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1.
Hydrogeochemical characteristics of acid mine drainage in the vicinity of an abandoned mine, Daduk Creek, Korea 总被引:2,自引:0,他引:2
Acid mine drainage discharged from the abandoned Daduk mine towards the Daduk creek has a pH of 3.3, and concentrations of Al, Mn, Fe, Zn and SO4 of 18, 41, 45, 38 and 1940 mg/L, respectively. In particular, As concentration in acid mine drainage is 1000 μg/L. Removing order of metal ions normalized by SO4 concentration downstream from discharge point is Fe > As > Al > Cu > Zn > Mn > Cd > Pb. In the Daduk creek, Fe and As are the most rapidly depleted downstream from acid mine drainage because As adsorbs, coprecipitates and forms compounds with ferric oxyhydroxide. From the results of geochemical modeling using the Phreeq C program, goethite (FeOOH) is oversaturated, and schwertmannite (Fe8O8(OH)4.5(SO4)1.75) is the most stable solid phase at low pH in the Daduk creek. Yellowish red (orange ochre) precipitates that occurred in the study area are probably composed of goethite or schwertmannite. 相似文献
2.
N. F. Gray 《Environmental Geology》1996,27(4):358-361
Both sulfate and conductivity are useful indicators of acid mine drainage (AMD) contamination. Unlike pH, they are both extremely sensitive to AMD even where large dilutions have occurred. The advantage of using sulfate to trace AMD is that unlike other ions it is not removed to any great extent by sorption or precipitation processes, being unaffected by fluctuations in pH. These two parameters are also closely associated as would be expected, as conductivity is especially sensitive to sulfate ions. Therefore, as sulfate analysis is difficult in the field, conductivity can be used to predict sulfate concentration in both AMD and contaminated surface waters using regression analysis. Most accurate predictions are achieved by using equations given for specific conductivity ranges or AMD sources. There is also potential to use conductivity to predict approximate concentrations of key metals when the pH of the water is within their respective solubility ranges. 相似文献
3.
Hydrochemical characterization of acute acid mine drainage at Iron Duke mine, Mazowe, Zimbabwe 总被引:8,自引:0,他引:8
Acid mine drainage (AMD) with a minimum pH of 0.52 was recorded at Iron Duke mine near Mazowe, Zimbabwe during an investigation
of the environmental geochemistry of mine waters in the Greenstone Belts of Zimbabwe. Hydrochemical data for waters emanating
from the Iron Duke waste-rock pile indicate their super-saturation with respect to Fe and SO4
2–. Extremely high dissolved concentrations of Al, Zn, Cu, Co, Ni, V, Cr, Cd and As also prevail. Substantial losses of metals
from solution occur within 400 m of the AMD source through the precipitation of crystalline sulphates, principally melanterite.
Further downstream, hydrous oxide precipitation forms the dominant mechanism of metal attenuation in waters characteristically
under-saturated with respect to Fe sulphates. Speciation and saturation index data generated using the equilibrium model WATEQ4F,
suggest that such codes have broad utility for generic prediction of the mineralogical contraints on metal mobility in acute
AMD systems. Major discrepancies between modelled and empirical hydrochemistries are, however, evident for super-saturated
waters in which the kinetics of Fe precipitation are slow, and in which total ionic strengths markedly exceed their theoretical
maximum.
Received: 28 August 1998 · Accepted: 7 December 1998 相似文献
4.
Interaction of acid mine drainage with waters and sediments at the Corona stream, Lousal mine (Iberian Pyrite Belt, Southern Portugal) 总被引:1,自引:0,他引:1
E. Ferreira da Silva C. Patinha P. Reis E. Cardoso Fonseca J. X. Matos J. Barrosinho J. M. Santos Oliveira 《Environmental Geology》2006,50(7):1001-1013
This study investigates the geochemical characteristics of the acid mine drainage discharged from the abandoned mine adits and tailing piles in the vicinity of the Lousal mine and evaluates the extent of pollution on water and on the stream sediments of the Corona stream. Atmospheric precipitation interacting with sulphide minerals in exposed tailings produces runoff water with pH values as low as 1.9–2.9 and high concentrations of
(9,249–20,700 mg l−1), Fe (959–4,830 mg l−1) and Al (136–624 mg l−1). The acidic effluents and mixed stream water carry elevated Cu, Pb, Zn, Cd and As concentrations that exceed the water quality standards. However, the severity of contamination generally decreases 4 km downstream of the source due to mixing with fresh waters, which causes the dilution of dissolved toxic metals and neutralization of acidity. Some natural attenuation of the contaminants also occurs due to the general reduced solubility of most trace metals, which may be removed from solution, by either co-precipitation or adsorption to the iron and aluminium precipitates. 相似文献
5.
