EPA-650/2-74-131
DECEMBER 1974
Environmental Protection Technology Series

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                  RESEARCH REPORTING SERIES


Research reports of the Office of Research and Development, U.S. Environ-
mental Protection Agency, have been grouped into series.  These broad
categories were established to facilitate further development and applica-
tion of environmental technology. Elimination of traditional grouping was
consciously planned to foster technology transfer and maximum interface
in related fields. These series are:

          1. ENVIRONMENTAL HEALTH EFFECTS RESEARCH
          2. ENVIRONMENTAL PROTECTION TECHNOLOGY
          3. ECOLOGICAL RESEARCH
          4. ENVIRONMENTAL MONITORING
          5. SOCIOECONOMIC ENVIRONMENTAL STUDIES
          6. SCIENTIFIC AND TECHNICAL ASSESSMENT REPORTS
          9. MISCELLANEOUS

This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series.  This series describes research performed to
develop and demonstrate instrumentation, equipment and methodology
to repair or prevent environmental degradation from point and non-
point sources of pollution.  This  work provides the new or improved
technology required for the control and treatment of pollution sources
to meet environmental quality standards.

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                                          EPA-650/2-74-131
DETERMINATION  OF  HAZARDOUS  ELEMENTS
   IN  SMELTER-PRODUCED SULFURIC  ACID
                           by

             W.H. Hedluy, S.M. Metha, andP.L. Sherman

                  Monsanto Research Corporation
                      Dayton Laboratory
                      Dayton, Ohio 45407
                  Contract No. 68-02-0226, Task 8
                     ROAP No. 21ADE-021
                   Program Element No. 1AB013
                 EPA Project Officer: L. Stankus

                   Control Systems Laboratory
               National Environmental Research Center
             Research Triangle Park, North Carolina 27711
                        Prepared for

              OFFICE OF RESEARCH AND DEVELOPMENT
             U.S. ENVIRONMENTAL PROTECTION AGENCY
                   WASHINGTON,  D.C. 20460

                       December 1974

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                        EPA REVIEW NOTICE

This report has been reviewed by the National Environmental Research
Center - Research Triangle Park, Office of Research and Development,
EPA, and approved for publication.  Approval does not signify that the
contents necessarily reflect the views and policies of the Environmental
Protection Agency, nor does mention of trade names or commercial
products constitute endorsement or recommendation for use.
This document is available to the public for sale through the National
Technical Information Service, Springfield, Virginia  22161.
                                  11

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                           ABSTRACT

The Control Systems Laboratory of the Environmental Protection
Agency is presently collecting data to determine whether there
are any potentially hazardous impurities in the non-ferrous
smelter produced sulfuric acid and if these materials could
present a potential threat to vegetation and life at a later
time.  Therefore, potentially hazardous element composition of
the non-ferrous smelter produced sulfuric acid was determined.

There were two aspects to this study (1) to acquire sulfuric
acid samples of non-ferrous smelter produced sulfuric acid;
(2) analyze the samples by atomic absorption spectrometry for
potentially hazardous impurities.  Sulfuric acid samples were
received from seven plants and were analyzed for trace elements,
including lead, copper, zinc, mercury,  arsenic, cadmium, selenium,
antimony, beryllium, and other elements detected at significant
levels during  screening tests.  Analyses of sulfuric acid were
also received  from five other non-ferrous smelters.
                               iii

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                         TABLE OF CONTENTS

                                                          Page

  ABSTRACT                                                 iiJ

  I.   OBJECTIVES                                            1

 II.   SAMPLE COLLECTION                                     2

III.   SAMPLE PREPARATION AND ANALYSIS                       3

 IV.   RESULTS AND DISCUSSION                                6

  V.   RECOMMENDATIONS FOR ANALYTICAL METHODOLOGY           12
      DEVELOPMENT

 VI.   REFERENCES                                           13

      Appendix A - List of Smelter Sulfuric Acid Plants    15

      Appendix B - Sample Identification                   17

      Appendix C - Analytical Procedure                    19

      Cl.O  Introduction                                   20
      C2.0  Multi-Element Screening Analysis               20
      C3.0  Atomic Absorption                              21
      C3.1  Introduction                                   21
      C3.2  Sample and Standard Preparation                22
      C3.3  Instrument Operating Parameters                22
      C3.4  Sample Analysis Methods                        25
      C3.4.1  General Atomic Absorption Analyses           25
      C3.4.2  Special Atomic Absorption Analyses           25
      C3.4.2.1  Arsenic (As) and Selenium (Se)             25
      C3.4.2.2  Beryllium (Be) and Cadmium (Cd)            31
      C3.4.2.3  Antimony (Sb)                              33
      C3.4.2.4  Mercury (Hg)                               33
      C3.4.3  Spectral Background Interferences            34
              from Non-Atomic Absorption
      C4.0  Asarco Methods for Arsenic (As)  and            35
            Selenium (Se)
      C4.1  Determination of Arsenic in Sulfuric           35
            Acid - Photometric Ag-DDC Method
      C4.2  Colorimetric Determination of Se in            38
            Sulfuric Acid
      C4.3  Colorimetric Determination of                  41
            Selenium and Tellurium

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                        LIST OF FIGURES

                                                          Page

Figure Cl.  Atomic Absorption Calibration Curve for
            Cu in 25% Sulfuric Acid                        26

Figure C2.  Atomic Absorption Calibration Curve
            for Mn in 25% Sulfuric Acid                    27

Figure C3.  Atomic Absorption Calibration Curve
            for Pb in 25% Sulfuric Acid                    28

Figure C4.  Atomic Absorption Calibration Curve
            for Zn in 25% Sulfuric Acid                    29

Figure C5.  Arsine Evolution Apparatus                     37

Figure C6.  Arsenic Calibration Curve                      39
                              VI

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                        LIST OF TABLES
Table 1.   Semi-Quantitative Emission Analyses

Table 2.   Summary of Analysis for Sulfuric Acid
           Samples Received by MRC Analysis Results

Table 3.   Sulfuric Acid Analysis by American Smelting
           and Refining Co. (ASARCO) Analysis Results

Table 4.   Results of ASARCO Analyses of MRC Samples
           Analysis Results

Table 5.   Trace Element Quantities in Sulfuric Acid

Table 6.   Trace Element Quantities in Sulfuric Acid
           (American Smelting and Refining Company)
Page

  4


  7


  8


  9

 10


 11
Table Cl.  Actual Analysis of Ultrex Sulfuric Acid
           by J.T. Baker Chemical Company

Table C2.  Atomic Absorption Instrument Operating
           Parameters Perkin-Elmer Model 303

Table C3.  Instrument Operating Parameters
 23


 24

 32

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                           SECTION I
                           OBJECTIVES

The overall objectives of this project were to:

1.  Acquire samples of sulfuric acid produced at certain
    non-ferrous smelters;

2.  Subject these samples to a multi-element analytical
    approach to provide a preliminary indication of trace
    element concentrations of potentially hazardous
    impurities;

3.  Analyze the samples by atomic absorption spectrometry
    for potentially hazardous trace elements, including lead,
    copper, zinc, mercury, arsenic, cadmium, selenium,
    antimony, beryllium, and other elements detected at
    significant levels during screening tests; and

4.  Define the end uses of the smelter-produced acid,
    determine how much acid is produced by each company,
    and calculate the quantity of each element contained
    in the acid produced on a yearly basis.

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                          SECTION II
                       SAMPLE  COLLECTION

Monsanto Research Corporation (MRC) was to acquire sulfuric
acid samples from nine companies that operate seventeen non-
ferrous smelter plants.  These companies and their plants are
listed in Appendix A.  All 17 plants were contacted either by
telephone or by correspondence to outline the program and to
convince their management to participate in the study.  Out of
these nine companies, six (with seven plants) agreed to supply
MRC with sulfuric acid samples from their operations.  American
Smelting and Refining Company (with five plants) agreed to supply
us with only analyses of their sulfuric acid.  The remaining
plants declined to supply us any sulfuric acid samples.

Each company was requested to supply random samples from their
non-ferrous smelter-produced sulfuric acid plants.  Companies
involved were to supply about a pint of sulfuric acid represent-
ing three days of production during the period of one week.  In
order to avoid contamination, MRC supplied each plant with three
acid-washed bottles and a brief sampling procedure.  The three
samples that were received from each plant were then composited
at MRC's Dayton Laboratory for analysis.

