CONTROL TECHNIQUES
FOR BERYLLIUM
AIR POLLUTANTS
U.S. ENVIRONMENTAL PROTECTION AGENCY
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CONTROL TECHNIQUES
FOR BERYLLIUM AIR POLLUTANTS
ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Water Programs
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
February 1973
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The AP series of reports is published by the Technical Publications Branch of the Information
Services Division of the Office of Administration for the Office of Air and Water Programs,
Environmental Protection Agency, to report the results of scientific and engineering studies, and
information of general interest in the field of air pollution. Information reported in this series
includes coverage of intramural activities and of cooperative studies conducted in conjunction
with state and local agencies, research institutes, and industrial organizations. Copies of AP
reports are available free of charge to Federal employees, current contractors and grantees, and
nonprofit organizations — as supplies permit — from the Air Pollution Technical Information
Center, Environmental Protection Agency, Research Triangle Park, North Carolina 27711, or
from the Superintendent of Documents.
Publication No. AP-116
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, B.C. 20402
11
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PREFACE
This document contains information about the nature and control of a hazardous air
pollutant — beryllium. The primary purpose is to provide information useful to those involved in
the control of emissions of beryllium from industrial sources. The language and approach are
largely technical, but the first two Sections should be of interest and value to the general reader.
The requirement to publish this document was established when the Administrator of the
Environmental Protection Agency listed beryllium as a hazardous air pollutant by notice in the
Federal Register (Vol. 36, pg. 5931) on March 21, 1971. The Administrator acted under the
authority granted him by Section 112 of the Clean Air Act which defines a hazardous air
pollutant as, ". . .an air pollutant to which no ambient air quality standard is applicable and
which in the judgment of the Administrator may cause, or contribute to, an increase in mortality
or an increase in serious irreversible, or incapacitating reversible, illness."
Messrs. J. F Peoples, Jr., J. A. Desantis, and J. U. Crowder of the Office of Air and Water
Programs, Environmental Protection Agency, were primarily responsible for compiling the infor-
mation contained in this document. This information represents the efforts of the Environmental
Protection Agency, as well as the advice of the members of the advisory committees listed on the
following pages and the contributions of many individuals associated with other Federal agencies,
State and local governments, and private businesses.
in
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NATIONAL AIR POLLUTION CONTROL TECHNIQUES
ADVISORY COMMITTEE
Chairman
Mr. Donald F Walters
Office of Air and Water Programs
Office of Air Quality Planning and Standards
Environmental Protection Agency
Research Triangle Park, N.C. 27711
Mr. Raynal W. Andrews
150 Guyasuta Road
Pittsburgh, Pennsylvania 15215
Mr. Robert L. Chass
Air Pollution Control Officer
Los Angeles County Air
Pollution Control District
434 South San Pedro Street
Los Angeles, California 90013
Mr. Charles M. Copley, Jr.
Commissioner, Division of Air
Pollution Control
City of St. Louis
Room 419 City Hall
St. Louis, Missouri 63103
Mr. C. G. Cortelyou
Coordinator of Air and Water
Conservation
Mobil Oil Corporation
150 E. 42nd Street - Room 1650
New York, N.Y. 10017
Mr. Arthur R. Dammkoehler
Air Pollution Control Officer
Puget Sound Air Pollution
Control Agency
410 W.Harrison Street
Seattle, Washington 98119
Dr. Aaron J. Teller
Teller Environmental Systems, Inc.
295 Fifth Avenue
New York, N.Y. 10016
Mr. William W. Moore
President, Belco Pollution Control Corp.
100 Pennsylvania Avenue
Paterson, New Jersey 07509
Mr. William Munroe
Chief, Bureau of Air Pollution Control
State of New Jersey
Dept. of Environmental Protection
P.O. Box 1390
Trenton, New Jersey 08625
Mr. Vincent D. Patton
Executive Director
State of Florida Air and Water
Pollution Control
315 S.Calhoun Street
Tallahassee, Florida 32301
Dr. Robert W. Scott
Coordinator for Conservation Technology
Esso Research and Engineering Co.
P.O. Box 215
Linden, New Jersey 07036
Dr. R. S. Sholtes
University of Florida
Environmental Engineering Department
College of Engineering
Gainesville, Florida 32001
Mr. W. M. Smith
Director, Environmental Control
National Steel Corporation
Box 431, Room 159, General Office
Weirton, West Virginia 26062
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Mr. George P. Ferreri
Chief, Division of Compliance
Bureau of Air Quality Control
Maryland State Department of
Health and Mental Hygiene
61 ON. Howard Street
Baltimore, Maryland 21201
Mr. Benjamin F. Wake
Director, Division of Air Pollution
Control and Industrial Hygiene
Montana State Department of Health
Helena, Montana 59601
Mr. Charles M. Heinen
Executive Engineer
Materials Engineering
Chrysler Corporation
Box 1118,Dept. 5000
Highland Park, Michigan 48231
Mr. A. J. von Frank
Director, Air and Water
Pollution Control
Allied Chemical Corporation
P.O. Box 70
Morristown, New Jersey 07960
VI
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FEDERAL AGENCY LIAISON COMMITTEE
Chairman
Mr. Donald F Walters
Office of Air and Water Programs
Office of Air Quality Planning and Standards
Environmental Protection Agency
Research Triangle Park, N.C. 27711
FEDERAL POWER COMMISSION
Mr. T. A. Philips
Chief, Bureau of Power
Federal Power Commission, Room 3011
411 G Street, N.W.
Washington, D.C. 20426
GENERAL SERVICES ADMINISTRATION
Mr. Harold J. Pavel
Director, Repair and Improvement Division
Public Building Service
General Services Administration
9th and D Streets, S.W.
Washington, D.C.
NATIONAL AERONAUTICS AND
SPACE ADMINISTRATION
Mr. Ralph E. Cushman
Special Assistant
Office of Administration
National Aeronautics and Space Administration
Washington, D.C. 20546
NATIONAL SCIENCE FOUNDATION
Dr. O. W. Adams
Program Director for Structural Chemistry
Division of Mathematical and Physical Sciences
National Science Foundation
1800G Street, N.W.
Washington, D.C. 20550
POSTAL SERVICE
Mr. Robert Powell
Assistant Program Manager
U.S. Postal Service
Room 4419
1100 L Street
Washington, D.C. 20260
DEPARTMENT OF TRANSPORTATION
Dr. Richard L. Strombotne
Office of the Assistant Secretary
for Systems Development and Technology
Department of Transportation
400 7th Street, S.W.
Washington, D.C. 20591
DEPARTMENT OF DEFENSE
Harvey A. Falk, Jr., Commander, USN
Office of the Assistant Secretary
of Defense
Washington, D.C. 20301
DEPARTMENT OF HOUSING AND
URBAN DEVELOPMENT
Mr. Samuel C. Jackson
Assistant Secretary for Metropolitan Development
Department of Housing and Urban Development
Room 7100
7th and D Streets, S.W.
Washington, D.C. 20410
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DEPARTMENT OF AGRICULTURE
TENNESSEE VALLEY AUTHORITY
Dr. Theodore C. Byerly
Assistant Director of Science and Education
Office of the Secretary
U.S. Department of Agriculture
Washington, D.C. 20250
DEPARTMENT OF COMMERCE
Dr. James R. McNesby
Room A361, Materials Building
National Bureau of Standards
Washington, D.C. 20234
DEPARTMENT OF THE TREASURY
Mr. Gerard M. Brannon
Director, Office of Tax Analysis
Room 4217 MT
Department of the Treasury
15th and Pennsylvania Avenue, N.W.
Washington, D.C. 20220
DEPARTMENT OF THE INTERIOR
Dr. LeRoy R. Furlong
Research Advisor to the Assistant Secretary
Office of Assistant Secretary — Mineral
Resources
Bureau of Mines
Interior Building
Washington, D.C. 20240
DEPARTMENT OF HEALTH, EDUCATION,
AND WELFARE
Dr. Douglas L. Smith
Department of Health, Education, and Welfare
National Institute of Occupational Health
Rockville, Maryland
Dr. F. E. Gartrell
Director of Environmental Research and Development
Tennessee Valley Authority
715 Edney Building
Chattanooga, Tennessee 37401
ATOMIC ENERGY COMMISSION
Dr. Martin B. Biles
Director, Division of Operational Safety
U.S. Atomic Energy Commission
Washington, D.C. 20545
VETERANS ADMINISTRATION
Mr. Gerald M. Hollander, P.E.
Director of Architecture and Engineering
Office of Construction
Veterans Administration
Room 619 Lafayette Building
811 Vermont Avenue, N.W.
Washington, D.C. 20420
DEPARTMENT OF JUSTICE
Mr. Walter Kiechel, Jr.
Land and Natural Resources Division
Department of Justice
Room 2139
10th and Constitution Avenue, N.W.
Washington, D.C. 20530
DEPARTMENT OF LABOR
Mr. Robert D. Gidel
Deputy Director, Bureau of Labor Standards
Department of Labor
Room 401, Railway Labor Building
400 1st Street, N.W.
Washington, D.C. 20210
Vlll
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TABLE OF CONTENTS
Page
LIST OF FIGURES xi
LIST OF TABLES xiii
ABSTRACT xv
SUMMARY xvii
1. INTRODUCTION 1-1
1.1 REFERENCES FOR SECTION 1 1-2
2. BACKGROUND INFORMATION 2-1
2.1 DEFINITIONS 2-1
2.2 PHYSICAL AND CHEMICAL PROPERTIES OF BERYLLIUM 2-1
2.2.1 Physical Properties 2-1
2.2.2Chemical Properties 2-2
2.3 ORIGINS AND USES OF BERYLLIUM 2-3
2.4 MAJOR SOURCES OF BERYLLIUM EMISSIONS 2-4
2.5 REFERENCES FOR SECTION 2 2-4
3. BERYLLIUM EMISSION SOURCES AND CONTROL TECHNIQUES 3-1
3.1 BERYLLIUM EXTRACTION PLANTS 3-1
3.1.1 Introduction 3-1
3.1.2 Extraction of Beryllium Hydroxide from Beryl Ore 3-1
3.1.3 Extraction of Beryllium Hydroxide from Bertrandite Ore 3-3
3.1.4Conversion of Plant-Grade Beryllium Hydroxide 3-6
3.1.5 Beryllium Extraction Plant Emissions and Controls 3-10
3.2 BERYLLIUM METAL, BERYLLIUM OXIDE, AND BERYLLIUM-COPPER
ALLOY MACHINE SHOPS 3-18
3.2.1 Machining and Emissions 3-18
3.2.2 Emission Control Techniques 3-18
3.2.3 Beryllium Fires 3-20
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3.3 BERYLLIUM-COPPER FOUNDRIES 3-21
3.3.1 Foundry Operations and Emissions 3-21
3.3.2Emission Control Techniques 3-22
3.4 MANUFACTURE OF BERYLLIUM CERAMIC PRODUCTS 3-22
3.4.1 Ceramic Production and Emissions 3-23
3.4.2 Emission Control Techniques 3-24
3.5 BERYLLIUM PROPELLANT MANUFACTURE, TESTING, AND DISPOSAL .3-24
3.5. IPropellant Manufacture 3-24
3.5.2 Beryllium-Rocket-Motor Static Test Firing 3-26
3.5.3 Disposal of Beryllium Propellant 3-27
3.6 DISPOSAL OF BERYLLIUM-CONTAINING WASTES 3-28
3.6.1 Process 3-28
3.6.2 Emissions 3-28
3.6.3 Control Techniques 3-28
3.7 REFERENCES FOR SECTION 3 3-29
4. COSTS OF BERYLLIUM EMISSION CONTROL 4-1
4.1 BERYLLIUM EXTRACTION PLANTS 4-1
4.2 BERYLLIUM METAL, BERYLLIUM OXIDE, AND BERYLLIUM-COPPER
ALLOY MACHINE SHOPS 4-2
4.3 BERYLLIUM-COPPER ALLOY FOUNDRIES 44
4.4 MANUFACTURE OF BERYLLIUM CERAMIC PRODUCTS 44
4.5 BERYLLIUM PROPELLANT MANUFACTURE 4-6
4.6 REFERENCES FOR SECTION 4 4-8
APPENDIX: GAS-CLEANING DEVICES A-l
A.1 PREFILTERS A']
A.2 FABRIC FILTERS A'3
A.3 HEPA FILTERS A'5
A.4 REFERENCES FOR APPENDIX A'9
SUBJECT INDEX I"1
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LIST OF FIGURES
Figure Page
3-1 Sulfate Process for Conversion of Beryl Ore to Plant-Grade
Beryllium Hydroxide 3-2
3-2 Fluoride Process for Conversion of Beryl Ore to
Plant-Grade Beryllium Hydroxide 3A
3-3 Hypothetical Plant Process for the Organophosphate
Conversion of Bertrandite Ore to Beryllium Hydroxide 3-5
3-4 Conversion of Beryllium Hydroxide to Beryllium
Metal Billets 3-7
3-5 Conversion of Beryllium Billets to Beryllium
Metal Forms 3-8
3-6 Conversion of Plant-Grade Beryllium Hydroxide
to Alloys 3-9
3-7 Conversion of Beryllium Hydroxide to Beryllium Oxide
Powder and Ceramics 3-11
3-8 Types of Dry Mechanical Collectors Used by Beryllium
Extraction Facilities 3-15
3-9 Types of Wet Collectors Used in Beryllium Production Plants 3-16
3-10 Types of Fabric Filters Used in Beryllium Production Plants 3-17
3-11 Unitized Fabric Tube Filter, Prefilter, and HEPA Filter for
Beryllium or Beryllium Oxide Machining Facility 3-19
3-12 Unitized Multiple Dry Cyclone Collector, Prefilter, and
HEPA Filter for Beryllium or Beryllium Oxide
Machining Facility 3-20
3-13 Air Cleaning System for Beryllium or Beryllium Oxide
Machine Shop Process and Ventilation Air Streams 3-21
3-14 Manufacture of Beryllium Oxide Ceramic Products 3-23
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3-15 Configuration of Emission Control Devices for
Beryllium Ceramic Plant 3-25
3-16 Emission Control Devices for Spray Dryer 3-25
3-17 Schematic Diagram of Rocket-Motor Test Cell 3-27
A-l Group I, Viscous-Impingement-Panel Prefilter Installed
at the Entrance to a Group II or Group III Prefilter A-l
A-2 Group II or Group III, Dry-Type, Extended-Medium Prefilter A-l
A-3 Sectional View of a Baghouse Using a Fabric Filter A-4
A-4 Construction of Open-Faced HEPA Filters A-6
A-5 Influence of Prefilter on Service Life of HEPA Filter A-8
A-6 Effect of Increased Filter Resistance on Service Life
of HEPA Filter A-9
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LIST OF TABLES
Table page
2-1 Physical Properties of Beryllium 2-2
2-2 Beryllium Minerals 2-3
2-3 Uses of Beryllium 2-3
2-4 World Production of Beryl 2-4
2-5 United States Imports of Beryl 2-5
3-1 Characterization of Beryllium Extraction Plant Emissions 3-12
3-2 Particulate Collection Equipment 3-13
3-3 Control Equipment and Collection Efficiencies for
Beryllium Production Plants 3-14
3-4 Gas Cleaning Equipment for Beryllium and Beryllium
Oxide Machine Shops 3-22
3-5 Sources of Beryllium Ceramic Plant Emissions 3-24
4-1 Emission Control Costs for Conversion of Ore to Beryllium
Hydroxide by Sulfate Process 4-2
4-2 Emission Control Costs for Conversion of Ore to Beryllium
Hydroxide by Fluoride Process 4-3
4-3 Emission Control Costs for Conversion of Bertrandite Ore
To Beryllium Hydroxide 4-4
4-4 First Example of Emission Control Costs for Conversion of
Beryllium Hydroxide to Beryllium Billets 4-5
4-5 Second Example of Emission Control Costs for Conversion of
Beryllium Hydroxide to Beryllium Billets 4-6
4-6 Emission Control Costs for Conversion of Beryllium Billets
to Beryllium Metal Forms 4-7
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4-7 Emission Control Costs for Conversion of Beryllium Hydroxide
to Beryllium Alloys 4-7
4-8 Emission Control Costs for Conversion of Beryllium Hydroxide
to Beryllium Oxide and Ceramics 4-8
4-9 Emission Control Costs for Beryllium Machine Shop 4-9
4-10 Emission Control Costs for Beryllium-Copper Alloy Foundry 4-9
4-11 Emission Control Costs for Beryllium Ceramic
Manufacturing Plant 4-9
A-l Efficiencies of Prefilters A-2
A-2 Fractional Efficiencies of Prefilters A-2
A-3 Operating Parameters of Prefilters A-2
A-4 Specifications and Operating Parameters for Fabric Filter
Installations to Control Secondary Beryllium Emissions A-6
A-5 Nominal Specifications of Standard HEPA Filters A-6
A-6 Recommended Limiting Service Temperatures for
Steel-Framed, Fire-Resistant HEPA Filter Units Sealed
with Elastomeric Adhesives A-7
A-7 Recommended Limiting Service Temperatures for Wood-Framed,
Fire-Resistant HEPA Filter Units A-7
A-8 Shock Overpressure Resistance of Open-Face HEPA Filters A-8
xiv
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ABSTRACT
Beryllium in almost all forms is known to have adverse effects upon human health.
Concentrations as large as 0.01 microgram per cubic meter of air-over a 30-day period have been
determined to be safe for nonoccupational exposures. Properties of beryllium such as high
strength-to-weight ratio, high modulus of elasticity, and low coefficient of thermal expansion
make it ideally suited for many aerospace and precision instrument applications. It is also utilized
as an alloying constituent in other metals, most extensively with copper, to induce improvements
in physical properties. The oxide of beryllium is used as a high-temperature ceramic.
Domestically, approximately 300 facilities either extract beryllium or manufacture
beryllium-containing products. Beryllium extraction processes generate atmospheric emissions
that include beryllium salts, acids, beryllium oxide, and other beryllium compounds in the form
of dust, fume, or mist. Facilities engaged in processing beryllium-containing materials into
finished products generate a more restricted range of emissions, including beryllium dust from
machine shops, beryllium oxide dust from ceramic production, and beryllium-containing dust
and fume from beryllium-copper foundry operations. Beryllium emissions can be controlled by
the following classes of gas-cleaning equipment: prefilters, dry mechanical collectors, wet
collectors, fabric filters, and high-efficiency particulate air filters (HEPA filters). The choice of
specific control equipment is governed by process variables, effluent properties, and economics.
In most cases, emission control costs, including capital investment, operating and maintenance
costs, and capital charges, do not exceed 10 to 15 percent of the cost of manufacturing
equipment. Beryllium-contaminated waste can be buried at controlled disposal sites unless
it presents an explosion hazard. Beryllium propellant and other hazardous beryllium-contami-
nated wastes can be disposed of by controlled incineration or detonation employing appropriate
emission control devices. An appendix to this document presents descriptions of geometrical
configurations and performance characteristics of filters and presents examples of specific
design parameters and operational features of filters in use in beryllium machine shops and
foundries.
Key words: beryllium, emissions, control techniques, gas-cleaning devices, costs
xv
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SUMMARY
Beryllium in almost all forms is known to
have adverse effects upon human health.
Beryllium concentrations as large as 0.01
microgram per cubic meter of air, averaged
over a 30-day period, have been determined
to be safe for nonoccupational exposures.
