.
                                          43

-------
CYANIDE
Chemical Intermediates and Polymers

       Important current uses of HCN include use in production  of acrylonitrile, nylon
       (adiponitriie intermediate product), and methacrylate polymers (acetone-cyanohy-
       drin  intermediate in formation of methyl methacrylate monomer).  In 1991, U.S.
       sales to major markets included:
                   acrylonitrile
                   acrylic polymers
                   (only portions use cyanohydrin process)
                   nylon
                   Total nylon + acrylonitrile
           117 million Ib
           672 million Ib

           556 million Ib
           673 million Ib
       For comparison, U.S. polyethylene sales to major markets totaled -20,000 million
       Ib  (Modern  Plastics, 1992).  Recent  research has  targeted development  of
       processes that avoid the use of HCN and improve process efficiency.
Use alternatives to HCN-produced chemi-
cals.  Chemical intermediates and polymers
that are prepared using HCN in their produc-
tion include some monomers and performance
polymers.

Control HCN-produced chemicals. Improved
control of these processes would  reduce risk
and treatment needs.
Research needs.   Research is needed  to
identify and evaluate processes to  minimize
the use of HCN in polymer production.
Research needs.   Research is needed  to
improve efficiency  of processes to prepare
intermediates and  polymers to  reduce CN
waste.
REFERENCES FOR CYANIDE

       Asturquimica, S.A. 1975. "Potassium Permanganate to Treat Cyanide Effluents."
       Spain.

       Conner, J.R. 1990.  Chemical Fixation and Solidification of Hazardous Wastes.
       Van Nostrand and Reinhold, New York.

       ES&T.  1971.  "New Process Detoxifies Cyanide Waste." ES&T5: 496-497.

       FMC Corp.  1975.  A  Guidebook to Hydrogen Peroxide for Industrial Wastes,
       Philadelphia, PA.

       Ger. Pat 2,260,248 (June 12, 1974), H. Karwat (to Linde A.G.).
                                         44

-------
                                                                       CYANIDE
Jola, M.  1976.  "Destruction of Cyanides by the Cyan-Gat Process."  Painting
Surf. Finish., pp. 42-44, September 1976.

Kirk, R., and D. Othmer (Eds.).  1979.  Encyclopedia of Chemical Technology, 3rd
ed., Vol. 7, John Wiley & Sons, New York, NY.

Modern Plastics. 1992. "U.S. Resin Sales." Modern Plastics, January, pp. 85-95.

Ottinger, R.S., J.L. Blumenthal,  D.F. Dal Porto, G.I. Gruber, M.J. Santy, and C.C.
Shih.  1973.  Recommended Methods of Reduction, Neutralization, Recovery or
Disposal of Hazardous Waste.  EPA-670/2-73-053-f, Washington, DC.

U.S. Environmental  Protection Agency.  1988.  1988 Toxics Release Inventory
(TRI) Releases/Transfers Database, Washington, DC.,»-

U.S. Pat. 3,505,217.

U.S. Pat. 3,692,661  (Sept.  19, 1972) to M.H.'Shockcor.

U.S. Pat. 3,697,421.

Zievers, J.F.,  R.W. Grain, and F.G. Barclay. 1968.  "Waste Treatment in Metal
Finishing: U.S. and European Practice."  Plating, 55: 1171-1179.
                                  45

-------
               5  LEAD POLLUTION PREVENTION RESEARCH NEEDS
                             FOR THE 33/50 PROGRAM
SOURCES AND PRODUCTION
CHARACTERISTICS AND RATES

      Lead (chemical symbol Pb) is a bluish-white, silvery, gray metal that is highly
      lustrous when freshly cut, but tarnishes when exposed to air.  It is very soft and
      malleable; has a high density (11.35 g cm"3) and low melting point (327.4°C); and
      can be cast, rolled, and extruded. Lead was well known in ancient times, and was
      extensively used because of its ease of fabrication.                 ;

      Lead occurs in the earth's continental crust at concentrations of about 15 g/ton, or
      13 ppm (Hurlbut and Klein, 1977). Although lead is a comparatively rare element
      in the  earth's crust, lead ore deposits are unexpectedly numerous and widely
      distributed throughout the world. In addition to galena (PbS), which is the major
      ore mineral for lead, other source minerals include anglesite (PbSO4), cerrusite
      (PbCO3), mimetite (PbCI2-3Pb3(AsO4)2), and pyromorphite  (PbCI2-»3Pb3(PO4)2).
      Lead is produced with other metals, such as zinc and copper, then smelted to
      remove impurities.

      Of the estimated 1,400,000 tons of lead consumed in 1990, the U.S.  Bureau of
      Mines (1991) has estimated apparent consumption patterns for lead as follows:
                   batteries
                   ammunition
                   non-battery oxides
                   cast, sheet, or extruded products
                   solder
                   other uses
80%
 5%
 4%
 4%
 1%
 6%
       About half of the lead used in the  United  State comes from recovery and
       reprocessing of scrap  lead.  The  main sources of  scrap are battery plates,
       drosses, skimmings, solders, babbitts, and cable sheathing. Of these secondary
       sources  of lead, storage batteries make up more than half the total recovered.
       Channels for collecting used batteries are well emplaced, so that >90% are recov-
       ered for  recycling.

       Lead has two oxidation states, +II and +IV, with the former being more common.
       Pb(ll) compounds are regarded as ionic, whereas Pb(IV) compounds are covalent.

       Table 7 shows the pollution prevention research needs for lead.
                                         46

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                                                                                LEAD
       Lead is an amphoteric metal, meaning that its oxides and hydroxides form both
       acidic and basic aqueous species. Almost all lead compounds are produced from
       pig lead to form lead monoxide, PbO, which is also called litharge. Other oxides
       of lead are PbO2, the mixed oxide Pb3O4, and a black oxide (lead suboxide) that
       contains 60 to 80% PbO and the rest finely divided lead metal.

       Lead and its compounds are cumulative poisons. However, because of its long
       history of use, more is known about lead poisoning than about poisoning by any
       other metal.  Allowable lead levels have been established for drinking water, and
       various regulatory controls are in place for disposal of lead-bearing wastes. Lead
       is a probable human carcinogen, and it may also damage human chromosomes.
       It causes a range of systemic effects, including central nervous system and behav-
       ioral effects.  It causes adverse acute and chronic effects in aquatic organisms and
       can be bioconcentrated.
POLLUTION PREVENTION OPPORTUNITIES
AND SUPPORTING RESEARCH NEEDS

Emissions from Primary Lead Smelting

       Smelting of lead ores is a source of lead emissions to the air, soil, and water. The
       primary method of lead smelting is the sinter-blast furnace  method (Kirk and
       Othmer, 1979).  Process modifications, such as using updraft sintering in place of
       downdraft  sintering, have led to improvements  in  plant hygiene,  as well as
       increases in output, economic production, and blast furnace performance.  Still,
       overall problems in air pollution and waste disposal have led to the development
       of new approaches in lead smelting (AIME, 1979). Thermalinefficiency is inherent
       in the two-stage sinter-blast-furnace process. The heat generated by exothermic
       reactions should be adequate to reduce lead concentrates to metallic lead, but in
       practice additional fuel is needed. A one-stage process would be more efficient
       and would generate less waste.  A number of one-stage processes have been
       commercialized  or developed at  the pilot scale  (Matyas and Mackey, 1976).
       These include smelting  lead concentrates and fluxes with oxygen-enriched air.
       Their products include sulfur-bearing bullion, slag, and a sulfur dioxide-rich gas.
Develop an  electrolysis  process  to  help
eliminate air pollution.  The U.S. Bureau of
Mines has been investigating a hot iron  chlo-
ride-sodium  chloride leach-electrolysis  tech-
nique to produce lead from galena.  The filtrate
contains > 99% of the lead, which is precipitat-
ed as lead  chloride and  electrolyzed to  yield
lead metal and chlorine gas.
Research  needs.   New developments of
improving lead production technology should
be investigated. These may include improve-
ments and adaptations of traditional pyrometal-
lurgical and electrorefining processes. Conver-
sion from batch to continuous modes of opera-
tion is a prime objective of future processes.
                                         51

-------
LEAD
Alloys
       Lead is easily fabricated because of its softness, but it is not easily drawn because
       of its low tensile strength and absence of work-hardening at room temperature
       (Kirk and Othmer, 1979).  Alloying is commonly done to add strength and other
       useful properties. The most commonly used elements for this purpose are copper
       (Cu), antimony (Sb), calcium (Ca), tin (Sn), arsenic (As), tellurium (Te), silver (Ag),
       and strontium (Sr). Bismuth (Bi), cadmium (Cd), and indium (In) are used less
       often for this purpose.

       Lead-Copper Alloys.    Alloying with  copper  produces  considerable  grain
       refinement and gives resistance to grain growth. Adding 0.04 to 0.08% copper (by
       weight) in lead,  with  or without the addition of silver, produces ASTM B  29-79
       grades, which are suitable for sulfuric acid containment.  Larger amounts of
       copper, 64% Cu (eutectic) or  higher,  are  added  in leaded brass or bronzes.
       General uses include stock for bearings and  bushings in the automotive and
       aircraft industries, lead sheet, pipe, and wire.  Lead-copper alloys are also used
       for continuous  extrusion  of lead cable  coverings in  electrical power cable.
       Extruded  or rolled alloys contain uniformly  dispersed copper particles that produce
       a self-passivating layer of lead  sulfate  on the alloy  surface  in  sulfuric acid
       solutions.

       Lead-Antimony Alloys.  Lead-antimony  comprises the most important class of
       lead alloys. Almost all lead products use  antimony  alloys in some fashion. Most
       commercial alloys contain 11.1% Sb (eutectic) or  less. The solubility of antimony
       in lead decreases from 3.5% Sb at 252°C  to 0.25% Sb at room temperature. This
       behavior allows Pb-Sb alloys to be precipitation-hardened by proper heat treatment
       procedures.  The rate at  which the alloy is cooled and its composition can be
       controlled to give a wide variety of mechanical properties.  Like Pb-Cu alloys, Pb-
       Sb alloys  develop a protective coating of lead oxide and lead carbonate that keeps
       them practically  inert  to  further  oxidative attack.  Lead-antimony alloys are used
       for flashing material in roofing, and for making ammunition. Lead shot contains 0.5
       to 8% Sb and has an  arsenic content equal to about 20 to 30% of the Sb content.
       Arsenic is used to reduce any lead or antimony oxides present in the  molten
       material  and helps  improve  roundness of  the  globules during production;
       quenching is done by  dropping the shot into towers of water.  Shot larger than 5.8
       mm and bullets are cast.

       The principal use of  Pb-Sb alloys  is in  the manufacture of grids, straps, and
       terminals  for lead storage batteries.   The antimony content of the  lead alloy
       improves  creep resistance and castability, which increase up to the eutectic point.
       It also provides a rigid strengthening network, which is important for hardness and
       stiffness of cast  grids. Conventional automotive batteries use 4 to 6% Sb alloys
       for grids.  New low-gassing, maintenance-free batteries use only 1.8 to 2.75% Sb.
       Large industrial batteries, deep-discharge batteries, and electric-vehicle batteries
                                          52

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                                                                           LEAD
use  higher (5 to 9%) Sb  contents.
commonly made from a 3% Sb alloy.
Internal  connections and terminals are
Lead-antimony (0.5 to 1.0%) alloys are also used for cable sheathing, and provide
higher strength, and  resistance to  vibration than Pb-Cu alloys.  The  excellent
strength of Pb-Sb alloy cables permit them to be reeled and unreeled  and bent
around corners without cracking or breaking.

Alloys with less  than 3.5%  Sb have structures that are highly  susceptible to
solidification-shrinkage  porosity and cracking.  This problem is overcome by the
addition of nucleating agents, such as copper and arsenic, sulfur,  or selenium.

Other uses Pb-Sb alloys include anode material for metal electrowinning and metal
plating, qollapsible tubes, and wheel balancing weights for automobiles and trucks,
and specialty weights.

Lead Calcium Alloys.  Low-calcium-lead alloys exhibit certain properties that give
them  advantages over traditional Pb-Sb alloys.  Extruded Pb-Ca alloys are much
stronger than either  Pb-Cu or Pb-Sb (1%) alloys and  have good ductility and
excellent fatigue and creep resistance.  Pb-Ca is used mainly as  a grid alloy for
large  storage batteries because of its resistance to self-discharge  and electrolyte
loss upon  standing and under full charge conditions.  These alloys are increasingly
being used for lead anodes in electrowinning, because they form  a hard, adherent,
corrosion-resistant layer of PbO2 during use in sulfuric acid baths and  greatly
reduce  lead  contamination in the product.  Alloys of 0.04 to 0.07% Ca are
commonly used for these purposes, as well as for cable sheathing, sleeving, and
specialty  tapes.   Further strength and performance improvements  have  been
realized in the ternary system that includes tin, Pb-Sn-Ca, where  0.01 to 0.11 % Ca
and 0.3% Sn are used.  Substitution of strontium for calcium in either the  binary
or ternary system improves strength.