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                           SECTION  III
                 SAMPLE  PREPARATION AND ANALYSIS

 Seven  commercial-grade  sulfuric  acid samples  from  seven plants
 comprising  three types  of  non-ferrous smelters were  analyzed by
 atomic absorption spectrometry for 14 elements.  The samples
 are  identified  in Appendix B.  The elements analyzed were
 dictated  either by the  work statement for this project or by
 the  results of  emission analysis of the  samples.   A  portion of
 sample was  evaporated in a heated  graphite electrode.  The
electrode was then analyzed by emission  spectroscopy.  Evaporation
of the  samples  in the graphite electrode could have  resulted in
the  loss of more  volatile  species, such  as metal halides.  This
was  not a problem in that  ASARCO found less than 1 ppm of chloride
in the  samples  they analyzed.  The work  statement  for the project
required analysis  by atomic absorption for Pb, Cu, Zn, Hg, As,
Cd,  Se, Sb,and  Be.  Pb,  Zn,  Hg,  As, Cd,  Se, and Sb  cover fairly
well the elements  that  are  volatile and  have volatile compounds
which might be  found in concentrated sulfuric acid.   The results
of the emission analyses are shown in Table 1.

Twenty-five ml  of  each  sample  (entire sample shaken  to ensure
uniformity) was diluted to  100 ml with deionized-distilled
water.  This operation  was  performed to  permit the aspiration
of the  diluted  samples  directly  into the flame of  a  Perkin-
Elmer Model 303 atomic  absorption  spectrometer.  The  Perkin-
Elmer was fitted with a triple slot burner.   The elements
analyzed in this manner were As, Cr, Cu, Fe, Mg, Mn,  Ni, Pb,
Se,  and Zn.  The  instrument conditions were standard  as set
forth  in the Perkin-Elmer manual1 except for Ni, where the
352.4 run line was  used as recommended by  Perkin-Elmer  for iron-
containing matrices, and for Fe, where the 252.7 nm  line was

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                                        Table 1.  SEMI-QUANTITATIVE EMISSION ANALYSES

                                                          (ppm by wt)
Impurity
Aluminum (Al)
Chromium (Cr)
Copper (Cu)
Iron (Fe)
Magnesium (Mg)
Manganese (Mn)
Nickel (Ni)
Lead (Pb)
Silicon (Si)
Zinc (Zn)
Sample No. 1 Sample No. 2
St. Joe New Jersey Zinc
Lead Smelter Zinc Smelter
0.032
0.93
>1.5 0.33
11.9 4.5
0.03 <0.005
0.03
4.5 0.1
0.43
0.43
4.5
Sample No. 3 Sample No. 4
City Service Missouri Lead
Copper Smelter Lead Smelter
1.19
>1.5 >3.0
0.76 2.1
0.02
<0.03
0.92 1.2
<0.32
0.32
1.52 9.2
Sample No. 5
National Zinc
Zinc Smelter
»1.5
3.0
0.01

1.52
0.16

4.5
Sample No. 6
Bunker Hill
Zinc Smelter
>1.5
9.2
0.01
0.03
1.2
<0.16
0.32
3.04
Sample No. 7
Bunker Hill
Lead Smelter
>1.5
0.76
<0.005

1.03
0.32
0.32
3.04
Note:  As, Be, Cd, Hg, Sb, and Se are at a level that was not
       detectable by the semi-quantitative emission analysis
       method used for any of these seven samples.

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used due to higher concentrations.   (Possible Hg interference of
this line is low because of the low sensitivity of Hg in a flame
[1*10 yg/m£]).  Hg was analyzed by the now widely accepted cold
vapor flamelss method.2  Sb was determined using a Perkin-Elmer
model 303-0849 volatile hydride generator and methods developed
by Perkin-Elmer and others. 3ft*  Be and Cd were analyzed using a
Varian Model 61 carbon rod flameless atomic absorption atomizer
power supply and a Model 63 Varian carbon rod head assembly.  The
micro tube furnace was used in both cases.  The micro tube furnace
is made of pyrolytic graphite and is sheathed from oxidation at
high temperatures by a flow of argon or nitrogen.  Extremely high
atomization temperatures are obtainable with this furnace
(>3000°C).

All standards were prepared from regular atomic absorption stock
solutions in matrices matching the sample matrices as far as acid
concentration is concerned.  Ultrex, ultra high purity acid, sold
by J. T. Baker, Co. was used to prepare standards.

Appendix C presents in detail the analytical procedure for
analysis of potentially hazardous trace element impurities in
concentrated sulfuric acid from non-ferrous smelters.

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                          SECTION IV
                    RESULTS AND DISCUSSION

Table 2 summarizes the results of atomic absorption spectrometric
analysis for potentially hazardous trace metals along with annual
production and end uses of sulfuric acid from the seven non-
ferrous smelters.  The annual production and end uses of sulfuric
acid were obtained from the operators of seven non-ferrous
smelters.  American Smelting and Refining Company (ASARCO)
supplied typical analyses of sulfuric acid produced at five of
their smelters and these are summarized in Table 3.

A review of the data in Tables 2 and 3 shows fairly good agree-
ment between MRC data and ASARCO for samples from similar plants.
Arsenic and selenium data were not reported in Table 2 because
their concentrations were below the MRC detection limit.  MRC
contacted Mr. L. W. Anderson, Superintendent, Analytical Services
at ASARCO's Central Research Laboratories.  Mr. Anderson gra-
ciously agreed to analyze our seven samples via the methods they
normally use for arsenic and selenium in concentrated sulfuric
acid samples from non-ferrous smelters.  The results of these
analyses are shown in Table 4.  These values are similar to the
values reported earlier by ASARCO for their acids.  Anderson
stated, "These levels of both arsenic and selenium are well below
the detection limits by normal flame atomic absorption using
EDL  (electrodeless discharge lamps).  Atomic absorption could
possibly be used for these levels of arsenic and selenium using
hydride evolution methods."  The procedures used by ASARCO for
these two analyses are reproduced in their entirety in Section
C4.0.

Tables Sand 6 show the pounds of each trace metal contained in
the sulfuric acid produced on a yearly basis and analyzed by
MRC and ASARCO respectively.   The majority of the non-ferrous
smelter-produced sulfuric acid is used in fertilizer and ore
processing.

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                              Table 2.   SUMMARY OF ANALYSIS FOR SULFURIC ACID SAMPLES RECEIVED BY MRC

                                                         ANALYSIS  RESULTS

                                                            (ppra by wt.)

               Sample No.  1  Sample No. 2    Sample No. 3   Sample  No.  4   Sample No.  5 Sample No. 6 Sample No. 7
                 St.  Joe    New Jersey Zinc  City Service  Missouri Lead National Zinc  Bunker  Hill   Bunker Hill
 Trace Metals  Lead Smelter  Zinc  Smelter   Copper Smelter  Lead Smelter   Zinc Smelter Zinc Smelter Lead Smelter
Atomic Absorption
   Method Used
Beryllium (Be)
Cadmium (Cd)
Chromium (Cr)
Copper (Cu)
Iron (Fe)
Mercury (Hg)
Magnesium (Mg)
Manganese (Mn)
Nickel (Ni)
Lead (Pb)
Antimony (Sb)
Zinc (Zn)
Annual Acid
Production
(tons/yr)
Major End
Uses
<0.001
0.11
3.28
0.47
167
0.029
0.21
1.35
1.63
2.78
0.032
0.24
70,000
Fertilizer
<0.001
0.017
0.28
0.11
22
O.OS6
0.15
0.24
<0.11
0.38
0.010
1.83
150,000
Batteries,
Plastic & Paper
<0.001
0.001
0.30
0.13
9
0.046
0.03
0.15
c
0.11
0.33
0.012
0.05
135,000
Fertilizer
Textile
<0.001
0.002
2.83
0.36
124
0.009
1.33
0.76
1.68
0.48
0.018
0.1
50,000
Fertilizer
<0.001
0.005
0.39
0.14
37
2.28
0.15
0.28
0.18
<0.13
0.003
0.07
73,500
Detergent,
Vfeter Treatment
<0.001
0.005
1.85
0.21
183
0.20
1.74
1.35
0.28
<0.13
0.026
1.1
220,
<0.001
0.114
0.78
0.18
52
0.161
0.22
0.48
0.37
2.0
0.02
0.08
000
Carbon Rod
Carbon Rod
Flame-Air-C2H2
Flame-Air-C2H2
Flame-Air-CjHj
Flameless
Flame-Air-C2H2
Flame-Air-C 2H2
Flame-Air-C 2H 2
Flame-Air-C 2H 2
Hydride Generator
Flame-Air-C 2H2
Fertilizer
Estimated accuracy of analytical procedures used to determine results listed above ±5% or better.