Approximately 300 facilities that either
extract beryllium or manufacture beryllium-
containing products are the major domestic
users of beryllium. Processing operations and
characteristics of potential emissions vary
widely among the various types and methods
of product manufacture. The principal
sources of atmospheric beryllium emissions
that can potentially cause dangerous concen-
trations of beryllium in the ambient air are
presently believed to be those listed below
when the operations employ beryllium or a
beryllium-containing material:
1. Extraction plants.
2. Ceramic plants.
3. Foundries.
4. Machine shops.
5. Propellant plants.
6. Incinerators.
7. Rocket-motor test facilities.
8. Open burning sites for waste disposal.
Other sources of beryllium emissions are
known, but present information does not
indicate that dangerous ambient concentra-
tions of beryllium are likely to result from
such sources.
BACKGROUND INFORMATION
Beryllium is one of the lightest commer-
cially used metals. Properties such as high
strength-to-weight ratio, high modulus of elas-
ticity, and low coefficient of thermal expan-
sion make this metal ideally suited for many
aerospace and precision instrument applica-
tions. The metal is protected by the forma-
tion of an oxide coating that resists further
oxidation below 400° Celsius. Beryllium is
also utilized as an alloying constituent in
other metals to induce improvements in
physical properties; the most extensive use of
beryllium in alloys is with copper. The oxide
of beryllium (BeO) has unique properties that
have resulted in its use as a high-temperature
ceramic.
Beryllium is widely distributed in the crust
of the earth, but it rarely exists in a concen-
trated form economically suitable for mining.
Presently, beryl and bertrandite are the only
beryllium-containing ores mined for their
beryllium content. The majority of beryl ore
processed in the United States is imported,
and the only large-scale domestic mine pro-
duces bertrandite ore.
BERYLLIUM EMISSION SOURCES AND
CONTROL TECHNIQUES
The production of beryllium, beryllium
oxide, and beryllium-copper alloy constitutes
the main source of beryllium-containing
materials, which are fabricated into a wide
variety of products. Three basic processes are
employed to prepare beryllium hydroxide,
which is subsequently converted into the
desired product of metal, oxide, or alloy.
These latter beryllium-containing materials
are further processed into finished products at
extraction plants or are sold to other facilities
for processing or fabrication into finished
products.
The beryllium extraction process generates
atmospheric emissions with various physical
states and chemical compositions. Emissions
include beryllium salts, acids, beryllium
oxide, and other beryllium compounds in the
form of dust, fume, or mist. In contrast, those
facilities engaged in the processing of specific
xvn
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forms of beryllium-containing materials into
finished products generate a more restricted
range of beryllium and beryllium compounds
in emissions. Examples of these emissions are
beryllium dust generated by shops which
machine beryllium, beryllium oxide dust
generated during ceramic production, and
beryllium-containing fumes and dusts
produced by beryllium-copper foundry opera-
tions.
Beryllium emissions can be controlled by
the following classes of gas-cleaning equip-
ment :
1. Prefilters of the viscous impingement
and dry extended-medium types.
2. Dry mechanical collectors.
3. Wet collectors.
4. Fabric filters.
5. High efficiency particulate air filters
(HEPA filters).
The choice of specific control equipment is
governed by process variables, effluent pro-
perties, and economics.
Dry cyclones and fabric filter collectors in
series are commonly used to control beryl-
lium emissions generated during ore handling
operations such as crushing and milling. The
wet chemical beryllium extraction processes
employ wet collectors, such as venturi and
packed-tower scrubbers.
Beryllium foundries and machine shops
utilize dry cyclones, fabric filters and, in some
cases, HEPA filters. Beryllium ceramic plants
and propellant plants usually operate series
arrangements of prefilters and HEPA filters.
Emission controls for beryllium-
rocket-motor test facilities are in a state of
development. Present applications of high-
energy scrubbers and HEPA filters have been
moderately successful in controlling emissions
from the combustion of limited quantities of
rocket propellant. Further development of
control systems is necessary to adequately
control emissions from the combustion of
larger quantities of propellant.
The disposal of some beryllium-con-
taminated wastes can be accomplished by
burying at controlled disposal sites. Scrap
beryllium propellant should not be buried,
however, because of its explosive nature. One
method of propellant disposal involves
detonation in an underground chamber and
subsequent filtering of exhaust gases through
HEPA filters.
COSTS OF BERYLLIUM EMISSION CON-
TROL
Emission control costs can be divided into
three categories:
1. Capital investment.
2. Operating and maintenance costs.
3. Capital charges
The installed costs of emission control equip-
ment include expenditures for:
1. C on trol hardware.
2. Auxiliary equipment.
3. Clarifiers and liquid treatment systems.
4. Insulation material.
5. Transportation of equipment.
6. Site preparation.
7. Erection.
In most cases, the cost of equipment
necessary to effectively control beryllium
emissions does not exceed 10 to 15 percent of
the cost of manufacturing equipment.
GAS CLEANING DEVICES
Brief descriptions of geometrical configu-
rations and performance characteristics of
prefilters, fabric filters, and HEPA filters are
presented in an appendix. Examples of speci-
fic design parameters and operational features
of fabric filters that are in use in beryllium
machine shops and foundries are shown.
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CONTROL TECHNIQUES
FOR BERYLLIUM AIR POLLUTANTS
1. INTRODUCTION
Control Techniques for Beryllium Air
Pollutants is issued in accordance with Sec-
tion 112 (b) (2) of the Clean Air Amend-
ments of 1970.1
Beryllium in almost all forms is known to
have adverse effects upon human health.
Beryllium concentrations as large as 0.01
microgram per cubic meter of air, averaged
over a 30-day period, have been determined
to be safe for nonoccupational exposures.
The primary extraction of beryllium, the
alteration of beryllium-containing products
by various physical and chemical processes,
and the end use and disposal of beryllium-
containing materials can generate atmospheric
beryllium emissions. Such emissions occur as
dust, fume, and mist.
Beryllium extraction plants, machine
shops, foundries, ceramic plants, propellant
plants, incinerators, beryllium-rocket-motor
test facilities, and open burning sites for the
disposal of beryllium-containing wastes are
major potential sources of airborne beryllium.
Other sources of beryllium emissions, such as
combustion of coal and oil, beryllium ore
mining, and movement and stockpiling of
beryllium material, are known; however, it
has not been demonstrated that these sources
generate dangerous concentrations of beryl-
lium in ambient air. Approximately 300
facilities in the United States comprise the
major users of beryllium, but the total num-
ber of facilities that process or use material
containing beryllium may be in the thou-
sands.
This report discusses the application of
gas-cleaning equipment to the control of
beryllium emissions. Many of these control
devices, methods, and principles have been
developed and operated over many years.
They are recommended as the techniques
generally applicable to the control of emis-
sions during processing of beryllium-
containing materials. Brief descriptions of
processes and the classes, types, efficiencies,
installed costs, and annual operating costs of
accompanying control equipment are in-
cluded. Disposal practices for beryllium scrap
and solid waste generated by various indus-
trial processes are briefly discussed with refe-
rence to emission control.
Scrubbers, packed towers, chemical wet
collectors, and wet cyclones are used to
control emissions from wet-chemical pro-
cesses in the primary extraction of beryllium.
Cyclones, fabric filter units, and a variety of
prefilter and high efficiency particulate air
(HEPA) filters are common control devices
for dry operations, and for some wet opera-
tions not associated with beryllium extrac-
tion. (The Appendix to this document pre-
sents descriptions of geometric configurations
and performance characteristics of filters and
presents examples of specific design para-
1-1
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meters and operational features of filters in
use in beryllium machine shops and founda-
ries.)
Regardless of the type and size of beryl-
lium operation, emission control equipment
capable of maintaining ambient concentra-
tions of beryllium below 0.01 microgram per
cubic meter of air is readily available. Nu-
merous measurements of beryllium concentra-
tions in ambient air near emission sources are
available, but data on stack emissions of
beryllium are generally lacking.
The methodology used for estimating
installed costs and annual operating costs of
gas-cleaning equipment follows that used in
Control Techniques for Paniculate Air Pollu-
tants.'1 Costs have been adjusted to February
1972. It is not the purpose or intent of this
report to provide specific costs for installing
or operating gas-cleaning equipment for parti-
cular plants and processes, especially since
several alternative control systems can serve
equally well for a given emission control
situation. However, the estimating procedure
can produce total installed-equipment costs
that are accurate to within ±50 percent when
reasonably detailed requirements of a specific
installation are known.
1.1 REFERENCES FOR SECTION 1
1. Clean Air Amendments of 1970. U.S.
Environmental Protection Agency.
Washington, D.C. Publication No. P.L.
91-604. December 31, 1970.
2. Control Techniques for Particulate Air
Pollutants, U.S. Department of Health,
Education, and Welfare, National Air
Pollution Control Administration.
Washington, D.C. NAPCA Publication
No. AP-51. January 1969. p. 159-166.
1-2
-------
2. BACKGROUND INFORMATION
2.1 DEFINITIONS
The following definitions apply to terms
that are used in this document:
Beryllium—The element beryllium, excluding
any associated elements.
Extraction plant—A facility that chemically
processes beryllium ore to beryllium me-
tal, alloys, or oxide, or that performs any
of the intermediate steps in these proces-
ses.
Beryllium ore—Any material that is mined,
hand cobbed, or gathered in any way
solely for its beryllium content.
Machine shop—A facility that performs cut-
ting, grinding, turning, honing, milling,
deburring, lapping, electrochemical ma-
chining, etching, or other similar opera-
tions on beryllium metal, alloys, or oxide.
Ceramic plant—A manufacturing plant that
produces ceramic items or stock forms
from beryllium oxide.
Foundry—A facility engaged in the melting or
casting of beryllium metal or alloys.
Propellant—A fuel and oxidizer that are physi-
cally or chemically combined and that
undergo combustion to provide rocket
propulsion.
Beryllium alloy—Any metal to which beryl-
lium is deliberately added to enhance the
properties of the metal.
Propellant plant-Any facility engaged in the
mixing, casting, or machining of propel-
lant that contains beryllium.
Dust—Solid particles predominantly larger
than collodial size and capable of tempo-
rary suspension in air or other gases.
Derivation from larger masses of material
through the application of physical force
is usually implied.
Fume—Particles formed by condensation, sub-
limation, or chemical reaction, of which
the predominant part, by weight, consists
of particles smaller than 1 micron in
diameter. Condensed metal oxides are
examples of fume.
Mist—A low-concentration dispersion of rela-
tively small, liquid droplets.
Rocket-motor-test site -Any^ building, struc-
ture, or installation where the static test
firing of a beryllium-containing rocket
motor or the disposal of beryllium pro-
pellant is conducted.
2.2 PHYSICAL AND CHEMICAL PRO-
PERTIES OF BERYLLIUM
2.2.1 Physical Properties
Beryllium has a density of 1.85 grams per
cubic centimeter and is one of the lightest
metals. It is less dense than either aluminum
or titanium and is slightly more dense than
magnesium. Beryllium has a very high
strength-to-weight ratio and a modulus of
elasticity (36,000,000 to 44,000,000 pounds
per square inch) which exceeds that of alumi-
num, magnesium, or steels. In addition to
these properties that make beryllium advan-
tageous for use in precision structural compo-
nents, it also possesses unique properties
rarely encountered in other materials of a
similar nature. It has a permeability to x-rays
that is seventeen times greater than that of
aluminum. This property, in combination
with others, makes beryllium ideally suited
for x-ray windows and makes longer wave
x-rays possible.1 In addition, beryllium is one
of the few elements that is suitable as a
moderator in a nuclear-fission reaction.
Because beryllium is relatively expensive,
its use is limited to specific applications that
require its unique properties. Table 2-1 is a
list of the physical properties of beryllium.1
The values cited in this table vary slightly
2-1
-------
Table 2-1. PHYSICAL PROPERTIES
OF BERYLLIUM1
Property
Atomic number
Atomic weight
Melting point, UC
Boiling point, °C
Specific gravity at 4°C, g/cm
Crystal system
Lattice constant, A
Latent heat of fusion, cal/g
Coefficient of linear expansion.
25° to 200°C
200° to 800° C
Electrical conductivity, %
International Annealed Copper
Standard (IACS)
Specific heat, cal/(g) (°C)
0°C
100°C
800°C
Thermal conductivity,
cal/(sec)(cm2)(°C/cm)
0°C
100°C
800° C
Reflectivity (white light), %
Sound transmission velocity,
m/sec
Value
4
9.0133
1,283
2,970
1.85
Hexagonal
(close packed)
a = 2.286
c = 3.584
250 to 275
11.5
17.4
40 to 45
0.41
0.50
0.71
0.440
0.404
0.192
55
1 2,600
from other published values; this is probably
due to purity differences in the samples
tested.
When beryllium is incorporated in certain
metals, alloys that can be precipitation
hardened are produced.2 For example, the
following properties are improved when beryl-
lium is added to copper:
1. Hardness.
2. Tensile strength.
3. Fatigue resistance.
4. Corrosion resistance.
5. Elasticity.
The beryllium content of most alloys is
between 2 and 4 percent, but in some cases is
as low as 0.0042 percent.3 Adding small
amounts of beryllium to numerous different
metals can produce significant changes in
both physical and chemical properties, for
example, improved resistance to surface oxi-
dation, increased hardness, and increased
strength.
2.2.2 Chemical Properties
At ambient temperatures, beryllium is
stable in a dry atmosphere but will slowly
oxidize if moisture is present. As the tempera-
ture increases, beryllium begins to form a
highly protective oxide coating which inhibits
further oxidation. However, with further in-
creases in temperature, the oxide layer in-
creases, faults begin to occur, and flaking
destroys the protective coating at approxi-
mately 700° to 800° Celsius.1 >4
At elevated temperatures, beryllium also
reacts with carbon monoxide, carbon dioxide,
and water vapor. In all of these reactions, a
protective oxide coating is formed that has
characteristics that differ from those of the
coating formed by a reaction with oxygen.
The oxide coating formed during reaction
with carbon monoxide becomes nonprotec-
tive at a temperature approximately 100°
Celsius lower than that at which the coating
formed during the reaction with oxygen
becomes nonprotective. In contrast, oxidation
by carbon dioxide is protective at higher
temperatures; the protective characteristics of
oxidation by chemical reaction with water
vapor lie between those of carbon monoxide
and oxygen.
2-2
-------
The oxide of beryllium has unique pro-
perties. Its high melting point (225°Celsius),
sinterability, high heat conductance, and high
electrical resistivity make it an ideal high
temperature ceramic for many applications.
Unlike most metal oxides, the heat conduc-
tance of beryllium oxide exceeds that of the
metal itself.
Beryllium is reactive with sulfuric acid,
hydrochloric acid, and dilute nitric acid. It
dissolves in hot alkali to form beryllates.
When contained in beryl ore, beryllium is very
resistant to acid attack; the ore requires
pretreatment to increase its reactivity so that
an acid extraction can be performed. The
basic chemical processes for the extraction of
beryllium from beryl ore are discussed in
Section 3.1.
2.3 ORIGINS AND USES OF BERYLLIUM
Beryllium is widely distributed in the
earth's crust, but rarely in deposits of suffi-
ciently high concentration to make extraction
of beryllium economically feasible. Table 2-2
lists minerals which contain beryllium. At
present, only beryl and bertrandite ores are
commercially mined for their beryllium con-
tent.
Table 2-2. BERYLLIUM MINERALS3
Mineral
Beryl
Beryllonite
Bertrandite
Bromellite
Chrysoberyl
Euclase
Hambergite
Helvite
Herderite
Leucophanite
Phenacite
Formula
3BeO-AI203-6Si02
NaBeP04
Be4Si207(OH)2
BeO
Be(AIO2)2
BeHAISiOg
Be2(OH)B03
CaBeP04(OH,F)
(Ca, Na)2 BeSi2 (0,OH,F)
Be2Si04
The United States government, the major
domestic user of beryllium, uses beryllium
primarily for aerospace and nuclear applica-
tions. There are numerous similar applications
(Table 2-3) where beryllium is employed
because of its unique characteristics.
Table 2-3. USES OF BERYLLIUM
Form
Beryllium metal
Beryllium-copper alloy
Beryllium oxide
Use
Nuclear applications
Gyroscopes
Accelerometers
Inertial guidance systems
Rocket propellants
Aircraft brakes
Heat shields for space capsules
Portable x-ray tubes
Optical applications
Turbine rotor blades
Mirrors
Missile systems
Nuclear weapons
Springs
Bellows
Diaphragms
Electrical contacts
Aircraft engine parts
Welding electrodes
Nonsparking tools
Bearings
Precision castings
High-strength, current-carrying
springs
Fuse clips
Gears
Spark plugs
High-voltage electrical
components
Rocket-combustion-chamber
liners
Inertial guidance components
Laser tubes
Electric furnace liners
Microwave windows
Ceramic applications
Production data for beryl ore in the
United States are not published. However,
data do exist for the world production of
beryl ore (Table 2-4).s The United States
does not rank among the world's largest
2-3
-------
Table 2-4. WORLD PRODUCTION OF BERYL5
(Short tons)
Country
Argentina
Australia
Brazil
Congo (Kinshasa)
India
Kenya
Malagasy Republic
Mozambique
Portugal
Rhodesia, Southern
Rwanda
South Africa, Republic of
Uganda
U.S.S.R.b
United States (mine shipments)
Total"
1967
296
62
1,444°
2
1,435d
19
33
186
15
47e
120
114
346f
1,323
W9
5,442f
1968
654
17
2,291C
1,432b
8
85
104
140
97f
163
340
398
1,322
168
7,219
1969"
570b
3,100b
160
1,433
3
80
135
30
100b
276
345
316
1,378
W<)
7.926
1.
Preliminary.
Estimate.
cExports.
''Exports to United States as reported by Indian Department of Atomic
Energy.
eU.S. imports.
'Revised.
''Withheld to avoid disclosing confidential company data.
Totals are of listed figures only.
producers of beryl ore; however, a compari-
son of world production figures with U.S.
import figures in Table 2-5 shows that U.S.
imports of beryl ore account for a large
portion of world production.5
Numerous small-scale mining operations
exist in the United States in areas that contain
concentrated forms of beryllium ore. The
mines are usually small open pits or shallow
underground workings. Beryl is usually con-
centrated by hand sorting, and bertrandite or
mixtures of bertrandite and beryl are in some
cases enriched near the mine by flotation
processes. The contribution of these mines is
estimated to be less than 10 percent of the
beryl ore processed in the United States.
Only one large beryllium ore mine is
currently in operation in the United States;
the ore is mainly a hydrated bertrandite.
2.4 MAJOR SOURCES OF BERYLLIUM 4
EMISSIONS
The following sources, when engaged in
processes or operations involving beryllium,
are thought to be the most significant sources
of beryllium emissions:
1. Extraction plants.
2. Ceramic manufacturing plants.
3. Foundries.
4. Machining facilities.
5. Propellant manufacturing plants.
6. Incinerators.
7. Rocket-motor-test sites.
8. Open burning sites for waste disposal.
In addition, the emission of beryllium to
the atmosphere can occur during the mining
of beryllium ores; the improper transporta-
tion of beryllium, beryllium compounds, or
wastes contaminated with either; and the
burning of coal or oil containing trace
amounts of beryllium. Quantitative data on
the magnitude and frequency of these types
of emissions are not yet available. However,
no known data indicate instances of dan-
gerous concentrations of beryllium in the
atmosphere from such sources.
2.5 REFERENCES FOR SECTION 2
2.
3.
Schwenzfeier, C. W., Jr. Beryllium and
Beryllium Alloys. In: Kirk-Othmer Ency-
clopedia of Chemical Technology (Vol.
3). Standen, A. (ed.). New York, John
Wiley and Sons, Inc., 1964. p. 451.
Trends in Usage of Beryllium and Beryl-
lium Oxide. National Research Council.
