Environmental Geochemistry of Sulfide Oxidation

672 Pages·1994·62.16 MB·English

by  Charles N. Alpers and David W. Blowes (Eds.)

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In Environmental Geochemistry of Sulfide Oxidation; Alpers, C., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1993.
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In Environmental Geochemistry of Sulfide Oxidation; Alpers, C., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1993.
ACS SYMPOSIUM SERIES 550
Environmental Geochemistry
of Sulfide Oxidation
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550.f Charles N. Alpers, EDITOR
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4- U.S. Geological Survey
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2 David W. Blowes,
10 EDITOR
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1 University of Waterloo
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http://pubs.acs.org ecember 20, 1993 | Developed from a symposium sponsored
12 | e: D by the Division of Geochemistry, Inc.,
1, 20n Dat at the 204th National Meeting
1o
August ublicati of the AmWearischainng Ctohne,m DicCa, l Society,
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August 23-28, 1992
American Chemical Society, Washington, DC 1994
In Environmental Geochemistry of Sulfide Oxidation; Alpers, C., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1993.
Library of Congress Cataloging-in-Publication Data
Environmental geochemistry of sulfide oxidation : developed from a
symposium sponsored by the Division of Geochemistry, Inc., at the
204th National Meeting of the American Chemical Society, Washing
ton, DC, August 23-28, 1992 / Charles N. Alpers, David W. Blowes,
[editors].
p. cm.—(ACS symposium series, ISSN 0097-6156; 550)
1 Includes bibliographical references and indexes.
0
0
w
0.f ISBN 0-8412-2772-1
5
05 1. Sulphides—Oxidation—Congresses. 2. Environmental geochem
4- istry—Congresses.
9
9
k-1 I. Alpers, Charles N., 1958- . II. Blowes, David W., 1956- .
b III. American Chemical Society. Division of Geochemistry.
21/ IV. American Chemical Society. Meeting (204th: 1992: Washington,
10 D.C.) V. Series.
0.
1
doi: 6Q2E8.511'668.S312E—5d8c 2109 94 93-39250
TSp://pubs.acs.org thaember 20, 1993 | en dpaarpde rfo ur sIendf oirnm tahtiiso np uSbcileicnacteios—n Pmeeremtsa ntheen cme ionfi Pmaupmer rfeoqr uPirrienmteedn tLs iboCrfI aPAr ym Meraictearni aNlsa, tAioNnSaIl
httec Z39.48-1984.
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In Environmental Geochemistry of Sulfide Oxidation; Alpers, C., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1993.
1993 Advisory Board
ACS Symposium Series
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http://pubs.acs.org ecember 20, 1993 | RNMaoavbaregl raRtre esFet.a ArBc.rh Ca dLayavb,a onJrarau.t ogrhy MDNGoeealrmotrhrsogh nCeata l LrWl oaPlbi.nh oRaril aolStiboptarestiree ts s U niversity
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In Environmental Geochemistry of Sulfide Oxidation; Alpers, C., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1993.
Foreword
IHE ACS SYMPOSIUM SERIES was first published in 1974 to
provide a mechanism for publishing symposia quickly in book
form. The purpose of this series is to publish comprehensive
books developed from symposia, which are usually "snapshots
in time" of the current research being done on a topic, plus
1
00 some review material on the topic. For this reason, it is neces
w
0.f sary that the papers be published as quickly as possible.
5
5 Before a symposium-based book is put under contract, the
0
94- proposed table of contents is reviewed for appropriateness to
9
k-1 the topic and for comprehensiveness of the collection. Some
b
1/ papers are excluded at this point, and others are added to
2
0 round out the scope of the volume. In addition, a draft of each
1
10. paper is peer-reviewed prior to final acceptance or rejection.
oi: This anonymous review process is supervised by the organiz
d
p://pubs.acs.org ember 20, 1993 | wTmcearhhem^eon) e d caraoahutf-eit rohtcehnkoaes dr tsyhs oyathfcmt oeapbnploo ly srnt,h eieuav cnmietsdhs,e sew sa turhhyrboee m ivrrbeii eetvp wcitasoheipmeores ner fss i a tnhhnaaaedlcv c epeot dahrbpideetie oenrrnegs( d s mt)tioot oa o drtftsheh ,t.ee h eper redbecioptoooamrkrse. ,
httec
12 | e: D As a rule, only original research papers and original re
20Dat view papers are included in the volumes. Verbatim reproduc
1, n tions of previously published papers are not accepted.
1o
August ublicati M Joan Comstock
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Series Editor
In Environmental Geochemistry of Sulfide Oxidation; Alpers, C., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1993.
Preface
IHE STUDY OF SULFlDE-OXIDAnON REACTIONS, the characterization
of the products of these reactions, and the prediction of the fate of
sulfide-oxidation products in natural environments are increasingly active
areas of research. This research is motivated by the locally severe
environmental impacts and toxicity associated with the products of sulfide
1
00 oxidation. Mine wastes are of particular concern because of past and
pr
0. present disposal practices that have resulted in the widespread degrada
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05 tion of surface-water and ground-water quality. Mine wastes have there
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9 fore come under increasing regulation.