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CO
                               Table 3.  SULFURIC ACID ANALYSIS BY AMERICAN SMELTING AND  REFINING CO.  (ASARCO)
                                                              ANALYSIS RESULTS
                                                                (ppm by wt.)
Trace Metals
Arsenic (As)
Cadmium (Cd)
Copper (Cu)
Iron (Fe)
Mercury (Hg)
Manganese (Mn)
Nickel (Ni)
Lead (Pb)
Antimony (Sb)
Selenium (Se)
Zinc (zn)
Annual Acid
Production
(tons/yr)
Major End Uses
Tacoma ,
Washington
Copper Smelter
0.44
<0.005
0.20
51.0
0.003
0.25
0.15
0.25
0.18
<0.04
0.06
44,000

Explosives, Pulp
& Paper, Fertilizer
Hayden ,
Arizona
Copper Smelter
0.08
NA
0.28
32.3
0.010
0.38
0.48
1.6
<0.01
0.04
0.94
210,000

Ore Processing
El Paso,
Texas
Copper Smelter *
0.5
NA
0.1
8.0
0.003
0.06
0.10
1.0
<0.1
0.06
0.84
168,000

Ore Processing,
Fertilizer
Corpus Christi,
Texas
Zinc Smelter
0.13
0.01
<0.06
11.5
0.20
0.11
0.07
0.27
<0.05
0.48
0.14
53,000

Ore Processing,
Petroleum Refining
Columbus,
Ohio
Zinc Smelter
0.03
<0.005
0.07
24.2
0.16
0.15
0.08
<0.07
0.12
<0.04
0.11
70,000

Ore Processing,
Fertilizer
              * Also smelt zinc and lead  at this plant

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                                     Table 4.  RESULTS OF ASARCO ANALYSES OF HRC  SAMPLES
                                                      ANALYSIS RESULTS
                                                         (ppm wt.)
                Sample No. 1    Sample No. 2    Sample No.  3    Sample No. 4   Sample No.  5  Sample  No.  6   Sample  No.  7
                   St.  Joe    New Jersey Zinc   City Service    Missouri  Lead National  Zinc   Bunker Hill   Bunker Hill
Trace Elements  Lead Smelter    zinc Smelter   Copper Smelter  Lead Smelter   Zinc Smelter  Zinc  Smelter   Lead Smelter
Arsenic (As)
Selenium (Se)
•Sample lost
0.02
 *
 0.12
<0.02
 0.02
<0.02
 0.02
<0.02
0.03
0.17
 0.03
<0.02
0.03
0.03

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Table 5.  TRACE ELEMENT QUANTITIES IN SULFURIC ACID
            Produced on a Yearly Basis
   Quantities of Trace Elements in Sulfuric Acid
                     flb/yr)
Trace Metals
Arsenic (As)
Beryllium (Be)
Cadmium (Cd)
Cromium (Cr)
Copper (Cu)
Iron (Fe)
Mercury (Hg)
Magnesium (Mg)
Manganese (Mn)
Nickel (Ni)
Lead (Pb)
Antimony (Sb)
Selenium (Se)
Zinc (Zn)
Annual Acid
Production
(tons/yr)
Sample No. 1
St . Joe
Lead Smelter
2.8
<0.14
15.4
459.2
65.8
23,380.0
4.1
29.4
189.0
228.2
389.2
4.5
—
33.6
70,000
Sample No. 2
New Jersey Zinc
Zinc Smelter
36.0
<0.3
5.1
84.0
33.0
6,600.0
16.8
45.0
72.0
<33.0
114.0
3.0
<6.0
549.0
150,000
Sample No. 3
City Service
Copper Smelter
5.4
<0.27
0.27
81.0
35.1
2,430.0
12.4
8.1
40.5
29.7
89.1
3.2
<5.4
13.5
135,000
Sample No. 4
Missouri Lead
Lead Smelter
2.0
<0.1
0.2
283.0
36.0
12,400.0
0.9
133.0
76.0
168.0
48.0
1.8
<2.0
10.0
50,000
Sample No. 5
National Zinc
Zinc Smelter
4.4
<0.15
0.74
57.3
20.6
5,439.0
335.2
22.1
41.2
26.5
<19.1
0.44
25.0
10.3
73,500

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                  Table 6.  TRACE ELEMENT QUANTITIES  IN SULFURIC ACID
                               Produced on a Yearly Basis

                     Produced by American Smelting and Refining Co.
                                         db/yr)

                  Tacoma,          Hayden,        El Paso,      Corpus Christi,  Columbus,
                Washington        Arizona          Texas          Texas          Ohio
Trace Metals  Copper Smelter  Copper Smelter  Copper  Smelter*  Zinc Smelter  Zinc Smelter
Arsenic (As)
Cadmium (Cd)
Copper (Cu)
Iron (Fe)
Mercury (Hg)
Manganese (Mn)
Nickel (Ni)
Lead (Pb)
Antimony (Sb)
Selenium (Se)
Zinc (Zn)
38.7
<0.44
17.6
4,488
0.26
22
13.2
22
15.8
<3.5
5.3
33.6
NA
117.6
13,566
4.2
159.6
201.6
672
<4.2
16.8
394.8
168
NA
33.6
2,688
1.0
20.2
33.6
336
<33.6
20.2
282.2
13.8
1.06
<6.4
1,219
21.2
11.6
7.42
28.6
<5.3
50.9
14.8
4.2
<0.7
9.8
3,388
22.4
21.0
11.2
<9.8
16.8
5.6
15.4
Annual Acid     44,000          210,000
Production
(ton/yr)

 *Also smelt zinc and lead at this plant
168,000
53,000
70,000

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                          SECTION V
    RECOMMENDATIONS FOR ANALYTICAL METHODOLOGY DEVELOPMENT

As a result of the detailed analytical procedure described in
Appendix C, the following investigations are recommended:

1.  Development of a solvent extraction procedure for As and Se
    in concentrated sulfuric acid from non-ferrous smelters.
    (See Section C3.4.2.1 for description of procedure recom-
    mended for investigation).

2.  Check a series of samples of each element using the known
    addition method of analysis:  This is done as follows:
    four aliquots of the samples are taken.  The first aliquot
    is diluted to volume with solvent.  The other three aliquots
    are made to volume using suitable quantities of known stand-
    ards.  Each of the latter three should have different quan-
    tities of the element being analyzed.

    Determine the absorbance (or peak height for scale expanded
    samples)  of each of the four solutions.  Plot absorbance
    versus concentration and extrapolate the resulting straight
    line through zero absorbance.   The intercept on the concen-
    tration axis gives the concentration of the element in the
    diluted sample solution.

    This method allows for variations in sample matrix composi-
    tion and would serve as a cross check on the answers obtained
    for the sample using a standard curve.

3.  A synthetic sample could be prepared with various concentra-
    tions of potentially hazardous trace elements.   This sample
    would serve as a check on the  accuracy of the methods
    employed by the analyst.
                               12

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                           SECTION VI

                           REFERENCES
 1.  "Analytical Methods for Atomic Absorption," Perkin-Elmer
     Corporation, Norwalk, Connecticut, 06586, USA, #303-0152
     March 1973, Supplement of March 1971 edition.

 2.  "Methods for Chemical Analysis of Water and Wastes," EPA,
     NERC, AQCL, Cincinnati, Ohio 45268, 1971, pp 121-130.

 3.  Fernandez, F. J. and Manning, D. C., "The Determination of
     Arsenic at Sub-Microgram Levels by Atomic Absorption,"
     Atomic Absorption Newsletter, 10^(4):  86-88, July-August,
     1971.

 4.  Fernandez, F. J., "Atomic Absorption Determination of Gaseous
     Hydrides Utilizing Sodium Borohydride Reduction," Atomic
     Absorption Newsletter, 12^(4):  93-97, July-August, 1973.

 5.  "Instruction Manuals for Model 61 and Model 63 Carbon Rod
     Atomizer," Varian Techtron, April 1972.

 6.  Kahn, H. L., Advances in Chemistry Series, Number 73, "Trace
     Inorganics in Water," Chapter 12, "Prinicples and Practice
     of Atomic Absorptions," pp 183-229, 1968.

 7.  Ramlerez-Munoz, J., Atomic Absorption Spectroscopy, Elsevier
     Publishing Co., New York, New York, 493 pages, 1968.

 8.  Private communication with L. W. Anderson, ASARCO, February
     8, 1974.

 9.  Stary, J., The Solvent Extraction of Metal Chelates, The
     MacMillian Company, New York, New York, pp 164-167 (1964).

10.  Bode, H., Neumann, F., Z. Analyst Chem. 172, pp 1-21 (1960)

11.  Wyatt, P. F., Analyst 80, pp 368-379 (1955).

12.  "Instruction Manual for Model 63 Carbon Rod Atomizer,"
     Varian Techtron, April 1972.