Washington, D. C. Materials Advisory
Board Report MAB-238. February 1968.
p. 1.
Krejci, L. E. and L. D. Scheel. The
Chemistry of Beryllium. In: Beryllium —
Its Industrial Hygiene Aspects. Stokinger,
H. E. (ed.). New York, Academic Press,
Inc., 1966. p. 47,99.
Songma, O. A. Beryllium. In: Rare Me-
tals. Washington, D. C., Israel Program for
Scientific Translations Ltd., 1971. p. 322.
2-4
-------
Table 2-5. UNITED STATES IMPORTS OF BERYL5
Customs
district
Philadelphia
New York City
Baltimore
Grand Total
Country
of origin
Angola
Argentina
Australia
Bolivia
Brazil
Burundi & Rwanda
Congo
Kenya
Malagasy Republic
Malaysia
Mozambique
Portugal
Rhodesia, Southern
South Africa
Spain
Tanzania
United Kingdom
Uganda
Zambia
Total
Australia
Brazil
Burundi & Rwanda
South Africa
Uganda
Total
Brazil
Mozambique
Uganda
Total
1968
Volume,
short tons
549
124
15
1,600
176
56
52
140
67
97
359
23
398
3
3,659
31
99
33
163
3,822
Value, $
214,000
53,000
5,000
579,000
60,000
12,000
16,000
88,000
29,000
32,000
131,000
7,000
129,000
1,000
1,356,000
1 1 ,000
34,000
12,000
57,000
1,413,000
1969
Volume,
short tons
17
600
13
4,098
143
70
44
78
11
69
94
-
691
3
22
6
295
-
6,254
,
22
12
34
40
27
67
134
6,422
Value, $
7,000
227,000
6,000
1,695,000
55,000
27,000
19,000
27,000
4,000
30,000
44,000
308,000
1,000
9,000
2,000
117,000
-
2,578,000
8,000
5,000
13,000
19,000
12,000
26,000
57,000
2,648,000
5. Eilertsen, D. C. Beryllium. In: Minerals
Year Book 1969; Vol. I-II, Metals, Mine-
rals, and Fuels. Schreck, A. E. (ed.). U.S.
Department of the Interior, Bureau of
Mines. Washington, D. C. 1971. p.
216-217.
2-5
-------
3. BERYLLIUM EMISSION SOURCES AND CONTROL TECHNIQUES
3.1 BERYLLIUM EXTRACTION PLANTS
3.1.1 Introduction
Beryllium extraction plants manufacture
the following classes of materials and pro-
ducts: (1) beryllium: powders, pressed blocks,
mill products, fabricated products; (2) beryl-
lium oxide: powders, ceramic shapes, ceramic
wares, fabricated products; and (3) beryllium
alloys: cast billets, mill products, fabricated
products.
Beryllium extraction plants produce
beryllium powders and metals of at least 95
percent purity. The beryllium metal products
are made almost entirely from pressed powder
and are forged, extruded, formed, and ma-
chined. Beryllium oxide (beryllia) powders of
various qualities are pressed, extruded, fired,
and machined by conventional ceramic tech-
niques. Alloy products, mainly the types with
small percentages of beryllium in copper, are
produced from melts of copper and master (4
percent) alloy. The products include rods,
bars, plates, wires, strips, forgings, and billets.
Beryllium is also alloyed with nickel and with
aluminum.
Primary beryllium extraction plants pro-
cess beryllium in all forms, from ores to
intermediate commercial products to end
items. In 1968, the production of beryllium
in all forms totaled about 348 tons.1 The
production of beryllium fluctuates widely
from year to year in response to the market
demand, and no long-term trend is discerni-
ble.
There are three basic processes in com-
mercial use for extracting beryllium from
beryllium ore. The sulfate process and the
fluoride process recover beryllium from beryl
ore, whereas the remaining process uses ber-
trandite ore. All of the processes extract
beryllium from ore in the form of beryllium
hydroxide. The hydroxide is then converted
to the desired product of beryllium oxide,
beryllium metal, or beryllium-copper alloy.
Only four domestic facilities either ex-
tract beryllium from ore or process beryllium
into beryllium oxide, beryllium-copper alloy,
and beryllium metal billets. One installation
ships its entire beryllium hydroxide produc-
tion to a second facility for further proces-
sing, together with additional beryllium
hydroxide produced at the latter facility. A
third extraction installation performs addi-
tional processing of beryllium hydroxide on-
site and also ships beryllium hydroxide to the
fourth installation, which does not carry out
extraction operations.
3.1.2 Extraction of Beryllium Hydroxide
from Beryl Ore
3.1.2.1 Sulfate Process
Figure 3-1 is a flow diagram for the
sulfate process. The atmospheric emission
control equipment, discussed in Section
3.1.5.2, is also shown.
In the treatment of beryl ore by the
sulfate process, crushed beryl ore is first
melted in an electric furnace at about 1650°
Celsius. It is then poured through a high-velo-
city cold water jet; the quenched material, in
frit form, is screened, heat-treated in a rotary
kiln to increase its reactivity, and dry-ground
to minus 200 mesh. Weighed batches of this
material are mixed with concentrated sulfuric
acid to form a smooth slurry, which is
pumped into a sulfating reactor regulated to
300° Celsius. Beryllium sulfate, aluminum
sulfate, and silica are thus formed from the
ore.
3-1
-------
PROCESS STEPS
EMISSION CONTROL EQUIPMENT
^—SILICA-
_B__^
CRUSHING
FURNACE MELTING
FRIT PRODUCING
(QUENCHING)
ACTIVATING
(HEAT TREATING)
MILLING
SULFATING
CENTRIFUGING
-*- ALUM -
CHELATING-
AGENTS
—
x:
_i
j_
•
CRYSTALLIZING
CENTRIFUGING
BERYLLATING
1
HYDROLYZING
I
PRECIPITATING
i
FILTERING
|
DRYING,
PACKAGING
1
h 1— 1
2EA ^oo j,
o-J
f>— 2500 cfm— DC -
— r r ——5000 cfm— ^
f^k^^
0—450 cfm— F F -
f*w
1^
fs._2400— . HST EVS _
l^^ cfm 2 EA. 2 EA. 1
P*~l I
L.2460 p-p | PTS
cfm -j PA
6400 cfm—
O-i
F F FABRIC FILTER
1
STACK
EVS EJECTOR VENTURI SCRUBBER
DC DRY CYCLONE
0^ HST HYDRAULIC SCRUBBING TOWER
PTS PACKED TOWER SCRUBBER
f ~\ Vb VtNIUKI M^KUBbtK
(^ PLANT-GRADE BERYLLIUM HYDROXIDE J
Figure 3-1. Sulfate process for conversion of beryl ore to plant-grade beryllium hydroxide.
3-2
-------
In a continuous process, water is added
for leaching, and silica is removed from the
sulfate liquor by centrifuging. Ammonium
hydroxide is added to the liquor, and ammo-
nium alum is crystallized from solution and
removed by centrifuging. The liquor is con-
tinuously proportionated with the chelating
agent EDTA (ethylenediaminotetraacetic
acid, for solubilizing impurities) and with
dilute sodium hydroxide as it is fed into a
water-cooled "beryllating" reactor. The so-
dium beryllate solution formed is tranferred
to a hydrolyzer where it is held at boiling to
precipitate a granular-form beryllium hydrox-
ide from the solution. The slurry is then
centrifuged, and the liquid portion is recycled
to the alum crystallization step. The product,
plant-grade beryllium hydroxide, is packaged
in steel drums to await conversion to berylli-
um metal, alloy, or ceramic material.
3.1.2.2 Fluoride Process
Figure 3-2 is a flow diagram of the
fluoride process. Included in this diagram are
the atmospheric emission control devices,
which are discussed in Section 3.1.5.2. It
should be noted that similar control methods
are incorporated in all of the extraction
processes discussed in this chapter.
In the treatment of beryl ore by the
fluoride process, crushed beryl ore is ground
in a ball mill to minus 200 mesh and then
mixed with powdered sodium silicofluoride,
soda ash, water, and oil in a mix muller. This
blend is briquetted, and the briquettes are fed
continuously to a rotary hearth gas-electric
furnace for sintering at 760° Celsius. The
sintered briquettes are crushed and ground to
minus 100 mesh in vibratory ball mills. The
ground sinter is slurried in water and is
progressively thickened and hot-water-leached
through four stages. Ammonium persulfate is
added to precipitate impurities, which are
removed by filtration of the sodium fluo-
beryllate leach liquor. Sodium hydroxide is
added to 5500-gallon batches of the filtered
leach liquor to precipitate beryllium hydrox-
ide. The precipitated slurry is filtered, dried,
and drummed as plant-grade beryllium hy-
droxide, approximately 97.5 percent pure, for
further conversion to alloy or metal.
For subsequent conversion to beryllium
oxide powder and to ceramics, a higher purity
beryllium hydroxide is obtained by dissolving
the plant-grade beryllium hydroxide in sul-
furic acid, adding chelating agents to
sequester impurities, and reprecipitating the
beryllium hydroxide with ammonium
hydroxide.
3.1.3 Extraction of Beryllium Hydroxide
from Bertrandite Ore2 >3
The process used for domestic production
of beryllium hydroxide from bertrandite ore
is proprietary. Consequently, the hypothetical
conversion of bertrandite ore by a phosphate
process is described below; this process has
been extensively investigated by the U. S.
Bureau of Mines.
Figure 3-3 is a flow diagram of the
hypothetical extraction process utilizing ber-
trandite ore. Included in the diagram are the
atmospheric emission control devices, which
are discussed in Section 3.1.5.2.
Bertrandite ore is hammer-milled, dry
ball-milled, and classified to minus 200 mesh
for leaching with sulfuric acid. The leaching
with agitation requires 24 hours at 65°
Celsius. Afterward, the solids are flocculated,
and the liquid is decanted and adjusted to a
pH of 0.5. To suppress extraction of ferric
iron, the leach liquor is treated with sodium
hydrosulfate to reduce ferric to ferrous ions.
It is then contacted with a kerosene solution
of EHPA (di-2- ethylhexyl phosphoric acid).
The extraction is a countercurrent process
that can be carried out in eight stages, with
about 40 minutes retention and contact time
between stages. The aqueous raffinate is
discarded, and the enriched EHPA solvent
then encounters 5-normal-concentration caus-
tic soda in a two-stage countercurrent strip-
ping process. The stripped EHPA is recycled
for renewed contact with leach liquor. The
succeeding steps are similar to sulfate process
steps (Figure 3-1) for the 100° Celsius hydro-
lysis of sodium beryllate and precipitation of
beryllium hydroxide.
3-3
-------
PROCESS STEPS
EMISSION CONTROL EQUIPMENT
BERYL ORE.
I
CRUSHING
MILLING
OIL, WATER —
•*• RED MUD-
STEAM +•
..METAL,
SALTS
STEAM fr
»
MULLING
1
BRIQUETTING
1
SINTERING
1
CRUSHING,
MILLING
— m^ ^
1 .
*^ TO ATMOSPHERE
PLANT AIR-J
*n
II TO ATMOSPHERE
"^cfm DC F F ,innnrfm._. ,k-
. TO ATMfKPHFBF
SLURRYING
THICKENING
|V^
O-i
FILTERING
I
LEACHING
1
r
IMPURITY
PRECIPITATING
l
FILTERING
PRECIPITATING
I
FILTERING
I
DRYING,
PACKAGING
1
rs. — HST b,UUU cim >•
^^ TO ATMOSPHERE
o-1
* 1
AIR FROM OTHER PROCESSES ^
F F FABRIC FILTER
DC DRY CYCLONE
VS VENTURI SCRUBB
HST HYDRAULIC SCRU
(^ PLANT-GRADE BERYLLIUM HYDROXIDE )
u
•a:
t;
F F
> ULTRA
COLLECTOR
ER
BEING TOWER
Figure 3-2. Fluoride process for conversion of beryl ore to plant-grade beryllium hydroxide.
34
-------
PROCESS STEPS
EMISSION CONTROL EQUIPMENT
BERTRANDITE ORE
CRUSHING AND
GRINDING
H2S04 »
FLOCCULANT
1
LEACHING
DC
EVS
F F
>
NaHS-
SETTLING AND
DECANTING
i
IRON REDUCING
^
EVS
EVS
^ p- EHPA S(
*m WCUT
DLUTION— •
CAUSTIC SODA
EVS
1 EA. PER
STAGE
EXTRACTING*
(MULTISTAGE)
-^-RAFFINATE.
•_TL
CAUSTIC
STRIPPING
EHPA SOLUTION
FILTERING
(Na^BeO?
SOLUTION
HYDROLYZING,
PRECIPITATING
FILTERING
DRUM PACKAGING
C
BERYLLIUM HYDROXIDE CAKE (TO 99% PURITY)
*EHPA SOLVENT IS 0.25N DI-2-ETHYLHEXYL PHOSPHORIC ACID
WITH 2 WT VOL PERCENT ISODECYL ALCOHOL IN KEROSENE.
DC
EVS
F F
DRY CYCLONE
EJECTOR VENTURI SCRUBBER
FABRIC FILTER
Figure 3-3. Hypothetical plant process for the organophosphate conversion of bertrandite ore
to beryllium hydroxide.
3-5
-------
3.1.4 Conversion of Plant-Grade Beryllium
Hydroxide
3.1.4.1 Metal Billets
Figure 3-4 is a flow diagram of the
conversion of plant-grade beryllium hydrox-
ide to metal billets. The atmospheric emission
control equipment is discussed in Section
3.1.5.2.
Plant-grade beryllium hydroxide powder
is dissolved in boiling ammonium fluoride
solution to form ammonium beryllium fluo-
ride. Calcium carbonate, lead oxide, and
sulfides are added in steps to precipitate
impurities, which are filtered from the solu-
tion. The purified ammonium beryllium fluo-
ride solution is brought to high pH by the
addition of ammonium hydroxide and then
concentrated by evaporation.
Ammonium beryllium fluoride salt is
obtained by crystallization from the liquor
and by centrifuging or by drum drying. This
salt is fed continuously into a high-frequency
induction furnace and melted at 540° Celsius.
Liquid beryllium fluoride flows out of the
furnace onto a continuous casting wheel or
onto a cooling turntable. The decomposition
product, ammonium fluoride, is collected by
scrubbing and is cycled, with added hydro-
fluoric acid, back to the initial step of
solution of the beryllium hydroxide.
The beryllium fluoride flakes or pellets
are then mixed in excess with lumps of
magnesium and heated in carefully controlled
stages in a high-frequency induction furnace
for approximately 3J/2 hours. When the tem-
perature is raised to 1300° Celsius, the molten
beryllium rises to the surface as small beads in
a matrix of magnesium fluoride and beryllium
fluoride slag. The molten charge is cast in
graphite molds as "salt pigs." These are
subsequently crushed and ball-milled with the
aid of steel balls to free the beryllium from
the slag.
The magnesium fluoride and beryllium
fluoride are removed from the beads by
washing with hydrofluoric acid and water,
and the steel balls are removed magnetically
3-6
or by shaker screen. The beryllium beads are
nitric acid-pickled and gravity-separated in a
bath of ethylene dibromide and mineral oil,
washed with isopropyl alcohol and water, and
dried. The beads are then weighed and
charged with a mixture of fine beryllium
metal scrap into a tiltable vacuum-cast fur-
nace. The beryllium is melted under vacuum
and poured into billet molds. Gaseous and
solid impurities are allowed to separate, and
the cooled billets are pickled, washed, and
dried in preparation for conversion to beryl-
lium powder.
3.1.4.2 Finished Forms
Figure 3-5 is a flow diagram which
illustrates the conversion of beryllium metal
billets to finished forms. The emission control
equipment illustrated is discussed in Section
3.1.5.2.
To produce beryllium finished forms,
beryllium billets are first machined into chips
on a lathe. The chips are reduced to minus
200 mesh powder by milling between berylli-
um-faced plates under a dry nitrogen atmos-
phere. Beryllium scrap, such as ingot crop-
ends, may also be crushed in a hammer mill
and added in the attrition milling process. The
resulting powder is then screened and loaded
into a steel or graphite die where it is pressed
to about 1000 pounds per square inch and
sintered at about 1050° Celsius under vac-
uum. Alternative powder methods are warm
pressing, performed in air at 400° to 650°
Celsius and 25 to 100 tons per square inch,
and cold pressing, performed in air at room
temperature and 10 to 50 tons per square
inch. The billets thus formed may be subse-
quently single-stroke press-forged at 750°
Celsius and 3 to 20 tons per square inch,
extruded, or rolled. During these operations,
the billets are usually steel-jacketed to protect
against oxidation and to prevent seizing and
galling of the tools. Hot-pressed powder bil-
lets can be machined approximately as well as
cast iron, with the use of tungsten carbide-
tipped tools.
3.1.4.3 Beryllium-Copper Alloy
Figure 3-6 is a process flow diagram for
-------
FIRST EXAMPLE
EMISSION CONTROL EQUIPMENT
1,000
cfm'
PROCESS STEPS
PLANT-GRADE
Be(OH)2
NH4F,HF
HST
DISSOLVING
CaCOs, PbO-
1,325
cfm
PbCr04,
Mn02,CaF2
1
THICKENING,
FILTERING
SULFIDES-
Pb,Ni,Zn —
Cu SALTS
-NH40m
2,500
' cfm ~^
H20-
FILTERING
ADJUSTING,
CONCENTRATING
EVAPORATING,
CRYSTALLIZING,
CENTRIFUGING,
AND DRYING
•*-BeF2 —
•*MgF2-
FURNACE
REDUCING
JL
WET SLAG MILLING
ANDSLURRYING
-<-SLAG —
TO ATMOSPHERE
I 9,500 __^
cfm
I
Be PEBBLE
CLEANING
600
- DROSS ~
_L
VACUUM MELTING,
BILLET CASTING
SECOND EXAMPLE
EMISSION CONTROL EQUIPMENT
(BERYLLIUM BILLETS
PTS PACKED TOWER SCRUBBER DC
HST HYDRAULIC SCRUBBING TOWER VS
OS ORIFICE SCRUBBER EVS
FBS FLOATING BED SCRUBBER F F
DRY CYCLONE
VENTURISCRUBBER
EJECTOR VENTURI
FABRIC FILTER
Figure 3-4. Conversion of beryllium hydroxide to beryllium metal billets.
3-7
-------
BERYLLIUM BILLETS.
SCRAP CHIPS'
PROCESS STEPS
C
PICKLING,
WASHING
CHIPPING
POWDERING
SCREENING
COMPACT
LOADING
VACUUM
HOT PRESSING
JL
MACHINING,
FINISHING
EMISSION CONTROL EQUIPMENT
SPENT SALT RECOVERY.
6,000
" cfm
600_ DC -
TO ATMOSPHERE
43,000 cfm
10,200 cfm
0—
DC
17 EA.
FINISHED BERYLLIUM FORMS
DC DRY CYCLONE
HST HYDRAULIC SCRUBBING
TOWER
F F FABRIC FILTER
Figure 3-5. Conversion of beryllium
the production of beryllium-copper alloy. The
illustrated emission control equipment is dis-
cussed in Section 3.1.5.2.
The process for beryllium-copper alloy
production is based on the ability of beryl-
lium oxide to undergo reduction by carbon,
under atmospheric pressure in the presence of
a metal that forms an alloy with beryllium at
the reduction temperature.
Plant-grade beryllium hydroxide powder
is calcined at 800° Celsius to beryllium oxide.
The oxide is blended with carbon dust, and
together with copper chips and the dross from
previous melts, it is fed into a three-phase arc
furnace at 1800° to 2000° Celsius.