9
1
k- This book provides an interdisciplinary overview of recent research on
b
1/ geochemical processes of sulfide oxidation. Researchers from a wide
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10 variety of disciplines are represented: geochemistry, microbiology, hydrol
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1 ogy, mineralogy, physics, and civil engineering. The studies included
doi: range from theoretical modeling exercises to laboratory- and field-based
g 3 | studies.
ubs.acs.orer 20, 199 this Obnoeo ko ifs obuars emd awina so tboj efcotsivteers nienw o rcgoalnlaibzionrga ttihoen s saymmopnogs iruemse aornc hwerhsi cihn
pb related fields. Our hope is that the interdisciplinary nature of this volume
012 | http://ate: Decem wmaniodll d eetnolic noignu, craosgurperf oarrceaeste ea crrhcehecmeernists ttraoyd ,vl oaeonqkcu eiblsie byirnoiu nkmdi nthesetoi lcuhsbi,g imhliltiyyc rsorpebelicaoitlaioloignzyes,d, n alunitmaelreyarttiiuccraaell
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1, n methods, and remediation technology in their future research efforts. We
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st ati understand that the seeds sown at the symposium have already begun to
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The structure of this volume is similar to that of the symposium:
Twelve different themes related to sulfide oxidation processes are
represented as different parts of the book. The order follows a progres
sion of geochemical environments starting at the source area and evolving
with increasing distance along both surface-water and ground-water flow
paths. Hence, the first two sections of the book deal with laboratory
studies of sulfide-oxidation reaction kinetics and microbiological
processes.
Subsequent sections of the book include chapters on the solubility
and sorption control of aqueous metal concentrations, the transport of
sulfide-oxidation products in surface waters, the transport and storage of
sulfides and sulfide-oxidation products in sediments, and the effects on
ground-water geochemistry. Additional sections are included on ana-
xiii
In Environmental Geochemistry of Sulfide Oxidation; Alpers, C., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1993.
lytical methods, on the stable isotopes of sulfur and oxygen in systems
undergoing sulfide oxidation, and on "supergene" (weathering-related)
oxidation and enrichment of sulfide-bearing ore deposits.
The final section of the book presents chapters on remediation and
the prevention of environmental impacts of sulfide oxidation. This topic
is of growing concern to mining companies, government regulators, and
environmentalists. It is clear that environmental aspects of mining must
play an important role in mine design from the initial planning stages.
Progress will be necessary in many areas of science to ensure that the
mistakes of the past are not repeated and that the environmental impacts
of mining will be minimized or eliminated in the decades to come.
1
00 Acknowledgments
pr
0.
5
5 We thank the authors of the chapters in this book for their commitment
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94- to meeting the necessary deadlines and for their patience with our
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k-1 numerous requests. We also thank the many researchers who assisted in
1/b the review of the chapters in this book. Each chapter was reviewed by at
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0 least one and in most cases two or more external referees as well as by
1
10. both editors. Many of the reviews were highly constructive and provided
oi: new insights that were generously shared with the authors.
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g 3 | We gratefully acknowledge financial assistance from the Waterloo
s.or199 Centre for Groundwater Research and the ACS Division of Geochemistry
s.ac20, for the travel costs of foreign speakers at the symposium. The program
pubber chairs of the ACS Division of Geochemistry, James A. Davis and Mary
p://em Sohn, and the treasurer, Dan Melchior, were helpful and supportive in
012 | httate: Dec tahses istpelda nwniinthg tahned fienxale cpurtiooonf reoafd itnhge asnydm ptyopseiusemtt.i ngC horfi s seHvaenratol no-fF otnhge
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1, n manuscripts; her efforts are gratefully appreciated. Finally, we thank
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st ati Rhonda Bitterli, Meg Marshall, and the rest of the ACS Books staff for
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ugbli their assistance during the editing and production of this volume.
Au
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CHARLES N. ALPERS DAVID W. BLOWES
Water Resources Division Waterloo Centre for Groundwater
U.S. Geological Survey Research
Room W-2233 University of Waterloo
2800 Cottage Way Waterloo, Ontario N2L 3G1
Sacramento, CA 95825 Canada
RECEIVED August 10, 1993
xiv
In Environmental Geochemistry of Sulfide Oxidation; Alpers, C., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1993.
Chapter 1
Rates of Reaction of Galena, Sphalerite,
Chalcopyrite, and Arsenopyrite with Fe(III)
in Acidic Solutions
J. Donald Rimstidt1, John A. Chermak2,a nd Patrick M. Gagen3
1Department of Geological Sciences, Virginia Polytechnic Institute and
1 State University, Blacksburg, VA 24061
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h 2Mineralogisches Institut, Universität Bern, 3012 Bern, Switzerland
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50. 3O.H.M. Corporation, 1000 Holcomb Woods Parkway, Roswell, GA 30076
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9
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k- We measured the rates of reaction of Fe(III) with galena, sphalerite,
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10 found:
0.