N. F. Gray 《Environmental Geology》1997,30(1-2):62-71
Work carried out at the abandoned copper (Cu) and sulphur (S) mine at Avoca (south east Ireland) has shown acid mine drainage
(AMD) to be a multi-factor pollutant. It affects aquatic ecosystems by a number of direct and indirect pathways. Major impact
areas are rivers, lakes, estuaries and coastal waters, although AMD affects different aquatic ecosystems in different ways.
Due to its complexity, the impact of AMD is difficult to quantify and predict, especially in riverine systems. Pollutional
effects of AMD are complex but can be categorized as (a) metal toxicity, (b) sedimentation processes, (c) acidity, and (d)
salinization. Remediation of such impacts requires a systems management approach which is outlined. A number of working procedures
which have been developed to characterise AMD sites, to produce surface water quality management plans, and to remediate mine
sites and AMD are all discussed.
Received: 16 January 1996 · Accepted: 5 March 1996 相似文献
6.
Acid mine drainage (AMD) from abandoned underground mines significantly impairs water quality in the Jones Branch watershed
in McCreary Co., Kentucky, USA. A 1022-m2 surface-flow wetland was constructed in 1989 to reduce the AMD effects, however, the system failed after six months due to
insufficient utilization of the treatment area, inadequate alkalinity production and metal overloading. In an attempt to improve
treatment efficiencies, a renovation project was designed incorporating two anoxic limestone drains (ALDs) and a series of
anaerobic subsurface drains that promote vertical flow of mine water through a successive alkalinity producing system (SAPS)
of limestone beds overlain by organic compost. Analytical results from the 19-month post-renovation period are very encouraging.
Mean iron concentrations have decreased from 787 to 39 mg l–1, pH increased from 3.38 to 6.46 and acidity has been reduced from 2244 to 199 mg l–1 (CaCO3 equivalent). Mass removal rates averaged 98% for Al, 95% for Fe, 94% for acidity, 55% for sulfate and 49% for Mn during the
study period. The results indicate that increased alkalinity production from limestone dissolution and longer residence time
have contributed to sufficient buffering and metal retention. The combination of ALDs and SAPS technologies used in the renovation
and the sequence in which they were implemented within the wetland system proved to be an adequate and very promising design
for the treatment of this and other sources of high metal load AMD.
Received: 29 June 1998 · Accepted: 15 September 1998 相似文献
7.
Bo Peng Xiaoyan Tang Changxun Yu Shurong Xie Meilian Xiao Zhi Song Xianglin Tu 《Environmental Geology》2009,57(2):421-434
The acid mine drainage (AMD) discharged from the Hejiacun uranium mine in central Hunan (China) was sampled and analyzed using
ICP-MS techniques. The analyzing results show that the AMD is characterized by the major ions FeTotal, Mn, Al and Si, and is concentrated with heavy metals and metalloids including Cd, Co, Ni, Zn, U, Cu, Pb, Tl, V, Cr, Se,
As and Sb. During the AMD flowing downstream, the dissolved heavy metals were removed from the AMD waters through adsorption
onto and co-precipitation with metal-oxhydroxides coated on the streambed. Among these metals, Cd, Co, Ni, Zn, U, Cu, Pb and
Tl are negatively correlated to pH values, and positively correlated to major ions Fe, Al, Si, Mn, Mg, Ca and K. The metals/metalloids
V, Cr, Se, As and Sb are conservative in the AMD solution, and negatively-correlated to major ions Na, Ca and Mg. Due to the
above different behaviors of these chemical elements, the pH-negatively related metals (PM) and the conservative metals (CM)
are identified; the PM metals include Cd, Co, Ni, Zn, U, Cu, Pb and Tl, and the CM metals V, Cr, Se, As and Sb. Based on understanding
the geochemistry of PM and CM metals in the AMD waters, a new equation: EXT = (Acidity + PM)/pH + CM × pH, is proposed to
estimate and evaluate extent of heavy-metal pollution (EXT) of AMD. The evaluation results show that the AMD and surface waters
of the mine area have high EXT values, and they could be the potential source of heavy-metal contamination of the surrounding
environment. Therefore, it is suggested that both the AMD and surface waters should be treated before they are drained out
of the mine district, for which the traditional dilution and neutralization methods can be applied to remove the PM metals
from the AMD waters, and new techniques through reducing the pH value of the downstream AMD waters should be developed for
removal of the CM metals. 相似文献
8.
