Schwertmannite and the chemical modeling of iron in acid sulfate waters

Bigham, Jerry M.; Schwertmann, U.; Traina, Samuel J.; Winland, Ronald Lee; Wolf, Moritz

doi:10.1016/0016-7037(96)00091-9

Cited by 956 publications

(710 citation statements)

References 15 publications

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“…These so-called "ochre precipitates" consist of Fe-phases precipitated from the AMD. In contrast with other well crystallized products of pyrite oxidation, such as hematite or goethite, these mine drainage minerals (MDM; Murad et al, 1994) consist of poorly crystallized oxyhydroxides and oxyhydroxysulphates of fibrous to spherical morphology such as ferrihydrite and schwertmannite, in addition to jarosite and goethite, showing extremely small particle size (b 1 nm spherical particle diameter) (Bigham et al, 1990(Bigham et al, , 1996Carlson and Schwertmann, 1981;Dold, 2003;Fukushi et al, 2003;Kawano and Tomita, 2001;Majzlan et al, 2004;Murad et al, 1994;Nordstrom and Alpers, 1999;Regenspurg et al, 2004;Williams et al, 2002;Yu et al, 1999), which greatly enhance the reactive surface area, allowing the metal adsorption to these mineral phases.…”

Section: Discussionmentioning

confidence: 99%

An integrative assessment of environmental degradation of Caveira abandoned mine area (Southern Portugal)

Silva

Durães

Reis

et al. 2015

Journal of Geochemical Exploration

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Since the end of the 1990s the Portuguese Iberian Pyrite Belt (IPB) is a typical European post-mining region with significant problems related to acid mine drainage (AMD), metal dispersion, mine waste management and unsafe mining infra-structures. The Portuguese government is providing particular attention on the sulphide abandoned mines and doing considerable investments on the mining recovery all over the country. The former Caveira mine was closed in the 1980s. It is considered an extremely impacted site due to the dimension of the areas affected by mining activities. Tailings, mine addicts and associated waste rock dumps, resulting from 129 years of pyrite and Cu exploitation, are spread along the Grândola stream. Despite the semi-arid climatic conditions of the area, the tailings are considerably eroded by the surficial waters, particularly during rainfall events. The past mining and smelting activities have resulted in severe contamination of the Grândola stream and its tributary by AMD (pH b 2) as well as degradation of surrounding stream sediments, soils and vegetation. In order to evaluate possible environmental risks, a sediment and surface water survey was carried out downstream the Caveira mine. The acidic effluent and mixed stream water show high Al, As, Ca, Cd, Cu, Fe, Hg, Mg, Mn, Ni, Pb and SO 4 concentrations, with several of these contaminants exceeding local and/or surface water quality standards. The data show a strong seasonal variation of surface water quality with poorer water quality during the dry and rainy seasons caused by evaporation and efflorescent salt dissolution, respectively. The variable flow regime at the local streams causes dilution of AMD rich in trace metals reaching background within 14 km downstream. The potential toxicity of stream metal concentrations was determined using cumulative criterion unit (CCU) scores and the modified AMD index (MAMDI), which highlighted As, Cd, Cu, Pb and Zn as the major sources of potential chronic stream toxicity, with emphasis on winter season. Although the threshold of the likely harm to aquatic life is exceeded at all sites, the two indexes highlight differences relating to the extension of contamination effects. The Average Index of Toxicity (AIT) showed that sediment contamination is very high even when the distance to mine promoted a decreasing in water metal concentrations, which are being precipitated in the sediments due to pH increase.

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Section: Discussionmentioning

confidence: 99%

An integrative assessment of environmental degradation of Caveira abandoned mine area (Southern Portugal)

Silva

Durães

Reis

et al. 2015

Journal of Geochemical Exploration

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“…The presence of sulfates (e.g., gypsum) in the lake sediments was also documented by XRD. The presence of schwertmannite, commonly found in acidic and iron-and sulfate-rich environments, was not confirmed by XRD probably due to its low crystallinity relative to detrital materials or its transformation to goethite with time (Bingham et al 1996;Cornell and Schwertmann 2003;Jönsson et al 2005Jönsson et al , 2006. Overall, the isotopic composition of all of the lakes reflects varying degree of evaporation, which is correlated with their ages.…”