At a furnace temperature of 2200° to
2400° Celsius, the beryllium oxide is succes-
billets to beryllium metal forms.
sively reduced by the carbon to beryllium and
beryllium carbide, both of which dissolve in
the molten copper to form a beryllium-copper
alloy. The less soluble beryllium carbide and
carbon monoxide leave the melt when the
alloy is cooled in a foundry crucible to the
casting temperature, approximately 1000°
Celsius. The solid impurities are skimmed
from the melt, and, together with furnace
dust, are recycled into a dross storage bin for
addition to subsequent furnace charges of
beryllium oxide, copper, and carbon.
Master alloy containing 4 to 4.25 percent
beryllium is cast into ingots which are sold in
this form or subsequently remelted with
additional copper to produce 0.25 to 2.75
percent beryllium-containing commercial
3-8
-------
PLANT-GRADE
Be(OH)2
tfZ
5,000 cfm.
DROSS
STORING
>
Cu CHIPS-
CARBON
•DROSS-
Be MASTER ALLOY
COPPER CHIPS
Be ALLOY
PROCESS STEPS
CALCINING
400
OXIDE STORING
±L
BLENDING
ARC FURNACE
ALLOYING
TEMPERATURE
NORMALIZING
PIG CASTING
HEAT TREATING,
SHAPING, AND
FINISHING
I
4% Be MASTER ALLOY
EMISSION CONTROL EQUIPMENT
F F
i
•22,000 cfm-
F F
EA.
6,000 cfm-
2,200 cfm •
12,000 cfm-
4,200 cfm-
TO ATMOSPHERE
1
LOADING
FURNACE
MELTING
1
PIG CASTING
[\_7,500
IX rfm 1
PSC
SEA.
1
• 12,000 cfm-
SHAPING AND
FINISHING
F F FABRIC FILTER
PSC PARTICULATE SETTLING CHAMBER
FINISHED 2% Be STOCK FORMS
J)
Figure3-6. Conversion of plant-grade beryllium hydroxide to alloys.
3-9
-------
alloys. .At extraction plants, alloys are rolled
or drawn to rod, bar, sheet, strip, or stock
forms, or are trimmed for sale as billets,
which may weigh up to 1500 pounds.
3.1.4.4 Beryllium Oxide
The beryllium extraction plant produc-
tion of beryllium oxide involves many varia-
tions in materials, purification processes, mil-
ling processes, and temperatures to meet
specifications of purity, particle size, particle
specific surface area, and molecular structure;
the last two characteristics are determined by
the temperature of firing. Some commercial
beryllia powders are derived from decom-
position of beryllium sulfate, rather than
beryllium hydroxide. Producers describe pro-
ducts as "hydroxide-derived," "sulfate-de-
rived," "low-fired," or "high-fired," or
blends of these, in addition to furnishing
information on particle characteristics and
purity. Beryllium oxide and ceramic produc-
tion are described below with reference to
hydroxide-derived, low-fired material.
Figure 3-7 is a process flow diagram for
the production of beryllium oxide. The il-
lustrated emission control devices are dis-
cussed in Section 3.1.5.2.
High-purity beryllium hydroxide is
blended with recycled beryllium oxide pow-
der, and iron is removed magnetically in a
ferro filter. The blend is then heated in a
beehive- or rotary-type furnace to about 750°
Celsius to decompose the beryllium hydrox-
ide and obtain a powdered, low-fired beryllia
product. The powder can be further refined
to remove impurities. It is either screened and
milled to specified mesh and grade for packag-
ing and sale, or it is further processed within
the plant to kiln-fired stock forms or wares.
For ceramic production, binders and lu-
bricants are added, and the oxide powder is
slurried and milled to fine mesh sizes, usually
minus 200 mesh. The material is either
spray-dried and subjected to dry or isostatic
pressing, or it is pan-dried and mull-mixed
with water to a clay-like paste for extruded-
shape production. Both forms are kiln-fired at
about 1450° Celsius. The firing produces a
sintered, hard ceramic which can be wet-
ground, bored, machined into wafers, or
surface-finished by vibro-milling.
3.1.5 Beryllium Extraction Plant Emissions
and Controls
3.1.5.1 Emissions
Definitive quantitative data on beryllium
emissions from extraction plants are not
available. However, these facilities have been
designed to limit ambient concentrations of
beryllium to 0.01 microgram per cubic meter
and have demonstrated the capability for
operation within this limit.
Beryllium extraction plant emissions are
more varied than those of any other beryllium
emissions source. The type and amount of
emissions vary with each specific operation of
the extraction process. Table 3-1 lists emis-
sion-producing operations, emissions, and fea-
sible classes of control equipment for a
typical extraction plant. The control tech-
niques and corresponding operating charac-
teristics are discussed in Section 3.1.5.2.
3.1.5.2 Control Techniques
The following are appropriate practices
for the control of emissions from beryllium
extraction plants:
1. Local pickup of contaminated gases
from fully or partially enclosed
sources.
2. Tandem use of primary and secon-
dary air-cleaning devices, the former
mainly to remove reactive gases or
larger participates, and the latter to
provide high-efficiency cleaning of
smaller particulates.
3. The use of high-energy wet collectors
or scrubber devices to obtain high
particle collection efficiency for the
removal of wet, hygroscopic, or cor-
rosive contaminants.
4. Application of fabric filters for high-
efficiency collection of dry particu-
lates. i
In chemical processes which involve high-
3-10
-------
PROCESS STEPS
EMISSION CONTROL EQUIPMENT
HIGH PURITY
Be(OH)2
1
Be POWDER
PACKAGING
1
BLENDING
FURNACE OXIDE
PRODUCING
1
SCREENING
I SLURRYING | [>-
[ MILLING [ [>-
| ADDING BINDER"! £>
600
cfm-
1,100.
cfm
.1,800_
cfm
F F
PTS
SEA.
F F
2EA.
F F
F F
1,100 cfm-
• 20,000 cfm-
"1—1,700 cfm
SPRAY DRYING
MULLING
EXTRUDING
PAN DRYING | [>
t
PRESSING |
F F
2,800 cfm-
TO ATMOSPHERE
300 cfm
• 20,000 cfm.
-KILN FIRING
MACHINING
cfm
SURFACE
TREATING
NIC __
6EA.| I
30,000 cfm-
rti
•50,000 cfm-
PACKAGING
( FINISHED CERAMIC FORMSJ
F F FABRIC FILTER
PTS PACKED TOWER SCRUBBER
MC MIST COLLECTOR
Figure 3-7. Conversion of beryllium hydroxide to beryllium oxide powder and ceramics.
3-11
-------
Table 3-1. CHARACTERIZATION OF BERYLLIUM EXTRACTION PLANT EMISSIONS3
Extraction plant
operation
Emissions
Control device
Ore crushing
Ore milling
Mulling
Briquetting
Sintering
Briquette
crushing and milling
Slurrying
Thickening
Filtering
Leaching
High purity beryllium
hydroxide production
Beryllium metal
production
Beryllium oxide
production
Beryllium-copper
alloy production
Beryl ore dust
Beryl ore dust
Beryl ore dust,
Na2SiF6,
Briquette dust
Beryl dust,
sinter dust
Briquette
dust
Ground sinter
Sinter slurry
Sodium fluoberyllate
Ammonium persulfate
fume
Be(OH)2 slurry,
H2SO4 fume
(NH4)2BeF4 slurry,
PbCr04
CaF2, HF, Be(OH)2,
BeF2, NH4F fume,
Mg, Be, MgF2, BeO
acid fume
BeO furnace
fume and dust,
BeO dust
Alloy furnace
dust. Be, Cu
BeO
Dry cyclone, baghouse
Dry cyclone, baghouse
Baghouse
Baghouse
Venturi scrubber
Dry cyclone, baghouse
Baghouse
Scrubber
Scrubber
Scrubber
Scrubber
Packed tower scrubber,
scrubbing tower,
floating bed scrubber,
dry cyclone,
venturi scrubber,
baghouses
Packed tower scrubber,
baghouse
mist collector
Settling chamber,
cyclone,
baghouse
The variety of different possible chemical compositions in extraction plant
emissions is not meant to be limited to those contained in this table. The purpose
of this table is to give an indication of the most probable emissions.
temperature oven or furnace fumes, wet
collectors are effective; in milling and fabrica-
tion processes, fabric filters can be used.
With minor exceptions, the types of gas
cleaning equipment applied for control of
emissions from beryllium production plants
are of three main classes:
1. Mechanical dry collectors (centrifugal
separators).
2. Wet collectors (scrubbers).
3-12
-------
3. Fabric filters (baghouses).
Prefilters and high efficiency participate air
filters (HEPA filters) are occasionally em-
ployed. These types of filters are discussed in
more detail in Section 3.2.2.3 and in the
Appendix.
Table 3-2 gives pressure losses, effi-
ciencies, and power requirements for each of
the above classes of gas-cleaning equipment.
These parameters are seen to vary widely
within each class of equipment.
An appraisal of the present gas-cleaning
capabilities of beryllium production plants is
presented in Table 3-3.4
3.1.5.2.1 Mechanical dry collectors.
Mechanical dry collectors are widely em-
ployed in beryllium metal, alloy, and ceramic
production processes that generate dry parti-
culates. Most frequently, these devices are
used to capture the larger participates in the
exhausts of machining operations, mill pro-
cesses, and fabrication operations. Often these
collectors perform initial cleaning of dust-
laden air prior to the application of addi-
tional, more efficient gas-cleaning equipment.
Relatively simple construction, low installa-
tion and maintenance costs, dry and continu-
ous disposal of dust, and low sensitivity to
temperature are advantages of mechanical
collectors.
Power requirements (Table 3-2) of dry
mechanical collectors are usually low by
comparison with those of wet collectors. The
efficiency of mechanical collectors varies di-
rectly with inlet gas velocity and particle
density, and inversely with gas viscosity. The
collection efficiencies of even the most effi-
cient types of mechanical collectors decrease
rapidly for particles smaller than 5 microns in
diameter.5
Beryllium extraction plants utilize me-
chanical collectors in a wide range of sizes and
configurations. Gas entry may be either invo-
lute (axial) or tangential. Axial entry, small
diameter, high inlet velocity, and pressure
decreases as large as 5 inches of water, where
employed together, characterize the high-
efficiency types of mechanical collectors.
Other types that have a mechanically driven
rotor element are not widely employed in
beryllium production plants, probably be-
cause of a tendency for solids to build up on
the rotor, resulting in plugging or rotor
unbalance.
Dry cyclones can be used individually or
in multiple banks, as shown schematically in
Figure 3-8. Packaged units with clusters of
small-diameter tubes are preferred for their
higher efficiency, but power consumption is
greater. Collected particulates are usually re-
moved continuously to a collection hopper.
Table 3-2. PARTICULATE COLLECTION EQUIPMENT
Equipment class
Mechanical dry
collector
Wet collector
Fabric filter
Gas pressure loss,
in. water
1 to 5
1.5to80b
0.5 to 12C
Efficiency,3
percent
50 to 90
60 to 99+
95 to 99.9
Power requirement,
hp/cfm
0.0003 to 0.002
0.0005 to 0.03b
0.0002 to 0.004
aFor an aerosol having approximately 10 to 15 percent of particles less than 10 microns in
diameter, by weight count.
consumption can be mainly in pressure loss (for example, venturi scrubbers) or mainly in
water pumping (for example, hydraulic scrubbing towers).
cHigher efficiencies can be obtained at lower pressure drops, where the goal is to maximize
diffusion capture of fine particles by decreasing the filter velocity.
3-13
-------
Table 33. CONTROL EQUIPMENT AND COLLECTION
EFFICIENCIES FOR BERYLLIUM PRODUCTION PLANTS4
Operation or process
Ore handling, crushing,
ball milling, "tc.
Sinter furnace
Leaching and hydroxide
filter
Sodium fluoride ha'ndlmg
(no Be)
Beryllium hydroxide, dry
Beryllium hydroxide dryer
and calcmer
Beryllium fluoride mixer
Beryllium fluoride furnace
Reduction furnace
Machining, powder metals
handling
Welding, heat-treating
Miscellaneous laboratory
hoods
Type of gas cleaner
Reverse |iM or shaking
fabric: filter
Wet cell or spray
scrubber
Wet cell or spray
scrubber
Wet cell or spray
scrubber
Reverse |i:t or shaking
fabric filtef
Wet spray unit for
cooling, then to
above unit
Wet cell or spray
tower
Ventun scrubber,
orifice scrubber,
or packed tower
and wet Cottrell
unit
Ventun scrubber,
orifice scrubber,
or packed tower
and wet Cottrell
unit
Small cyclone units
plus fabric filter with
asbestos filter aid
Fabric filtor with filter
aid and dilution air
to bring tem|>eraturc
to 80 C
Roughing filter plus
HEPA filters
Expected
efficiency,
percent b'y weight
99
80
80
80
99
99
80
95
95
99.9
99.9
99.95
3.1.5.2.2 Wet collectors. Wet collectors
are used to treat exhausts from chemical
processes, such as the conversion of ore to
beryllium hydroxide and beryllium hydroxide
to billets, which emit hot, corrosive, or toxic
vapors. For example, sulfur trioxide, silicon
fluoride, hydrogen fluoride, ammonium fluo-
ride, and ammonia occur in process exhausts
that contain beryllium compounds. Wet col-
lection of some beryllium compounds, for
example, extremely hygroscopic beryllium
fluoride fume from furnaces, is advantageous.
In general, wet collectors are applied to
remove hot, corrosive, wet, sticky, hygro-
scopic, agglomerating, or inflammable ma-
terials from gas streams.
Collection efficiencies (Table 3-2) of wet
collectors are closely related to the energy
expended in providing contact between par-
ticulates and scrubbing liquid. The design
details of individual types of scrubbers in the
same energy range are, however, important in
directing input power to achieve maximum
contact and collection efficiency. Large in-
creases in scrubbing power are required to
collect submicron particles; pressure decreases
of 50 inches of water or more are necessary
for better than 99 percent efficiency when a
large portion of the entrained particulate is of
submicron size.
Wet collectors are classified as low-
energy, medium-energy, and high-energy
types. The most frequently used wet collec-
tors in beryllium production plants are classi-
fied as follows:
1. Low-energy type: orifice scrubbers.
2. Medium-energy type: packed-tower
scrubbers, hydraulic scrubbing
towers, and floating-bed scrubbers.
3. High-energy type: ejector venturi
scrubbers and venturi scrubbers in
series with cyclones or packed
towers.
Schematic diagrams of the construction fea-
tures of these scrubbers are shown in Figure
3-9.
Packed-tower scrubbers and venturi
scrubbers excel in removal of vapors from gas
streams, the packed tower by provision of
large surface area of liquid-gas contact and the
venturi scrubber by provision of contacting
large numbers of liquid droplets with the gas
stream. The ability of these collectors to
provide simultaneous gas-to-liquid extraction
and efficient particle removal is advantageous
in controlling emissions from beryllium pro-
duction. Power consumption and efficiencies
of particle and vapor removal of packed-tower
scrubbers depend largely on bed depth.
Problems encountered in the use of wet
collectors are listed below:
1. Water and fine-particle carry-over.
3-14
-------
AIR OUT
AIR
OUT
\
AIR IN
DRY CYCLONE
(TANGENTIAL ENTRY)
MULTIPLE CYCLONE
COLLECTOR
V
DRY CYCLONE
(AXIAL ENTRY)
Figure 3-8. Types of dry mechanical collectors used by beryllium extraction facilities.
2. Buildup of corrosive compounds in the
liquid and of residue in the apparatus;
clogging of nozzles, particularly at large
recirculation ratios.
3. High installation cost.
4. High operational cost.
5. Leakage of contaminated liquids.
3.1.5.2.3 Fabric filters. Fabric filters are
used to control emissions from the processes
of converting beryllium metal billets to metal
forms, beryllium hydroxide to alloys, and
beryllium hydroxide to beryllia powder and
ceramics. These operations require highly
effective removal of toxic dusts and fumes.
A typical fabric filter application is a
compartmented, shaker-type collector utilized
as a secondary air cleaner for dry gases. This
collector contains several thousand Orion*
bags, each coated with asbestos "floats" as a
filter aid. It operates at a 6:1 filter ratio and
* Mention of commercial products or company name
does not constitute endorsement by the Environmen-
tal Protection Agency.
handles a flow rate of approximately 70,000
cubic feet per minute. (The filter ratio is
defined as the volumetric flow rate in cubic
feet per minute divided by the fabric surface
area in square feet.)
The following are characteristics of par-
ticulate collection by the use of fabric filters:
1. High efficiencies (better than 99.5
percent) can be achieved.
2. Collectors can be frequently regen-
erated, or cleaned to a condition of
lower pressure decrease.
3. Periodic recovery of valuable materi-
als is practical.
Power requirements and a range of attain-
able efficiencies for fabric filters are specified
in Table 3-2. The buildup of a filter cake and
the use of filter aids are important in the
attainment of optimum efficiency of opera-
tion. Beryllium production plants usually
operate pulse-jet and reverse-jet filters at
pressure decreases of 6 to 9 inches of water.
3-15
-------
WATER IN
t
AIR IN
AIR IN-
WATER
IN
EJECTOR VENTURI SCRUBBER
AIR OUT
AIR
AND
WATER
OUT
VENTURI SCRUBBER
WATER
IN
WATER
OUT
DEMISTER
V
SCREENS
WATER
' IN
ORIFICE TYPE COLLECTOR
AIR OUT
WATER
IN
FLUIDIZED
BALLS
WATER
OUT
WATER
IN
WATER OUT
HYDRAULIC SPRAY TOWER FLOATING BED SCRUBBER
Figure 3-9. Types of wet collectors used
Fabric filters are characterized by the
following variables:
1. Materials: woven or felted structure;
type of weave or felting; material
composition; use of fabric condi-
tioner or filter precoat.
2. Fabric geometry: tube or envelope;
dimensions.
3. Construction: open or closed
housing; internal or external flow of
burdened gases; pressure or suction;
compartmentation for cleaning while
in service.
4. Method of cleaning: shaking; bag
collapse; bag inversion; pulse jet; tra-
WATER OUT
PACKED TOWER SCRUBBER
in beryllium production plants.
veling reverse jet; other variations,
including air horns.
The various types of fabric filters, a wide
variety of which are used by beryllium pro-
duction plants, are shown in Figure 3-10.
Beryllium production plants employ
closed suction (i.e., closed housing and suc-
tion operation) filters to protect the fan from
contamination. The larger, shaker-type filters
are compartmented to allow cleaning during
operation. Tube, rather than envelope, bags
are preferred for ease of replacement. For
particulates with large portions of submicron
particles, bags made of Dacron, Orion, or
Nylon are used because the conventional
3-16
-------
AIR OUT
REVERSE
JET
BLOWER
VIBRATOR
JET
RING
TRAVEL
TRAVELING REVERSE JET CLEANING METHOD
SHAKER CLEANING METHOD
AIR
OUT
AIR JET
CLEANING ~^"Tp
~-^~ AIR OUT
AIR
IN
PULSE JET CLEANING METHOD
AIR
DUST BEING
DISLODGED
BAG COLLAPSE CLEANING METHOD
Figure 3-10. Types of fabric filters used in beryllium production plants.
cotton sateen bags appear to be more easily
"blinded" by fine dusts. For high-temperature
exhausts, the relatively recent use of Nomex
fabric bags, at temperatures of up to 220°
Celsius, extends the applicability of fabric
filters to situations which previously required
scrubbers with higher operating costs and
lower efficiencies.
Fabric filters usually have woven tube
bags that are dependent on filter cake buildup
for highly efficient collection of participates.