1 MINERAL RATE LAW ACTIVATION ENERGY
oi: Galena r 3+= -2.82x10-3 (A) (m 3+)0.98 40 kJ mol-1
d Fe Fe
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p://em Where rFe3+ is the rate of reduction of Fe(III) to Fe(II) (mol sec-1),
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The oxidation of sulfide minerals is a beneficial process in some cases and a detrimental
one in others. This process is responsible for the secondary enrichment of many ore
deposits making them more valuable; in addition, the natural sulfide mineral oxidation
process has been adapted to recover metals from sulfide ores through hydrometallurgy.
On the other hand, the oxidation of sulfide minerals exposed naturally, or more often by
mining activities, often produces serious pollution problems.
Iron plays a central role in oxidizing sulfide mineral deposits. When pyrite or
pyrrhotite oxidize, they release Fe(II) into solution. The dissolution of iron-bearing
sUicates, oxides, or carbonates in the acidic solutions that are common in this
environment also releases Fe(II). At near neutral pH, Fe(II) is rapidly oxidized to Fe(III)
by dissolved oxygen (1 2). At low pH, the rate of this reaction via the inorganic route
is quite slow but Thiobacillus ferrooxidans and related bacteria accelerate the rate as they
0097-6156/94A)550-0002$06.00/0
© 1994 American Chemical Society
In Environmental Geochemistry of Sulfide Oxidation; Alpers, C., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1993.
1. RIMSTTDT ET AL. Reactions of Minerals with Fe(III) in Acidic Solutions 3
derive metabolic energy by using O2 to oxidize the Fe(II) to Fe(III) (1,2). Moses (4)
suggests that Fe(HI) is the primary oxidant of pyrite even at near neutral pH even though
it is relatively insoluble under these conditions, and his reaction model suggests that
Fe(ni) is probably involved in the oxidation of most sulfide minerals. Some of the
Fe(HI) reacts with other nonferrous sulfides, as well as the iron-bearing ones, to release
other metal ions into solution (£) and during this process it is converted to Fe(II). This
Fe(D) is reoxidized to Fe(III) to complete the cycle. Finally, the excess Fe(III)
precipitates as iron oxyhydroxides whose solubility is controlled by the Fe(III) activity
and the pH (6).
The primary goal of this study was to gather information on the rate of reaction
of Fe(in) with galena, sphalerite, chalcopyrite, and arsenopyrite in acidic solutions
similar to those found in weathering sulfide deposits. These data can be used in models
which account for the sources and sinks of Fe(III) in weathering sulfide deposits.
Berner (2) reports that dissolved iron concentrations in acidic mine waters are often as
high as 100 to 500 mg L"1 (2 to 9xl0-3 m), with pH values of less than two. In our
1 experiments, Fe(III) concentrations ranged from 10"2 to 10-4 molal (m) and the pH was
0
h0 near two. The predominant galena oxidation reaction under these conditions is
c
50. PbS + 8 Fe3+ + 4 H0 -> 8 H+ + S02" + Pb2+ + 8 Fe2+ (1)
4-05 where some of the Pb2+ and SO42- 2react to precipita4te anglesite (PbSCU). The overall
99 sphalerite oxidation reaction is:
1
bk- ZnS + 8 Fe3+ + 4 H0 -> 8 H+ + S02" + Zn2+ + 8 Fe2+. (2)
21/ The most important oxidation react2ion for arsenopyr4ite is
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s.acs.or20, 199 galenaA,C asuresFceoennSodp2 y +gr oi1tae6l, Fosfpe ht3h+a il+se r8sitt euH,d 2ya0n w-d> ac shC tauolc2 +coop +my rp1ita7er eFw teiht2h+e +Fc he2a( IrSIaIOc)t 4et2or-i st+thi ce1s 6p oyHfr+i tth.e e r ereaacctitoio(n4n. ) o f
pubber There have been several quantitative studies of the reaction of pyrite with Fe(III) both
p://em because it is a geochemically important reaction and because pyrite may serve as a model
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1, n Little is known about the reaction rates of galena and sphalerite in dilute Fe3+
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ust cati solutions similar to those found in nature as compared to the relatively extensive
ugbli hydrometallurgical research using very strongly oxidizing solutions. Previous
APu hydrometallurgy studies on galena and sphalerite, tabulated by Chermak (&), used very
concentrated (up to 3 molal) FeCl solutions which are much more reactive than natural
3
waters. The numerous previous studies of the oxidation rate of chalcopyrite under
various conditions were designed to improve the hydrometallurgical recovery of copper,
and also were performed using much higher concentrations of oxidants than are
normally found in nature; examples are tabulated by Gagen (9). Most of these studies
indicated that a significant amount of elemental sulfur is produced by intense oxidation
of chalcopyrite; however, our experiments which used much lower concentrations of
Fe(III) produced no elemental sulfur. Although arsenic pollution from mine waste
dumps is a potentially serious environmental problem, arsenopyrite oxidation has
received very little study and there are no reported values of rate constants or activation
energy.
In Environmental Geochemistry of Sulfide Oxidation; Alpers, C., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1993.