13.  Pustinger, J. V.,  Shaw, D. A., Sherman, P. L. and Snyder, "'
     A. D., "Instrumentation for Monitoring Specific Particulate
     Substances in Stationary Source Emissions," EPA Contract
     No. 68-02-0216, EPA-R2-73-252, 415 pages, September 1973.
                                13

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References - cont'd
14.  "Instructions - High Sensitivity Arsenic-Selenium Sampling
     System," Perkin-Elmer Corporation, Publication 990-9832,
     12 pages (1973).

15.  "Determination of Mercury by Atomic Absorption Spectro-
     photometric Method," The Dow Chemical Company Method CAS-AM-
     70.13, Midland, Michigan 48640, June 1970.
                                 14

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             APPENDIX A
                 «



List of Smelter Sulfuric Acid Plants
                 15

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       COPPER SMELTERS WITH SULFURIC ACID PLANTS


    Smelter                        Location

  Asarco                     Tacoma, Washington**

  Asarco                     Hayden, Arizona**

  Asarco                     El Paso, Texas*** t

  Phelps Dodge               Morenci, Arizona

  Kennecott                  Hayden, Arizona

  Kennecott                  Garfield, Utah

  City Service               Copper Hill, Tennessee*


        LEAD SMELTERS WITH SULFURIC ACID PLANTS

  Bunker Hill                Kellogg, Idaho*

  Missouri Lead              Boss, Missouri*

  St. Joe                    Herculaneum, Missouri*


        ZINC SMELTERS WITH SULFURIC ACID PLANTS

  Asarco                     Corpus Christi, Texas**

  Asarco                     Columbus, Ohio**

  Asarco                     Amarillo, Texas***

  National Zinc              Bartlesville, Oklahoma*

  Bunker Hill                Kellogg, Idaho*

  St. Joe                    Monaca, Pennsylvania

  New Jersey Zinc            Palmerton, Pennsylvania*
  * Supplied MRC with their sulfuric acid samples
 ** Supplied only analysis of their sulfuric acid
*** No sulfuric acid plant
  t Also smelt zinc and lead at this plant
                           16

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     APPENDIX B
Sample Identification
         17

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Sample
 No.

  1

  2

  3

  4


  5

  6

  7
Type of
Smelter

Lead

Zinc

Copper

Lead


Zinc

Zinc

Lead
    Company
    Location
St. Joe

New Jersey Zinc

City Service

Missouri Lead
(Amex Lead Co.)

National Zinc

Bunker Hill

Bunker Hill
Herculaneum, Mo.

Palmerton, Pa.

Copper Hill, Te.

Boss, Mo.


Bartlesville, Ok.

Kellogg, Id.

Kellogg, Id.
                              18

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     APPENDIX C



ANALYTICAL PROCEDURE
         19

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              ANALYTICAL PROCEDURE FOR ANALYSIS OF
        POTENTIALLY HAZARDOUS TRACE ELEMENT IMPURITIES IN
      CONCENTRATED SULFURIC ACID FROM NON-FERROUS SMELTERS
Cl.O  INTRODUCTION

The samples of sulfuric acid from non-ferrous smelters were
screened by emission spectroscopy to establish which trace
elements were present in the samples and their approximate con-
centrations.  The samples were then analayzed by atomic absorption
spectrometry to quantitatively determine the concentrations of
the potentially hazardous trace elements of interest.

C2.0  MULTI-ELEMENT SCREENING ANALYSIS

Samples of concentrated sulfuric acid from three types of non-
ferrous smelters; lead, zinc and copper; were screened by emission
spectroscopy.  Two milliliters of each sample were vaporized by
dropwise addition to a heated graphite electrode.  The electrodes
were heated in a metal plate holder on a laboratory hot plate.
When the evaporation was completed, ten milligrams of lithium
carbonate was added to each electrode.  Standards were prepared
by weighing ten milligrams of 0.1%, 0.01% and 0.001% emission
standards, containing seventy elements in a lithium carbonate
matrix, into graphite electrodes.  Sample and standard electrodes
were arced using a Spex Industries arc/spark stand with an Applied
Research Laboratories (ARL) power supply.  Optical emission from
the electrodes was passed through a Bausch and Lomb  (B&L) dual
illuminator to a 1.5-meter B&L grating spectrograph.  Emission
spectra in the region of 250-350 nm were recorded on a 4" x 10"
Kodak photographic plate (Spectrum Analysis Plate, Type #1).

Concentrations of elements found to be present in the samples
were determined by visual comparison of emission lines in the
samples with emission lines in the standard.  An ARL densitometer
                               20

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was used  for  the visual comparison.  Elements of a potentially
hazardous nature found to be present by emission spectroscopy
in the  samples were  then quantified by atomic absorption  spec-
troscopy.

C3.0  ATOMIC  ABSORPTION

C3.1  INTRODUCTION

Atomic  absorption spectroscopy  (AAS) has come to the forefront
as an analytical tool for the quantitative determination  of
trace elements in environmental samples.  The advantages  of
adoption  of AAS for  analysis of environmental samples include
minimal sample preparation, specificity and relative freedom
from interferences,  usefulness for both low and high concentra-
tion of metals, speed, and accuracy.  A number of reviews have
been written  containing information on the basic principle of
AAS.  The reviews of Kahn6 and Ramirez-Munoz7 are excellent
sources of background information for AAS.

Most instrument manufacturers of atomic absorption spectrometers
supply  cookbook manuals outlining basic instrument operating
parameters for the various trace metals.  In addition, these
manuals include specific methodology or references for the
determination of the various trace elements in different  matrices.
The term matrix in this case refers to the gross compostion of
the sample, i.e., seawater, ground water, petrochemicals,
geological samples, biological samples, or agricultural samples.
When methods of analysis for trace elements in a particular
type of sample have not been defined, as is the case for  con-
centrated sulfuric acid from non-ferrous metal smelters,  the
methods must be developed by the analyst to the best of his
ability within the time and cost restraints placed by the sub-
mitter  of the samples.  With the information outlined above as
                                21

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a guideline, the following sections describe analytical proced-
ures for the analysis of specific, potentially hazardous, trace
elements in concentrated sulfuric acid samples from non-ferrous
smelters by atomic absorption spectroscopy.

C3.2  SAMPLE AND STANDARD PREPARATION

A sample to be analyzed by AAS must in some way be vaporized to
give a significant population of atoms in the ground state then
passed through a beam of light.  Three main devices for pro-
ducing the vapor needed are a flame, cold vapor generation, and
carbon rod atomization.  A flame is the most general type of
vaporization.  The sample is normally nebulized into the flame
as an aerosol from an aqueous solution.  The nebulizer of our
P. E. Model 303 atomic absorption spectrometer will accept acid
concentration up to approximately 25%.  The concentrated sulfuric
acid samples from non-ferrous smelters were diluted to 25% of the
origianl concentration with deionized-distilled H20 so they could
be nebulized directly into the flame.  Standards and blank were
prepared by proper dilution of atomic absorption stock solutions
(made by Harleco, 60th and Woodbine Ave., Philadelphia, Penn.,
19143) with sulfuric acid to match the matrix (25% sulfuric
acid) of the samples.  The sulfuric acid used was Ultrex, J. T.
Baker, Co. with low trace elements content.  The actual analysis
of sulfuric acid is given in Table Cl.