Lead-Tin  Alloys. Tin alloys have lead in all proportions, providing a wide range
of alloy compositions for many different applications. Lead-tin  alloys are mainly
used as solders. Generally, lead-tin solders range in composition from 30 to 98%
Pb. Pb(98%)-Sn(2%) solder is used to solder side seams of tin cans. However,
substitution of 0.5%  silver for Pb significantly improves creep strength, which is
essential  for pressurized  cans.   The  high  lead content and the  practice of
pretinning cans permit soldering to be performed at high speeds.  General-purpose
soldering  is done with an alloy in the 40 to 50% tin range.  Electronic soldering,
as for printed circuit boards, uses  Pb(37%)-Sn(63%) alloys.   Solders  in the
composition range of  70  to  85% Pb  are used for manufacturing  automobile
radiators and other kinds of heat exchangers.

Lead-tin alloys are also  used as  coatings on  steel and copper for  corrosion
protection. Terne-coated steel is coated with an alloy of  80 to 85% lead. This
                                    53

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LEAD
       composition gives good wetting and surface alloying with the steel. These coated
       sheets are used for radio and television chassis, roofs, fuel tanks, air filters, oil
       filters, gaskets, radiator components, metal furniture, gutters, and downspouts.

       Alloys of Pb(96%)-Sn are applied to copper sheet for building flashing.  Other
       alloys of Pb, in the 50% Sn range, are used to coat steel and copper electronic
       components for corrosion protection, appearance, and ease in soldering.

       Lead and  Pb-Sn coatings can also  be applied by electroplating, usually from a
       fluoroborate solution. This method allows the coating to be applied in any desired
       thickness. Ordinarily, electroplated coatings are not used for corrosion protection,
       because they tend to be porous.

       Lead-Antimony-Tin Alloys. The Pb-Sb-Sn system is an important series of alloys
       used in  industry. Some materials made in this series include printing-type, lead-
       base sleeve  bearings, special  casting  alloys, slush castings,  and decorative
       casting  alloys.   These  alloys  are  characterized  by low melting points, high
       replication of detail in printing and mold in casting, and  high wear hardness  and
       strength, even at elevated temperatures. Kirk and Othmer (1979) provide proper-
       ties of printing-type alloys and  lead-base bearings. Pb-Sb-Sn alloys are also used
       in bushing and sleeve bearings,  for their antifriction properties.  They are used to
       make journal bearings  in freight cars  and mobile  cranes.  Arsenic and copper
       additives are also used to improve compression-,  fatigue-,  and creep-resistant
       properties at high temperature.

       Lead-Silver Alloys.  Lead-silver (0.75 to 1.25% Ag) alloys are used as insoluble
       anodes  in zinc and manganese  electrowinning.  These alloys form a conductive
       layer of PbO2 on the surface  in  sulfuric acid, which prevents lead contamination
       on the zinc or manganese coating.

       Lead-Tellurium Alloys.   Low  tellurium (0.04 to  0.10%)  alloys are  used in
       fabrication of chemically resistant pipe and sheet. They are also used in materials
       for x-ray and nuclear radiation shielding.
Use a non-lead alloy.  Non-lead alloys may
be  used to fabricate  products  that  do not
specifically require lead's physical properties to
perform their functions.  For example, bear-
ings,  bushings,  pipe, wire, .cable  coverings,
and flashing material may be constructed from
metals that do  not contain  lead.   Another
example is to use alternative materials in place
of terne-coated  steel  for use  in  radio  and
television  chassis.   In addition,  use another
Research  needs.   Research is needed to
examine the properties of pure metals  and
alloys in order to  determine  if they may be
adapted for use in  place of lead alloys.
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                                                                                 LEAD
metal or alloy for casting and making printing-
type.

Use a  plastic  or composite  alternative.
Products that do not require lead's electrical or
physical properties to perform their functions
may be  fabricated instead  from  plastic  or
composite materials. Substitutions of this sort
may be possible in low-temperature applica-
tions, such as decorative  cast  materials.
Another example would be to use plastic or
glass containers for food  storage instead of
metal cans, which have lead-solder joints. Use
plastics or composites in place of terne-coated
steel  for  use  in gutters, downspouts, and
furniture. Use a high-impact composite materi-
al for making printing type.

Use a ceramic material alternative.   An
alternative  substrate,  such as an  advanced
ceramic, may be use in place of lead alloys for
purposes  of wear resistance or chemical
inertness. For example, machine components
such as bearings or bushings may be replaced
by ceramics. Ceramic coatings may also be
applied to base metals in order to be used for
containing caustic chemicals.

Use a non-lead solder.  Low-melting electri-
cally conductive, corrosion-resistant alloys may
be  found  in a  non-lead system.  Non-lead
solders  are now being used in household
plumbing. Non-lead solders may also be used
to form joints in canning. In electronics, some
success  has been found using electrically
conducting epoxies in place of solder.
Eliminate  ancillary  hazardous  materials
from lead-alloy processes. Eliminate the use
of arsenic by controlling oxidation  of lead in
melts using  some  other chemical or electro-
chemical method. Eliminate the use of arsenic
Research needs.  Research is needed  to
examine the properties of plastics and com-
posites  in order to determine if they may be
adapted for use in place of lead alloys.
Research needs.  Research is needed to
examine the properties of advanced ceramic
materials in order to determine if they may be
adapted for use in place of lead alloys.
Research needs.  Research is  needed  to
examine the properties of alternative metals to
be used in place of conventional lead solders.
Replacement solders must have melting points
near those of  conventional solders and  pos-
sess similar flow and adhesion characteristics.

Research is  needed to find and improve ways
of making electrical connections without using
solder. Electrically conducting epoxies already
exist, but they  have  limitations.

Research needs.  Research is  needed  to
understand what redox conditions exist at melt
temperatures,  in order to develop alternative
methods for controlling the oxidation state of
lead in the melt.
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LEAD
and  selenium  by  controlling  solidification
shrinkage using sulfur or some other chemical
additive.  Prevent arsenic and selenium from
entering the waste stream by careful attention
of their use.
Research  is needed to find what structural
controls can be  used in place of arsenic to
prevent shrinkage.

An investigation of arsenic and selenium loss
in lead production  processes should be con-
ducted to determine if greater concern should
be attached to their usage.

Research needs. Areas of need may exist to
reduce waste and  improve recycling in  tradi-
tional processing operations.
                                             Research  needs.   Research is needed to
                                             improve the performance of separation tech-
                                             nology. Ion-specific techniques may be used
                                             in this regard.
Optimize traditional alloying operations. If
lead alloys cannot be avoided, improvements
can be developed to reduce waste in tradition-
al operations.

Recover or recycle lead in alloying process.
Develop methods to remove impurities in lead
alloys used for casting, plating, or  other pro-
cesses, to extend  lifetime of the melt.   For
example, ion-specific separation methods may
be needed to allow reprocessing.

Storage Batteries

       About half of the total U.S. lead consumption is for manufacture of automobile and
       other  storage batteries.  A typical automobile  battery  contains the following
       component distribution:

                    lead alloy (5% Sb)                      36%
                    lead oxides and sulfate                   34%
                    case (hard rubber or polypropylene)
                           and separators (PVC)             30%
Use an alternative cell design. The technol-
ogy involved in the lead storage battery is fairly
old and well entrenched in a number of impor-
tant applications, for example in  automobile
electrical systems.  Nevertheless, it may be
possible to develop a different electrochemical
cell that will meet the  power storage require-
ments of modern internal  combustion engines
or of future engines.

Use recycling.  To recover the lead  compo-
nents, several approaches have been used:
Research  needs.  This  is a  fairly mature
technology that probably cannot be changed
by  a  simple substitution of  components.
Research is needed to find new alternatives in
electric power storage.
Research needs.  A system for recycling can
be created so that virtually all lead-acid batter-
ies are recovered.
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                                                                                 LEAD
(1)     the battery case may be broken manu-
       ally, the sulfuric acid poured off, and
       plates removed;
(2)     the  battery  case  is  crushed  and
       screened,  and  the  components are
       separated by density;
(3)     the complete battery is drained of acid
       smelted in  a blast furnace; the organic
       components serve as fuel and as re-
       ducing agents.
Canonie  Environmental Services,  Inc., has
recently developed a cleanup operation for the
Gould  Battery Superfund site in  Portland,
Oregon.  A field demonstration involving 250
tons of material was processed using  a 10-
ton/hour unit (HazTECH News, 1992).

Catalysts

       Lead  compounds  are used  as  catalysts in polymer  manufacture and  other
       reactions (Kirk and Othmer, 1979), for example:

                    Lead fluoride is used in the manufacture of picoline, a pyri-
                    dine compound (Ger. Offen. 1,903,879);
                    Lead  chloride  is  used  as a co-catalyst  for  producing
                    acrylonitrile (Fr. Pat. 1,556,127), and for polymerization of
                    alpha-olefins to highly stereoregular polymers  (Brit. Pat.
                    1,078,854);
                    Lead carbonate catalyzes the polymerization of formalde-
                    hyde to high-molecular-weight crystalline poly-oxymethylene
                    products (Jpn.  Pat. 18,963);
                    Basic lead carbonate, 2PbCO3.Pb(OH)2, or white lead, was
                    once the major white  hiding pigment before replacement
                    with TiO2, but is  still  used for its catalytic  properties for
                    preparing polyesters from terephthalic acid and diols (Jpn.
                    Pat. 64 20,533);
                    Lead sesquioxide,  Pb2O3, is used as an oxidation catalyst
                    for  carbon monoxide in  exhaust  gases  (Ger.  Offen.
                    2,142,001; Ger. Offen. 2,156,414);
                    Pb3O4  is used as a  catalyst for combustion  of carbon
                    monoxide in exhaust gases.

       In recent years,  many producers have been pursuing non-lead components.
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 LEAD
 Change synthesis path to avoid the need of
 a catalyst or use a nonhazardous catalyst.
 Different combinations of chemical feedstocks
 may allow preparations of the desired product
 without the need of a catalyst.
 Electrical Components
 Research  needs.   Research is needed to
 determine the requirements for specific reac-
 tions and to identify test methods to measure
 the purity, yield, and other requirements. Then
 candidate reaction paths can be identified and
 tested as alternatives for paths requiring lead
 compounds as catalysts.
       Lead oxide, PbO, is most used in the manufacture of plates for lead-acid batteries.
       Other uses of lead compounds in electrical components include:

                    Lead  fluoride is  used  in making low power fuses (S. Afr.
                    Pat. 68 04,061); activators for electroless plating of nickel
                    on  glass (Jpn.  Kokai  74 27,442); electro-optical coatings
                    (U.S.  Pat.  3,745,044); and in zinc oxide varistors  (Jpn.
                    Kokai 74 14,996);
                    Lead telluride and lead arsenate are used in making semi-
                    conductors and photoconducting devices;
                    Lead zirconate titanate use for piezoelectric material;
                    Lead chloride is used as a photochemical-sensitizing agent
                    for  metal patterns on printed circuit  boards (U.S. Pat.
                    3,452,005);
                    Lead  iodide is used in mercury-vapor arc lamps (Fr. Pat.
                    1,467,694;  USSR Pat. 457,121);
                    Lead  hydroxide is used in sealed nickel-cadmium battery
                    electrolytes (Jpn. Kokai 75 16,045);
                    Pb3O4 is used to make positive battery plates.
Use a different fluorescent gas in lamps. It
may be possible to use a substance other than
a lead halide to  convert the mercury-vapor
spectrum to visible light in fluorescent lamps.

Use a non-lead material in electrical fuses.
Find an electrically resistive, low-melting point
substance  to  use in  place of  PbF2 in low
amperage fuses.

Recover or recycle activator solutions for
plating of nickel  and  other coatings.  Solu-
tions containing  a lead halide  can be pro-
cessed for reuse  to minimize waste.  Tradi-
tional  separation  processes can be used  to
Research needs. Research is needed to find
a replacement for fluorescent lead  iodide in
mercury-vapor lamps, or to redesign the lamp
without using lead or mercury compounds.

Research needs.  Research is  needed  to
study electrical resistance and other physical
properties of materials for use in fuses.
Research needs.   To expand the uses  of
current separation methods, such as evapora-
tion, reverse osmosis, or ion exchange for
processing spent plating solutions, research is
needed to improve performance with high-salt-
                                          58

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                                                                                LEAD
recycle  solution  that are no  longer  usable,
unless they are contaminated by impurities.  If
the solution is contaminated with impurities,
more advance ion-specific separation methods
are needed to allow reprocessing.
concentrations and low-pH solutions (Walker et
al., 1990).

To extend the life of contaminated solutions,
new ion-specific separation methods  meed to
be developed. Advanced selective ion separa-
tion methods to consider include advanced ion
exchange resins, crown ethers, or membranes.
Replace lead hydroxide in Ni-Cd batteries    Research needs
Alternative  materials  may  be available  for
battery electrolytes.
Research  is needed to determine the perfor-
mance  requirements  for  rechargeable  and
high-performance batteries and to identify test
methods to measure performance with respect
to those standards. Then candidate materials
can be  identified and tested  as alternatives
lead hydroxide.
Paints and Pigments
       Lead compounds are not used as pigments in house paints any longer, since they
       have been  replaced by titanium dioxide, which  is not toxic.  However,  lead
       compound have historically been used in other areas of paint production as  well.