Section: Water Column and Sediments Of Amlmentioning

confidence: 95%

Generation of Acid Mine Lakes Associated with Abandoned Coal Mines in Northwest Turkey

Yücel

Balcı

Baba

2016

Arch Environ Contam Toxicol

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A total of five acid mine lakes (AMLs) located in northwest Turkey were investigated using combined isotope, molecular, and geochemical techniques to identify geochemical processes controlling and promoting acid formation. All of the investigated lakes showed typical characteristics of an AML with low pH (2.59-3.79) and high electrical conductivity values (1040-6430 lS/cm), in addition to high sulfate (594-5370 mg/l) and metal (aluminum [Al], iron [Fe], manganese [Mn], nickel [Ni], and zinc [Zn]) concentrations. Geochemical and isotope results showed that the acid-generation mechanism and source of sulfate in the lakes can change and depends on the age of the lakes. In the relatively older lakes (AMLs 1 through 3), biogeochemical Fe cycles seem to be the dominant process controlling metal concentration and pH of the water unlike in the younger lakes (AMLs 4 and 5). Bacterial species determined in an older lake (AML 2) indicate that biological oxidation and reduction of Fe and S are the dominant processes in the lakes. Furthermore, O and S isotopes of sulfate indicate that sulfate in the older mine lakes may be a product of much more complex oxidation/dissolution reactions. However, the major source of sulfate in the younger mine lakes is in situ pyrite oxidation catalyzed by Fe(III) produced by way of oxidation of Fe(II). Consistent with this, insignificant fractionation between d 34 S SO 4 and d 34 S FeS 2 values indicated that the oxidation of pyrite, along with dissolution and precipitation reactions of Fe(III) minerals, is the main reason for acid formation in the region. Overall, the results showed that acid generation during early stage formation of an AML associated with pyrite-rich mine waste is primarily controlled by the oxidation of pyrite with Fe cycles becoming the dominant processes regulating pH and metal cycles in the later stages of mine lake development.Acidic and highly metal-loaded effluents (acid mine drainage [AMD]) resulting from the exposure of pyrite and other metal sulfide minerals to weathering conditions are the principal environmental problems faced by the mining industry today (Dold and Spangerberg 2005).The formation mechanisms of AMD (e.g., oxidation of pyrite and other sulfide minerals) has been extensively studied

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“…Greater SIs indicate that schwertmannite was the predominant precipitated phase in the systems (Table 4). Schwertmannite was also likely the main phase in the OH1 and OH2 trials since schwertmannite is the most common poorly crystalline Fe mineral that forms by direct precipitation from pH 2.8-4 water with sulphate concentrations between 1000 and 3000 mg/L (Bigham et al 1996). The conditions in the VFR trials also indicate that schwertmannite was likely, since it is typically formed in aerobic environments through bacterially mediated Fe oxidation after exposure to the atmosphere (Fernandez-Martinez et al 2010).…”

Section: Moderately Acidic Mine Waters (Ph 3-45)mentioning

confidence: 98%

“…The wateq4f database was modified to account for the schwertmannite solubility products (log K sp ) 7.06 (Kawano and Tomita 2001) and 18.0 (Bigham et al 1996) at the temperature at which the tests were conducted. Redox couple Fe 2 /Fe 3 was used in speciation calculations in the case of missing ORP values.…”

Section: Geochemical Modelingmentioning

confidence: 99%

International Trials of Vertical Flow Reactors for Coal Mine Water Treatment

Blanco

Sapsford

Trumm³

et al. 2017

Mine Water Environ

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previous research confirmed that VFRs can be used as standalone passive treatment systems for iron removal from mine waters with a footprint less than half of the area required by a conventional aerobic wetland. A VFR can also provide useful iron pretreatment for other passive treatment systems under circumneutral conditions, but would have to be combined with alkaline generating systems to achieve full iron removal from acidic mine waters.

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Schwertmannite and the chemical modeling of iron in acid sulfate waters

Cited by 956 publications

References 15 publications

An integrative assessment of environmental degradation of Caveira abandoned mine area (Southern Portugal)

An integrative assessment of environmental degradation of Caveira abandoned mine area (Southern Portugal)

Generation of Acid Mine Lakes Associated with Abandoned Coal Mines in Northwest Turkey

International Trials of Vertical Flow Reactors for Coal Mine Water Treatment

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