Sampling acid mine drainage (AMD) or natural acid rock drainage (ARD)-impacted sediments is complex, requiring appropriate
field sampling techniques to ensure representative samples that are both repeatable and reproducible. The important factors
affecting sampling of riverine sediments are examined. These include sample site location, field observations, representative
sampling, sample collection techniques, and sample preservation. A recommended sampling and processing protocol is presented
for AMD- and ARD-impacted riverine sediments, which includes sediment sampling, Fe hydroxide floc sampling, chemical analysis,
interstitial (pore) water collection, sediment elutriates, sediment fractionation, and physical analysis. The importance of
bioassay testing is discussed, as is quality assurance and assessment approaches to define sediment quality criteria.
Received: 18 September 1995 · Accepted: 23 October 1995 相似文献
9.
J. A. Grande R. Beltrán A. Sáinz J.C. Santos M. L. de la Torre J. Borrego 《Environmental Geology》2005,47(2):185-196
The present work describes the process of acid water discharge into the Andévalo Dam (Iberian Pyrite Belt, Huelva-Spain) starting from the interpretation of rainfall data and chemical analyses regarding pH, conductivity, metal and sulphate content in water, from a time series corresponding to the sampling of two confluent channels that discharge water into the referred dam. Statistical data treatment allows us to conclude the existence of acid mine drainage processes in the Chorrito Stream, which are translated into very low pH values and high sulphate and metal concentrations in the water coming from Herrerías Mine. On the other hand, the Higuereta Stream shows, for the same parameters, much lower values that can be interpreted as the channel response to acid rock drainage processes in its drainage basin induced by the rocky outcrops of the Iberian Pyrite Belt. 相似文献
10.
《Australian Journal of Earth Sciences》2013,60(5):797-809
Sulfide‐rich materials comprising the waste at the abandoned Montalbion silver mine have undergone extensive oxidation prior to and after mining. Weathering has led to the development of an abundant and varied secondary mineral assemblage throughout the waste material. Post‐mining minerals are dominantly metal and/or alkali (hydrous) sulfates, and generally occur as earthy encrustations or floury dustings on the surface of other mineral grains. The variable solubility of these efflorescences combined with the irregular rainfall controls the chemistry of seepage waters emanating from the waste dumps. Irregular rainfall events dissolve the soluble efflorescences that have built up during dry periods, resulting in ‘first‐flush’ acid (pH 2.6–3.8) waters with elevated sulfate, Fe, Cu and Zn contents. Less‐soluble efflorescences, such as anglesite and plumbojarosite, retain Pb in the waste dump. Metal‐rich (Al, Cd, Co, Cu, Fe, Mn, Ni, Zn) acid mine drainage waters enter the local creek system. Oxygenation and hydrolysis of Fe lead to the formation of Fe‐rich precipitates (schwertmannite, goethite, amorphous Fe compounds) that, through adsorption and coprecipitation, preferentially incorporate As, Sb and In. Furthermore, during dry periods, evaporative precipitation of hydrous alkali and metal sulfate efflorescences occurs on the perimeter of stagnant pools. Flushing of the streambed by neutral pH waters during heavy rainfall events dissolves the efflorescences resulting in remobilisation and transport of sulfate and metals (particularly Cd, Zn) downstream. Thus, in areas of seasonal or irregular rainfall, secondary efflorescent minerals present in waste materials or drainage channels have an important influence on the chemistry of surface waters. 相似文献
11.