                    Pb3O4 (red  lead) is used as  an anticorrosive pigment in
                    paint for steel  surfaces;
                    Lead chromate  is used  in high tint strength  pigments
                    (chrome  yellow,  chrome  orange, and  chrome  green,  a
                    mixture with iron blue) for road paints, plastics, leather, and
                    printing inks;
                    Lead phosphates  are  used  for high  temperature  and
                    pearlescent pigments for plastics;
                    Lead sulfide is used as a pigment in inks;
                    A number of lead compounds, called metallic soaps, are
                    added to paints and varnish oils to hasten their drying.
Use nonhazardous materials for  pigment.
Alternative  nonhazardous  materials may  be
available for pigment  to be used  in paints,
varnishes, and inks.

Minimize use  of lead pigments.   It may be
possible to reduce the amount of lead oxide, or
other pigment,  used on a coating material.
Research needs.   Research  is needed to
determine the performance requirements for
lead pigments and find alternative substances
that are nonhazardous.

Research needs.   Research  is needed to
determine the performance requirements for
lead pigments and to find methods of improv-
                                         59

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LEAD
                                             ing  performance without adding more lead
                                             pigment.

                                             Research needs.  Research is needed to find
                                             alternatives to metallic soaps for acceleration
                                             of paint and varnish drying.
Use non-lead-containing metallic soaps. A
large  number  of metals  are used in soaps,
such as Al, Ba, Ca, Cu, Co, and Fe, in addition
to Pb. Specific lead  chemicals include lead
tallage, lead naphthenate, and lead  linoleate.
It may be possible to use other compounds to
accelerate drying of paints and varnishes.

Plastics and Rubber
       Lead monoxide, PbO, is a component of heat stabilizers used for polyvinyl chloride
       resins, for which 8,616 metric tons of lead salts were used in 1979 in the United
       States (Smouluk, 1979).  Specific lead compounds  used in plastics include the
       following:

                    Lead stearate is used as a vinyl stabilizer.
                    Dibasic lead phosphate is  used as a  stabilizer for PVC to
                    improve  weathering resistance,  thermal  stability, and
                    electrical insulating  properties; some  applications include
                    garden hose, flexible and rigid vinyl foams, coated fabrics,
                    plastisols, electrical insulation, and extruded profiles for
                    outdoor use.
                    Lead naphthenate is used as an accelerator for vulcanizing
                    rubber.
                    Lead  dioxide,  PbO2, is  used in  the  production of liquid
                    polysulfide polymers (Greninger et al., 1975).
                    Lead sesquioxide, Pb2O3, is used as a vulcanization  accel-
                    erator for neoprene rubber (Jpn. Kokai 76 20,248).
Use components  other than  lead  com-
pounds for stabilizers. Elimination of lead in
stabilizers would account for a large savings in
lead usage.
Use other substances that can act as vulca-
nization accelerators in natural and synthet-
ic rubbers. Alternatives to lead sesquioxide
and lead naphthenate, for example,  may be
found to accelerate vulcanization.
                                             Research needs.   Research  is  needed to
                                             determine if there are nonhazardous materials
                                             that can be substituted for lead  compounds to
                                             give PVC and other polymers their weathering
                                             resistance,  thermal   stability,  and electrical
                                             insulating properties.

                                             Research needs.   Research  is  needed to
                                             explore alternative vulcanization accelerators
                                             in natural and synthetic rubber.
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                                                                                LEAD
Ceramics and Glasses

       After batteries, the next largest use for lead is in the ceramics industry in glasses,
       glazes, and vitreous enamels. The raw material, lead monoxide, or litharge, is
       .used in ceramics and other industries.  Lead monoxide combines with silicon
       dioxide to form a low melting silicate (Jpn.  Pat. 69 18,745) that is used in  the
       production of certain types of glazes and glass. When used as a glaze or vitreous
       enamel, lead oxides are converted to mono-, bi-, and'tribisilicate frits to make the
       lead compounds  insoluble.   Some  other important lead compounds used in
       ceramics and their properties are as follows:

                    Lead fluoride is added to glass coatings for infrared reflec-
                    tion (Ger. Offen. 1,421,872) and is used in phosphors for
                    television screens (Ger. Offen. 2,106,118).
          ,-  • i     PbCO3 is a white pigment used in ceramics.
                    Lead antimonate is used in  tile painting, staining glass,
                    crockery, and porcelain.
Use nonhazardous materials for glazes and
vitreous enamels. Alternative nonhazardous
materials may be available as coatings.
Minimize use of lead compounds. It may be
possible to reduce the amount of lead used in
a glaze or vitreous coating.
Specialty Uses
Research needs.   Research  is needed to
determine the  performance requirements for
lead compounds for glazes and vitreous coat-
ings and to find alternative substances that are
nonhazardous.

Research needs.   Research  is needed to
determine the  performance requirements for
lead compounds in coatings and to find meth-
ods of improving performance without adding
more lead itself.
       Lead compounds  are used in a large number of  industrial  applications, for
       example:

                    Lead oxide is used to make ammunition and detonating
                    agents.
                    Lead nitrite is used in explosives.
                    Lead  iodide is  used in  lubricating greases  (U.S.  Pat
                    3,201,347).         ,            ,                 .
             •      Lead silicate is used in fireproofing fabric.
             •      Lead thiocyanate is used to make  safety matches and car-
                    tridge priming.
                    Lead  naphthenate is used as  a  wood preservative and
                    insecticide.
                                         61

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LEAD
                    Sodium plumbite is used to remove sulfur compounds in
                    petroleum refining.
                    Lead arsenate and lead arsenite are used in insecticides for
                    larvae of gypsy moth, boll weevil, and other insect larvae.
                    Lead chloride (Brit. Pat.  1,235,100) and lead iodide (Brit.
                    Pat.  1,235,100) are used to  make  asbestos  clutch and
                    brake linings.
                    An aqueous paste of lead bromide  is used as general-pur-
                    pose welding flux  for welding aluminum and aluminum
                    alloys to other metals (U.S. Pat. 3,287,540).
                    Lead chloride (U.S. Pat.  3,475,372) is used as a flame-
                    retardant inorganic filler in polycarbonates.
                    Lead bromide (Fr. Pat. 2,039,700) is used for flame retard-
                    ing in polypropylene, polystyrene, and ABS plastics.
                    Lead chloride is used as a flame retardant in nylon-6,6 wire
                    coatings (U.S. Pat. 3,468,843).
                    Lead dioxide, PbO2, is used because of its vigorous oxidiz-
                    ing power to smake matches and pyrotechnics,  and to pro-
                    duce certain chemicals.
                    Lead bromide and lead iodide are  used in film  developing
                    as an intensifier.
                    Lead is used in wastewater filters to remove  chromate.
Eliminate lead from lubricating grease. Use
alternative  substances in  lubricating grease
that will preserve the desired lubricating prop-
erties.

Use a substitute for lead compounds  in
flame-retardant and  heat-resistant materi-
als.  Use alternative substances.
Use a lead-free compound for insecticides
and wood pres»ervatives.  Find alternatives
for  insecticides and wood preservatives that
are nonhazardous.
Research needs.   Research  is needed to
determine what physical properties are impart-
ed to lead-containing lubricating grease and to
find alternative substances.

Research needs.   Research  is needed to
understand how lead  compounds behave to
give materials flame retardant and heat resis-
tant properties.  Then, alternative compounds
that are nonhazardous may be sought to give
a material these same properties.

Research needs. Research is needed to find
suitable insecticides and wood preservatives
that do not contain lead.
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                                                                                LEAD
REFERENCES FOR LEAD

      AIME. 1979. "Lead-Zinc-Tin'80." In: AIME World Symposium on Metallurgy and
      Environmental Controls, The Metallurgical Society of the American Institute of
      Mining, Metallurgical, and Petroleum Engineers (AIME).

      Brit. Pat. 1,078,854 (Aug. 9, 1967), (to Mitsui Petrochemical Industries, Ltd.).

      Brit. Pat. 1,235,100 (June 9,1971), (to Toyota Central Research and Development
      Laboratories, Inc.).

      Fr. Pat. 1,467,694 (Jan. 27, 1976), (to N.F. Philips Goeilampenfabrieken).

      Fr. Pat. 1,556,127 (Jan. 31, 1969), (to Imperial Chemical Industries, Inc.).

      Fr. Pat. 2,039,700 (Jan. 15, 1971), J.A. Peterson and H.W. Marciniak (to Hooker
      Chemical Corp.).

      Ger. Offen. 1,421,872 (Feb. 19, 1970), W. Reichelt and H. Eligehausen  (to W.C.
      Heraeus GmbH).

      Ger. Offen. 1,903,879 (Oct. 30,1969), S. Cane and LE. Cooper (to BP Chemicals,
      Ltd., UK).

    ., Ger. Offen. 2,106,118 (Sept. 2, 1971), F.  Auzel.

      Ger. Offen. 2,142,001 (Apr. 6, 1972), T. Sakai, S. Kobayashi, K. Miyazaki, and M.
      Yamamoto (to Mitsui  Mining and Smelting Co., Ltd.).

      Ger. Offen. 2,156,414 (July 13, 1972), Y. Kuniyasu, T. Sakai, and T. Ogami (to
      Mitsui Mining and Smelting Co., Ltd.).

      Greninger, D., V. Kollonitsch, and C.H. Kline. 1975. Lead Chemicals.  Internation-
      al Lead Zinc Research Organization, Inc., New York, p. 69.

      HazTECH News.  1992.  HazTECH News, 7: 13, Jan,. 23.

      Hurlbut, C.S., Jr., and C. Klein. 1977. Manual of Mineralogy, John  Wiley & Sons,
      New York, pp. 123,124.

      Jpn. Kokai 74 14,996 (Feb. 8, 1974), N. Ichinose and  Y. Yokomizo (to Tokyo
      Shibaura Electric Co., Ltd.).

      Jpn. Kokai 74 27,442 (Mar. 11, 1974), K. Morimoto and M. Kuroda  (to Matsushita
      Electric Industrial Co., Ltd.)
                                         63

-------
LEAD
      Jpn. Kokai 75 16,045 (Feb. 20, 1975), Y. Morioka (to Sanyo Electric Co., Ltd.).

      Jpn. Kokai 76 20,248 (Feb. 18, 1976), H. Kato (to Dainichi-Nippon Cables, Ltd.).

      Jpn. Pat. 18,963 (Sept. 4, 1964), S. Futami (to Teijin Ltd.).

      Jpn. Pat. 64 20,533 (Sept. 19, 1964),  K. Nuruchina, Y. Takehisa, and J. Ichikawa
      (to Toyo Rayon Co., Ltd.).

      Jpn. Pat 69 18,745 (Aug. 15, 1969), M. Mikoda and  T. Hikino (to Matsushita
      Electric Industrial Co., Ltd.).

      Kirk, R., and D. Othmer (Eds.).  1979.  Encyclopedia of Chemical Technology, 3rd
      ed., Vol. 14, John Wiley & Sons, New York.

      Licis, Ivars J., Herbert  S.  Skovronek,  and Marvin Drabkin.   1991.   Industrial
      Pollution Prevention Opportunities of the 1990s.  EPA/600/8-91/052, Task 0-9,
      Contract 68-C8-0062. Risk Reduction  Engineering Laboratory, U.S. Environmental
      Protection  Agency, Cincinnati, Ohio, August.

      Matyas*, A.G., and P.J. Mackey.  1976.  J. Met, 28: 110, November.

      Nelson, K.E., 1990.  "Use These Ideas to Cut Waste."  Hydrocarbon Processing.
      March.

      Sax, N., and R. Lewis. 1987. Hawley's Condensed Chemistry Dictionary, 11 th ed.
      Van Nostrand.

      S. Afr. Pat. 68 04,061 (Dec. 18,  1968),  J. Prior and A.  Florin (to Dynamit Nobel
      A.G.).

      Smouluk, G.  1979.  Mod. Plast, 56:  74.

      U.S. Bureau of Mines.  1991. Mineral Commodity Summaries.

      U.S. Pat. 3,201,347 (Aug.  17, 1965), J.J.  Chessick and  J.B. Christian (to U.S.
      Dept. of the Air Force).

      U.S. Pat, 3,287,540 (Nov. 22, 1966),  T.J. Connelly (to Allied Chemical Corp.).

      U.S. Pat. 3,452,005  (Feb. 9, 1971), M.A. DeAngelo and D.J. Sharp (to Western
      Electric Co.).

      U.S. Pat 3,475,372 (Oct. 28, 1969), C.L. Gable (to  Mobay Chemical Co.).
                                          64

-------
                                                                         LEAD
U.S. Pat. 3,468,843 (Sept. 23, 1969), W.F. Busse (to E.I. duPont de Nemours &
Co., Inc.).