An effective dust layer normally accumulates
on the fabric within the initial few minutes of
operation. In beryllium plants, woven bag
filters are operated at filter ratios of 1:1 to
3:1, and pressure decreases range from 2 to 8
inches of water. Felted fabrics are employed
in reverse-jet and pulse-jet filters, and pressure
decreases average about 6 inches of water
between cleaning cycles. These latter types of
filters are operated at filter ratios ranging
from 5:1 to 10:1 and can accommodate high
dust loadings. However, the tendency of
felted fabrics to become irreversibly clogged
by fine fumes has limited the application of
this type of fabric.
Two of the problems encountered in the
use of fabric filters are:
1. Relatively large space requirements.
2. Limitations imposed by temperature,
wetness, and abrasive qualities of
particulate-laden gas streams.
3-17
-------
3.2 BERYLLIUM METAL, BERYLLIUM
OXIDE, AND BERYLLIUM-COPPER
ALLOY MACHINE SHOPS
Beryllium and beryllium-containing pro-
ducts are processed by numerous domestic
machine shops and fabrication plants into
end items for industry, defense, and space
flight. Most of this material is beryllium-
copper alloy. About 60 percent, or 225
tons, of beryllium production in 1970 is
estimated to have gone into alloys that
nominally have 2 percent beryllium con-
tent;1 >6 beryllium metal and beryllium oxide
accounted for approximately 35 and 5 per-
cent, respectively, of production.
3.2.1 Machining and Emissions
Machine shops obtain numerous forms of
beryllium, such as pressed, extruded, rolled,
or forged material, from primary producers.
Examples of the subsequent machining opera-
tions are turning, milling, grinding, drilling,
lapping, honing, and electrical discharge
machining.
The Air Force Machinability Data Center
recommends that beryllium machining be
performed dry wherever possible,7 and the
majority of machine shops follow this prac-
tice. One benefit of dry machining is the
resultant higher reclamation value of clean
beryllium chips generated by machining, by
comparison with mixtures of chips and cut-
ting fluids. A cutting fluid is necessary,
however, for deep-hole drilling, reaming, and
tapping. Liquids do not seem to be necessary
for grinding, honing, and polishing, but they
are widely used in these operations and in
others for which it is desirable to decrease
tool replacement costs. Various machining
operations, such as milling, grinding, drilling,
lapping, and honing, are also performed on
beryllium oxide forms and beryllium-copper
alloy stock.
The nature and quantity of potential
atmospheric emissions from beryllium, beryl-
lium oxide, and beryllium-copper alloy ma-
chining facilities are widely variable. The type
of machining operations (rough cutting, finish
cutting, dry, wet) determines whether the
emissions are beryllium-containing chips,
dust, mist, or fume. When finish cutting or
grinding is performed, emissions are primarily
in the form of dust, mist, or fume, whereas
rough cutting produces chips and a smaller
quantity of dust, mist, or fume. The use of
cutting fluids is the primary source of mists
and fumes in most operations. The extent to
which the machining operations are ventilated
to the atmosphere affects the quantity of
uncontrolled emissions. In contrast with
beryllium and beryllium oxide machine shops,
beryllium-copper alloy machine shops are
essentially uncontrolled except where low-
efficiency collectors are used to capture larger
chips for recycling.
Accidental combustion of beryllium par-
ticles generated by machining operations has
occurred, and such fires are potential beryl-
lium emission sources at machining facilities.8
Finely divided beryllium dust that adheres to
the surfaces of ventilation ducts and gas
cleaning equipment can be ignited by sparks.
The use of oils, especially kerosene, as cutting
fluids for wet machining can increase the
possibility of beryllium fires. Fires can occur,
for example, at locations where chips, dust,
and kerosene are carried into a dry-type
particulate collector which directly serves a
machining operation.
Secondary beryllium emissions can result
from the removal of beryllium-containing
dust and machining chips from gas cleaning
devices, from the packaging of these for
disposal, and from changing contaminated
disposable-type filters.
3.2.2 Emission Control Techniques
Individual processes for machining beryl-
lium-containing materials require local ventila-
tion to control beryllium emissions to the
surrounding work space. The geometrical con-
figurations and air flow capacities of dust
capture hoods should be tailored to effici-
ently collect wastes from each type of ma-
chine. Practical dust and chip capture velo-
cities are usually 500 to 3000 feet per minute,
3-18
-------
and those for large chips are as high as 14,000
feet per minute. Open-face hood velocities are
seldom smaller than 150 and may exceed 300
feet per minute. Hose, pipe, and duct trans-
port velocities are usually 3000 to 4000 feet
per minute, but may range from 2500 to
6000 feet per minute.9 -1 °
Various beryllium emission control air
streams from individual processes for machi-
ning beryllium-containing materials can be
manifolded together prior to eventually ex-
hausting these from a work space. Beryllium
emissions to the atmosphere can subsequently
be controlled by successively passing the gas
stream through more than one gas-cleaning
device (Figures 3-11 through 3-13). Table 3-4
indicates the current frequency of use of
various gas-cleaning devices in beryllium and
beryllium oxide machine shops and specifies
the location of each device in a multiple-
collector installation.
3.2.2.1 Mechanical Collectors
Exhaust streams from wet machining
operations can undergo initial cleaning in
oil-mist collectors or in centrifugal fan wet
scrubbers. The latter are suitable for collect-
ing chips and dust. In normal situations where
the composite beryllium-containing ventila-
tion stream from wet machining operations is
much smaller than that from dry machining,
the initial cleaning and combining of the two
streams prior to final-stage gas cleaning reduce
the possibility of condensation and resultant
clogging of the final filters.
3.2.2.2 Fabric Filters
Fabric filter installations can be used as
either intermediate or final collectors. As an
intermediate collector, a fabric filter precedes
a bank of HEPA filters to prevent the
overloading of the HEPA filters and to make
possible the reclamation of significant quan-
tities of valuable beryllium-containing particu-
MANUAL SHAKER
FABRIC FILTER
TUBES
.-FLANGED ACCESS
/V DOORS FOR FILTER
/ CHANGE
HEADER OR MANIFOLD
S
LOCAL EXHAUST
FEEDERS
TO
STACK
5-hp MOTOR AND
CENTRIFUGAL FAN
SYSTEM CAPACITY = 600 cfm
Figure 3-11. Unitized fabric tube filter, prefilter, and HEPA filter for beryllium or beryllium
oxide machining facility.
3-19
-------
HEADER OR MANIFOLD
^ofi
LOCAL
EXHAUST
FEEDERS
MULTIPLE
CYCLONE
COLLECTOR
PLASTIC
ADAPTER
FLANGED ACCESS
DOORS FOR FILTER
CHANGE
TO
STACK
55-gallon
DRUM "*•
SYSTEM CAPACITY = 600 dm
5-hp MOTOR AND
CENTRIFUGAL FAN
Figure 3-12. Unitized multiple dry cyclone collector, prefilter, and HEPA filter for beryllium
or beryllium oxide machining facility.
lates. For example, smaller machining chips
and dust from beryllium machine shops can
be discharged directly from the filter cake of
a fabric filter into a shipping barrel for sale
and eventual reclamation. When operated as
final collectors, fabric filters are usually pre-
ceded by either a screening- or a cyclone-type
collecting device. Ventilation streams from
both wet and dry machining operations can
be cleaned by fabric filters.
3.2.2.3 HEPA Filters
HEPA filters can reduce beryllium emis-
sions from machine shops to concentrations
smaller than those attainable with fabric
filters. As previously indicated in Table 3 -4,
HEPA filters are used in some instances as
final filters by beryllium and beryllium oxide
machine shops.
In many cases, a precleaning device
should precede a HEPA filter installation to
extend the lifetime of the HEPA filter
(Figures 3-11 through 3-13). HEPA filters can
remain in service for a year or more, depend-
ing upon inlet particulate loading.
3.2.3 Beryllium Fires
The use of water or carbon dioxide to
extinguish the combustion of beryllium-
containing materials can be ineffective or even
detrimental.8 jl x A recommended practice is
smothering of the fire with a suitable dry
powder.11 Local fire departments and fire-
fighting units controlled by manufacturing
facilities should be informed of the presence
of beryllium-containing materials that are
subject to combustion.
Equipment surfaces on which fine beryl-
lium-containing dust can be deposited, for
example ducts of local ventilation systems,
should be periodically cleaned and should be
protected from the incidence of sparks which
can initiate combustion. High-velocity air
flows, which may induce spontaneous com-
3-20
-------
CYCLONE
DIFFERENTIAL PRESSURE GAUGE
S-FOLDED FILTER MEDIUM
X
ROOM AIR IN
SALVAGED MATERIAL DRUM
PREFILTER SERVICE
BANK ACCESS
HEPA FILTER BANK
Figure 3-13. Air cleaning system for beryllium or beryllium oxide machine shop process and
ventilation air streams.
bustion of mixtures of volatile cutting fluids
and fine beryllium dust in ducts and in
gas-cleaning devices, should be avoided.
3.3 BERYLLIUM-COPPER FOUNDRIES
Foundries melt beryllium-copper alloy
ingots, which usually contain 1.90 to 2.05
percent beryllium by weight, and recast these
into end products. A small number of
foundries use 4 percent beryllium-copper
master alloy. The quantities of beryllium-
copper alloy processed at various foundries
vary widely from occasional use for special
jobs to casting on a continued basis; the
largest foundries individually cast more than
30 tons of alloy per year.
3.3.1 Foundry Operations and Emissions
The casting of beryllium-copper alloys
into end products begins by placing ingots
into a crucible and subsequently melting these
by heating the material in an electrical or
induction furnace or by a natural-gas-fired
lance which is directed against the material in
the crucible. No fluxes, slag covers, or de-
oxidizers are required since the alloy is
typically heated to a pouring temperature of
1100° to 1130° Celsius. As the melting
proceeds, an empty transfer crucible may be
preheated to receive the molten alloy prior to
casting of the metal into molds. The degree of
shielding of melting and preheating operations
from the adjacent work space can vary be-
tween the limits of complete exposure and
rather complete enclosure of the processes.
Upon completion of the melting cycle,
the contents of the primary crucible are
typically poured into a transfer crucible, and
waste metal oxides and impurities are manu-
ally ladled, or drossed, from the top of the
transfer crucible. Subsequently, the transfer
crucible is covered and transported to a
casting area. The molten alloy is usually
poured directly from the transfer crucible
into molds of various types, for example,
3-21
-------
Table 3-4. GAS CLEANING EQUIPMENT FOR BERYLLIUM
AND BERYLLIUM OXIDE MACHINE SHOPS
Equipment
Oil-mist collector
Wet rotary cyclones
Dry rotary cyclones
Multiple (dry) cyclones
Fabric filters
Prefilter and HEPA filter
Frequency of use
Fairly common
Fairly common
Fairly common
Frequent
Fairly common
Fairly common
Location
Initial
Initial
Initial
Initial
Intermediate
or final
Final
centrifugal, permanent, precision investment,
pressure casting, or vacuum assist molds.
Foundry practices also include the direct
charging of molds from a primary crucible
and the indirect filling by operations other
than pouring. The solidified casting products,
after being removed from the molds, are often
given such finishing operations as rough cut-
ting, grinding, cleaning, and polishing. Anneal-
ing, precipitation hardening, and welding of
beryllium-copper alloys are also performed at
foundry facilities.
Beryllium-containing fumes can be gene-
rated by the following foundry operations:
1. Melting ingots in primary crucibles,
particularly when a gas-fired lance is
used.
2. Preheating transfer crucibles that
have previously contained beryllium-
copper alloy.
3. Transferring molten beryllium-copper
alloy from a primary to a transfer
crucible.
4. Dressing and dross handling.
5. Charging molds with beryllium-cop-
per alloy.
Finishing operations, such as cutting, grind-
ing, and buffing, which are performed on cast
products, are potential sources of beryllium-
containing dust emissions.
In an overall sense, atmospheric emissions
of beryllium from beryllium-copper foundries
are not well controlled at present.12 Emis-
sion-producing operations are often locally
ventilated by suction hoods, but the exhausts
are discharged to the atmosphere without
treatment to remove contaminants. Heated
gases generated during foundry operations are
frequently permitted to mix with work space
ventilation air to form natural draft currents
that are emitted from roof ventilators of an
enclosing structure.
3.3.2 Emission Control Techniques
Beryllium-containing emissions from the
various emission sources listed in Section
3.3.1 can be entrained at the source into an
air stream by the use of local particulate
capture hoods. Ventilated enclosures are of-
ten effective, for example, in containing
potential emissions from melting furnaces. At
those beryllium-copper foundries that control
atmospheric emissions, it is common practice
to manifold together numerous emission
streams to form a single contaminated gas
stream, which is then treated in a large-scale
final collector prior to discharge into the
atmosphere.
Emissions from beryllium-copper foun-
dries can be controlled by the use of fabric
filters as final collectors; settling chambers or
conventional cyclones can be employed as
precollectors to remove larger particulates and
thereby reduce the required cleaning fre-
quency of final fabric collectors. Fabric filter
installations containing Dacron bags with air
flow permeabilities in the range of 15 to 25
cubic feet per minute per square foot have
been successfully operated at filter velocities
of approximately 2 feet per minute to control
emissions from beryllium-copper foundries.
3.4 MANUFACTURE OF BERYLLIUM CE-
RAMIC PRODUCTS
Three domestic ceramic manufacturing
plants, in addition to the beryllium extraction
plants, produce beryllium oxide ceramic stock
material. Hundreds of companies, the majo-
rity in the electronics industry, purchase
ceramic stock and special ceramic forms, and
subsequently convert these into finished pro-
ducts. It is estimated that approximately 5
percent of total domestic beryllium produc-
tion was used in ceramic manufacture in
3-22
-------
1970.1 The consumption of beryIlia ceramics
is expected to increase by more than 10
percent per year for the next 5 years.1 •'3
3.4.1 Ceramic Production and Emissions
The production of beryllium oxide
ceramic materials at beryllium extraction
plants is briefly described in Section 3.1.4.4.
Other plants manufacture beryllium ceramics
from low-fired beryllium oxide as the initial
raw product. Figure 3-14 illustrates the se-
quence of processing operations at a typical
beryllium ceramic plant; the basic steps are as
follows:
1. The raw material (beryllium oxide) is
received and weighed.
2. The beryllium oxide is ball-milled to
a size that is determined by its end
use. The particular end application
also dictates which binders, such as
water, polyvinyl alcohol (PVAL), and
polyethylene glycol (PEG), should be
added to aid in processing the oxide.
Dyes are placed into the material to
code it for specific applications.
3. The material is screened to minus
200 mesh.
4. Spray drying is carried out by pump-
ing the oxide into a counter current
stream of dry air which has a tem-
perature range of approximately 80°
to 150° Celsius. The product is col-
lected by negative pressure at the
base of the enclosed spray drying
chamber or by particulate collection
equipment such as a fabric filter.
5. The dried oxide is discharged either
to a dry screening operation or to a
process in which additional binders
are added to produce extrusion-grade
beryllium oxide. In the extrusion
process, material is forced through
dies to create desired cross-sectional
shapes.
6. Material that is not extruded is
passed through a dry screening ferro
filter to remove undesired material.
RECEIVING
BeO
0.4-0.75
H20,
PVAL,
PEG
WET MILL TO
400 -1000A
SCREENING
(200 MESH)
SPRAY DRYING
1800 F
1
• t-
DRY SCREENING
FERRO FILTER
1
FORMING
1
DEDUSTED,
VIBRATED
*l
ADD BINDERS
AND MIX
FOR EXTRUSION
GRADE BeO
1
EXTRUSION
1
SINTERING
INSPECTION
GRINDING,
MACHINING
Figure 3-14. Manufacture of beryllium oxide
ceramic products.
3-23
-------
7. Forming of the oxide is carried out in
high-pressure presses enclosed in a
negative-pressure dry box. Isostatic
forming, which applies uniform pres-
sure to all surfaces of an article,
ensures the attainment of uniform
density of the pressed form.
8. All extruded or formed material is
dedusted and then sintered to volati-
lize the binders (water, PVAL, and
PEG). Kilns are either electric or gas
fired, and no measures are usually
taken to collect emissions of the
binders.
9. The ceramic articles are inspected
and then subjected to various
machining operations, for example,
drilling, grinding, and lapping. Other
production processes include metal-
lizing, brazing, and soldering.
Emissions of beryllium-containing materi-
al from ceramic manufacturing plants are
almost entirely in the forms of dust, fume,
and mist that contain beryllium oxide. Table
3-5 lists potential beryllium emission sources
and indicates the presence of beryllium oxide
and other emissions.
Table 3-5. SOURCES OF BERYLLIUM
CERAMIC PLANT EMISSIONS
Source
Spray dryer
Dry boxes
Kilns
Machining
Development
laboratory
Emissions
Water
Beryllium oxide
Beryllium oxide
Beryllium oxide
Binders
Water
Beryllium oxide
Binders
Water
Cutting fluids
Traces of acids
Beryllium oxide
Binders
3.4.2 Emissions Control Techniques
Emissions from beryllium ceramic plants
can be controlled by the use of primary solid
participate collectors and HEPA filters ope-
rated in tandem. The submicron size of the
beryllium oxide powder used in these plants is
an important factor in considering the appli-
cation of HEPA filters for final filtering. Fiber
glass or expanded metal prefilters installed at
dry boxes and ventilation hoods can provide
effective initial collection of larger particu-
lates. It is accepted practice to operate pri-
mary HEPA filters in close proximity down-
stream from these prefilters even when the
composite air stream formed by manifolding
together numerous individual emission con-
trol streams is passed through a second HEPA
filter unit prior to exhaust into the at-
mosphere as illustrated in Figure 3-15.14 The
second HEPA filter unit is also protected by
an appropriate prefilter. In at least one
instance, an electrostatic precipitator has been
employed as a primary filter in combination
with HEPA filters for final collection. The
primary filtering of effluents from spray
driers can be performed by fabric filters as
illustrated in Figure 3-16. Combustion gases
generated for heating fuel-fired kilns can be
exhausted to the atmosphere independently
of beryllium-containing process streams.
3.5 BERYLLIUM PROPELLANT MANU-
FACTURE, TESTING, AND DISPOSAL
A common method of increasing solid-
propellant-rocket-motor performance is the
inclusion of finely divided metals in the
polymer matrix of the propellant. Beryllium
is ideally suited to this application because it
possesses an extremely high heat of reaction.
The specific impulse of rocket motors is
significantly increased by the inclusion of
beryllium. (The specific impulse is the time
integral of the thrust produced by a rocket
motor divided by the total mass of propel-
lant.)
3.5.1 Propellant Manufacture
3.5.1.1 Process
Propellant manufacturing facilities typi-
3-24
-------
EXPANDED METAL FILTER
BLOWER PREFILTER
HEPA FILTER
AIR IN
FROM OTHER DRY
BOXES OR HOODS
HEPA FILTER
EXPANDED METAL
FILTER
NEGATIVE PRESSURE
DRY BOX OR
VENTILATION
HOOD
AIR IN
FROM OTHER DRY
BOXES OR HOODS
AIR IN
Figure 3-15. Configuration of emission control devices for beryllium ceramic plant.14
EXHAUST
HEATED
AIR IN
SPRAY DRYER
CYCLONE
HEPA FILTER
BANK
FABRIC
FILTER
BLOWER
Figure 3-16. Emission control devices for spray dryer.
cally receive beryllium powder in plastic
bottles that have been shipped in steel drums.
The powder is weighed and charged into a
high-shear mixer (dough mixer) into which
binders and oxidizers have been added. Subse-
quently, the propellant ingredients are
blended for a measured period of time to
form a homogeneous mixture of components.