Pan Wu Changyuan Tang Congqiang Liu Lijun Zhu TingQuan Pei Lijuan Feng 《Environmental Geology》2009,57(7):1457-1467
The chemical characteristics, formation and natural attenuation of pollutants in the coal acid mine drainage (AMD) at Xingren
coalfield, Southwest China, are discussed in this paper based on the results of a geochemical investigation as well as geological
and hydrogeological background information. The chemical composition of the AMD is controlled by the dissolution of sulfide
minerals in the coal seam, the initial composition of the groundwater and the water–rock interaction. The AMD is characterized
by high sulfate concentrations, high levels of dissolved metals (Fe, Al, Mn, etc.) and low pH values. Ca2+ and SO4
2− are the dominant cation and anion in the AMD, respectively, while Ca2+ and HCO3
− are present at significant levels in background water and surface water after the drainage leaves the mine site. The pH and
alkalinity increase asymptotically with the distance along the flow path, while concentrations of sulfate, ferrous iron, aluminum
and manganese are typically controlled by the deposition of secondary minerals. Low concentrations of As and other pollutants
in the surface waters of the Xingren coalfield could be due to relatively low quantities being released from coal seams, to
adsorption and coprecipitation on secondary minerals in stream sediments, and to dilution by unpolluted surface recharge.
Although As is not the most serious water quality problem in the Xingren region at present, it is still a potential environmental
problem.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
12.
Several mines in the Witbank coalfield in South Africa are affected by acid mine drainage. This has led to a deterioration
in the water quality in many surface streams. The Loubert Mine is one such mine. Hence, an initial investigation was carried
out to determine the source of acid mine drainage pollution and the associated hydrogeological conditions. The investigation
showed that most of the acid mine drainage is emanating from old opencast workings which have been backfilled. Most of the
water from the backfilled area drains into control reservoirs. Unfortunately their capacity is limited, which means that water
overspills and seeps from them. This water finds its way into a nearby stream, the water of which accordingly has an unacceptably
low pH value and high sulphate content. The proposals advanced to control the problem basically involve inhibiting the amount
of water infiltrating the backfilled opencast area on the one hand and reducing the amount of water entering the control reservoirs
on the other.
Received: 5 March 1997 · Accepted: 17 June 1997 相似文献
13.
Prediction of acid mine drainage generation potential in selected mines in the Ashanti Metallogenic Belt using static geochemical methods 总被引:1,自引:1,他引:1
Acid mine/rock drainage (AMD/ARD) is the biggest environmental threat facing the mining industry. This study investigates
AMD/ARD possibilities in three mines in the Ashanti Belt, using acid base accounting (ABA) and net acid generation pH (NAGpH)
tests. Twenty-eight samples of rock units and mine spoil from these mines were collected for ABA and NAGpH tests. Two tailing
dumps at Prestea and Nsuta were confirmed by both methods as acid generating with NAGpH of 4.5 and 4.6 and neutralization
potential ratio values of 4.38 and 4.60, respectively. Six other samples are classified as potentially acid generating using
a variety of established classification criteria. The rest of the samples either exhibited very low sulphur and carbonate
content or had excess carbonate over sulphur. Consistency between results from ABA and NAGpH tests validates these tests as
adequate tools for preliminary evaluation of AMD/ARD possibilities in any mining project in the Ashanti Belt. 相似文献
14.
Geochemical modeling of coal mine drainage, Summit County, Ohio 总被引:4,自引:1,他引:4
A. Foos 《Environmental Geology》1997,31(3-4):205-210
Geochemical modeling was used to investigate downstream changes in coal mine drainage at Silver Creek Metro-park, Summit
County, Ohio. A simple mixing model identified the components that are undergoing conservative transport (Cl–, PO4
3–, Ca2+, K+, Mg2+ and Na+) and those undergoing reactive transport (DO, HCO3
–, SO4
2–, Fe2+, Mn2+ and Si). Fe2+ is removed by precipitation of amorphous iron-hydroxide. Mn2+ are removed along with Fe2+ by adsorption onto surfaces of iron-hydroxides. DO increases downstream due to absorption from the atmosphere. The HCO3
– concentration increases downstream as a result of oxidation of organic material. The rate of Fe2+ removal from the mine drainage was estimated from the linear relationship between Fe+2 concentration and downstream distance to be 0.126 mg/s. Results of this study can be used to improve the design of aerobic
wetlands used to treat acid mine drainage.
Received: 4 June 1996 · Accepted: 17 September 1996 相似文献
15.