U.S. Pat 3,745,044 (July 10, 1973), E.G. Letter (to Bausch and Lomb, Inc.).

USSR  Pat. 457,121 (Jan. 15, 1975), S.G. Ashurkov, G.S. Sarychev, and E.F.
Fufaev; Chem. Abstr., 83:207,11 (1975).              .    .     ,

Walker, Jr.,  J.F.,  J.H. Wilson, and C.H. Brown,  Jr.   1990.   "Minimization of
Chromium-Contaminated Wastewater at a Plating  Facility in the Eastern United
States." Environmental Progress, 9(3): August.                          ,
                                  65

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                MERCURY POLLUTION PREVENTION RESEARCH NEEDS
                              FOR THE 33/50 PROGRAM
SOURCES AND PRODUCTION
CHARACTERISTICS AND RATES

       Mercury (chemical symbol Hg) has been used since antiquity as a pigment and for
       medicinal purposes.  The primary source of mercury is the sulfide ore, cinnabar.
       Mercury is also obtained in smaller quantities from ores containing mixed sulfides,
       oxides, and chloride minerals, which are usually associated with base and precious
       metals. Native or metallic mercury, is found in very small quantities in some ore
       sites.  Mercury is estimated to occur in concentrations of 10 to 1,000 ppb in the
       earth's continental crust and 2,000 to 20,000 ppb in petroleum.  By contrast, ore
       grade materials  typically contain 5,000,000 ppb (0.5%) mercury.  Some  early
       methods for purification included leaching the ores in sodium sulfide and sodium
       hydroxide solutions, or in a sodium hypochlorite solution. Today, sulfide ores are
       retorted and liquid metallic mercury is condensed from the vapor.

       Smaller amounts of mercury are produced from secondary sources, such as scrap
       batteries, lamps, switches, dental amalgams, measuring devices, and control
       instruments, and from laboratory and electrolytic refining wastes.  Kirk and Othmer
       (1979) provide the quantity of mercury used in these types of products.

       World production of mercury peaked around 1971 with annual production in excess
       of 10,000 metric  tons; in 1978 production declined to about 6,000 metric tons (Kirk
       and Othmer, 1979).  Production of mercury in the United States in those two years
       was 616 and 883 metric tons, respectively. This decline was due  primarily to a
       drop  in price, mining of lower grade ores,  a decrease in consumer use,  an
       increase in recycling, and curtailment of mining operations due to more stringent
       environmental protection regulations. The  standard unit of trade is  the "flask,"
       which weighs  76 pounds.

       Mercury consumption was reported in about  '200 plants in the  United States  in
       1988. Prime virgin mercury accounted for 66% of the total; secondary mercury,
       27%; and redistilled mercury,  7%. Mercury usage increases in  the manufacture
       of chlorine and caustic soda were reported in 1988.  Other important uses include
       the manufacture of wiring devices and switches, which have declined steadily in
       the last decade, from 2,075 tons in 1984 to about 1,300 tons in 1990.  Mercury
       use in dry-cell batteries has declined steadily in recent years.
                                         66

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                                                                      MERCURY
The U.S. Bureau  of  Mines (1991) has  approximated apparent consumption
patterns for mercury in 1990 as follows:

             electrical and electronic devices           33%
             chlorine and caustic soda production       33%
             instrument, dental, paints, and other uses  34%

Some of the first modern uses of metallic mercury were as a fluid in the barometer
—Torricelli in 1643- and the thermometer— Fahrenheit in 1720. Both devices rely
on mercury's uniform volume expansion throughout  its  liquid range and its high
surface tension  that prevents it from wetting or clinging to glass. Today, mercury
continues to be of technological value because of its unique properties that include
high electrical and  thermal conductivity, and high thermal  neutron capture cross
section, and its  propensity to form amalgams, which it can do with almost every
metal except iron (and iron too at high temperatures).  Mercury compounds are no
longer  used as  a biocide in interior latex  paints but may still be used in some
exterior latex paints.

Although mercury was known to be toxic for many centuries, the level of health
hazard has come to light only since the 1970s.  Metallic mercury, its vapor, and
many of its compounds are  protoplasmic poisons,  which are toxic to all forms of
life.  Ingesting sufficient quantities, by mouth, through the skin, or by inhalation,
can cause severe neurological damage and fatality in humans (Budavari, 1989).
The alkyl organic compounds are the most toxic forms of mercury. Acute toxicity
from mercury poisoning has on occasion manifested  itself in catastrophic events.
For example, 100 deaths or severe neurological damage resulted from consump-
tion of fish in Minamata, Japan, contaminated with methyl mercury and mercuric
chloride;  another event in Iraq cause injuries from  consumption of contaminated
rice. It is now  known that  some marine  organisms can  biologically methylate
inorganic mercury and concentrate it up to 3,000 times.

Table 8 shows the  pollution  prevention research needs for mercury.
                                   67

-------







PREVENTION RESEARCH NEEDS
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MERCURY
POLLUTION PREVENTION OPPORTUNITIES
AND SUPPORTING RESEARCH NEEDS

Batteries

       Batteries make up the largest specific use of mercury, which in 1984 accounted
       for more than half of the  mercury consumption  in the United States (Kirk and
       Othmer, 1979).   Mercury has historically  been used  to coat the zinc anode
       (negative electrode) in nonrechargeable household batteries.  A few examples of
       these dry cell-type batteries are listed below:
             Battery Type

             Zinc-Carbon
             Alkaline-Manganese Dioxide
             Mercuric Oxide
             Zinc-Silver Oxide
             Carbon-Zinc Air
Size/Configuration

AAA, AA, C, D, 9V
AAA, AA, C, D, 9V
Button  cells (hearing aids)
Button  cells
Button  cells (hearing aids and pagers)
       Mercury is used to prevent the evolution of hydrogen gas from the battery, which
       results from internal chemical reactions.  Hydrogen may pressurize the cell and
       cause internal leaking or explosion, although blowout valves are now installed at
       the tips to minimize this possibility. In the alkaline-manganese battery, zinc anodic
       material is added as a powder.  In the past, 1 to 3% mercury was mixed with the
       powdered  zinc to form  a mercury-zinc amalgam that will inhibit zinc oxidation
       caused by chemical  reactions with other  components  in  the battery.   The
       proportion  of mercury in the amalgam decreases the rate  of oxidation.

       Alternatives to mercury have  been sought within the  battery manufacturing
       industry. Notable success has been found with some organo-silicate compounds.
       Testing by Rayovac (Tillman,  1991) has shown that these compounds restrict H2
       evolution.  Results are listed below in order of increasing performance:

                    sodium dimethylsiloxane = polydimethylsiloxane
             «      phosphate functional silate
                    nonhydrolyzable silicone copolymer = polydimethylsiloxane-
                    polyoxyethylene copolymer
                    DC-193™ (proprietary compound)

       The actual mechanism for restricting H2  evolution is not known with certainty.
       Coating the zinc/mercury amalgam may form a physical barrier to diffusion, or it
       may increase mercury's efficiency in preventing zinc oxidation.  Note that mercury
       is still used in  this treatment, but smaller amounts are now needed.  Batteries
       manufactured in the 1960s contained up to 1.3% mercury, by total battery weight.
                                          70

-------
                                                                             MERCURY
       An international standard set for implementation in 1992 calls for no more than
       0.025% mercury.

       Another development in mercury  reduction in  batteries has been reported  by
       Battery Technologies Inc. (BTI, Mississauga, Ontario) (Roy, 1991). In developing
       a rechargeable alkaline zinc-manganese dioxide battery, they prepared "a cleaner,
       more precise (electrochemical) system" than is  used in conventional single-use
       batteries.  Their system claims to convert any hydrogen gas generated to water,
       and requires less mercury in the process.  The BTI battery contains organic and
       other metallic inhibitors that perform the function normally assumed by  mercury.
Improve efficiency  of  inhibitors.  Improve
the performance characteristics of the material
used to coat zinc/mercury amalgams.  Such
improvements should permit less mercury to
be used.

Search for new organic or metallic  inhibi-
tors.  Use a different method of preventing
zinc oxidation and subsequent H2  evolution
that does not involve zinc amalgamation with
mercury. Following the example of BTI, mer-
cury content should decrease to zero  as the
process is improved.

Develop batteries that last longer.  Extend
the lifetime of batteries  so that they are dis-
posed of less often. This proposal is based on
the simple theory that a battery that lasts twice
as  long should  end  up in  a landfill half as
often.

Encourage use of rechargeable-type batter-
ies.  Rechargeable batteries will provide up to
20 times longer service hours than convention-
al  single-use batteries.  This option  would
translate into  fewer  batteries  entering  the
waste disposal cycle.

Catalysts

       Mercury (HgCI2) is used as a catalyst primarily for the production of vinyl chloride
       monomers (Ulrich, 1988, p. 73)  and urethane foams (Oertel, 1985, p. 114). It is
       also used to produce anthraquinone derivatives and other products. Discharges
Research  needs.   Research is needed to
verify whether organic coatings on Zn/Hg
amalgams work synergistically to improve the
efficiency of the  amalgam  in restricting H2
evolution.

Research  needs.   Research is needed to
explore  new ways of inhibiting zinc oxidation,
or catalyzing H2 to form water in a manner that
does not diminish the lifetime of performance
of the battery.
Research  needs.  Research is, needed to
improve  existing  battery technology so that
batteries maintain a longer useful lifetime.
Research needs.  Studies would first be con-
ducted to discern the expected level of con-
sumer participation in this pollution prevention
strategy.
                                          71

-------
MERCURY
       from plants that produce these substances are sources of mercury-containing
       wastes. Old disposal areas may eventually require cleanup.
Change synthesis path to avoid the need of
a catalyst or use a nonhazardous catalyst.
Different combinations of chemical feedstocks
may allow preparations of the desired product
without the need of a catalyst.
Chlorine and Caustic Soda
.Research needs.  Research is  needed to
determine the requirements for specific reac-
tions and to  identify test methods to measure
the purity, yield, and other requirements. Then
candidate reaction paths can be identified and
tested as alternatives for paths requiring lead
compounds as catalysts.
       Production of chlorine gas and caustic soda  accounts for the largest use of
       mercury in the United States.  The manufacturing process is also responsible for
       the largest loss of mercury into the environment., One process uses mercury and
       a following cathode in an electrolytic cell into which sodium chloride brine is intro-
       duced. A current is applied to electrolytically oxidize chloride anions to form CI2
       gas, which is collected at the anode, and an.alkali metal amalgam is formed with
       the mercury  cathode.  The amalgam is then  decomposed with water, to form
       caustic soda (sodium hydroxide) and hydrogen and relatively pure mercury metal.
       Although mercury metal is recycled back to the cell, large losses do occur in brine
       purification muds and in wastewater treatment sludges. The brine sludge contains
       small amounts of mercuric ions, mostly as the tetrachloro complex,  HgCI22~.

       The membrane cell is another method of producing caustic  soda and one which
       does" not use mercury.  The membrane cell uses cation and anion selective semi-
       permeable membranes to allow electrolytic separation of chlorine and caustic soda
       from brine. The membrane cell has advantages  over the mercury cell that include
       lower operating voltage and higher efficiency, and it does not  require the high capi-
       tal investment in mercury.
Use membrane cells for caustic production.
Improve the performance of membrane cells
that do not require the use of mercury.
Switching Devices and Control Instruments
Research needs.   Research is  needed to
better implement electrolysis methods for the
conversion of sodium chloride to caustic soda
and chlorine.
       Mercury is used in  higlWIow-voItage mercury-arc  rectifiers,  oscillators, power
       control switches for motors, phanatrons, thyratrons, ignitrons, reed switches, silent
       switches, thermostats, and cathode tubes in radios, radar, and telecommunications
       equipment.
                                         72

-------
                                                                            MERCURY
       Mercury is also used in  many medical and industrial instruments to control or
       measure reactions and equipment functions.  This list includes mostly metallic
       mercury equipment, such  as thermometers, manometers, barometers, the calomel
       electrode,  and  other  pressure-sensing devices,  gauges, valves,  seals,  and
       navigational controls.
                                            Research  needs.  Research is  needed  to
                                            explore what  alternative methods  exist for
                                            replacing mercury instruments and  to judge
                                            whether they are economical to use.
Use alternative methods for sensing. There
are some situations where electronically con-
trolled devices can replace the role of mercury
in  mechanical  instruments.    For example,
temperature can be detected using a thermo-
couple instead of a thermometer.

Electrical Lamps

       Mercury vapor is used in both the low-pressure "fluorescent"  lamp and high-
       pressure mercury lamp. Fluorescent lamps are commonly used for indoor lighting,
       whereas high-pressure mercury lamps are used for street lighting, industrial work
       areas, aircraft hangers, and floodlighting. Other mercury-vapor lamps are used for
       photographic purposes, including motion picture projection, and for heat therapy.
Use a different fluorescent gas in lamps. It
may be possible to use substances other than
mercury for fluorescent lighting.
Fungicides
                                            Research  needs.  Research is  needed  to
                                            explore the electronic  molecular properties of
                                            nonhazardous substances for use in fluores-
                                            cent lamps.
       Mercury is used primarily in latex paint as a fungicide to prevent mildew of the
       applied coating and as a bactericide or preservative to inhibit bacterial  attack
       during storage. The most commonly used fungicides are phenylmercuric acetate
       (PMA) and phenylmercuric  oleate.  Alkyl mercury compounds are no  longer
       produced, due to their extreme toxicity and long lifetimes.