The beryllium powder does not undergo
chemical reaction during the mixing or during
later phases of propellant fabrication.
Upon completion of the mixing cycle or
cycles, the propellant is cast directly into the
rocket-motor case, or a mold of the desired
shape, and oven-cured at temperatures that
range from ambient to 80° Celsius. The
3-25
-------
propellant binders and crosslinking agents
react during curing to form a hard rubber-like
material, which may be trimmed or machined
into the final configuration.
3.5.1.2 Emissions
Potential sources of beryllium emissions
from the manufacture of beryllium-containing
propellant include:
1. Handling, weighing, and charging into
mixers of dry beryllium powders.
2. Mixing of propellant ingredients.
3. Casting of propellant into molds.
4. Curing, or polymerization, of pro-
pellant.
5. Releasing of propellant from molds.
6. Sawing, trimming, machining, and
perforating of propellant.
Facilities which manufacture beryllium pro-
pellant have demonstrated the capability for
effective control of atmospheric beryllium
emissions.
3.5.1.3 Emissions Control Techniques
Potential emissions from beryllium pro-
pellant manufacturing process operations not
shielded from adjacent work spaces can be
captured by local ventilation hoods. Some
operations, such as material weighing and
emission-producing quality control tests, can
be performed in ventilated dry boxes.
Beryllium-containing p articulates
entrained in the emission control air streams
cited above can be effectively removed by the
use of HEPA filters. Operations, such as
machining, that produce relatively large con-
centrations of larger particulates require that
a prefilter or mechanical collector be placed
upstream from the HEPA filters.
3.5.2 Beryllium-Rocket-Motor Static Test
Firing
3.5.2.1 Process
Beryllium rocket motors are test fired
statically in order to verify calculated perfor-
mance characteristics and establish reliability
of motors. Tests are performed on motors
which contain quantities of propellant ranging
from less than ten to several thousand
pounds. The total amount of beryllium pro-
pellant employed in these activities can be
gauged by observing that propellant con-
taining approximately 8700 pounds of beryl-
lium was static fired, or aborted in static
firings, at one of the major test facilities
during the period from March 1963 through
October 1967.
3.5.2.2 Emissions
The combustion of beryllium rocket pro-
pellant during a static test firing produces
heated gases that may contain such beryllium
compounds as beryllium oxide, beryllium
nitrate, beryllium carbide, and beryllium
chloride;15 other beryllium compounds can
also be formed. The potential beryllium emis-
sions are characterized by discharge over a
short duration of time and containment in a
gas stream with relatively high mass flow rate.
In numerous static tests of beryllium
rocket motors, the combustion products have
been exhausted directly into the atmosphere
without treatment to remove air contami-
nants. However, attempts have been made to
minimize adverse effects of these contami-
nants by performing many tests, under fa-
vorable meteorological conditions, at sites
that are remote from locations of human
activity. In some cases, the resultant concen-
trations of beryllium in the vicinity of the test
area have been monitored.
3.5.2.3 Emission Control Techniques
One approach to the control of atmos-
pheric emissions from test firing of rocket
motors is the collection of all products of
combustion in a sealed container and the
subsequent cleaning of the particulate-laden
gas stream as it is released from the container
at a much smaller mass rate of flow. A facility
of this type, including a tank 40 feet in length
by 10 feet in diameter and HEPA filters for
gas cleaning, has been successfully used to
control emissions from the test firing of
50-pound beryllium rocket motors.
A second method of controlling at-
mospheric emissions of beryllium from test
firing of rocket motors is the application of
3-26
-------
a gas-cleaning device to treat the products of
combustion as these are exhausted from the
motor. A subscale gas-cleaning unit, which
includes a water-spray cooling duct followed
by a cyclone water-spray scrubber, has been
reported to have a particulate control effi-
ciency of greater than 99.9 percent for
rocket-motor flow rates of up to 10 pounds
per second.16 The further development of
scrubbers of this type has permitted the static
testing of approximately 100-pound charges
of propellant at mass flow rates of up to 30
pounds per second.
Emissions from beryllium-rocket-motor
test firing have also been controlled, by use of
water sprays for cooling and for subsequent
gas scrubbing, in the absence of a downstream
cyclone-type collector. A shell-and-tube heat
exchanger (Figure 3-17) has been reported to
be an effective impingement collector for
beryllium-containing mist during tests of pro-
pellant charges as large as 170 pounds.17
Even though a particulate collection effi-
ciency of 99.98 percent has been reported for
a scrubbing system of the type shown in
Figure 3-17, including collection in the heat
exchangers and gas compressors,17 HEPA
filters have been utilized as final collectors
before exhaust to the atmosphere. A coarse
screen impingement separator protects the
21,000-gpm WATER SPRAY
1,500-gpm WATER WALL SPRAY
7,000-gpm WATER SPRAY
TEST CELL
HEPA filters by removing any entrained water
that may be present in the compressor ex-
haust.
The use of water scrubbers to control
beryllium emissions during rocket motor test
firings requires extremely large water flow
rates. These would be prohibitively large for
the testing of the largest proposed full-scale
propulsion motors, for example, an estimated
3 million gallons per minute for a 350,000-
pound-thrust beryllium rocket motor.17 The
beryllium contamination of a test facility,
including ejectors, heat exchangers, and com-
pressors, is also a disadvantage of this emis-
sion control method because special personnel
protection must be employed during mainte-
nance of equipment.
3.5.3 Disposal of Beryllium Propellant
3.5.3.1 Process an d Emissions
Beryllium-containing wastes are generated
during the manufacture of beryllium solid
propellant. These wastes must be disposed of
in a manner which controls any accom-
panying atmospheric emissions of beryllium.
In numerous cases, the disposal of beryl-
lium propellant waste has been accomplished
by open burning. Disposal has been carried
out at sites remote from human activity,
under meteorological conditions favorable to
ATMOSPHERE
O.Sji DRY PAPER
ABSOLUTE FILTERS
/ \
EXHAUST GAS COMPRESSORS •
Figure 3-17. Schematic diagram of rocket motor test cell.18
3-27
-------
rapid dispersion, to minimize adverse effects
of the resulting beryllium contaminants.
3.5.3.2 Control Techniques
The susceptibility of waste propellant to
explosion excludes burial as a suitable method
of disposal. However, the deliberate explosion
of beryllium propellant can be carried out in
an enclosed tank, and atmospheric beryllium
emissions can be controlled by exhausting the
resultant gases, at a controlled flow rate,
through HEPA filters. This method has been
successfully used to dispose of small quanti-
ties of beryllium propellant.
Section 3.6 contains a more detailed
discussion of the disposal of beryllium-
containing wastes.
3.6 DISPOSAL OF BERYLLIUM-
CONTAINING WASTES
3.6.1 Process
Beryllium-contaminated single-service fil-
ters, fabric filter precoat materials, clothing,
rags, brushes, and plastic bags, frequently
wetted with oil or other liquids, are generated
by industrial beryllium activities and must
undergo disposal. The disposal of beryllium
propellant and some beryllium-containing
wastes generated by the manufacture of pro-
pellant is complicated by the explosive char-
acter of the materials.
Beryllium-contaminated wastes are cur-
rently disposed of by numerous methods.
Some examples are:
1. Burial in a designated dump owned
by the company that generates the
wastes.
2. Burial in a segregated portion of a
city or county dump.
3. Encasement of irradiated, beryllium-
containing material in concrete and
subsequent burial.
4. Burial at sites controlled by the
United States Government.
5. Burial at sites managed for the dispo-
sal of toxic materials.
6. Storage in abandoned underground
mines.
7. Incineration at facilities owned by
the company that generates the
wastes.
Significant quantities of beryllium-containing
wastes, including beryllium propellant, have
also been disposed of by open burning. At the
other extreme, large quantities of beryllium-
containing materials removed by machining
processes and subsequently collected by gas-
cleaning devices are routinely sold for repro-
cessing into raw materials.
3.6.2 Emissions
Atmospheric beryllium emissions can oc-
cur during the handling and packaging of
wastes, during transport to a disposal site, and
in the process of carrying out ultimate dispo-
sal. Much of the beryllium-containing waste is
packaged in plastic bags, metal drums, or
plastic drums and is adequately sealed to
control emissions during transportation and
during initial deposition of those material that
undergo ultimate disposal at dumping and
burial sites.
3.6.3 Control Techniques
If beryllium waste materials are incin-
erated, the products of combustion should be
subjected to gas cleaning prior to discharge
into the atmosphere. Wet scrubbers can be
employed for gas cooling and primary collec-
tion of particulate contaminants; HEPA filters
can perform efficient secondary collection.
An incinerator with this type of beryllium
emission control equipment is now under
construction.18
Beryllium-contaminated wastes are pref-
erably enclosed in plastic bags or containers
and then sealed in metal drums prior to
deposit and burial at a dump area. A burial
site that will not be subject to uncovering of
the waste at a later date should be chosen,
and a portion of the site should be reserved
and clearly marked for the disposal of berylli-
um-contaminated wastes only. If the burial
site management is not under the control of
those persons who have released material for
disposal, then those persons should verify that
appropriate disposal techniques are practiced.
3-28
-------
Beryllium propellant can be chemically
reclaimed on a full-scale basis at a cost of
approximately $100 per pound of propel-
lant.19 However, this process has not yet
been adopted as a waste disposal method and
is uneconomical for small quantities. Rela-
tively small quantities of beryllium propellant
can be burned or exploded in a closed
container to convert the solid waste propel-
lant into a parti culate-containing gas from
which the contaminants can be removed by a
gas-cleaning device. Charges of propellant as
large as 10 pounds have been exploded in a
sealed underground tank; emissions have been
controlled by the subsequent venting of the
tank contents through HEPA filters.19
3.7 REFERENCES FOR SECTION 3
1. Heindle, R. A. Beryllium. In: Mineral
Facts and Problems (1970 Ed.). U. S.
Department of Interior, Bureau of Mines.
Washington, D. C. Bulletin 650. 1970. p.
494,497.
2. Crocker, L., R. O. Dannenberg, D. W.
Bridges, and J. B. Rosenbaum. Recovery
of Beryllium from Spor Mountain, Utah,
Ore by Solvent Extraction and Caustic
Stripping. U. S. Department of Interior,
Bureau of Mines. Washington, D. C. Re-
port of Investigations 6173. 1963. 27 p.
3. Dannenberg, R. O., L. Crocker, and D. W.
Bridges. Expanded Investigation of Beryl-
lium Solvent Extraction of Spor Moun-
tain, Utah, Ore. U. S. Department of
Interior, Bureau of Mines. Washington, D.
C. Report of Investigations 6469. 1963.
31 p.
4. Silverman, L. Control of Neighborhood
Contamination Near Beryllium-Using
Plants. AMA Arch. Ind. Health. 79:176,
1959.
5. Control Techniques for Particulate Air
Pollutants. U. S. Department of Health,
Education, and Welfare, National Air
Pollution Control Administration.
Washington, D. C. NAPCA Publication
No. AP-51. January 1969. p. 47.
6. Trends in Usage of Beryllium and Beryl-
lium Oxide. National Research Council.
Washington, D. C. Materials Advisory
Board Report MAB-238. February 1968.
p. 4.
7. Snider, R. E. and J. F. Kahles. Machining
Data for Beryllium Metal. Air Force
Machinability Data Center. Cincinnati,
Ohio. AFMDC 66-3. June 1966.
8 Hammond, S. E. and J. E. Hill. Beryllium
Control at Rocky Flats. U. S. Atomic
Energy Commission, Washington, D. C.
Report RFP-384, USAEC Contract AT
(29-D-l 106. April 1964. p. 10-11
9. Breslin, A. J. and W. B. Harris. Health
Protection in Beryllium Facilities, Sum-
mary of Ten Years of Experience. U. S.
Atomic Energy Commission, New York
Operations Office. New York, N. Y.
USAEC Report HASL-36. May 1, 1969.
p. 11-21.
10. Dieringer, L. F. Health Control Program
in a Beryllium Facility, 3 Years' Experi-
ence. J. Occupational Med. 7(9)A51-46Q,
1965.
11. Fire Protection Guide on Hazardous Ma-
terials (2nd Ed.). National Fire Protection
Association. Boston, Mass. 1967. p.
46-49.
12. Hardy, H. L. Statement to Subcommittee
on Air and Water Pollution of the Com-
mittee on Public Works, U. S. Senate, 89
Session, Second Session on S.3112. Wash-
ington, D. C. June 1966.
13. Schilling, S. A. Beryllium. Eng. Mining J.
777:116-117, March 1970.
14. Wolff, C. T. Private communication to J.
Desantis, U. S. Environmental Protection
Agency, Research Triangle Park, N. C.
American Lava Corporation, Chatta-
nooga, Tenn. October 14, 1971.
15. Beardall, J. S. and N. L. Eatough. Evalua-
tion of Subscale Rocket Exhaust Gas
Scrubber. Hercules Powder Company,
Bacchus Works. Magna, Utah. Report No.
HPC-050-12-1-53. December 1963. p. 1.
3-29
-------
16. Industrial Hygiene Functions in the Man-
ufacture of Beryllium Propellants Safety
Department, Hercules Incorporated, Bac-
chus Works. Magna, Utah. October 11,
1968. p. 6-8.
17. LaBlonde, C. J. and D. W. Male. Control
of the Toxic Effluents from Beryllium
Rocket Motors during Simulated Altitude
Testing. Arnold Engineering Development
Center, Air Force Systems Command.
Tullahoma, Tenn. TN37389. March 1972.
p. 8, 18.
18. Private Communication to J. F. Peoples,
U. S. Environmental Protection Agency,
Research Triangle Park, N. C., from a
beryllium processing company.
19. Christofano, E. E. Private Communica-
tion to J. F. Peoples, U. S. Environmental
Protection Agency, Research Triangle
Park, N. C. Hercules Incorporated, Wil-
mington, De. June 28, 1971.
3-30
-------
4. COSTS OF BERYLLIUM EMISSION CONTROL
The analyses of emission control costs
that are presented in this section are based
upon the costing method discussed in Refe-
rences 1 and 2. Accordingly, the costs of
emission control are separated into three
categories:1
1. Capital investment.
2. Operating and maintenance costs.
3. Capital charges.
The installed cost of an emission control
system includes charges for the following
items:
1. Control equipment.
2. Transportation of equipment.
3. Auxiliary equipment and materials
such as fans, motors, control instru-
mentation, ductwork, and piping.
4. Clarifiers and liquid treatment sys-
tems for wet collectors.
5. Insulation material.
6. Site preparation.
7. Field installation.
Maintenance cost is defined as the expen-
diture required to sustain the operation of a
system at its designed collection efficiency
with a scheduled maintenance program and
the prompt replacement of any defective
parts. Total operating cost depends upon the
following parameters:
1. Volumetric flow rate of gas that
requires cleaning.
2. Pressure differential across control
system
3. Duration of control system opera-
tion.
4. Consumption and unit cost of electri-
city.
5. Consumption and unit cost of scrub-
bing liquor.
6. Maintenance costs.
The annual operating cost for a continu-
ous-duty emission control system is based
upon 8760 hours of operation. The annual
cost of emission control is the depreciation of
the capital investment for purchase and instal-
lation of control equipment divided by the
expected life of the equipment plus the
annual capital charges (interest, taxes, and
insurance) and the annual total operating
cost.
The specific installed costs of control
systems that are cited in the following sec-
tions have been estimated by the method
outlined above, except in instances for which
actual costs were available. The estimated
costs are accurate to within ±50 percent in
most cases. However, wide variations in engi-
neering design among specific collectors of a
given type and in freight rates, gas stream
characteristics, construction codes, and labor
rates can occasionally produce less accurate
estimates. Because many facilities consider it
impractical to maintain detailed records of
operating and maintenance costs for control
equipment, the costs presented in this section
are estimated values rather than actual ones.
The cost data presented in Reference 2
are based upon March 1968 prices and wages.
The increases in wholesale commodity prices
of metals and metal products and increases in
employment earnings have been used to ad-
just costs to February 1972; cost increases of
21, 26, and 17 percent were determined,
respectively, for installed costs, maintenance
costs, and power costs.
4.1 BERYLLIUM EXTRACTION PLANTS
The basic processes in the primary pro-
duction of beryllium are discussed in Section
3.1, and appropriate classes of emission con-
trol devices are described in Section 3.1.5.2.
4-1
-------
Figures 3-1 through 3-7 provide details of
locations, types, and capacities of individual
gas-cleaning devices that can control emissions
from the numerous sources in extraction
plants. Installed costs, annual maintenance
costs, and annual power costs for emission
control are shown in Tables 4-1 through 4-8.
4.2 BERYLLIUM METAL, BERYLLIUM
OXIDE, AND BERYLLIUM-COPPER
ALLOY MACHINE SHOPS
The installed cost of emission control
equipment for small beryllium-material ma-
chining facilities can be greater than 10
percent of the cost of machining equipment.
For example, a specific packaged gas-cleaning
unit that has the capability for controlling
emissions from three lathes or milling ma-
chines is rated at 600 cubic feet per minute (6
inches of water pressure differential) and has
an installed cost of approximately $4000. The
unit includes a multiple cyclone, prefilter,
HEPA filter, 5-horsepower fan and motor,
valves, adapters for emptying collected partic-
ulates into disposal drums, and structural
supports.
The installed cost of emission control
equipment for large beryllium or beryllium
oxide machine shops is usually less than 10
percent of the total value of machining
equipment. The estimated control costs listed
in Table 4-9 apply to a beryllium machining
facility equipped with approximately 100
Table 4-1. EMISSION CONTROL COSTS FOR CONVERSION OF ORE TO
BERYLLIUM HYDROXIDE BY SULFATE PROCESS
Equipment
class
Fabric filter
Ejector-venturi
scrubber, 2 each
Dry cyclone
Fabric filter
Fabric filter
Packed tower
scrubber, 2 each
Ejector-venturi
scrubber, 2 each
Hydraulic scrubbing
tower, 2 each
Paci^ed tower
scrubber
Type
Shaker
High energy
High
efficiency
Pulse jet
Shaker
Med. high
energy
High
energy
Med. high
energy
Med. high
energy
Gas flow
rate,
cfma
5,000
1,250 each
2,500
450
5,000
1 ,200 each
1 ,200 each
1 ,200 each
6,400
TOTAL
Annual
maintenance
cost, $
495
200
75
55
495
175
175
175
475
2,320
Annual
power
cost, $b
450
3,175
225
60
450
1,015
3,060
685
2,705
11,825
Installed
cost, $
16,935
17,640
3,635
3,025
16,935
12,095
17,640
7,255
12,095
107,255
Annual
operating
cost, $
945
3,375
300
115
945
1,190
3,235
860
3,180
14,145
a Actual flow rate. Capacity flow rates are as much as 30 percent higher; where known, they are used for installed
cost estimates.
Makeup water is included in power cost.
4-2
-------
Table 4-2.EMISSION CONTROL COSTS FOR CONVERSION OF ORE TO
BERYLLIUM HYDROXIDE BY FLUORIDE PROCESS
Equipment
class
Fabric filter
Dry cyclone
Dry cyclone,c
fabric filter
Fabric filter
Venturi scrubber
Dry cyclone
Fabric filter
Hydraulic scrubbing
tower
Fabric filterd
Type
Reverse jet
High
efficiency
Combined;
conveying
Reverse jet
High energy
High
efficiency
Pulse jet
Med. high
energy
TOTAL
Shaker
Gas flow
rate,
cfma
12,600
750
1,000
5,000
2,000
2,700
3,900
6,000
1/3x
65,000
Annual
maintenance
cost, $
1,265
25
140
500
165
85
375
225
2,780
2,150
Annual
power
cost, $b
2,250
70
1,325
1,005
2,675
235
505
1,840
9,905
2,920
Installed
cost, $
26,670
2,425
7,255
11,235
14,555
3,630
11,235
24,190
101,195
28,250
Annual
operating
cost, $
3,515
95
1,465
1,505
2,840
320
880
2,065
12,685
5,120
aActual flow rates. Capacity flow rates are as much as 30 percent higher; where known, they are used for installed
cost estimates.