C3.3  INSTRUMENT OPERATING PARAMETERS

Table C2 is a listing of all of the trace elements analyzed in
the concentrated sulfuric acid samples from non-ferrous smelters
and the instrument operating parameters for each.  The instru-
ment used was a Perkin-Elmer Model 303.l  The operating param-
eters listed include:  hollow cathode lamp manufacturer  (all
of the hollow cathode lamps are single element cathode except
Cr, Cu, Fe, Mn and Ni which were in one multicomponent lamp);
                              22

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     Table Cl.   ACTUAL ANALYSIS OF ULTREX SULFURIC ACID SOLD BY
                  J.  T. BAKER CHEMICAL COMPANY
       Formula:   H2SOi*                     ACTUAL ANALYSIS
       FW 98.08


       Assay  (H2SOit)                           95.3%
       Residue after  Ignition                   1 ppm
       Specific Gravity  at  60°/60°F             1.84

       NON-METALLIC IMPURITIES
       in parts per million (ppm)

       Ammonium  (NH4)                           0.8
       Arsenic  (As)                             0.001
       Boron  (B)*                               0.02
       Chloride  (Cl)                           <0.05
       Nitrate  (N03)                            0.2
       Phosphate  (PO^)                         <0.05
       Selenium  (Se)                            0.2
       Silicon  (Si)*                            0.04

       METALLIC IMPURITIES*
       in parts per billion (ppb)

       Aluminum  (Al)                            3
       Barium  (Ba)                             <1
       Bismuth  (Bi)                            <1
       Cadmium  (Cd)                            <1
       Calcium  (Ca)                            20
       Chromium  (Cr)                            1
       Cobalt  (Co)                             <1
       Copper  (Cu)                              2
       Iron (Fe)                                3
       Magnesium  (Mg)                           3
       Manganese  (Mn)                           0.4
       Mercury  (Hg)                           <10
       Nickel  (Ni)                            <  1
       Potassium  (K)                          <10
       Sodium  (Na)                             90
       Strontium  (Sr)                         <  1
       Zinc (Zn)                              <  1

*Average  value for three samples vaporized and analyzed spec-
trographically (DC-arc,  indium internal standard in graphite
matrix against commercial standards), reading of lines  in
2450-3875 A region; strontium, calcium, and barium  determined
on a single composite sample, reading at 4078 A,  4227 A,  and
4554 A, respectively; key elements found absent  are reported
as < (less than) the detection limit.

                               23

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Table C2.  ATOMIC ABSORPTION INSTRUMENT OPERATING PARAMETERS PERKIN-ELMER MODEL  303
Element
Arsenic (As)
Berryllium (Be)
Cadmium (Cd)

Chromium (Cr)
Copper (Cu)
Iron (Fe)
Mercury (Hg)
Magnesium (Mg)

Manganese (Mn)
Nickel (Ni)
Lead (Pb)
Antimony (Sb)
Selenium (Se)
Zinc (Zn)
Hollow
Cathode
Lamp Mfq.
Perkin-Elmer
Perkin-Elmer
Westinghouse

Westinghouse
Westinghouse
Westinghouse
Perkin-Elmer
Perkin-Elmer

Westinghouse
Westinghouse
Perkin-Elmer
Jarrell-Ash
Westinghouse
Perkin-Elmer
Lamp
Current
ma.
18
30
12

25
24
25
10
12

25
25
30
20
14
15
Wave
Length
run.
193.7
235.0
228.8

357.9
324.7
252.7
253.6
285.2

279.5
352.4
283.3
217.0
196.0
213.9
Gain
4.6
3.0
1.0

3.0
3.9
4.5
3.0
1.0

4.5
3.4
1.3
4.8
4.0
2.8
Slit
Width
nm.
2.0
0.14
0.2

0.7
0.2
0.2
0.2
0.7

0.2
0.2
0.7
0.2
2.0
0.7
Air
Flow
1/min.
—
—

26.5
25.2
25.2
—
26.5

26.5
26.5
25.7
—
—
25.2
Acetylene
Flow
t/min.
—
—
	

4.8
4.2
3.9
~
4.0

4.1
4.1
4.9
~
—
4.2
Scale
Expansion
Factor
10
1
3
10
10
10
1
3
1
3
3
10
10
1
10
3
Noise
Suppression
3
1
2
3
3
3
1
2
1
2
3
2
3
2
3
3

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 lamp operating  current  in milliamps; wavelength used  for  the
 analysis  in nanometers; amplifier gain potentiometer  setting;
 slit width in nanometers; the air flow rate  in liters/minute
 and the acetylene  flow  in liters/minute, where these  are  appli-
 cable; scale expansion  factor, and noise suppression  setting.

 C3.4  SAMPLE ANALYSIS METHODS

 C3.4.1  General Atomic Absorption Analyses

 Cr, Cu, Fe, Mg, Mn, Ni, Pb, and Zn were analyzed in the concen-
 trated HaSOit samples using an air-acetylene  flame by  nebulizing
 the dilute samples described in section C3.2 directly into the
 flame.  The calibration curves for Cu, Mn, Pb and Zn  are  shown
 in Figures Cl, C2, C3, and C4.  The calibration curves are
 typical of the curves developed for the elements listed above.
 The eight elements listed above were all easily analyzed  by
 conventional atomic absorption techniques.   The remaining six
 elements  (As, Se, Be, Cd, Sb, and Hg) are more difficult  to
 analyze by this technique.  Each requires some special treat-
ment; therefore, they are described separately.

C3.4.2  Special Atomic Absorption Analyses

C3.4.2.1  Arsenic  (As) and Selenium  (Se)

Arsenic and selenium are probably the two most difficult  elements
of the fourteen elements listed to analyze.  Their primary
resonance wavelengths are 193.7 and 196.0 nm, respectively.
These wavelengths are in the vacuum ultraviolet region where
almost all chemical species have at least some absorption char-
acteristics.   These absorptions and the noise associated with
flickering within the flame increase the lower detection  limits
for these elements.  Five methods of analysis were attempted:
                              25

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               40-
N)
                 0     0.02    0.04    0.06    0.08    0.10    0.12    0.14   0.16    0.18    0.20    0.22   0.24
                                                    Copper, micrograms / milliliter
              Figure Cl.   Atomic Absorption Calibration Curve  for Cu in  25% Sulfuric Acid

-------
   90




   80





   70




   60
E
E
   50
•   40
S
QL.
   30
   20
   10
    0      0.1    0.2     0.3     0.4    0.5     0.6    0.7    0.8     0.9     1.0

                            Manganese, micrograms / milliliter
         Figure C2.   Atomic Absorption Calibration Curve

                       for  Mn in 25%  Sulfuric Acid
                                   27

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  no
  100
   90
   80
   70
E  60
E
c.
en
«  50
03
O)
O_
   30
   20
   10
                       1.0               2.0
                     Lead, micrograms / milliliter
3.0
     Figure C3.  Atomic Absorption Calibration Curve
                  for Pb in 25% Sulfuric  Acid
                              28

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  240


  220


  200


  '180



  160


  140



  120
.2-100
CJ
X
s
   80
   60
   40
   20
           .1      .2     .3      .4     .5      .6      .7
                            Zinc, micrograms / milliliter
.8      .9
1.0
         Figure C4.   Atomic Absorption Calibration  Curve
                       for  Zn in  25% Sulfuric  Acid
                                   29

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 1.  Flame absorption  - Air-acetylene  flame
 2.  Flame Absorption  - Argon-hydrogen-entrained air  flame
 3.  Carbon Rod Atomization -  (See Be  and Cd analyses)
 4.  Hydride formation followed by flame absorption -
     (See Sb analyses)
 5.  Addition of 1 ml of 10% hydroxylamine hydrochloride to 40 ml
    of 25% sulfuric acid samples, standards and blanks followed
    by flame absorption - argon-hydrogen-entrained air flame.
In the arsenic analyses using Method 5, average signal  for the
samples was 15-27 mm above the average signal observed  for the
blank solution.  However, since the width of the noise  in the
signal is ^25 mm, the minimum detection limit would be  ^50 mm
if the rule, that the minimum detection limit is a signal twice
as large as the width of the average noise, is applied.  For
selenium average signal for the samples was 9.5-34 mm,  average
noise was 18 mm and minimum detection limit was 36 mm.  There-
fore, since the results were below the detection limit  of the
method, they will not be reported.  The values obtained by
ASARCO for these samples are shown in Table 4.  The author
recommends a solvent extraction procedure for separating As
and Se from sulfuric acid be investigated.  Diethylammonium
diethyldithiocarbamate has been found to form quantitatively
extractable chelates with As and Se from sulfuric acid  samples
as concentrated as 10 N9'10/11.