       Mercury was used as a slimicide in the paper and pulp industry, but its use has
       decreased considerably since 1970.
Replace fungicide in paint with non-mercu-
ry alternative.  Find alternative bactericides
and  preservatives  that are  compatible with
exterior latex paint to extend  storage life.
                                            Research needs. Search known bactericides
                                            and preservatives for suitable  alternatives to
                                            PMA and phenylmercuric oleate.
                                         73

-------
MERCURY
REFERENCES FOR MERCURY

      Budavari, S. (Ed.).  1989.  The Merck Index, 11th ed., Merck & Co., Inc., Rahway,
      NJ, p. 927.

      Conner, J.R. 1990. Chemical Fixation and Solidification of Hazardous Wastes,
      Van Nostrand Reinhold, pp. 140-148.                       . :              .

      Kirk, R., and D. Othmer.  1979. Encyclopedia of Chemical Technology, 3rd ed.,
      John Wiley & Sons, New York, NY,                                 .

      Licis, Ivars J., Herbert S. Skovronek,  and  Marvin Drabkin.  1991.  'jnddstrial
      Pollution Prevention Opportunities of the 1990s.  EPA/600/8-91/052,  Task 0-9,
      Contract 68-C8-0062. Risk Reduction Engineering Laboratory, U.S. Environmental
      Protection Agency, Cincinnati, Ohio, August.

      Nelson, K.E.  1990. "Use These Ideas to Cut Waste."  Hydrocarbon Processing,
      March.                                       '

      Oertel, G., Ed. 1985.  Polyurethane Handbook. Macmillan, New York.

      Roy, K.A. 1991. "Mercury-Free Products Charge Battery Market." Hazmat World,
      4:70-71.

      Tillman, J.W. 1991. Achievements in Source Reduction and Recycling for Ten
      Industries in the United States. EPA/600/2-91/051, U.S. Environmental Protection
      Agency, September, pp. 20-22.

      Ulrich,  Henri.  1988.  Raw Materials for Industrial Polymers. Oxford  University
      Press,  Mew York.

      U.S. Bureau of Mines.  1991. Mineral Commodity Summaries.
                                        74

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                   POLLUTION PREVENTION RESEARCH NEEDS FOR
                     ELEVEN TRI ORGANIC CHEMICAL GROUPS
SOURCES AND PRODUCTION
CHARACTERISTICS AND RATES

       Eleven organic chemicals have been selected from the Toxics Release Inventory
       (TRI) by EPA as target chemicals for the 33/50 Program.   These include six
       chlorinated compounds (i.e., methylene chloride, chloroform, carbon tetrachloride,
       1,1,1 -trichloroethane,   trichloroethylene,   and  tetrachloroethylene)  and   five
       nonchlorinated compounds (i.e., methyl ethyl ketone, methyl isobutyl ketone,
       benzene, toluene, and xylenes).

       Methylene chloride, chloroform, and carbon tetrachloride are chlorinated methanes.
       Methylene chloride, also known as dichloromethane, is a colorless liquid with  a
       sweet, penetrating odor.  It is manufactured primarily from the chlorination of
       methane (Budavari, 1989). Of the 452 million pounds used in 1988, paint stripping
       accounted for 28% of the consumption (Chemical Profile,  1989).   Methylene
       chloride is also used for vapor degreasing (8.8% [Chemical Profile, 1989] or 20%
       [Ulrich, 1988]), cold cleaning, and food processing, as well as in the production of
       aerosols (20% [Chemical Profile, 1989] or 9.7% [Wolf et al., 1991 ]), urethane foam
       (10% [Chemical Profile, 1989] or 11.2% [Wolf et al., 1991 ]), adhesives, pesticides,
       electronics,  Pharmaceuticals, and textiles.  Methylene chloride accounted for
       10.9%ofthe 1988 TRI top 50 four-digit Standard Industrial Category (SIC) release
       and transfer (TRI R&T) (see Table 3).                   '

       Chloroform  is a volatile,  colorless liquid with  a pleasant,  sweet odor.   It is
       manufactured from chlorination of methane or  from reaction of acetone and
       bleaching powder with the  addition of sulfuric acid. According to Chemical Profile
       (1989), chloroform consumption in 1989 totaled 484 million pounds.  Of this, 90%
       was used for CFC 22 synthesis, of which 70% was used as refrigerants and the
       remainder in the production  of fluoropolymers.  Chloroform  is also used for
       industrial degreasing and as a solvent for fats, oils, rubber, alkaloids, waxes, and
       resins (Budavari, 1989). Chloroform was once used as an anesthetic and in cough
       syrups and toothpastes; these uses have been restricted because of environmental
       and health  concerns.  Chloroform is also  a  chlorination by-product of some
       industrial processes, such as paper manufacturing. Chloroform accounted for only
       a small fraction of the 1988 TRI  R&T, i.e., 1.9% (see Table 3).

       Carbon tetrachloride is a colorless, clear, and sweet-smelling liquid. It is produced
       primarily by chlorination of either methane or carbon disulfide in the presence of
       a catalyst (Budavari, 1989).  The consumption in 1988 was 761 million pounds.
       Of this, 91 % of carbon tetrachloride was used for the production of chlorofluorocar-
                                         75

-------
ELEVEN TRI CHEMICALS
      bons (CF:Cs) 11 and 12 (Chemical Profile, 1989). It is also used in the production
      of dyes, drugs, lubricants, and semiconductors.  Carbon tetrachloride has been
      widely used as a household  and  industrial cleaning  solvent and  as a grain
      fumigant.  These uses have been discontinued due to health concerns. As shown
      in Table 3, carbon tetrachloride accounted for about 0.4% of the 1988 TRI R&T.

      The remaining three chlorinated compounds— 1,1,1-trichloroethane, trichloroethyl-
      ene,  and  tetrachloroethylene  — are  chlorinated  C2  chemicals.   The  basic
      feedstocks for these chemicals are ethylene,  ethane, and propane.  Chlorination
      of an intermediate — ethylene dichloride — yields a mixture of trichloroethylene and
      tetrachloroethylene. Chlorination of ethane yields trichloroethane, and chlorination
      of propane produces mixtures of tetrachloroethylene and carbon tetrachloride.

      The first, 1,1,1-trichloroethane— also known as  methyl chloroform or TCA — is a
      nonflammable liquid with  a pleasant  odor.  In 1988, about 650 million pounds of
      TCA were used (Wolf et al., 1991; Chemical Profile, 1989), 52%  of which was
      used in vapor degreasing  and cold cleaning. TCA is also used in aerosol (13.5%),
      adhesive  (8.7%), and  coating (5.8%) formulations.  TCA can be  used as a
      photoresist developer and for printed  circuit board defluxing and synthesis of
      hydrochlorofluorocarbon (HCFC). A smaller amount is used in textile  processing,
      pesticide formulations, and flexible foam. TCA accounted for 13.5%  of the 1988
      TRI R&T (see Table 3).

      Trichloroethylene (TCE) is a clear, volatile liquid with a sweet odor resembling that
      of chloroform. Its consumption in 1988 totaled  about 160 million pounds (Chemical
      Profile, 1989; Wolf et al., 1991).  TCE is used primarily in cleaning applications
      such as vapor degreasing and cold cleaning of fabricated metal parts (85% [Wolf
      et al., 1991; Chemical Profile, 1989]).  Some  TCE is used in the electronics and
      textile industries, and as a chain terminator in  the production of polyvinyl chloride.
      TCE accounted for about 4% of the 1988 TRI R&T (see Table 3).

      Tetrachloroethylene,  also known as  perchloroethylene  or PERC, is  a colorless
      liquid with an ethereal odor. The reported consumption of PERC in 1988 was 568
      million pounds (Wolf et al., 1991), 46.5% (or 53%  [Chemical Profile, 1986]) of
      which was used in dry cleaning and textile processing.  PERC is also used in
      metal degreasing and cold cleaning (10% [Chemical Profile, 1986]), and as a
      solvent and a chemical intermediate in producing CFC-113 and CFC-114 (Wolf et
      al., 1991).  PERC accounted for 2.7% of the 1988 TRI R&T (see Table 3).

      Two ketones are included in the TRI target chemicals: methyl ethyl  ketone and
      methyl isobutyl ketone.  Methyl ethyl ketone (MEK) is a colorless, flammable liquid
      with an acetone-like odor. It is manufactured by dehydration of 2-butanol or by
      catalytic oxidation of n-butenes (Budavari, Inc., 1989).   Its 1989 consumption
      totaled 429 million pounds. As summarized in  Chemical Profile (1990), MEK is
      used primarily as a solvent for coatings (51%) and in adhesives (11%), magnetic
                                         76

-------
                                                         ELEVEN TRI CHEMICALS
tapes (8%), and printing inks (3%).  A smaller amount is used as an intermediate
for a flavoring ingredient and as  a  solvent in nail enamel.  MEK accounted for
11.3% of the  1988 TRI R&T (see Table 3).

Methyl isobutyl ketone (MIBK)  is  another colorless, flammable  liquid  with a
pleasant, honey-like odor. It is derived by mild hydrogenation of mesityl oxide (4-
methyl-3-penten-2-one).  Its 1989  consumption was 156 million pounds (Chemical
Profile, 1990). MIBK is used primarily as a solvent for protective coatings (60%
[Chemical Profile, 1990) or 71% [Lawler, 1977]); a process solvent for adhesives,
inks, and Pharmaceuticals (10% [Chemical Profile, 1990]); in chemical production
including rubber processing (10% [Chemical Profile, 1990]); and in the extraction
of rare metals such as uranium from fission products (Sax and Lewis,  1987). It is
used as a raw material for manufacturing antioxidants to improve the shelf life of
some chemicals (Reilly, 1990). MIBK represented about 3% of the 1988 TRI R&T
(see Table 3).                                                   :    .
       t        .     "        . '    '           .   .
Benzene,  toluene, and xylenes,  often known  collectively as BTX, are the basic
feedstocks for many aromatic chemicals and polymers. Benzene is a volatile,
colorless,  and flammable liquid hydrocarbon with a slightly sweet aromatic odor.
It exists naturally  in crude oil and coal.  It is  manufactured or extracted  in very
large quantities in oil refining and coal coking  (Kirk and Othmer, 1978). It is also
produced  from hydrodealkylation of  toluene or as a by-product  from steel
production.  In 1989, its consumption totaled  1,785 million gallons  (Chemical
Profile, 1990).  Benzene is used primarily as  a chemical  raw material in the
synthesis of ethylbenzene/styrene (53% [ChemicalProfile, 1990]); cumene/phenol
(21%); cyclohexane (12%);  nitrobenzene/aniline (5%);  detergent alkylate (3%);
chlorobenzenes; and other products used in  the production  of drugs, dyes,
insecticides, and plastics (Kirk and Othmer, 1978). Benzene has also been used
in smaller amounts  in gasoline and as a solvent and degreasing agent  (Reilly,
1990), but these uses have been greatly reduced because of environmental and
health concerns. Benzene represented 2.4% of the 1988 TRI R&T (see Table 3).

Toluene is a  colorless, mobile liquid with  a distinctive aromatic  odor somewhat
milder than that of benzene.  It occurs naturally in crude oil, and 87% of toluene
is  produced  by catalytic reforming  of petroleum and subsequent fractional
distillation of  the  aromatics (Sax and Lewis, 1987; Kirk  and  Othmer,  1983).
(Toluene is usually  produced along with benzene, xylenes, and C9  aromatics.)
Toluene may  be separated from pyrolysis of gasoline produced in steam crackers
during the manufacture of ethylene and propylene..  It  is  also  a by-product of
styrene manufacturing:  Consumption of toluene totaled'5,589 million pounds in
1984  (Ulrich,  1988).  About 90%  of the toluene  generated by catalytic reforming
is used as a blending component in gasoline.  Toluene is an important feedstock
for benzene manufacturing and a solvent in  paints,  coatings,  adhesives, inks,
Pharmaceuticals,  and other formulated  products utilizing  a  solvent  carrier.
However, the  use of toluene as a solvent in surface coatings is declining because
                                   77

-------
ELEVEN TRI CHEMICALS
       of various environmental and health regulations.  Toluene represented about one
       quarter of the 1988 TRI R&T (see Table 3).