Makeup water is included in power cost.
°This collector is placed in series with the first four items of the table and serves additional sources in the plant.
The Orion bags, precoated with asbestos floats, perform secondary cleaning of "dry" exhaust gases. The flow is
as follows: 1/3 from the fluoride process, 1/6 from the Be(OH)2-to-billet process, 1/6 from a research faci-
lity, and 1/3 from a be(OH>2 purification process.
A unitized dry-cyclone fabric filter (manual-shaker type), used also for pneumatic transfer of dust collection at
about 60 inches of water pressure loss.
machines that range in type from automatic
chuckers and tracer mills to conventional
lathes. Seven individual fabric-filter installa-
tions with a combined capacity of 7900 cubic
feet per minute are included in the gas-
cleaning system. The installed cost per unit of
gas-handling capacity for this installation is
relatively high in comparison with that for
fabric filters. This results from the use of
small-diameter pipes to convey emission
streams at high velocity and from the use of
low-permeability (4 to 4.5 cubic feet per
minute per square foot) fabrics.
An important consideration in deter-
mining the total annual air pollution control
costs for beryllium metal machining facilities
is the resale value of beryllium collected by
gas-cleaning devices. In most beryllium
dry-machining operations, these waste pro-
ducts provide a significant monetary return.
4-3
-------
Table 4-3. EMISSION CONTROL COSTS FOR CONVERSION OF BERTRANDITE ORE
TO BERYLLIUM HYDROXIDE
Equipment
class
Dry cyclone, 4 each
Fabric filter, 2 eachc
Ejector-venturi
scrubber, 16 each0'
Fabric filter0
Fabric filter0
Type
High
efficiency
Shaker
High
energy
Shaker
Shaker
Gas flow
rate,
cfma
600 each
1,200 each
600 each
2,000
30,000
TOTAL
Annual
maintenance
cost, $
75
250
725
300
3,505
4,855
Annual
power
cost, $b
215
255
12,210
275
4,705
17,660
Installed
cost, $
7,745
12,095
87,360
12,095
48,385
1 67,680
Annual
operating
cost, $
290
505
12,935
575
8,210
22,515
aActual flow rates. Capacity flow rates are as much as 30 percent higher; where known, they are used for installed
cost estimates.
Makeup water is included in power cost.
C0ne fabric filter (30,000 cfm) is an ultra collector precoated with asbestos floats.
The ejector-venturi scrubber is 8-inch size, operates at 100 psig water pressure and provides a 4-inch water-gauge
pressure decrease.
For example, the beryllium collected by the
control system discussed in the last paragraph
had an annual resale value slightly less than
the cost of the emission control equipment.
4.3 BERYLLIUM-COPPER ALLOY FOUN-
DRIES
One estimate of emission control costs
for beryllium-copper alloy foundries is shown
in the last two cost items of Table 4-7; the
data apply to the production, in a beryllium-
extraction facility, of a 2 percent beryllium-
copper alloy by melting copper chips together
with a 4 percent master alloy previously
produced at the same facility. For individual
foundries that use beryllium-copper alloy
ingots as a raw material, the total installed
cost of adequate emission control equipment
will, in most cases, not exceed 13 percent of
the capital investment for plant equipment.
Estimated emission control costs for a
specific beryllium-copper alloy foundry are
listed in Table 4-10. This foundry intermit-
tently processes more than 60,000 pounds per
year of beryllium-copper alloy, even though
the foundry capacity based upon continuous
operation would be much larger than this
figure. In order to relate the size of the
foundry operation to the gas-handling capa-
city of the control system, it should be noted
that the melting capacity is 2000 pounds of
alloy per batch.
4.4 MANUFACTURE OF BERYLLIUM
CERAMIC PRODUCTS
HEPA filters are frequently used as final
collectors by beryllium ceramic-
manufacturing facilities, as noted in Section
3.4.2. A composite filter bank assembled
from four HEPA filter units, each measuring 2
by 2 feet, has a rated capacity of 4500 cubic
feet per minute of air at an initial pressure
decrease of 1 inch of water. The total
installed cost of such a filter installation
ranges from $1100 to $1500, and replace-
ment filters are priced from $80 to $120
4-4
-------
Table 4-4. FIRST EXAMPLE OF EMISSION CONTROL COSTS FOR CONVERSION
OF BERYLLIUM HYDROXIDE TO BERYLLIUM BILLETS
Equipment
class
Hydraulic scrubbing
tower
Hydraulic scrubbing
tower
Ejector-venturi
scrubber, 2 each
Venturi scrubber
Ejector-venturi
scrubber, 6 each
Venturi scurbber,
2 each
Ejector-venturi
scrubber, 5 each
Fabric filter
Dry cyclone
Type
Med. high
energy
Med. high
energy
High
energy
High
energy
High
energy
High
energy
High
energy
Bag
collapsing
High
efficiency
Gas flow
rate,
cfma
1,000
1,325
1 ,250 each
1,600
270 each
4, 500 each
1 ,500 each
9,500
600
TOTAL
Fabric filter0
Shaker
1/6 x
65,000
Annual
maintenance
cost, $
75
100
200
125
125
675
625
950
25
2,900
1,070
Annual
power
cost, $b
245
330
3,175
2,035
2,085
11,375
7,950
845
60
28,100
1,330
Installed
cost, $
3,275
4,000
17,640
12,095
18,900
36,290
44,000
21,785
1,945
1 59,930
14,120
Annual
operating
cost, $
320
430
3,375
2,160
2,210
12,050
8,575
1,795
85
31,000
2,400
aActual flow rate. Capacity flow rates are as much as 30 percent higher; where known, they are used for installed
cost estimates.
Makeup water is included in power cost.
cThis collector serves additional sources in the plant. The Orion bags, precoated with asbestos floats, perform
secondary cleaning of "dry" exhaust gases. The flow is as follows: 1/3 from the fluoride process, 1/6 from the
Be(OH>2-to-billet process, 1/6 from a research facility, and 1/3 from a Be(OH>2 purification process.
each. When the HEPA filters are effectively
protected by prefilters and/or mechanical
collectors, the average lifetime of a filter is at
least 1 year.
A specific beryllium ceramic fabrication
plant that processes 10,000 pounds per year
of beryllium oxide is capable of exhausting
50,000 cubic feet of air per minute. The
estimated installed costs and annual operating
costs of several alternate control systems are
given in Table 4-11; each system utilizes
HEPA filters for final collection, but it is
possible to use fabric filters as secondary
collectors. The total installed costs range from
$36,000 to $115,000, and the annual operat-
ing costs range from $13,000 to $23,000.
4-5
-------
Table 4-5. SECOND EXAMPLE OF EMISSION CONTROL COSTS FOR CONVERSION
OF BERYLLIUM HYDROXIDE TO BERYLLIUM BILLETS
Equipment
class
Packed tower
scrubber
Fabric filter
Packed tower
scrubber, 9 each
Orifice scrubber
Ejector-venturi
scrubber, 2 each
Packed tower
scrubber, 2 each
Floating bed
scrubber, 2 each
Packed tower
scrubber
Fabric filter
Type
Med. high
energy
Pulse jet
Med. high
energy
Low energy
High energy
Med. high
Med. high
Med. high
energy
Shaker
Gas flow
rate,
cfma
7,000
1,500
160 each
10,000
1 ,200 each
7,000 each
1 ,200 each
21,000
17,000
TOTAL
Annual
maintenance
cost, $
530
150
225
750
190
1,050
175
1,580
1,700
6,350
Annual
power
cost, $b .
2,940
215
665
1,690
3,060
5,935
510
8,895
1,510
25,420
Installed
cost, $
19,395
5,250
15,255
9,080
17,640
36,290
8,715
29,085
26,640
1 67,350
Annual
operating
cost, $
3,470
365
890
2,440
3,250
6,985
685
10,475
3,210
31,770
aActual flow rates. Capacity flow rates are as much as 30 percent higher;
cost estimates.
^Makeup water is included in power cost.
The effective control of beryllium emis-
sions from a beryllium oxide ceramic-
manufacturing facility can be attained at a
total installed cost for control equipment that
does not exceed 10 percent of the value of
the plant.
4.5 BERYLLIUM PROPELLANT
MANUFACTURE
Because beryllium propellant has not
been developed or manufactured on a large
scale, little information is available on the
costs that would be required to control
emissions from manufacturing facilities. The
costs of HEPA filters discussed in Section 4.4
are applicable also to propellant manufac-
where known, they are used for installed
turing plants. A preliminary evaluation of
installed costs of actual emission control
systems that provide adequate control indi-
cates that expenditures have ranged from
$25,000 to $50,000 per manufacturing faci-
lity; this is a small percentage of the total
installed cost of production equipment in
each facility.
As stated in Section 3.5.2, the control of
emissions during the static firing of beryllium
rocket motors is a unique problem because
large volumes of high-temperature exhaust
gases must be cleaned during short intervals of
time. No specific air pollution control cost
data for a production-rocket qualification
4-6
-------
Table 4-6. EMISSION CONTROL COSTS FOR CONVERSION OF BERYLLIUM BILLETS
TO BERYLLIUM METAL FORMS
Equipment
class
Dry cyclone
Hydraulic
scrubbing tower
Dry cyclone,
18 each
Fabric filter,
2 each
Type
High
efficiency
Med. high
energy
High
efficiency
Reverse jet
Gas flow
rate,
cfma
1,000
6,000
600 each
2 1,000 each
TOTAL
Annual
maintenance
cost, $
35
225
340
4,280
4,880
Annual
power
cost, $b
95
1,835
965
6,710
9,605
Installed
cost, $
2,415
24,190
34,840
53,235
1 14,680
Annual
operating
cost, $
130
2,060
1,305
10,990
14,485
aActual flow rates. Capacity flow rates are as much as 30 percent higher; where known, they are used for installed
cost estimates.
Makeup water is included in power cost.
Table 4-7. EMISSION CONTROL COSTS FOR CONVERSION OF
BERYLLIUM HYDROXIDE TO BERYLLIUM ALLOYS
Equipment
class
Fabric filter
Fabric filter, 2 each
Fabric filter
Dry cyclone
Dry cyclone
Fabric filter, 2 each
Particle settling
chamber, 3 each
Fabric filter
Type
Shaker
Shaker
High
efficiency
High
efficiency
Reverse jet
Low
efficiency
Reverse jet
Gas flow
rate,
cfma
1,500
2,500 each
400
5,000
400
11, 000 each
2,500 each
12,000
TOTAL
Annual
maintenance
cost, $
150
500
35
165
15
2,205
100
1,200
4,370
Annual
power
cost, $b
140
450
40
450
40
3,415
40
1,860
6,435
Installed
cost, $
6,050
16,935
3,025
5,325
1,450
43,545
965
22,985
1 00,280
Annual
operating
cost, $
290
950
75
615
55
5,620
140
3,060
10,805
aActual flow rates. Capacity flow rates are as much as 30 percent higher,
estimates.
^Makeup water is included in power cost.
where known, they are used for cost
4-7
-------
program have been determined. However, the
use of large-scale, high-efficiency water scrub-
bers for emission control would be very costly
because extremely high water flow rates
would be required.
4.6 REFERENCES FOR SECTION 4
1. Edmisten, N. G. and F. L. Bunyard. A
Systematic Procedure for Determining
the Cost of Controlling Particulate Emis-
sions from Industrial Sources. J. Air
Pollut. Contr. Assoc. 20(7):446-452, July
1970.
2. Control Techniques for Particulate Air
Pollutants. U. S. Department of Health,
Education, and Welfare, National Air
Pollution Control Administration.
Washington, D. C. NAPCA Publication
No. AP-51. January 1969. p. 155-182.
Table 4-8. EMISSION CONTROL COSTS FOR CONVERSION OF
BERYLLIUM HYDROXIDE TO BERYLLIUM OXIDE AND CERAMICS
Equipment
class
Fabric filter
Packed tower
scrubber
Packed tower
scrubber
Packed tower
scrubber
Fabric filter, 2 each
Fabric filter
Fabric filter
Fabric filter
Mist collector,
6eachc
Type
Shaker
Med. high
energy
Med. high
energy
Med. high
energy
Reverse jet
Shaker
Reverse jet
Pulse jet
Mist
col lector
Gas flow
rate,
cfma
1,000
3,000
5,000
12,000
300 each
1,100
1,800
300
7,150
TOTAL
Annual
maintenance
cost, $
110
225
375
905
65
110
190
35
225
2,240
Annual
power
cost, $b
165
1,275
2,065
5,085
50
165
285
50
1,050
10,190
Installed
cost, $
6,655
12,095
16,945
26,640
7,265
6,655
7,865
2,415
4,840
91,375
Annual
operating
cost, $
275
1,500
2,440
5,990
115
275
475
85
1,275
12,430
aActual flow rates. Capacity flow rates are as much as 30 percent higher; where known, they are used for in-
stalled cost estimates.
Makeup water is included in power cost.
cFor operations such as wet grinding; four sized for 625 cubic feet per minute, one for 1050 cubic feet per
minute, and one for 3600 cubic feet per minute.
4-8
-------
Table 4-9. EMISSION CONTROL COSTS
FOR BERYLLIUM MACHINE SHOP
Item
Cost, $
Emission control equipment
Air conditioning with
special filters3
Installation
Annual maintenance
Annual power
50,000
40,000
35,000
20,000
12,000
Table 4-10. EMISSION CONTROL COSTS FOR BERYLLIUM-COPPER
ALLOY FOUNDRY
Equipment
class
Fabric filter
Dry cyclone
Type
High
efficiency
Reverse
Gas flow
rate,
cfma
18,000
18,000
Annual
maintenance
cost, $
1,060
320
Annual
power
cost, $
1,140
900
Installed
cost, $
36,800
10,360
Annual
operating
cost, $
2,200
1,220
aActual flow rates.
Table 4-11. EMISSION CONTROL COSTS FOR BERYLLIUM CERAMIC
MANUFACTURING PLANT
Collector
Primary
Pref liters, bank of 60, 95 percent
efficient
Fabric filters3
Electrostatic precipitator, 97 percent
efficient
Secondary
HEPA filters, bank of 60, 99.97 percent
efficient
Installed cost, $
16,000
70,000
95,000
20,000
Annual
operating cost, $
12,000 (change 4
11,000
2,000
11,000 (change 1
times/yr)
time/yr)
aFabric filters can be used as either primary or secondary collectors.
4-9
-------
APPENDIX: GAS-CLEANING DEVICES
This appendix briefly discusses applica-
tions and operating characteristics of prefil-
ters, fabric filters, and high efficiency particu-
late air filters (HEPA filters). Where available,
specific practices for the control of beryllium
emissions are noted.
A.1 PREFILTERS1
Prefilters, which are frequently used to
protect HEPA filters from high particulate
concentrations, are classified as either
viscous-impingement panel filters or dry-type,
extended-medium filters. The former category
is designated as Group I and includes filters
with low collection efficiency. The dry-type,
extended-medium filters are categorized as
either Group II or Group III if their collection
efficiencies are, respectively, moderate or
high.
Group I filters are constructed of shallow
mats of fibrous material coated with an
adhesive to prevent reentrainment; the mats
are attached to metal or cardboard mounting
frames. Figure A-l illustrates this type of
GROUP II OR GROUP III PRETlLTER
GROUP I PREFILTER
Figure A-1. Group I, viscous-impingement-
panel prefliter installed at the entrance to a
Group II or Group III prefilter.
filter installed at the entrance to a dry-type,
extended-medium filter. Relatively coarse
glass, plastic, wool, or vegetable fibers are
frequently employed as filtering media.
Group I filters are available in throwaway,
replaceable-medium and cleanable-medium
types; the filter medium of cleanable filters is
usually metal mesh.
The filtering material of Group II and
Group III filters is arranged in a folded
configuration or formed into bags to maxi-
mize the filtering area for a given frontal area
of the filter unit (Figure A-2). Filtration is
Figure A-2. Group II or Group III, dry-type,
extended-medium prefilter.
accomplished by finer, more densely packed
fibers than those used in Group I filters.
Group II and III filters are available in
throwaway, replaceable-medium and clean-
able-medium types.
Table A-l lists ranges of collection effi-
ciency, measured by the National Bureau of
Standards (NBS) Dust-Spot Test Method, for
the three groups of prefilters.1 >2 The NBS
A-l
-------
Table A-1. EFFICIENCIES OF PREFILTERS1
Group
I
II
III
Efficiency
Low
Moderate
High
Filter type
Vicous-impingement, panel-type
Extended-medium, dry-type
Extended-medium, dry-type
Efficiency,3
%
5 to 35b
40 to 75b
80 to 98C
aNational Bureau of Standards Dill Dust-Spot Method.2
^~est using synthetic dust.
cTest using atmospheric dust.
test determines the average particulate collec-
tion efficiency as dust accumulates on a filter
during an accelerated test. Filters with collec-
tion efficiencies up to 70 percent are tested
with dust from a Cottrell precipitator; higher
efficiency filters are tested with atmospheric
dust. Efficiencies determined by the NBS test
are measures of collection efficiency for small
particulates approximately 1 micron or less in
effective diameter. A more detailed evaluation
of collection efficiencies of prefilters is listed
in Table A-2.1 Nominal air flow capacities,
resistances, and dust holding capacities of
prefilters are shown in Table A-3.1 The cited
dust-holding capacities are those determined
by the NBS test method for Cottrell-
precipitator dust. The properties of the dust
collected from a particular emission stream
can produce a considerably different dust-
holding capacity.
Table A-2. FRACTIONAL EFFICIENCIES OF PREFILTERS1
Group
I
II
III
Efficiency
Low
Moderate
High
Removal efficiency by
particle size, %
0.3/z
Oto 2
10 to 40
45 to 85
1-OjLt
1 0 to 30
40 to 70
75 to 99
5.0/1
40 to 70
85 to 95
99 to 99.9
IQ.Oju
90 to 98
98 to 99
99.9
Table A-3. OPERATING PARAMETERS OF PREFILTERS1
Group
I
II
III
Efficiency
Low
Moderate
High
Air flow
capacity, cfm/ft^
frontal area
300 to 500
250 to 750
250 to 750
Resistance,
in. water
Clean
filter
0.05 to 0.1
0.1 to 0.5
0.2 to 0.5
Used
filter
0.3 to 0.4
0.2 to 0.5
0.6 to 1.4
Dust-holding
capacity, lb/1000 cfm
air flow capacity
1 to 3
1 to 5
1 to 5
A-2
-------
Group I prefilters operate at a low pres-
sure decrease and can effectively collect high
concentrations of larger particulates. These
prefilters are not damaged by exposure to
high concentrations of soot and smoke, but
they are quite susceptible to plugging by
fibrous materials. The higher collection effi-
ciencies of Group II and Group III prefilters
are accomplished at the expense of higher
pressure losses. The geometrical configuration
of these filters permits use at duct velocities
that are equal to or greater than those for
panel filters. Plugging of these two groups of
prefilters can occur at high concentrations of
soot and smoke, but Group II filters are
suitable for filtering streams with high fiber
loadings.