The extracted chelate in an organic solvent could be analyzed
by a number of techniques.   The organic solvent may be  atomized
directly into the flame or applied to the carbon rod and
analyzed by flameless absorption.   The organic solvent  can
be evaporated and the As and Se containing chelate residue
analyzed by x-ray fluorescence.  By shaking the organic solvent
                               30

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with a basic solution  (pH > 8), the chelate is destroyed and
the As and Se are transferred  to the aqueous layer.  This
aqueous layer may then be used for flame or flameless atomic
absorption.  The aqueous layer could also be analyzed via a
colorimetric analysis.
C3.4.2.2  Beryllium  (Be) and Cadmium  (Cd)

Beryllium and cadmium were analyzed using a Varian Model 61
carbon rod flameless atomic absorption atomizer power supply
and a Model 63 Varian carbon rod head assembly.  The reader
is referred to Varian instruction manuals5*12 for a complete
description of the carbon rod assembly.  The microtube furnace
was used in both cases.  The micro tube furnace is made of
pyrolytic graphite and is sheathed from oxidation at high tem-
peratures by a flow of argon.  Extremely high atomization
temperatures are obtainable with this furnace  (>3000°C).  The
methodology for analysis of Be and Cd in strongly acid solutions
had been developed by MRC on an earlier EPA contract13.  The
carbon rod assembly is used for Be analyses because the refrac-
tory nature of Be compounds requires a very high temperature to
atomize the compounds.  Lower detection limit for Be is 5x 10"10
gram/milliliter using the carbon rod assembly to analyze 25%
sulfuric acid samples.  Dry, ash, and atomize times and voltages
for Be analysis using the carbon rod assembly are shown in Table C3<

Cadmium analyses of the 25% H2SOU samples and standards were per-
formed using both an argon-hydrogen-entrained air flame for
higher concentration samples and the carbon rod assembly.  The
lower detection limit using the flame was 1.6 x 10~8 gram/
milliliter and 1 x 10~10 gram/milliliter using the carbon rod
                                31

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                           Table C3

                Instrument Operating Parameters


           For a Varian Model 63 Carbon Rod Atomizer
              Used with a Perkin-Elmer Model 303
                Atomic Absorption Spectrometer
              Dry Cycle          Ash Cycle           Atomize

                                                         Cut-Off
           Time    Voltage    Time    Voltage    Ramp    Voltage
Element    (sec)    (volts)    (sec)     (volts)    Rate     (volts)

  Be        12        5        10        7         4        9

  Cd        12        5        10        7         6        5
                              32

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assembly.  Operating parameters for the carbon rod are  shown
in Table C3.  Flow rate of argon when using the carbon  rod
assembly was 4.5 liters/minute.

C3.4.2.3  Antimony  (Sb)

Antimony was determined using a Perkin-Elmer Model 303-0849
volatile hydride generator and methods developed by Perkin-
Elmer. 3/11*  Forty milliliters of 25% sulfuric acid sample is
reacted first with a reducing agent such as stannous chloride
then with a source of nascent hydrogen.   The hydrogen  produced
reacts with Sb to form stibine, SbH3, a gas.  The hydrogen and
stibine are collected in a balloon-type reservoir after the
reaction is complete, two minutes for Zn, 30 seconds for sodium
borohydride.  The gas is swept from the generator and reservoir
to the argon-hydrogen-entrained air flame by argon.  Standards,
blanks and samples are all treated in the same manner.  Note:
Although the hydrides of arsenic and selenium can be formed in
a similar manner, attempts at using this method for arsenic and
selenium were not successful.

C3.4.2.4  Mercury (Hg)

The basic method for analysis of Hg is based on a procedure
originally developed by Dow Chemical Company15 for analysis of
Hg in water.  An aliquot of sample is placed in an erlenmeyer
flask, 1 milliliter of 5% potassium permanganate is added and
a watch glass is placed on the top of the flask.  The sample
is heated on a hot plate until the sample boils for two minutes.

After the sample is cooled to room temperature, 10% hydroxylamine
hydrochloride is added dropwise to destroy excess permanganate.
An aliquot of the sample is transferred to a bubbler flask and
2 ml of 40% stannous chloride in 9N hydrochloric acid is added
                               33

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to the flask.  This reduces all Hg present to Hg°.  A flow of
argon is then diverted through the bubbler and carries Hg vapor
through a 10-crn gas cell in the beam of the atomic absorption
spectrometer.

C3.4.3  Spectral Background Interferences from
        Non-Atomic Absorption	

Non-atomic absorption is due to molecular absorption and/or
light scattering by solid particles in the flame or other form
of atomization.  Molecular absorption is caused by the presence
of molecular species in the flame which absorb light at the
same wavelength as the element resonance line.  Light scatter-
ing by particles in the flame results when solutions of high
total solids are aspirated into a burner.  Both types of non-
atomic absorption occur over wide spectral bands  (>10 nm)
compared with the 0.01 nm absorption for atomic lines in the
flame.

Corrections for non-atomic absorption interferences can be made
by comparing the absorption at a specific wavelength obtained
with a hollow cathode lamp versus the absorption values obtained
with a continuum  lamp (hydrogen or deuterium).  The absorption
measurement obtained with a hollow cathode line source is the
sum of an element's atomic absorption and the non-atomic
absorption.  The absorption measured with the continuum lamp
is, to a close approximation, the non-atomic absorption only.
The sample's true atomic absorption is the absorption measured
using the hollow cathode line source less the absorption
measured using the continuum source.

A hydrogen continuum lamp was used to check for non-atomic
absorption during the analyses described in the previous
sections.  No non-atomic absorption was observed for any of
the elements analyzed.

                              34

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C4.0   ASARCO METHODS FOR ARSENIC  (As) AND SELENIUM  (Se)

The methods described in this section are the procedures ASARCO
normally uses for measurement of low levels of arsenic and
selenium in concentrated sulfuric acid samples.  MRC has not
tried these methods, therefore MRC cannot substantiate the
validity of these methods.  The methods are reproduced exactly
as submitted to MRC by ASARCO.  With the selenium procedure, an
additional pretreatment of "black acid" samples should be made
by cautiously mixing 5 ml of 30% H2O2 with the H2SOt| aliquot in
a 250 ml beaker and heating until the acid is decolorized and
the H202 decomposed.  After cooling, mix with the calculated
amount of water in step 4 of the procedure and proceed from
there.

C4.1  DETERMINATION OF ARSENIC IN SULFURIC ACID - PHOTOMETRIC
      Ag-DDC METHOD

Principle
Arsine is evolved with granulated zinc and hydrochloric acid
and absorbed in a silver diethyldithiocarbamate-pyridine
solution.  The red color is measured photometrically at 540 nm.

Reagents
Standard Arsenic - Dissolve 0.132 g of arsenic trioxide (As203)
in 50 mil water containing 5-6 pellets of NaOH.  Transfer to a
1-liter volumetric flask and dilute to the mark with water.
(1 ml = 0.1 mg As).  Transfer by pipet 5.00 ml of this solution
to a 100-ml volumetric flask and dilute to the marks with water.
(1 ml - 0.005 mg As).

Ag-DDC - Dissolve 0.5 g of silver diethyldiethiocarbamate
(Fisher #5-666) in pyridine and dilute to 100 ml with pyridine.
                               35

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15% KI solution - 15 g KI dissolved in 100 ml water.

40% SnCl2 solution - 40 g SnCl2 dissolved in concentrated HC1.
Dilute to 100 ml with concentrated HC1.

Apparatus

This procedure is written for use with a photometer employing
a 2-cm cell.  See Figure C5.
0.001 mg to 0.25 mg As.

Procedure

Transfer a 5 ml aliquot  (^9.2 g) of the sulfuric acid sample to
a 125 ml Erlenmeyer flask.  Add cautiously 5 ml HN03 and heat
to dense fumes.  If charring of any organics present begins to
occur, add additional HNC>3 to prevent any losses of arsenic.
Heat to dense fumes.  Cool to room temperature.  Wash down
walls of flask with a small amount of water and refume.  Cool.
Add 50 ml of water and cool again.  Add 10 ml HC1.

Add 2 ml of 15% KI solution and then decolorize with 1 ml of
SnCl2 solution.  Let stand at room temperature 15-20 minutes.
Assemble the apparatus.  Have the 15 ml of Ag-DDC solution in
the tall graduate ready.  Quickly add 5.0 gm of 40 mesh granu-
lated Zn (low in As), restopper the flask and evolve arsine
for 20-30 minutes.

Disconnet apparatus, transfer Ag-DDC pyridine solution to a
dry photometer tube and determine % T. at 540 nm.  Calculate %
As.  Run blanks through entire procedure.  Large amounts of Sb
interfere Sb reads ^8% of the As.
                               36

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00
          One Hole
       Rubber Stopper
                             6 mm I.D. Glass Tubing
                                 Lead Acetate Impregnated
                                     Glass Wool Plug
                                                                          Glass Wool Plug
                                                                          (unimpregnated)
                                                                          Glass Tubing with
                                                                        Constricted Lower End
                                                                       15 ml Ag-DDC/ Pyridine
                 125 ml Erlenmeyer Flask
25 ml Graduate
                             Figure C5.  Arsine Evolution Apparatus

-------
 Calibration

 Transfer  0.0,  1.0,  2.0,  3.0  and 5.0  ml  of Standard Arsenic
 Solution  (1 ml =  0.005 mg  As)  to each of  five  125-ml Erlenmeyer
 flasks, respectively.  Add 50  ml water, 5 ml I^SO/t and  10  ml  HC1
 to  each flask,  cooling between additions.   Add 2  ml of  15% KI
 solution,  and  1 ml  of 40%  SnCl  in HC1.   Let stand 15-20 minutes.