Mineralogical constraints on the determination of neutralization potential and prediction of acid mine drainage 总被引:4,自引:1,他引:3
A. D. Paktunc 《Environmental Geology》1999,39(2):103-112
Acid-base accounting tests, commonly used as a screening tool in acid mine drainage (AMD) predictions, have limitations in
(1) measuring with confidence the amount of neutralizers present in samples and (2) affording an interpretation of what the
test results mean in terms of predicting the occurrence of acid mine drainage. Aside from the analytical difficulties inherent
to the conventional methods, a potential source of error in neutralization potential (NP) measurements is the contribution
from the dissolution of non-carbonate minerals. Non-carbonate alkalinity measured during static tests may or may not be available
to neutralize acidity produced in the field. In order to assess the value-added of extending the NP with the knowledge of
mineralogical composition and evaluate potential sources of errors in NP measurements, a suite of samples were examined and
characterized in terms of their mineralogical and chemical compositions. The results indicate that although the acid-base
accounting tests work well for simple compositions, the tests may result in overestimation or underestimation of NP values
for field samples. Mineralogical constraint diagrams relating NP determinations to Ca, Mg and CO2 concentrations were developed with the purpose to serve as supplementary guides to conventional static tests in identifying
possible NP contributions from non-carbonate minerals and checking the quality of the chemical testing results. Mineralogical
NP makes it possible to interpret the meaning of NP results and to assess the behaviour of samples over time by predicting
the onset of AMD and calculating NP values for individual size fractions.
Received: 1 June 1998 · Accepted: 6 October 1998 相似文献
16.
Hongfu SUN Fenghua ZHAO 《中国地球化学学报》2006,25(B08):26-27
In this study, geochemical characteristics of acid mine drainage (AMD) and its sediments from the Malan and Sitai coalmines, Shanxi Province, China, were investigated. Many analytical approaches such as IC, ICP-MS, XRD, XRF, and modeling calculation of hydrogeochemistry using PHREEQCI software were employed. The AMD is characterized by higher concentrations of iron and sulfate, a low pH, and elevated concentrations of a wide variety of heavy metals. The results of modeling calculation by PHREEQCI software demonstrate the metals in AMD are present mainly as Me^n+ and MeSO4^n-2 species. The sediments of AMD are composed mainly of iron-beating minerals such as goethite and schwertmannite, which are controlled by pH, Fe and SO4^2- concentrations. The schwertmannite mineral has been found for the first time in China. 相似文献
17.
Louis R. Bernier 《Environmental Geology》2005,47(5):670-684
The efficiency of serpentinite as an alternative alkalinity generating material for the passive treatment of acid mine drainage (AMD) was assessed in the laboratory. Three series of batch experiments were designed for the passive treatment of a low pH (1.6) AMD synthetic solution containing 2,500 ppm Fe2+, 6,600 ppm SO42–, 10.5 ppm Al, 15 ppm Ni, and traces of Cr, Mn and Cu. The influencing factors studied were: the effect of water/rock ratio, residence time, type of the alkalinity generating material (dolomite, magnesite, marble, serpentinite), and nature of the system (open vs. closed cells). The variations in solution chemistry observed in the open cells indicate that a lower water/rock ratio (0.33 ml/g) was the most efficient for metals removal. The optimal residence time in open cells was 24 h to reach the higher pH values. In the closed cells laboratory setup, synthetic AMD was placed in contact with the various alkaline materials for three different contact times (24, 48, 72 h). The optimal pH was reached after 48 h and did not change appreciably for longer contact time, and the best results for metal removals were obtained with marble and serpentinite. Single treatment efficiency was compared with a successive treatment approach. The most promising results were obtained with a five step treatment: (1) pre-treatment in a closed cell using serpentinite, (2) aeration and settling, (3) treatment in an open cell using marble, (4) final aeration and settling, and (5) filtration with a coarse silica sand. With this configuration, the final pH was 6.5 and pronounced metals depletion was achieved (100% for Al, 99.95% for Fe, 85.7% for Ni). 相似文献
18.