Underwriters' Laboratories rates prefilters
for fire resistance as either Class 1 or Class 2
filters. Class 1 filters contain no combustible
material and emit a negligible quantity of
smoke when exposed to flame. Class 2 filters
contain some combustible material, but do
not contribute significantly to a fire. The use
of Class 1 or 2 filters does not eliminate the
danger of filter fires, however, because the
collected particulate material may be highly
combustible.
The maximum continuous operating tem-
perature of most prefilters ranges from 150°
to 250° Fahrenheit. However, operating tem-
peratures as high as 400° Fahrenheit can be
employed with fiber glass filters housed in
metal or mineral-board frames.
A.2 FABRIC FILTERS
Fabric filters have been used commer-
cially for many years and provide one of the
most reliable methods for cleaning solid par-
ticulate material from gas streams. With this
type of filter, a gas stream passes through the
woven or felted-fabric filtering medium and
deposits entrained particulate material on the
upstream or dirty-gas side of the fabric.
Subsequently, the gas flows to the down-
stream or clean-gas side of the filter. The most
common geometric configuration of the
fabric, illustrated in Figure A-3, is in a group
of vertical tubes to form a baghouse; flat areas
of fabric are also employed.3 Dust is periodi-
cally or continually dislodged from the sur-
face of the filter either by flexing the fabric
or by directing a stream of air against the
layer of collected material.
The collecting mechanism of a fabric
filter is quite complicated; solid particles
much smaller in diameter than the open
spaces in clean filtering material can be
collected with high efficiencies.3 The material
accumulation on the filter fabric in the form
of a cake or mat of particulate matter, most
of which is removed during filter cleaning, is
an important factor in realizing high collec-
tion efficiencies.
A measure of the flow resistance of clean,
new filtering material is its ASTM (American
Society for Testing and Materials) permea-
bility; this is defined as the volumetric rate of
air flow in cubic feet per minute produced by
a pressure decrease of 0.5 inch of water across
a new, clean filtering fabric, divided by the
square feet of the fabric. An important
operating parameter of a fabric filtering instal-
lation is the gas-to-cloth ratio, or filtering
velocity; this is defined as the total volumetric
flow rate through the filter, expressed in
cubic feet per minute, divided by the square
feet of filtering area.3
Fabric filters are capable of removing
solid particulates from gas streams with a
mass efficiency of at least 99.9 percent; this
assertion is based upon the operating experi-
ence of numerous industries that clean
particulate-containing gas streams, the mass
fractions of which are composed predomi-
nately of particles larger than 1 micron in
diameter. Theoretically, the collection effi-
ciency of a clean, relatively open fabric can be
quite low for most particles smaller than 2
microns in diameter; a minimum efficiency of
less than 20 percent is predicted for particles
approximately 0.9 micron in diameter.4
Laboratory tests have confirmed this decrease
in fractional efficiencies for small particles
and have indicated that the addition of a filter
A-3
-------
CLEAN AIR
OUTLET
DIRTY AIR
INLET
/ COLLECTION
/ HOPPER
/ i!
CLEAN AIR
SIDE
FILTER
BAGS
CELL PLATE
A-4
Figure A-3. Sectional view of a baghouse using a fabric filter 2
-------
cake can greatly increase collection effi-
ciencies for smaller-sized particles.5 These
same tests reveal a substantial decrease in
small-particle fractional efficiencies as a por-
tion of the filter cake is removed by a
cleaning process. Fractional efficiencies of
operating baghouses for the particles smaller
than 2 microns are not available; even data
from realistic laboratory tests are sparse.
Some of the different methods of clean-
ing commercial fabric filters are noted in
Section 3.1.5.2.3; methods included are
mechanical shaking, reverse gas flow through
the filter either with or without appreciable
flexing of the fabric, release of a pulse of
compressed air against the fabric, use of a
reverse flow jet of air that is traversed along
the bag axis, and the use of air horns. The
type of cleaning device employed can signifi-
cantly affect the useful lifetime of the filter-
ing fabric; this is primarily a result of dif-
ferences in the severity of mechanical flexing
imposed on the fabric. The method of clean-
ing can also affect collection efficiency,
especially during the start-up period imme-
diately after cleaning. If excessively severe
cleaning has removed too much of the residu-
al deposit of collected particulates, the filter
operates at unnecessarily low collection effi-
iciencies until a new filter mat is built up.
Further, the various cleaning methods do not
uniformly clean the surface of a fabric filter.
Felted fabrics are cleaned almost exclusively
by the pulse jet or reverse jet methods,
whereas woven fabrics are usually cleaned by
other techniques.
The consideration of specific design
parameters such as gas stream temperature,
concentration of entrained particulates, size
distribution of particulates, and probable ease
of releasing particulates from various fabrics
facilitates selecting effective combinations of
fabric and cleaning methods for controlling
emissions. However, the choice of an effective
emission control system from among these
alternatives can be made with confidence only
on the basis of previous successful operating
experience with a similar system. If this
experience is not available, the determination
of an appropriate combination of fabric and
cleaning method should be viewed as a
development program rather than as an engi-
neering task.
Some examples of specifications and
operating parameters for fabric-filter installa-
tions now employed as final filters to control
beryllium emissions from dry machining
operations, wet machining operations, and
foundry facilities are listed in Table A-4.
Characteristics of fabric filters used by pri-
mary beryllium extraction plants are dis-
cussed in Section 3.1.5.2.3. These specifica-
tions are not intended to be recommendations
for designing beryllium emission control
equipment because emissions from the cited
sources are not completely quantified at
present.
A.3 HEPA FILTERS
A HEPA filter is defined by the following
specifications:
1. The filter is an extended-medium,
dry, throwaway type.
2. The collection efficiency is no less
than 99.97 percent for particulates
0.3 micron in diameter.
3. The flow resistance of a clean filter at
rated air-flow capacity is no larger
than 1.0 inch of water.
4. A rigid housing extends the entire
depth of the filtering medium.
The collection efficiency is specified for
particulates of 0.3 micron in diameter because
it is generally accepted that particles with
diameters in the range 0.1 to 0.3 micron are
the most difficult ones to collect when
filtering a gas stream. Further, the use of a
monodispersed, laboratory-generated
dioctylphthalate (DOP) aerosol has proven to
be a practical and efficient method of check-
ing the efficiency of these filters on a produc-
tion basis.
The construction features of typical
open-faced HEPA filters that are sufficiently
strong to be used to clean contaminated
A-5
-------
Table A-4. SPECIFICATIONS AND OPERATING PARAMETERS FOR FABRIC FILTER
INSTALLATIONS TO CONTROL SECONDARY BERYLLIUM EMISSIONS
Application
Beryllium dry
machining
Beryllium wet
machining
Beryllium
foundry
operations
Operation
Intermittent
Intermittent
Intermittent
Fabric
Silicone
treated
cotton
-
Woven
Dacron
Permeability,
cf m/ft2 at
0.5 in. water
4 to 41/2
-
15 to 25
Bag length,
in.
48
48
168
Bag diameter,
in.
4 to 6
3%
5
Filtering
velocity,
ft/min
2 to 5
2 to 5
1 to 3
Expected pressure
decrease,
in. water
2 to 6
2 to 6
2 to 4
exhausts are illustrated in Figure A-4.1 The
filtering medium, which is fiber glass (fire
resistant) or cellulose-asbestos (combustible)
paper, is ' wrapped in an S pattern across
corrugated metal or ceramic strips, which
maintain the appropriate spacing between
adjacent faces of the medium. The extreme
fragility of the filtering medium requires that
filters be carefully handled to avoid damage.
Proper installation of filter units into retain-
ing frames and the use of gasket materials of
appropriate hardness are critical factors in
preventing leakage around filter units.
Dimensions and nominal air-flow capa-
cities of some standard-sized HEPA filters for
contaminated exhaust service are shown in
Table A-5.1 Typical
CONTINUOUS SHEET OF
PAPER PLEATED BACK
AND FORTH OVER COR-
RUGATED SEPARATORS
limiting continuous-
Table A-5. NOMINAL SPECIFICATIONS OF
STANDARD HEPA FILTERS
Capacity at
dean-filter
resistance of
1.0 in. water, scfm
25
50
125
500
1000
Filter
face
dimensions,
in.
8 by 8
8 by 8
12 by 12
24 by 24
24 by 24
Filter depth
less gaskets,
in.
3-1/6
5-7/8
5-7/8
5-7/8
11-1/2
CORNER JOINT
DETAIL
NAIL OR SCREW
FROIVI EACH FACE
3/4 in. THICK
A-A EXTERIOR
PLYWOOD OR
WOOD-PARTICLE
BOARD
CORRUGATED
SEPARATORS
RIVETED OR BOLTED
CORNERS
RABBETED
GASKET CORNER
DETAIL
3/4 in.-
WOOD-CASED HEPA FILTER
3/4 in. WIDE
DOUBLE-TURNED'
FLANGES BOTH
FACES
NOTCHED STEEL-CASED HEPA FILTER
A-6
Figure A-4. Construction of open-faced HEPA filters.1
-------
service temperatures of fire-resistant steel-
framed and wood-framed HEPA filter units
are listed in Tables A-6 and A-7, respec-
tively.1 The American Association for Con-
tamination Control (AACC) Standard for
HEPA filters specifies three classifications of
fire resistance: fire resistant, semicombustible,
and combustible, depending upon the fire
resistance of the filter material, filter case,
and separators.1
The overpressurization of HEPA filters
for even short periods of time can seriously
damage the filtering medium.
Table A-6. RECOMMENDED LIMITING SERVICE TEMPERATURES FOR
STEEL-FRAMED, FIRE-RESISTANT HEPA FILTER UNITS
SEALED WITH ELASTOMERIC ADHESIVES1
Sealer
used
HT-30-FRb
Z-743C
EC-21 55d
Polyruethane6
Temperature to which filter was exposed,
by exposure time, °F
Up to
10 mina
750
750
750
750
Up to
2hr
350
325
250
325
Up to
48 hr
325
300
220
300
Up to
10 days
300
275
200
275
Indefinitely
260
200
200
230
aSome reduction in efficiency may occur after 5 minutes of exposure.
Goodyear.
Pittsburgh Plate Glass.
Minnesota Mining and Manufacturing (3M).
Proprietary formulation of Flanders Filters, Inc.
Table A-7. RECOMMENDED LIMITING SERVICE TEMPERATURES FOR
WOOD-FRAMED, FIRE-RESISTANT HEPA FILTER UNITS1-3
Frame
material
%-in. plywood0
%-in. wood
particle board0'*1'
Temperature to which filter was exposed,
by exposure time °F
Up to
10 min
750
750
Up to
2hr
300
300
Up to
48 hr
275
250
Up to
10 daysb
200
180
Indefinitely13
180
180
aSubject to sealant limitations given in Table 5-6.
Maximum temperature of 120°F where relative humidity is 75 percent or
higher.
GExterior-grade, fire-retardant treated.
Minimum density = 45 pounds per cubic foot.
A-7
-------
Shock overpressure resistance, which is
the maximum short-duration overpressure
that a filter can sustain with no visible
physical damage and no decrease in collection
efficiency, of typical open-faced HEPA filters
is shown in Table A-8.1 Overpressures of 0.5
to 1.0 pound per square inch greater than
those given in Table A-8 can cause bursting of
the downstream pleats of the filter medium.
Overpressures of 2 pounds per square inch
greater than the shock overpressure resistance
can produce large-scale rupturing or even
complete blowout of the filter core. The use
of 4- by 4-inch face guards significantly
increases the overpressure shock resistance
and protects the filter from damage during
handling and installation.
The primary function of a HEPA filter is
the removal of submicron particulates from a
gas stream that has a relatively low concen-
tration of particulate contamination. Gas
streams heavily loaded with particulates can
rapidly plug HEPA filters; particles with fiber
or flake form are capable of inducing particu-
larly rapid clogging. The nominal dust-holding
capacity of HEPA filters, which varies with
the type of particles collected, is approxi-
mately 4 pounds per 1000 cubic feet per
minute of rated gas-flow capacity.1 Prefilters
are recommended to protect HEPA filters
against rapid plugging when the particulate
loading of a stream is greater than 50 micro-
grams per cubic meter; this practice may be
advantageous even when the inlet concentra-
tion is as small as 5 micrograms per cubic
meter.1 Figure A-5 illustrates the extent to
which the service life of a HEPA filter can be
increased by the use of a prefilter.1
o
«vi
O
CC
LLJ
Or
12 18
SERVICE LIFE, months
HEPA FILTER ALONE
24
Table A-8. SHOCK OVERPRESSURE RESISTANCE
OF OPEN-FACE HEPA FILTERS
Filter
dimensions, in.
Face
8 by 8
8 by 8
12 by 12
24 by 24
24 by 24
Depth
3-1/16
5-7/8
5-7/8
5-7/8
11-1/2
Overpressure, psig
Test
value3
3.6
4.5
3.6
2.2
3.2
Recommended
design limit'1
With face
guards
3.1
3.8
3.1
1.9
2.7
Without face
guards
2.0
2.5
2.0
1.2
1.8
aClean filter with 4- by 4-inch face guards on both
faces.
bDirty filters.
6 12 18 24
SERVICE LIFE, months
HEPA FILTER WITH PREFILTER
HEPA FILTER REPLACED AT 4 in. H20 PRESSURE
DROP, AND PREFILTER REPLACED WHEN PRESSURE
DROP ACROSS IT REACHES 2 TIMES THE CLEAN-
FILTER PRESSURE DROP.
Figure A-5. Influence of prefliter on service
life of HEPA filter.
A-8
-------
Recommended practices frequently speci-
fy that HEP A filters be changed when the
filter resistance reaches 2 inches of water; this
means that power losses do not become
excessive and that ventilation fans can be
sized for relatively low delivery pressures.
However, HEPA filters are routinely capable
of sustaining pressure decreases of up to 10
inches of water in the absence of physical
damage to the filter medium and any decrease
in collection efficiency. Accordingly, if higher
filter resistance can be accommodated in a
particular installation, the service life of
HEPA filters can be substantially increased;
Figure A-6 presents a typical example of this
practice.1
« 80
1 60
t 40
jjj 20
_i
"- 0
0
X
f
f
S^
^n>*^
*^
*^~
23456
PRESSURE DROP, in. H20
Figure A-6. Effect of increased filter resist-
ance on service life of HEPA filter.^
A.4 REFERENCES FOR APPENDIX
1. Burchsted, C. A. and A. B. Fuller. Design,
Construction, and Testing of High-
Efficiency Air Filtration Systems for
Nuclear Application. Oak Ridge National
Laboratory. Oak Ridge, Tenn.
ORNL-NSIC-65, UC-80-React or Tech-
nology. January 1970. p. 2.2, 2.3,
3.1-3.9.
2. Dill, R. S. A Test Method for Air Filters.
National Bureau of Standards. Washing-
ton, D. C. 1938.
3. Control Techniques for Particulate Air
Pollutants. U. S. Department of Health,
Education, and Welfare, National Air
Pollution Control Administration.
Washington, D. C. NAPCA Publication
No. AP-51. January 1969. p. 103-105.
4. Stairmand, C. J. Design and Performance
of Modern Gas Cleaning Equipment. J.
Inst. Fuels (London). 29:58-81, 1956.
5. Whitby, K. T. and D. A. Lundgren.
Fractional Efficiency Characteristics of a
Torit Unit-Type Cloth Collector. Torit
Manufacturing Co. August 1961.
A-9
-------
SUBJECT INDEX
Alloy
beryllium, 2-1, 3-8, 3-9, 4-7
beryllium-copper, 3-1, 3-6 - 3-9, 3-18,4-4
Beryllium propellants (see Propellants)
Beryllium recovery, 3-29
Beryllium rocket motors (see Rocket motors)
B
Baghouse, A-4
Bertrandite ore, 3-3, 3-5
Beryl ore, 2-3, 2-4, 3-3, 3-4
Beryllium
chemical properties, 2-2, 2-3
combustion, 3-20
definition, 2-1
emissions (see Emissions)
machine shops, 3-22
minerals, 2-3
ore, 2-1, 3-1
physical properties, 2-1, 2-2
uses, 2-3
Beryllium alloy
definition, 2-1
physical properties, 2-2
Beryllium ceramics (see Ceramics)
Beryllium-copper alloy
machine shops, 3-18 — 3-21
production, 3-1, 3-8
Beryllium-copper foundries (see Foundries)
Beryllium extraction plants (see Extraction
plants)
Beryllium hydroxide, 3-6 - 3-10, 3-11
Beryllium oxide
emissions, 3-23
machine shops, 3-18, 3-19, 3-22
production, 3-10, 3-11, 3-24
properties, 2-2, 2-3
uses, 3-8
Beryllium production plants
control equipment, 3-14, 3-16, 3-17
Ceramics
control costs, 4-4
control techniques, 3-24, 3-25
emissions, 3-23
manufacture, 3-10, 3-11, 3-22, 3-23
plant, 2-1
Control costs
beryllium production, 4-2, 4-3, 4-6
ceramic manufacture, 4-4 — 4-6
extraction plants, 4-1 — 4-8
foundries, 4-4
machine shops, 4-2, 4-3, 4-7
propellant manufacture, 4-6
Control equipment
costs, 4-1 - 4-9
cyclones, 3-13, 3-15, 3-20, 4-4, 4-5, 4-7
fabric filters, 3-13, 3-15 - 3-17, 3-19, 4-4,
4-5,4-7, A-3-A-6
HEPA (high efficiency particulate air) fil-
ters, 3-13, 3-15, 3-19, 3-20, 3-24, 3-28,
3-294-5, A-5 - A-9
mechanical collectors, 3-13, 3-15, 3-19
prefilters, 3-13,3-14, 3-24, A-l - A-3
scrubbers, 3-13, 3-14, 3-16, 3-27, 3-28
D
Dust (see Emissions, ceramics manufacture
and machine shops)
1-1
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E
Emissions
beryllium extraction plants, 3-10
ceramics manufacture, 3-23, 3-24, 4-9
foundries, 3-21
machine shops, 3-18
major sources of, 2-4
propellants, 3-26
waste disposal, 3-27, 3-28
Extraction plants
control costs, 4-1 — 4-8
control equipment, 3-10 — 3-12
control techniques, 3-10 — 3-12
definition, 2-1
emissions, 3-12
process descriptions, 3-1 — 3-10
Fabric filters (see Control equipment)
Finished forms, 3-6, 3-8, 4-7
Foundries
control costs, 4-4, 4-9
control techniques, 3-22
definition, 2-1
emissions, 3-21
operations, 3-21
Fume, 2-1,3-22, 3-24
Gas-cleaning devices, 3-27 - 3-29, A-l - A-9
H
HEPA filters (see Control equipment)
M
Machine shops
control costs, 4-9
control techniques, 3-18, 3-19, 3-21
definition, 2-1
emissions, 3-18
processes, 3-18
Mechanical collectors (see Control equip-
ment)
Metal billets, 3-6 - 3-9, 4-5 - 4-7
Mist, 2-1,3-24
O
Open burning, 2-4
Prefilters (see Control equipment)
Propellants
control costs, 4-6
control techniques, 3-26
definition, 2-1
disposal (see Waste disposal)
emissions, 3-26
manufacture, 3-24, 3-25
R
Rocket motors
beryllium propellants, 3-25, 3-26
static firing
control costs, 4-6
control techniques, 3-26, 3-27
emissions, 3-26, 3-27
test sites, 2-1
Scrubbers (see Control equipment)
W
Waste disposal
beryllium propellants, 3-27 - 3-29
beryllium-containing wastes, 3-28
1-2
U. a. GOVERNMENT PRINTING OFFICE: 1973 746768/4127
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