 Transfer  15.0  ml  of Ag-DDC solution  to  a  25-ml graduate.   Add 5 g
 of  20 mesh zinc and quickly  assemble the  apparatus.   After 20-30
 minutes,  disassemble and transfer the absorbing solutions  to
 photometer tubes  and measure photometrically.   Plot mg  As  versus
 transmittance  on  semi-log  paper (Figure C6).

 C4.2  CQLORIMETRIC  DETERMINATION OF  Se  IN SULFURIC ACID

 Principle

 A 50-ml aliquot of  the sulfuric acid is diluted with enough water
 to  give a  6  normal  solution.   An amount of  ammonium chloride
 equivalent to  the amount of  H2SOit present  is added,  yielding  a
 solution that  is  6BN in  H+ and Cl~.   An arsenic separation is
 done on this solution, and the Se determination is completed  in
 the usual  manner.

 Procedure

 1.  If the normallity of the I^SOit is unknown,  determine it by
    titrating  a 1.0-ml aliquot with  IN NaOH, using methyl  orange
    or any other appropriate indicator.  The reading on the buret
    will be the normality  of the acid.

Example:   A 35.0 ml reading is equivalent to 35.0  N  acid.
                               38

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  .005
.010     .015     .020     .025
  Milligrams of Arsenic per 15 ml
.030
Figure C6.   Arsenic Calibration Curve
                      39

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2.  Calculate the volume to which 50 ml of the acid must be
    diluted to give a 6N solution, using the formula ml x N =
    ml x N.
                 Example:   (for 35.0 N
                            50 x 35.0 = ml x 6
                            vol. = 292 ml

3.  With a graduated cylinder measure a volume of distilled
    water about 100 ml less than that calculated in Step 2 and
    add it to a 800 ml beaker.
4.  Add 50.0 ml of the B^SOi, to the distilled water by pipet,
    swirling the tip of the pipet in the water and cooling, if
    necessary, to prevent the water from boiling excessively.
5.  Sometimes E^SOj, samples contain S02.  If there is any odor
    of S02 in the sample, boil the solution from Step 4 until
    no more odor of SO 2 can be detected.  (If this is not done,
    the S02 will react with the hypophosphorus acid in step 8
    to form sulfur) .

6.  Calculate the weight of NH^Cl that will be equivalent to
    50 ml of the acid.

    Example:  Normality x liters = number of equivalents
    No. of equivalents x equivalent wt. of NHitCl = grams
    of NH^Cl
               35.0 x .050 = 1.75 equivalents
                1.75 x 53.8  =  94.2 grams of NH,,C1

7.  Add the NH^Cl to the 800 ml beaker and add enough hot dis-
    tilled water to bring the volume up to that calculated in
    Step 2.  (Sometimes it is necessary to add a little more
    water to get all the NHi,Cl into solution, especially if
    the acid is strong.)
                               40

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 8.  Add 5 ml of arsenic solution  (1.0 mg As/ml) and 25 ml of
     hypophosphorous acid to the 800 ml beaker.  Cover, place
     on the hot place, and boil for 10 minutes.

 9.  Remove from the hot plate and add 50 ml of H20.  Cool and
     filter through a No. 42 filter paper or a 1.2y Millipore.
     If NH^ salts come out during the filtration, add a little
     hot water.

10.  Finish the Se determination in the usual manner.

11.  Calculate the ppm Se in the H2SOt, according to the formula:

                             mg Se           _     _
                     .050 x sp.gr. of I^SOi,  ~ Ppm Se

C.4.3  COLORIMETRIC DETERMINATION OF SELENIUM AND TELLURIUM

Discussion

The following methods for Se and Te both begin in the same way:
The sample dissolution is the same for both and both are separated
from other constituents by an arsenic co-precipitation.  If a
substance is to be analyzed for both Se and Te, a single sample
can often be used as the starting point for both determinations,
at a great saving of time and effort.  This is done by dissolving
the arsenic precipitate containing the Se and Te and diluting it
to 100 mis.  Then appropriate sized aliquots are drawn for Se and
Te and the determinations completed individually.

SELENIUM

Application

The method applies to the analysis of concentrates, matte, speiss,
slags, dusts, sinters, calcines, blister copper, anode copper
and copper tankhouse electrolytes.  For the determination of Se
                                41

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in cathode copper, lead bullion, refined lead, arsenic, tellurium,
etc., and solders, see methods applying specifically to these
substances.

The Method in Brief

The sample is decomposed with HMOs, HF, and HClOi*.  The first
two acids and Si02 are expelled by taking to HClOi* fumes.  The
resulting mixture is taken up with 1:1 HC1, arsenic solution is
added, and the Se (together with any Te present) co-precipitated
with the As by reduction with hypophosphorous acid.  The arsenic
precipitate is dissolved and treated with 3,3'-diaminobenzidine
at pH 2-3.  The intensely yellow-colored compound of Se and
diaminobenzidine is extracted with toluene at pH 8 and measured
photometrically at 420 my.

Interferences

This method is specific for Se.  There are no known interferences.

Reagents

Arsenic Solution - Dissolve 0.25 g of arsenious oxide  (As2O3)
plus 10 pellets of NaOH in 10 ml of distilled water by warming.
Dilute to 200 ml and mix.

META Cresol Purple Indicator Solution  (MCP) - Dissolve 0.10 g
of meta cresol purple plus 1 pellet of NaOH in 10 ml of dis-
tilled water by warming.  Dilute to 100 ml and mix.

EDTA Solution (2%) - Dissolve 20.0 g of disodium ethylenediamine-
tetraacetate, dihydrate, in 900 ml of distilled water.  Dilute
to 100 ml and mix.

Formic Acid Solution (1:9) - Mix 20 ml of formic acid with 180 ml
of distilled water.
                                42

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Diaminobenzidine Solution  (0.5%) - Dissolve 0.100 g of 3,3'-
diaminobenzidine (tetra) hydrochloride in 20 ml of distilled
water.  Prepare fresh daily and store under refrigeration.
Only enough solution should be prepared at a time as will be
used immediately, as the reagent in aqueous olution is not very
stable and is quite costly.

Standard Selenium Solution (1 ml = 0.02 mg Se) - Dissolve 0.5000 g
of high purity selenium in 20 ml of nitric acid and boil to expel
oxides of nitrogen.  Cool and dilute to 500 ml with distilled
water and mix.  Transfer a 10.0-ml aliquot to a 500 ml volumetric
flask, dilute to volume and mix.  1 ml = 0.02 mg Se.

Preparation of Calibration Curve

(a)  Transfer 0.00, 0.50, 1.00, 2.00, 3.00 and 4.00 ml of standard
     selenium solution (1 ml = 0.02 mg Se) to each of six 250 ml
     copper assay flasks respectively, using Mohr pipettes.  (3)
     To each flask add 3 ml of HClOi, and evaporate to not less
     than 2 ml volume.  Cool somewhat, add 50 ml of distilled
     water, and boil for about 1/2 to 1 minute.  Cool to room
     temperature.

(b)  Add 5.0 ml of 2% EDTA solution and 2 drops of MCP indicator
     solution.  Neutralize with NH^OH dropwise just to the yellow
     color of the indicator.   (2)   Add 2.0 ml of formic acid
     (1:9)  and 2.0 ml of freshly prepared diaminobenzidine solu-
     tion.   Heat for 5 min. in a boiling water bath.  A 600 ml
     beaker with approximately 200 ml of water makes an ideal
     bath.   Cool to room temperature.

(c)  Neutralize with concentrated ammonium hydroxide dropwise to
     the purple color of the  indicator pH = 8 (11-12 drops of
     cone.  NHijOH are required.)   Pour each solution into a 125 ml
     separatory funnel.   (3)  Drain well but do not wash.   From a
                               43

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     burette, add  12.0 ml  of  toluene,  stopper  and  shake
     vigorously  for  30 seconds.  Allow the  layers  to  separate
     and drain and discard the  lower aqueous layers.   Filter
     the organic layers  through dry, folded, 9 cm  Whatman  No.  41
     H papers into colorimeter  tubes.   Measure at  420  my
     against the reference blank.

 (d)  Plot the photometer readings against milligrams  of
     selenium on semi-logarithmic paper.