       Xylene is a colorless liquid with a slightly sweet aromatic odor.  Its three isomers,
       o.-xylene, nvxylene, and jD-xylene, coexist with ethylbenzene, and the mixture is
       usually called  "mixed xylenes"  (Kirk and Othmer, 1983).   Mixed xylenes are
       derived mainly from catalytic reforming of petroleum (94.5%). Smaller quantities
       are produced from pyrolysis of gasoline (4.4%).  Individual isomers are separated
       from mixed xylenes in oil refineries or petrochemical operations.  In 1984, usages
       totalled 688, 90, and  2068 million pounds for o.-xylene, rn-xylene, and £-xylene,
       respectively (Ulrich, 1988). All three xylene isomers are important feedstocks for
       industrial polymers: o.-xylene is mainly converted to phthalic anhydride, which is
       used for the synthesis  of unsaturated polyester resins; jD-xylene is oxidized  to
       terephthalic acid and  dimethyl terephthalate, which are the basic building blocks
       for synthetic polyester fibers  and  aramid fibers;  ni-xylene is converted  to
       isophthalic acid for the manufacture of aramid fibers. Smaller quantities of xylenes
       are used as  a solvent in paints, coatings,  and agricultural sprays (Reilly,-1990).
       Xylenes accounted for 14.4% of the  1988 TRI R&T (see Table 3).

       The pollution prevention approaches and research needs for the eleven organic
       chemicals are summarized in Table  9  and are outlined in the text following the
       table. Several points regarding the preparation of the table and the text are noted
       in the following:

             «      This document is  prepared  according to specific functions
                    and uses of these chemicals rather than chemical classes.
                    This is because chemicals in different chemical classes may
                    be used for one specific application.  For example, both
                    chlorinated  and   nonchlorinated solvents are  used  for
                    protective coatings and  as  cleaning solvents for printing.
                    Most chlorinated methanes  and chlorinated C2 chemicals
                    are  used for  vapor degreasing, cold cleaning, and paint
                    stripping for metal surface preparation.
             •      The pollution  prevention research  needs are  identified
                    based on the technical information available  in the public
                    domain. Certain industries, such as chemical manufacturing
                    and petroleum refining, do not provide information regarding
                    specific pollution  prevention techniques because of  the
                   diversity and specificity of the  industries and  the desire to
                   guard confidential  business information.  Therefore, this
                   document contains only limited  discussion .about  the
                   research needs for these industries.
             •     The research needs identified are applicable to most of  the
                    12 two-digit SIC codes that are primarily responsible for the
                   release of the target chemicals.
                                          78

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87

-------
 ELEVEN TRI CHEMICALS
 POLLUTION PREVENTION OPPORTUNITIES
 AND SUPPORTING RESEARCH NEEDS

 Paint Stripping

       Paints and organic coatings are applied to surfaces  of various substrates to
       enhance corrosion resistance and/or improve appearance.  Often coatings need
       to be removed as part of the manufacturing operations or to enable maintenance
       or repair. In aerospace and aviation industries, coatings must be removed to allow
       inspection of underlying substrates for cracks and structural defects. Conventional
       paint stripping technologies use chemical or physical methods or a combination
       of both to remove paints.  Chemical methods rely on the solvency, oxidizing, or
       swelling properties of the applied stripper to destroy coatings.  Physical methods
       use  abrasives, such as sandblasting, to scrape away paints.  The chemical
       strippers most commonly used include chlorinated and  aromatic solvents  (e.g.,
       methylene chloride and phenol-based solvents), caustic and acidic solutions, and
       molten salt.

       Paint stripping operations generate large quantities of spent solvents and solvent-
       bearing wastewaters and solid-phase wastes. The operations also result in air,
       emissibns through volatilization during storage, fugitive  losses during use, and
       direct ventilation of fumes.
Avoid solvent use. Several "clean" technolo-
gies that are either commercially available or
are being developed, eliminate the use of haz-
ardous solvents. These include plastic media
blasting (PMB), bicarbonate of soda blasting,
liquid nitrogen and carbon dioxide pellet cryo-
genic blasting, wheat starch blasting, ice crys-
tal blasting, high-pressure waterjet stripping,
and laser or flashlamp heating. These technol-
ogies  remove  coatings  by  using  abrasive
and/or impact action, extreme cold to embrittle
coatings, or heal: input to burn coatings.
PMB  and bicarbonate  of soda blasting use
nontoxic plastic beads  and sodium bicarbon-
ate, respectively, as stripping media for coating
removal.  These processes  do  not generate
noxious air emissions, but the disposal of the
spent media could be a problem because they
contain paint residues  that  often consist  of
hazardous metals or unreacted resins.  More-
over,  these processes  are  noisy and  may
generate toxic airborne particulates. The cryo-
Research  needs.  PMB  is a  more mature
technology, but there are still areas that war-
rant future research. These may include long-
term structural effects, PMB-induced substrate
damage  (especially to composites), and the
effects of PMB on the resistance of different
substrates  and substrate thickness to  crack
growth (Cundiff et al,, 1989).   The cleaning
requirements on different materials (e.g., clad
aluminum,  titanium,  magnesium,  stainless
steel, and  composites)  after PMB  (Galiiher,
1989) and  the effects  of PMB  on  substrate
inspection  need further investigation.   The
potential  for  corrosion  and  localized  paint
failure also  needs further study.

For bicarbonate of soda blasting, studies need
to be done  to determine the potential for sub-
strate damage on  sensitive materials,  the
degree of  masking  of fatigue  cracks,  the
effects of residual sodium bicarbonate and its
by-products on the substrate when exposed to
                                          88

-------
                                                                ELEVEN TRI CHEMICALS
genie blasting uses liquid nitrogen or carbon
dioxide pellets to embrittle coatings and subse-
quently remove them by PMB or carbon diox-
ide pellets.  Cryogenic strippings result in  a
low-volume solid waste stream but still consist-
ing of paint chips and spent  plastic media.
Wheat starch blasting uses particles of nontox-
ic,  biodegradable  wheat starch  to  remove
coating.   However, the  fractured particles
become less effective in coating removal, and
the dust generated increases the explosion
hazard.  Ice crystal blasting results in a small
volume of waste because ice crystals melt and
evaporate.   On the contrary, high-pressure
waterjet stripping produces a large volume of
aqueous waste. Laser and flashlamp coating
removal  use the thermal  energy input from a
laser beam and a xenon flashlamp, respective-
ly.  The last five technologies are mainly in the
advanced pilot testing stage.
 Use alternative stripping agents.  Alternative
 stripping  agents  with  less-toxic or  nontoxic
 properties may be available  to replace the
 hazardous stripping solvents. These stripping
 agents will be  used to remove coatings from
 workpieces for which other mechanical strip-
 ping methods are not suitable.
 Source reduction and recycling.  There may
 be ways to extend solvent life  and/or reduce
 solvent emissions  to air, wastewater  and/or
 solid-phase wastes.
operating temperature and humidity conditions,
and the optimal process conditions for thin-
skinned aluminum aerospace structures. The
handling and disposal of the wastes also need
to be evaluated.

Research is needed to determine the effects of
liquid  nitrogen  cryogenic blasting on  aircraft
substrates and adhesive bonding materials, the
long-term effects  of the  rapid changes  in
temperature on substrates, and the generation
of toxic airborne particulates in the workplace.
For carbon dioxide pellet  blasting,  further
testing must be done on fatigue life degrada-
tion, crack growth potential, and the possibility
of inducing microcracks in composite  materi-
als. Further optimization of the process is also
needed for a wide range of substrates, includ-
ing pellet size, shape, and hardness; pressure;
impingement  angle; and  stand-off distance
(Larson, 1990, ivey,  1990).

Research is needed to identify and validate
other  new  and emerging   nonsolvent paint
stripping methods.   Studies should focus  on
the assessment of method effectiveness, the
ability  of achieving satisfactory work products,
optimization of the  process conditions, the
benefits  of waste  reduction  and pollution
prevention, and the economics.

Research  needs.   Research  is needed to
identify less-toxic or nontoxic stripping agents
for workpieces that cannot be stripped using
the nonsolvent methods. The effectiveness of
the stripping agents, the quality of the work
products, the  waste reduction  potential, and
the economics are the major items to  be
examined.

Research  needs. When an alternative does
not exist, source reduction  and recycling may
be used to extend solvent life  and/or  reduce
solvent emissions (U.S. EPA, 1992a). System-
atic studies are needed to identify methods to
                                           89

-------
 ELEVEN TR1 CHEMICALS
                                              reduce solvent usage, opportunities to elimi-
                                              nate specific work steps, methods to maximize
                                              stripping efficiency, procedures to segregate
                                              stripping wastes, methods to reuse or regener-
                                              ate  solvents, and opportunities to  recycle
                                              stripping solvents.
 Solvent Cleaning/Degreasing
       Solvent cleaning/degreasing involves some of the most important steps during the
       surface preparation  and finishing of the fabricated metal products.   Clean-
       ing/degreasing is performed to remove adsorbed substances that interfere with
       process performance or that affect product appearance. In metal finishing, the
       materials to be removed (usually called "soils") from the surface of a workpiece
       may include lubricants, cutting oils, polishing and buffing compounds, and oils for
       quenching and rust prevention.  Other soils that may be encountered include rosin,
       solderfluxes, paints, adhesives, inks, toners, asphalt, particulates, and fingerprints.

       Chlorinated solvents have been widely used to remove organic contaminants. The
       solvents most commonly used  are trichloroethylene (TCE),  1,1,1-trichloroethane
       (TCA), CFC-113,  perchloroethylene  (PERC), and  methylene chloride.   The
       classical cleaning processes involve vapor degreasing and cold cleaning. Vapor
       degreasing uses solvent vapor to contact the suspended soiled parts, dissolving
       the soil and flushing the liquid/soil mixture back into the hot liquid.  TCE was once
       used as the prime vapor degreasing solvent, but because of its toxicity,  its use has
       been largely replaced by TCA and CFC-113.  Cold cleaning is usually performed
       in a tank containing TCA and other cleaning solvents at room temperature.  The
       performance of the cold cleaning solvent usually degrades with use as it becomes
       loaded with dissolved materials.

       The vapor degreasing and cold cleaning operations are major sources of emission
       of the chlorinated solvents.   Air emissions through volatilization during storage,
       fugitive losses during  use, and direct ventilation of fumes accounted for more than
       80% of the 1988 TRI  R&T (see  Table 3).  The degreasing and cold cleaning also
       produce large quantities of solvent-bearing wastewater and solid-phase wastes.
Avoid chlorinated solvents use by using
alternative cleaning solutions.  Nonhazard-
ous or less-hazardous cleaning solutions can
be used to replace the hazardous chlorinated
solvents. Examples include aqueous cleaners,
semiaqueous cleaners, aliphatic hydrocarbons,
HCFCs, and N-methyl-2-pyrrolidone. Aqueous
cleaners are made up  of several classes of
chemical  components   including  builders,
Research needs. Before using an alternative
cleaning solution, research is needed to identi-
fy and classify cleaners and soils,  establish
cleaner evaluation criteria, optimize cleaner
performance,  and determine its  ability  to
conform  with  specifications  and production
processes. In general, an extensive  industrial
and/or literature survey must be conducted to
identify candidate cleaners that are suitable for
                                          90

-------
                                                                ELEVEN TRI CHEMJCALS
surfactants, emulsifiers, deflocculants, saponifi-
ers, sequestering agents, and/or other addi-
tives.  Some aqueous cleaners have been in
constant use by metal finishers, but the effects
of various  aqueous cleaners  on  different
substrates have not  been fully characterized.
The drying of the cleaned parts also poses a
challenge.

The semiaquepus cleaners  are made up of
biodegradable  hydrocarbon  solvents   and
water-based surfactants that form an emulsion
upon  mixing.   The  hydrocarbons  used  are
usually terpenes (e.g., d-limonene, para-ment-
hadienes, and  terpene  alcohols) and  glycol
ethers.   The,«rnajor uncertainty about  the
semiaqueous cleaners is their ability to meet
biodegradability and  toxicity requirements for
economic recycling and disposal.

Aliphatic  hydrocarbons   include  petroleum
fractions such  as mineral spirits, kerosene,
white  spirits, and naphtha.  This technology
becomes  a  viable  alternative  when  water
contact with the workpieces is undesirable.
The  chronic toxicity and smog production
potential are among  the  subjects of  concern.

Other chemicals that may be beneficial as a
replacement solvent include alcohol,  esters,
glycol ethers, acetone, vegetable oils, and fatty
acids.  Many of these solvents have been used
for some time.

In addition, supercritical fluid cleaning, carbon
dioxide snow,  absorbent cleaning, vacuum
degreasing, and cold catalysis have  also been
suggested as new/emerging technologies to
replace solvent cleaning  and degreasing.  All
of these technologies need to be  tested to
determine their  cleaning efficiency  and their
effects on substrates.

Use alternative cleaning processes.   It  is
often  possible  to use   alternative cleaning
the  kind  of soils  (and  substrates) to  be
cleaned. The cleaner evaluation criteria may
include  cleaning efficiency of each candidate
cleaner,  etch  rate,  corrosion effects,  and
staining on substrates.  Adequate evaluation
methods and techniques must b.e established
for these evaluations and the optimization of
the cleaner  performance. The economics of
the alternative cleaners must also be assessed
before they can be fully accepted by industries.

