Iron and Aluminum Hydroxysulfates from Acid Sulfate Waters

Bigham, Jerry M.; Nordstrom, D. Kirk

doi:10.2138/rmg.2000.40.7

Cited by 475 publications

(402 citation statements)

References 179 publications

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“…Although we found no evidence for the formation of metastable schwertmannite or ferrihydrite during the dissolution, as observed by others (e.g., Bigham and Nordstrom, 2000), we sampled the residual solid only after several hundred hours had passed, and thus may have characterised only the stable end-product. The goethite that we characterised may comprise the original, or slightly re-arranged, FeO 6 octahedra that remain after the preferential dissolution of the K and SO 4 ions.…”

Section: Environmental Implicationsmentioning

confidence: 52%

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Dissolution of jarosite [KFe3(SO4)2(OH)6] at pH 2 and 8: Insights from batch experiments and computational modelling

Smith

Hudson‐Edwards

Dubbin

et al. 2006

Geochimica et Cosmochimica Acta

129

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Jarosite [KFe 3 (SO 4 ) 2 (OH) 6 ] is a mineral that is common in acidic, sulphate-rich environments, such as acid sulphate soils derived from pyrite-bearing sediments, weathering zones of sulphide ore deposits and acid mine or acid rock drainage (ARD/AMD) sites. The structure of jarosite is based on linear tetrahedral-octahedral-tetrahedral (T-O-T) sheets, made up from slightly distorted FeO 6 octahedra and SO 4 tetrahedra. Batch dissolution experiments carried out on synthetic jarosite at pH 2, to mimic environments affected by ARD/AMD, and at pH 8, to simulate ARD/AMD environments recently remediated with slaked lime (Ca(OH) 2 ), suggest first order dissolution kinetics. Both dissolution reactions are incongruent as revealed by non-ideal dissolution of the parent solids and, in the case of the pH 8 dissolution, because of a secondary goethite precipitate on the surface of the dissolving jarosite grains. The pH 2 dissolution yields only aqueous K, Fe and SO 4 . Aqueous, residual solid and computational modelling of the jarosite structure and surfaces using the GULP and MARVIN codes, respectively, show for the first time that there is selective dissolution of the A-and T-sites, which contain K and SO 4 , respectively, relative to Fe, which is located deep within the T-O-T jarosite structure. These results have implications for the chemistry of ARD/AMD waters, and for understanding reaction pathways of ARD/AMD mineral dissolution.

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Section: Environmental Implicationsmentioning

confidence: 52%

“…Jarosite is of considerable geological, environmental and metallurgical interest because it sorbs and co-precipitates considerable amounts of potentially toxic elements such as As and Pb (Dutrizac, 1983;Bigham and Nordstrom, 2000).…”

Section: Introductionmentioning

confidence: 99%

Dissolution of jarosite [KFe3(SO4)2(OH)6] at pH 2 and 8: Insights from batch experiments and computational modelling

Smith

Hudson‐Edwards

Dubbin

et al. 2006

Geochimica et Cosmochimica Acta

129

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“…Sulphate, Fe and H + are released into solution forming what is commonly known as acid mine drainage (AMD) (Bigham and Nordstrom, 2000;Jönsson et al, 2006). The oxidation reaction process of pyrite can be generalized by the following equations:…”

Section: Introductionmentioning

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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“…In an ideal jarosite [KFe 3 (SO 4 ) 2 (OH) 6 ], the B site cation is Fe(III), the A site is occupied by a cation (mainly K + , but also H 3 O + , hydronium; Brophy and Sheridan, 1965;Kubisz, 1970;Dutrizac and Kaiman, 1976;Ripmeester et al, 1986) in 12-fold coordination, and the T site is filled by sulphate (SO 4 2-) (Brophy and Sheridan, 1965;Kubisz, 1964). Jarosite minerals are important in acid Earth surface environments and metallurgy (Bigham and Nordstrom, 2000;Dutrizac and Jambor, 2000), because the A, B and T sites can be filled with metal and metalloid ions (e.g., Pb 2+ in the A site, Cu 2+ and Zn 2+ in the B site, As 5+ in the T site; Dutrizac and Jambor, 2000). Zinc atoms have also been found to occupy trigonal bipyramidal sites in half of the available six-membered rings of the layers of octahedral in a monoclinic segnitite (PbFe 3 H(AsO 4 ) 2 (OH) 6 )-related mineral by Grey et al (2008), giving PbZn 0.5 Fe 3 (AsO 4 ) 2 (OH) 6 .…”

Section: Introductionmentioning

confidence: 99%

Synthesis, characterization and thermochemistry of synthetic Pb–As, Pb–Cu and Pb–Zn jarosites

Forray

Smith

Navrotsky

et al. 2014

Geochimica et Cosmochimica Acta

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The enthalpy of formation from the elements of well characterized Pb-As, Pb-Cu, measured by high temperature oxide melt solution calorimetry and gave !Hº f = -3691.2 ± 8.6 kJ/mol, !Hº f = -3653.6 ± 8.2 kJ/mol, and !Hº f = -3669.4 ± 8.4 kJ/mol, respectively. Using estimated entropies, the standard Gibbs free energy of formation from elements at 298 K !Gº f of the three compounds were calculated to be -3164.8 ± 9.1 kJ/mol, -3131.4 ± 8.7 kJ/mol, and -3153.6 ± 8.9 kJ/mol, respectively. Based on these free energies, their logK sp values are -13.94 ± 1.89, -4.38 ± 1.81 and -3.75 ± 1.80, respectively. For tis compounds, a log 10 {Pb 2+ } -pH diagram is presented. The diagram shows that the formation of Pb-As jarosite may decrease aqueous arsenic and lead concentrations to meet drinking water standards. The new thermodynamic data confirm that transformation of Pb-As jarosite to plumbojarosite is thermodynamically possible.

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Iron and Aluminum Hydroxysulfates from Acid Sulfate Waters

Cited by 475 publications

References 179 publications

Dissolution of jarosite [KFe3(SO4)2(OH)6] at pH 2 and 8: Insights from batch experiments and computational modelling

Dissolution of jarosite [KFe3(SO4)2(OH)6] at pH 2 and 8: Insights from batch experiments and computational modelling

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

Synthesis, characterization and thermochemistry of synthetic Pb–As, Pb–Cu and Pb–Zn jarosites

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