Procedure

Transfer a 1-g sample  (1)  to  a  250 ml  copper assay flask  (3).
Add 10 ml of HNO3, 5 ml  of HC10U/ and  4-6 drops of HF  (1-2 ml
of HF for slags).  Heat  on a  hot plate  until brown fumes have
subsided, then swirl the flask  over a Meker burner until heavy
fumes of HClOi, appear.   If beads of sulfur remain,  set the flask
on the hot plate until they are oxidized or burn off.  Cool some-
what.  Add 3-4 ml  of water and  swirl to break  up the cake.  Add
100 ml of 1:1 HC1, 2 ml  of arsenic solution, and 1 or  2 Hengar
granules.  Mix.  (If a clear  solution is not obtained  at once,
the solution may be warmed, but should  not be  boiled.)  Add 15 ml
of 50% hypophosphorous acid (H3P02) and swirl  to mix.  Place the
flask on the hot plate and  simmer gently for approximately 10
minutes until the  arsenic  precipitate coagulates.   CAUTION:
Do not allow any of the  solution to splash or  leak on  to the
hot plate (4).  After the  precipitate has coagulated,  cool to
about 70°F by allowing the  flask to stand on the bench top for
10-15 minutes (5).

Filter the warm  solution through an 11  cm Whatman  No.  42 filter
paper.   Wash the flask three times with a hot  solution of 1-1
HC1 containing about 3-4 ml of H3PO2 per 100 ml of  solution,
pouring the washings into  the filter.   Wash the paper  two
additional times with small portions of the HC1-H3P02 wash

                              44

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solution.  Wash the flask three times with small portions of hot
distilled water, pouring the washings into the filter.  Wash the
paper 10 additional times with small portions of hot distilled
water.  Test this water coming out of the funnel with pH paper;
if it is still acid, continue washing until it is neutral.

Transfer the paper and precipitate back to the original flask.
Wipe out the funnel with a small piece of damp filter paper to
gather any precipitate adhering to the funnel and add to the
flask.  Add 10 ml of nitric acid and 5 ml of perchloric acid
to the flask.  Place the flask on the hot plate and boil until
the paper is destroyed  (6).  Swirl the flask over the Meker
burner until dense fumes of perchloric acid appear, but do not
evaporate to less than 2 ml.  Cool somewhat, add 50 ml of dis-
tilled water and boil for 1/2 to 1 minute.  Cool to room
temperature.   (If the Se in the sample is higher than 0.007%,
dilute to volume and pipet an aliquot  (1).  Add enough distilled
water to the aliquot to bring it up to 50 ml).
Prepare a blank from 10 ml of HN03 and 5 ml of HClOi, fumed down
to 2 ml in a copper assay flask.  Add 50 ml of distilled water
and boil for 1/2 to 1 minute.  Cool to room temperature.

Continue in accordance with paragraphs (b) and (c) under Prep-
aration of Calibration Curve.

By referring to the calibration curve, determine the milligrams
of Se present and compute the percentage of Se in the sample:

                   Milligrams of Se
                                       •"•  IB 06
                 grams of sample x 10
                               45

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Notes

(1)  The useful range of the colorimetric curve is from about
     0.005 mg Se to about 0.07 mg Se.  For a 1-g sample, this
     corresponds to 0.0005% Se to 0.007% Se.  If the Se present
     in the sample is in the 0.005% to 0.07% range, use a 1-g
     sample but dilute the dissolved arsenic precipitate to
     100 ml in a volumetric flask and pipet a 10 ml aliquot.
     This corresponds to a 0.1 g sample.

     If the Se present is in the 0.05%  to 0.7%  range, use a
     1-g sample but dilute the arsenic  precipitate to 500 ml
     in a volumetric  flask and pipet a  5 ml aliquot, corres-
     ponding to a 0.01-g sample.  Amounts of Se higher  than
     0.5% are within  the range where they can be done by atomic
     absorption which is much faster and easier.

     Samples of copper tankhouse electrolyte need not be given
     the preliminary  decomposition with HNOs, HC101+, and HF,
     but may be combined directly with  the 100  ml of 1:1 HC1.

(2)  The indicator color at this point must be  just barely
     yellow, so that  when the formic acid is added, the color
     will change from yellow to orange or pinkish-orange.

(3)  A set of flasks  and separatory funnels should be cleaned
     thoroughly and set aside for use only in this selenium
     determination to avoid contamination.  It  should be kept
     in mind, however, that repeated use with HF results in
     gradual erosion of the copper assay flasks and the devel-
     opment of thin spots, especially on the bottom.  Cases are
     known where thin copper assay flask have developed leaks
     while on the hot plate resulting in loss of samples and
     even explosions  (See Note 4).  To avoid this, it is
                              46

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     essential that the copper assay flasks be tested prior to
     each use by tapping the bottoms on a pointed wooden object
     such as the corner of a beaker tray or cabinet door.   This
     treatment will crack or break flasks with thin bottoms.

(4)   If the solution containing hypophosphorous acid and per-
     chloric acid should leak, bump, or be spilled so that
     the solution comes into direct contact with the hot plate,
     spontaneously flammable phosphine is formed.   With the
     oxidant, concentrated perchloric acid, also present,  a
     small but violent explosion may result.

     For this reason,  the solutions should not be boiled hard,
     one or two Hengar granules should be present, and flasks
     with thin bottoms should not be used.

(5)   Cooling to about 70°C is mandatory;  if the 1:1 acid solu-
     tion is much hotter than 70°C, the filter paper may break.

(6)   Destruction of filter paper with HN03 and HCIO^ is done by
     boiling the mixture at a moderate (not fast)  rate.  Oxida-
     tion of the last traces of organic matter occurs in about
     10 - 15 minutes and is indicated by a rather sudden onset
     of vigorous bubbling.  The bubbling subsides in 5 - 10
     seconds leaving a colorless solution of HClOit which may
     then be fumed over a Meeker burner.   If,  instead of bub-
     bling,  the solution turns suddenly dark,  more HN03 should
     be added.  The need for this arises only when the
           and the paper are boiled too fast.
                              47

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                                 TECHNICAL REPORT DATA
                           (Please read Inunctions on the reverse-be fore-completing)
 1. REPORT NO.
  EPA-650/2-74-131
                                     3. RECIPIENT'S ACCESSION>NO.
 4. TITLE AND SUBTITLE
 Determination of Hazardous Elements in Smelter-
   Produced Sulfuric Acid
                                                       S. REPORT DATE
                                                        December 1974
                                    6. PERFORMING ORGANIZATION CODE
 7. AUTHOR(S)

 W. H.Hedley, S.M.Mehta, and P.L.Sherman
                                    8. PERFORMING ORGANIZATION REPORT NO,
                                     MRC-DA-419
 9. PERFORMING OR6ANIZATION NAME AND ADDRESS
  Monsanto Research Corporation
  Dayton Laboratory
  Dayton, Ohio  45407
                                     10. PROGRAM ELEMENT NO.
                                     1AB013; ROAP 21ADE-021
                                     11. CONTRACT/GRANT NO.
                                     68-02-0226, Task 8
 12. SPONSORING AGENCY NAME AND ADDRESS
 EPA, Office of Research and Development
 NERC-RTP, Control Systems Laboratory
 Research Triangle Park, NC 27711
                                     13. TYPE OF REPORT AND PERIOD COVERED
                                      Final; Through 11/74 	
                                     14. SPONSORING AGENCY CODE
 IS. SUPPLEMENTARY NOTES
 is. ABSTRACT
               repOrt presents results of analyses of potentially hazardous impur-
  ities (trace elements) in sulfuric acid produced by  non-ferrous smelters. Sulfuric
  acid samples were obtained from acid plants attached to copper, lead, and zinc
  smelters. Results of analyses provided by some smelters are also included. Trace
  elements subjected to qualitative and quantitative determinations in this study
  include: Pb, Cu,  Zn, Hg, As, Cd, Se, Sb, and Be, as well as other elements
  detected in significant concentrations during screening tests. Based on this
  analytical data, the report indicates yearly outputs of hazardous trace elements
  contained in smelter-produced acid for possible consumption in a variety of
  industries. The report also presents information on analytical methods and
  procedures used in acquiring the reported data.
 7.
                              KEY WORDS AND DOCUMENT ANALYSIS
                 DESCRIPTORS
                        b.lDENTIFIERS/OPEN ENDED TERMS
                        c.  COSATI Field/Croup
 Air Pollution
 Sulfuric Acid
 Smelters
 Copper
 Lead (Metal)
 Zinc
Chemical Analysis
Air Pollution Control
Stationary Sources
Trace Elements
13B , 07D
07B
11F
 8. DISTRIBUTION STATEMENT
                                           19. SECURITY CLASS (ThisReport)
                                           Unclassified
                                                                    21. NO. OF PAGES
                                                    54
 Unlimited
                        20. SECURITY CLASS (Thispage)
                        Unclassified
                                                                   22. PRICE
EPA Form 2220-1 (9-73)
                                         49

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