When using  an  alternative cleaning solution, it
is important to  monitor emissions of cleaner
components to workplaces  and the  environ-
ment and the associated chronic toxicity.  It is
also highly desirable to develop methods that
extend  solution life  and reduce emissions.
When considering solution  regeneration  and
recycling, one   must   examine the  cleaner
performance both before and after the solution
regeneration.
Research needs. The major research need is
to identify and validate new process technolo-
                                           91

-------
 ELEVEN TRI CHEMICALS
 processes to reduce or eliminate the need to
 use the hazardous chlorinated solvents or to
 employ technologies that eliminate the need
 for cleaning.  Several cleaning processes  are
 commercially available, including  ultrasonic
 cleaning, automated aqueous washing, aque-
 ous power washing, no-clean flux (low solids
 fluxes),  no-clean solder.  Ultrasonic cleaning
 uses conventional technologies, but tests must
 be performed to obtain the optimum combina-
 tion  of  cleaning solution concentration  and
 cavitation level.  Automated aqueous washing
 and aqueous power washing combine an inno-
 vative  process  technology  with  the use  of
 aqueous solutions. However, some delicate or
 difficult-to-clean  parts may  not be  cleaned.
 No-clean flux and non-clean solder result in
 little  or  no visible residue on the integrated
 circuit boards; therefore, traditional flux may be
 eliminated.   But even  limited residues are
 sometimes not  acceptable to  many military
 specifications.

 Other examples of process  changes include
 surface  cleaning by  laser ablation, fluxless
 soldering, replacement of tin-lead joints, and
 temporary vapor storage (TVS). Research on
 TVS is being  conducted based on the fact that
 it may be impossible to totally eliminate chlori-
 nated solvent usage. Because regeneration of
 the carbon adsorbers that trap fugitive vapors
 from cleaning and degreasing  operations often
 poses problems in  terms of  the  operational
 efficiency and economics, systems such  as
 TVS  (Hickman and Goltz, 1991)  do provide
 attractive features — utilizing  an air lock and
 airtight equipment to allow temporary storage
 of solvent vapors from a solvent source and to
 return the vapors for reuse.

Source  reduction  and  recycling.   When
chlorinated solvents must be used, there may
be ways to extend solvent life and/or reduce
solvent  emissions to air, wastewater, and/or
solid-phase wastes.
 gies that could either reduce or eliminate the
 use of hazardous solvents or eliminate totally
 cleaning  requirements during the fabrication/
 manufacturing processes. The process chang-
 es  may  involve  the cleaning/degreasing or
 even the manufacturing processes.
Research needs.  When an alternative does
not exist, source reduction and recycling may
be used to extend solvent life and/or reduce
solvent emissions.   Studies  are  needed  to
identify methods  to  reduce  solvent usage,
                                          92

-------
                                                                ELEVEN TRI CHEMICALS
                                             opportunities to eliminate specific work steps,
                                             methods to  maximize  cleaning  efficiency,
                                             procedures to  segregate  stripping  wastes,
                                             methods to reuse or regenerate solvents, and
                                             opportunities to recycle cleaning solvents.
Solvent for Coatings
       Paints and other coatings are applied to the surface of various substrates primarily
       to improve appearance and to resist corrosion. The substrates include sheet steel,
       plastic composites, stainless steel, aluminum, titanium, and wood.  Examples of
       the  industries applying coatings to these substrates include manufacturers of
       automobiles, aircraft, appliances, and wood products. Classical organic coating
       materials are dilute solutions of organic resins (e.g., alkyd, polyester, epoxy,
       polyurethane, acrylic, vinyl, and  other resins); organic or inorganic (e.g., Cd, Cr,
       and Pb) coloring agents; and extenders dissolved in volatile organic solvents.  The
       organic solvents, such as MEK, M1BK, benzene, toluene,  and xylene,  provide
       solvency, surface tension, and  other properties to  allow application of coating
       materials on substrate surfaces.  The coating processes result in solvent waste,
       paint sludge wastes, paint-bearing wastewaters, and paint solvent  emissions.
       Paint cleanup operations may contribute to the  release of chlorinated solvents,
       such as carbon tetrachloride, methylene chloride, TCA, and PERC, and solid- and
       liquid-phase wastes from equipment washing, paint application emissions control
       devices, disposal materials used to contain paint overspray, and discarded paint
       materials.
Use alternative coating methods involving
little or no volatile organic solvents.  There
may be ways to apply coatings without the use
of volatile organic solvents. Examples include
100% dry resin formulations (powder coating),
100%  reactive  liquids  (without any volatile
components), water-dispersed or water-soluble
polymer  systems  (water-based coating), or
high solids polymer systems  with  reduced
levels of organic solvents (high solids coating).
In powder coating, a coating film is formed by
applying either thermoplastic or thermosetting
powders on the substrate surfaces and, subse-
quently, melting the powders in a fluidized bed
or by .electrostatic spray. High solids coatings
use a higher concentration of  solids with a
lower concentration of volatile organic solvents,
thus lowering fugitive solvent releases. Water-
based coatings use water to replace or supple-
Research needs.  Research is needed to
identify new coating methods that eliminate the
use of hazardous volatile organic solvents.  It
is also needed to determine the performance
requirements for these new coating methods
and to identify test  methods to measure the
performance with respect to these standards.
The candidate methods can then be identified
and tested as alternatives for coating.

For the  existing technologies,  studies  are
needed to improve  the quality of work prod-
ucts,  optimize  the  processes,  and identify
effects on human health and the environment.
For example, for powder coatings, research is
needed to develop  methods to apply thinner
coatings particularly  to  complex-shaped or
nonconductive substrates.   For high  solids
coatings, studies are needed to identify types
                                           93

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 ELEVEN TRI CHEMICALS
 ment organic solvents.  Ultraviolet radiation-
 cured coatings use  high-intensity UV light to
 initiate  free  radical crosslinking of acrylate
 oligomers  and prepolymers, thus  eliminating
 solvent use and reducing paint waste. Several
 other  technologies  have  also  emerged as
 possible alternatives, including electron beam-
 cured coatings,  radiation-induced  thermally
 cured coatings, two-component reactive  liquid
 coatings, water-based  temporary protective
 coatings, vapor permeation- or injection-cured
 coatings, and supercritical carbon  dioxide as
 solvent.
Source reduction and recycling.  Methods
may  be  available to reduce  the release of
volatile organic solvents through, for example,
the use of new/modified equipment and pro-
cesses and/or the  recovery of  the solvents
from  overspray.  These pollution prevention
approaches are especially useful for smaller
size paint shops.
 of  formulations that provide  good  coating
 adhesion,  flexibility,  and  impact  resistance
 while maintaining coating flexibility.  Methods
 to optimize pot life versus curing time are also
 needed.  Because high solids coatings  only
 reduce the amount  of organic solvents  in
 coating formulations, they may be considered
 only as near-term replacements for convention-
 al coatings. In water-based coatings, studies
 are  needed to establish compatibility  with
 metal substrates and to address concerns over
 corrosion.   Future work is also needed  to
 develop  low-cost  cleaning methods  for  a
 cleaner surface for water-based coatings.  UV-
 cured  coatings need further development for
 more widespread  future  use.   The specific
 areas are listed in Table 9.

 Research  needs.   Research  is needed  to
 develop equipment and processes that reduce
 the release of volatile organic solvents. Exam-
 ples include high-volume/low-pressure spray
 guns that replace  the airless  guns and  pro-
 cesses incorporating prepainted automotive
 parts before assembly  (Lietzke, 1992).   ReT
 search is also needed to develop methods that
 recover volatile  organic solvents from over-
 spray.
Dry Cleaning
       Dry cleaning has been extensively used for the cleaning of fabrics.  More than
       70% of the dry cleaning is carried out with chlorinated hydrocarbons, including
       PERC, TCE, TCA, carbon tetrachloride,  and fluorinated  chlorohydrocarbons,
       among which PERC is the most widely used dry-cleaning solvent.  Dry-cleaning
       washers usually consist of a metal shell and a  rotatable perforated inner cylinder
       or wheel.  The shell is  a container for  solvent, whereas the wheel holds the
       garment load.  The spent solvents are purified by distillation  or by activated char-
       coal  and fatty acid-adsorbing sweetener  powders.  The  solvent  vapors  are
       removed by a carbon  adsorber, and the  adsorbed solvent can be recovered by
       passing low-pressure steam through the adsorber.
Use an alternative solvent. It may be possi-
ble to  use an alternative solvent to  achieve
Research needs.  Research is needed to
determine the performance requirements and
                                          94

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cleaning results similar to those by PERC and
other hazardous solvents.
Use processes and equipment that elimi-
nate solvent  emissions  or use  resource
recovery  and recycling..  If an  alternative
solvent is  not available, it may be possible to
develop processes and equipment  that com-
pletely eliminate solvent emissions. It is also
possible to  recycle the spent solvents and
recover fugitive vapors.

Blending  Components in Gasoline
                                                               ELEVEN TRJ CHEMICALS
to identify test methods to measure the perfor-
mance with respective  to those  standards.
The candidate solvents can then be identified
and tested as alternatives for dry cleaning.

Research needs.  Technologies  to achieve
the pollution prevention goals are being devel-
oped.  For example, the  dry-cleaning industry
has developed a dry-to-dry process to replace
the old transfer method to handle the washed
garment loads.  However, research is needed
to improve solvent recovery efficiency, reduce
cost, and reduce worker  exposure.
       Toluene and some benzene have been used as blending components in gasoline,
       particularly  in  unleaded premium gasolines.   As  a blending  component in
       automotive fuels, toluene and benzene have several advantages, including a high
       octane number, relatively low volatility, and the tendency to reduce engine starting
       difficulties (Kirk"and Othmer, 1983).
Use alternative blending chemicals.  It may
be  possible to use  an alternative  blending
chemical.
Improve fuel-handling  practices.  Devices
and equipment may be developed to eliminate
or reduce fugitive emissions of gasoline during
automobile and household equipment refuel-
ing.

Emissions from Petroleum  Refining
and  Related Industries
Research needs.  Research is  needed to
identify alternative blending chemicals that will
provide an adequate octane number, relatively
low volatility, and other desirable chemical
properties.  The performance of the chemicals
will have to be evaluated for widespread use.

Research needs.  Research is  needed to
develop  new  gasoline  dispensing  nozzles,
automobile  and  household  equipment  fuel
intake devices, and  household gas storage
tanks.
       The primary emissions from petroleum refining and related industries are benzene,
       toluene, and xylene (U.S. EPA, 1992b). The individual process units responsible
       for these emissions include distillation, cat cracking, coking, and maintenance
       operation.  The distillation process separates the crude  oil components at
       atmospheric or reduced pressure by heating to temperatures of about 500°F and
       subsequent condensing of the fractions by cooling.  Cat cracking breaks down
       larger,  heavier,  more complex hydrocarbon molecules  into simpler and lighter
                                          95

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 ELEVEN TRI CHEMICALS
       molecules using controlled heat and pressure with catalysts. The coking process
       thermally decomposes heavier crude oil fractions to produce a mixture of lighter
       oils and petroleum coke. As for the chemical manufacturing industry, information
       relating to pollution prevention is not readily available.
 Systems analysis to reduce waste.  The
 Petroleum Environmental  Research  Forum
 (PERF), established in 1986 as a cooperative
 agreement among 24 petroleum companies,
 stimulates cooperative research for developing
 new environmental technology for the petro-
 leum industry.  Some of  PERF's research
 programs and proposals  reflect current re-
 search needs in the petroleum refining indus-
 try.

 Improve  source  reduction and  recycling
 practices to control  emissions.  Petroleum
 refining can result in various types of wastes
 and  air emissions.  It is important  to identify
 the source of the waste before various source
 reduction and recycling techniques may be
 applied.   The techniques  to  be used  may
 include  controlling fugitive emissions, source
 reduction and recycling of solid wastes, recy-
 cling process waters, and employing responsi-
 ble maintenance practices.
 Research needs.  Research needs as reflect-
 ed by the PERF research projects and propos-
 als  include auto  fuel  emission  screening,
 preheating  catalyst to reduce auto emissions,
 microbial control using dilute halogen concen-
 trations,  spent caustic  management, spent
 fluidized  bed catalytic cracking unit  (FCCU)
 catalyst management, oily emulsion formation
 and control, and valve fugitive emission reduc-
 tion.