Natural ferrihydrites (Fh) often contain impurities such as aluminum, especially in acid mine drainage, and these impurities can potentially impact the chemical reactivity of Fh with respect to metal (loid) adsorption. In the present study, we have investigated the influence of aluminum on the sorption properties of ferrihydrite with respect to environmentally relevant aqueous arsenic species, arsenite and arsenate. We have conducted sorption experiments by reacting aqueous As(III) and As(V) with synthetic Al-free and Al-bearing ferrihydrite at pH 6.5. Our results reveal that, when increasing the Al:Fe molar ratio in Fh, the sorption density dramatically decreased for As(III), whereas it increased for As(V). Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy analysis at the As K-edge indicated that the AsIIIO3 pyramid binds to FeO6 octahedra on both Al-free Fh and Al-bearing Fh, by forming bidentate mononuclear edge-sharing (2E) and bidentate binuclear corner-sharing (2C) surface complexes characterized by As–Fe distances of 2.9 Å and 3.4 Å, respectively. The decrease in As(III) sorption density with increasing Al:Fe ratio in Fh could thus be explained by a low affinity of the As(OH)3 molecule for Al surface sites compared to Fe ones. In contrast, on the basis of available literature on As(V) adsorption mechanisms, we suggest that, in addition to inner-sphere 2C arsenate surface complexes, outer-sphere arsenate surface complexes forming hydrogen bonds with both Al–OH and Fe–OH surface sites could explain the enhancement of As(V) sorption onto aluminous Fh relative to Al-free Fh, as observed in the present study. The presence of aluminum in Fh may thus enhance the mobility of arsenite with respect to arsenate in Acid Mine Drainage impacted systems, while mixed Al:Fe systems could present an alternative for arsenic removal from impacted waters, provided that As(III) would be oxidized to As(V). 相似文献
19.
Hun-Bok Jung Seong-Taek Yun Bernhard Mayer Soon-Oh Kim Seong-Sook Park Pyeong-Koo Lee 《Environmental Geology》2005,48(4-5):437-449
Transport and sediment–water partitioning of trace metals (Cr, Co, Fe, Pb, Cu, Ni, Zn, Cd) in acid mine drainage were studied
in two creeks in the Kwangyang Au–Ag mine area, southern part of Korea. Chemical analysis of stream waters and the weak acid
(0.1 N HCl) extraction, strong acid (HF–HNO3–HClO4) extraction, and sequential extraction of stream sediments were performed. Heavy metal pollution of sediments was higher
in Chonam-ri creek than in Sagok-ri creek, because there is a larger source of base metal sulfides in the ores and waste dump
upstream of Chonam-ri creek. The sediment–water distribution coefficients (K
d) for metals in both creeks were dependent on the water pH and decreased in the order Pb ≈ Al > Cu > Mn > Zn > Co > Ni ≈ Cd.
K
d values for Al, Cu and Zn were very sensitive to changes in pH. The results of sequential extraction indicated that among
non-residual fractions, Fe–Mn oxides are most important for retaining trace metals in the sediments. Therefore, the precipitation
of Fe(–Mn) oxides due to pH increase in downstream sites plays an important role in regulating the concentrations of dissolved
trace metals in both creeks. For Al, Co, Cu, Mn, Pb and Zn, the metal concentrations determined by 0.1 N HCl extraction (Korean
Standard Method for Soil Pollution) were almost identical to the cumulative concentrations determined for the first three
weakly-bound fractions (exchangeable + bound to carbonates + bound to Fe–Mn oxides) in the sequential extraction procedure.
This suggests that 0.1 N HCl extraction can be effectively used to assess the environmentally available and/or bioavailable
forms of trace metals in natural stream sediments. 相似文献
20.
A laboratory study of covers made of low-sulphide tailings to prevent acid mine drainage 总被引:2,自引:0,他引:2
Covers with capillary barrier effects (CCBE) are considered to be one of the most effective ways to control acid mine drainage (AMD) production from mine wastes. The use of low-sulphide tailings in CCBE has been proposed recently for cases where other types of material may be unavailable near the mining site. This paper presents leaching column test results showing that CCBEs with a moisture-retaining layer made of slightly reactive tailings, with three different sulphide contents, can effectively limit the production of AMD from the acid-generating tailings placed underneath. With these layered covers, the leachate pH was maintained near neutrality throughout the testing period. When compared to uncovered tailings, the efficiency of the cover systems for reducing the amount of contaminants in the percolated water was determined to be greater than 99% for zinc, copper and iron. This study shows that the use of low-sulphide tailings can improve the ability of a CCBE to limit gas diffusion by consuming a fraction of the migrating oxygen. 相似文献