 Research  needs.   Research is  needed  to
 identify the source of the waste in each of the
 refining processes.  Specific  methods  and
 techniques need to  be  identified to control
 fugitive emissions from sources such as crude
 oil and product  storage tanks,  coker, barge
 loading, etc. Methods also need to be identi-
 fied/developed to achieve source reduction and
 recycling of solid wastes and process waters.
 Some  areas of  concern  include recycling
 hydrocarbon-bearing sludges from API separa-
tor to coking operation, recycling wastewater
treatment plant sludge to coking operation, and
 recycling  water used to cool and cut coke
products.
Emissions from Primary Metal
Smelting and Refining
       The major pollutants from the primary metal industry are benzene, toluene, and
       xylenes.  These pollutants are produced primarily from heating coal in  high-
       temperature  coke ovens during  coking  operations.   The  coke oven gas  is
       processed through recovery units to separate saleable by-products (e.g., benzene,
       toluene, and xylenes) and is then used as fuel.   During cast or mold making,
       toluene and xylenes are used as mold washcoats.   During  hydrometallurgical
       refining, solvents can be used as extractants to recover metals from ores through
       leaching.  The primary metal  industry generates  high-volume wastes including
       slags, off-gases, and process wastewater at all  primary and secondary metal
                                         96

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                                                              ELEVEN TRI CHEMICALS
      smelting operations.  The primary metal industry is a major source of TRI R&T
      (See Table 3).
Control release of organics in metal smelt-
ing and refining.   For the primary metal
industry, source  reduction is a difficult task
because all the chemicals of concern  (except
cyanide) come from the raw materials.  Im-
proved process control and equipment modifi-
cation can decrease the amount or concentra-
tion of the VOC emissions, but do not entirely
eliminate them.  Changes in basic smelting
and refining processes hold more potential to
eliminate the wastes (U.S. EPA, 1992c).
Research needs.   Research  is needed to
assess the impact of basic process changes
on metal smelting and refining.  Systematic
studies must be carried out to  determine the
source of the waste  and to develop new pro-
cesses that replace the existing ones.  For
example, research is  under  way to develop
direct iron and steelmaking processes that turn
iron ore, coal, and limestone directly into iron
or steel in one vessel,  thus eliminating the
need  for coke ovens and blast furnaces (U.S.
EPA,  1992c).  Research  is  also needed to
improve process control and modify existing
equipment.  Examples  include modifying  a
blast furnace to reduce coke requirements and
adding coal tar decanter sludge to the coking
oven  to reduce tar residue  waste.
Solvents for Printing Processes
      Toluene, MIBK, PERC, and TCA are used extensively during printing processes,
       causing their  high releases to  the environment.  The chemicals are used as
       solvents in inks and adhesives, and as cleanup solvents.  The wastes generated
       during plate processing, printing, and binding generally include solvents from heat-
       set inks, waste inks and ink sludges with solvents, cleanup solvents (including
       halogenated and nonhalogenated), and solvents from adhesive use.
Use substitutions for  solvent-based inks
and adhesives. It is possible to develop new
nonsolvent-based  inks and adhesives.  For
example, water-based inks have been devel-
oped for flexographic and rotogravure printing
processes.   Water-based (Randall et al.,
1991), nonhalogenated, and high solids adhe-
sives have been developed or the ideas have
been suggested.

Use nonhazardous cleaning solutions.  It
may be possible to use/develop nonhazardous
cleaning solutions or non-solvent-based clean-
ers.
Research  needs.  Research is  needed to
determine the performance requirements for
the nonsolvent-based inks and adhesives and
to identify test methods to measure the perfor-
mance with respect to those standards.  The
candidate  materials can  be identified  and
tested as substitutions for printing and binding.
 Research  needs.   Research is needed  to
 identify and validate new non-solvent-based or
 nonhazardous cleaning solutions. The perfor-
 mance requirements and test methods need to
                                          97

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 ELEVEN TRI CHEMICALS
 Use source  reduction and recycling.   A
 variety of  source reduction and recycling
 methods  may be applicable to  reduce or
 eliminate the releases of the toxic solvents.

 Solvents for Rubber and Miscellaneous
 Plastic Manufacturing
 be  defined  and  identified.   New  cleaning
 solutions will then be identified and tested.

 Research  needs.   Research  is needed to
 identify the source of the waste and adequate
 techniques that may achieve source reduction
 and recycling objectives.
       Organic solvents are used during compounding, fabricating, and converting of the
       rubber and miscellaneous plastic products, and reclaiming of the waste materials.
       Rubber compounding  involves mixing,  calendaring,  and vulcanizing; plastics
       compounding includes  dry mixing of powders in a melt to produce pelletized or
       diced resin.  Fabricating operations  usually involve shaping and transforming
       rubber or plastic resin into a finished or semifinished product by molding, extrusion,
       or other fabricating methods. Converting operations involve removing the rubber
       or plastic overflow from the product before shipping.  And reclaiming treats rubber
       wastes with heat and chemical agents and transforms the material to its original
       plastic state. These operations often produce spent solvents and fugitive solvent
       emissions.
Avoid use of toxic solvents.  It  may  be
possible  to use  alternative solvents in the
production of rubber and plastic products.
Use source reduction and recycling. There
may be ways to limit the use of solvents and/or
eliminate or reduce solvent emissions.
Research  needs.   Research is needed to
identify and validated new solvents to be used
in the manufacturing of rubber  and plastic
products.

Research  needs.  When solvents must be
used, source  reduction and recycling tech-
niques may be used to limit their use and/or to
eliminate or reduce solvent emissions. Sys-
tematic studies are needed to identify methods
to reduce  solvent usage,  opportunities  to
eliminate process steps, methods to reuse or
recycle  spent solvents,  and  techniques  to
recover fugitive vapors.
Chemical Manufacturing
       All of the eleven TRI organic chemicals are used, in one form or the other, as
       basic feedstocks, intermediates, solvents, extractants, diluents, etc., in chemical
       manufacturing. The industry is  typified by its diversity in the types of processes,
       techniques, and equipment used for both chemical manufacturing and pollution
       prevention.  Because  of the competitive nature of the  business, the industry
                                          98

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                                                              ELEVEN TRl CHEMICALS
       usually uses its enormous in-house  research and development resources and
       capabilities to develop specific pollution prevention methods for the manufacturing
       of a given product. However, the results of these efforts are usually not available
       to the public.
Use generalized pollution prevention tech-
niques. There may be ways to minimize the
release of hazardous organic chemicals during
the chemical manufacturing processes.  The
best approach is to develop an understanding
of whatever general pollution prevention tech-
niques may apply to commonly used  unit
operations  within the industry  (U.S.  EPA,
1992e).
Research needs.  A considerable research
program  is needed to  systematically  study
common  unit  operations and  the pollution
prevention techniques that may apply.  The
information obtained can be used to determine
whether  common  industry  usage  of  these
techniques could result in more efficient pollu-
tion prevention.
REFERENCES FOR ELEVEN TRl
ORGANIC CHEMICAL GROUPS

       Budavari, S. (Ed.).  1989.  The Merck Index, 11th ed., Merck & Co., Inc., Rahway,
       NJ.

       Chemical Profile: Perchloroethylene. 1986.  Chemical Marketing Reporter, Schnell
       Publishing Co., New York, NY, February 3.

       Chemical Profile: Carbon Tetrachloride.  1989.  Chemical Marketing Reporter,
       Schnell Publishing Co., New York, NY,  February 13.

       Chemical  Profile: Chloroform.  1989.   Chemical  Marketing Reporter, Schnell
       Publishing Co., New York, NY, February 27.

       Chemical  Profile: Methylene Chloride.   1989.  Chemical Marketing Reporter,
       Schnell Publishing Co.. 1989. New York, NY,  February 20.

       Chemical Profile: Trichloroethylene. 1989. Chemical Marketing Reporter, Schnell
       Publishing Co., New York, NY, January 23.

       Chemical Profile: 1,1,1-Trichloroethane. 1989.  Chemical Marketing Reporter,
       Schnell Publishing Co., New York, NY, January 30.

       Chemical  Profile: Benzene.   1990.   Chemical Marketing  Reporter,  Schnell
       Publishing Co., New York, NY, April 23.

       Chemical Profile: Methyl Isobutyl Ketone.  1990. Chemical Marketing Reporter,
       Schnell Publishing Co., New York, NY, August 20.
                                         99

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ELEVEN TRI CHEMICALS
       Chemical Profile: Methyl Ethyl Ketone.   1990.  Chemical Marketing Reporter,
       Schnell Publishing Co., New York, August 27.

       Cheney, JM and P. Kopf.   1990.  "Paint Removal  and Protective Coating
       Development," Proc. 1990 DoD/lndustry Advanced Coatings Removal Conference,
       Atlanta, GA.

       Cundiff, C. H., O. L. Deel, and R. E. O'Sullivan. 1989. "Plastic Media Evaluation-
       A Compsirative Study of Performance Capabilities of Several Plastic Media," Proc.
       1989 DoD/lndustry Advanced Coatings Removal Conference, Ft. Walton Beach,
       FL

       Galliher, R. D.  1989.  "Surface Preparation and Paint Adhesion  on Aluminum
       Substrate after Blasting with Plastic Abrasive," Proc. 1989 DoD/lndustry Advanced
       Coatings Removal Conference, Ft. Walton Beach, FL.

       Hickman, J. C., and  H. R. Goltz. 1991. "Temporary Vapor Storage Technology,"
       Proc. International CFC and Halon Alternatives Conf.

       Ivey,  R. B. 1990. "Carbon Dioxide Pellet Blasting Paint Removal for Potential
       Application of Warner Robins Managed Air Force Aircraft," First Annual Internation-
       al Workshop on Solvent Substitution, DE-AC07-76ID01570, U.S. Department of
       Energy and U.S. Air Force, Phoenix, AZ, pp. 91-93.

       Kirk, R., and D. Othmer (Eds.).  1978. Encyclopedia of Chemical Technology, 3rd
       ed., Vol. 3, John Wiley & Sons, New York, NY.

       Kirk, R. and D. Othmer (Eds.). 1983.  Encyclopedia  of Chemical Technology, 3rd
       ed., Vol. 23, John Wiley  & Sons, New York,  NY.

       Kirk, R. and D. Othmer (Eds.). 1984.  Encyclopedia  of Chemical Technology, 3rd
       ed., Vol. 24, John Wiley  & Sons, New York,  NY.

       Larson, N.  1990. "Low Toxicity Paint Stripping of Aluminum and Composite
       Substrates," First Annual International Workshop on Solvent Substitution, DE-
       AC07-76ID01570, U.S. Department of Energy and U.S. Air Force, Phoenix, AZ, pp.
       53-60.

       Lawler, G. M., Ed..   1977.   Chemical Origins and Markets, 5th  ed., Chemical
       Information Services of SRI, Menlo Park, CA.

       Lietzke, R. 1992. "Corrosion Busting Research Goal: Pre-Painting Automotive
       Parts Could Become Integral in Future," The Columbus Dispatch,  February, 8.
                                        100

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                                                         ELEVEN TR1 CHEMICALS
 Randall, P. M., G. Miller, W. J. Tancig, and M. Plewa.  1991.  "Toxic Substance
 Reduction  for  Narrow-Web Flexographic  Printers," Proc. 7th Annual RREL
 Hazardous  Waste  Research  Symposium:  Remedial  Action, Treatment,  and
 Disposal of Hazardous Waste, EPA/600/9-91/002, U.S. Environmental Protection
 Agency, Office of Research and Development, Washington, DC.

 Reilly, W.  1990.  "EPA's Goals for Reducing Releases of High  Priority Toxic
 Chemicals," presented to the National Press Club, September 26.

 Sax,  N.I-., and R.J. Lewis,  Sr. (Eds.).  1987.  Hawley's Condensed Chemical
 Dictionary, 11th ed., Van Nostrand Reinhoid Co., New York, NY.

 1988 Toxics Release Inventory (TRI) Releases/Transfers Database. 1988.  ILS.
 Environmental Protection Agency, Washington DC.

 Ulrich, H., 1988. Raw Materials for Industrial Polymers,  Oxford University Press,
 New York, NY.

 U.S. EPA.   1992a.  Pollution Prevention Options in Metal Fabricated Products
 Industries: a  Bibliographic  Report,  EPA  560/8-92/002,  U.S. Environmental
 Protection Agency, Office of Toxic Substances, Washington, DC.

 U.S.  EPA.  1992b.   Pollution Prevention  Options in Petroleum Refining: a
 Bibliographic Report, SAIC Draft Report to U.S. Environmental Protection Agency,
 Office of Toxic Substances,  Washington, DC.

 U.S. EPA.  1992c.  Pollution Prevention Options in Primary Metal Industries: A
 Bibliographic Report, SAIC Draft Report to U.S. Environmental Protection Agency,
 Office of Toxic Substances,  Washington, DC.

 U.S. EPA. 1992d.  Pollution Prevention Options in Printing, Publishing and Allied
 Industries: a Bibliographic  Report,  SAIC  Draft Report to  U.S. Environmental
 Protection Agency, Office of Toxic Substances, Washington, DC.

 U.S. EPA. 1992e.  Possible Areas for Pollution Prevention Research, SAIC Draft
 Report to U.S.  Environmental  Protection Agency,  Office  of Toxic Substances,
Washington, DC.

Wolf,  K.,, A. Yazdani, and  P.  Yates.  1991.   "Chlorinated Solvents:  Will the
Alternatives be Safer?" J. Air Waste Manage. Assoc., 41(8): 1055.           ;
                   *U.S.COVHlNMENTPWNnNCOFFJCE:1992 -648 -003£0058


                                  101

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