A review: Pyrite oxidation mechanisms and acid mine drainage prevention

Evangelou, V. P.; Zhang, Y. L.

doi:10.1080/10643389509388477

Cited by 491 publications

(244 citation statements)

References 84 publications

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“…Framboidal FeS 2 consists of aggregates of very small FeS 2 crystals (\ 1 lm), whereas euhedral crystals are generally greater (tens to thousands of microns). Among a variety of morphologies, such as framboids, octahedral, and cubic crystals with irregular surfaces, the small, polycrystalline framboids are particularly susceptible to oxidation owing to their porosity and large surface area (Evangelou and Zhang 1995). FeS 2 crystals have a cubic crystal form in coals in the study area (Fig.…”

Section: Geochemical Datamentioning

confidence: 99%

Geochemical Characterization of Acid Mine Lakes in Northwest Turkey and Their Effect on the Environment

Yücel

Baba

2012

Arch Environ Contam Toxicol

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Mining activity generates a large quantity of mine waste. The potential hazard of mine waste depends on the host mineral. The tendency of mine waste to produce acid mine drainage (AMD) containing potentially toxic metals depends on the amounts of sulfide, carbonate minerals, and trace-element concentrations found in ore deposits. The acid mine process is one of the most significant environmental challenges and a major source of water pollution worldwide. AMD and its effects were studied in northwest Turkey where there are several sedimentary and hydrothermal mineral deposits that have been economically extracted. The study area is located in Can county of Canakkale province. Canakkale contains marine, lagoon, and lake sediments precipitated with volcanoclastics that occurred as a result of volcanism, which was active during various periods from the Upper Eocene to Plio-Quaternary. Can county is rich in coal with a total lignite reserve [100 million tons and contains numerous mines that were operated by private companies and later abandoned without any remediation. As a result, human intervention in the natural structure and topography has resulted in large open pits and deterioration in these areas. Abandoned open pit mines typically fill with water from runoff and groundwater discharge, producing artificial lakes. Acid drainage waters from these mines have resulted in the degradation of surface-water quality around Can County. The average pH and electrical conductivity of acid mine lakes (AMLs) in this study were found to be 3.03 and 3831.33 lS cm -1 , respectively. Total iron (Fe) and aluminum (Al) levels were also found to be high (329.77 and 360.67 mg L -1 , respectively). The results show that the concentration of most elements, such as Fe and Al in particular, exceed national and international water-quality standards.

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Section: Geochemical Datamentioning

confidence: 99%

Geochemical Characterization of Acid Mine Lakes in Northwest Turkey and Their Effect on the Environment

Yücel

Baba

2012

Arch Environ Contam Toxicol

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“…Muitos estudos já foram feitos para se compreender o mecanismo da lixiviação de metais por bactérias [4][5][6][7][8][9][10] , no entanto, o mecanismo eletroquímico dos processos de biolixiviação, principalmente a lixiviação do cobre, pouco se conhece. O entendimento destes mecanismos utilizando-se técnicas eletroquímicas, é de fundamental importância para orientar os estudos de otimização dos processos de recuperação de metais, principalmente em escala industrial.…”

Section: Introductionunclassified

“…A lixiviação bacteriana do cobre tem sido muito estudada em minerais sulfetados. Apesar da calcopirita (CuFeS 2 ) ser o mineral sulfetado de cobre mais abundante na natureza, existem outros dois minerais sulfetados também importantes economicamente, a calcocita (Cu 2 S) e a covelita (CuS).A principal bactéria envolvida neste processo é o T. ferrooxidans, uma espécie acidofílica que apresenta como metabolismo central a oxidação de sulfetos metálicos, enxofre reduzido e íon Fe 2+ , como forma de obtenção de energia para o seu metabolismo.O processo de lixiviação bacteriana é um fenômeno químico, no entanto, também pode ser considerado como um processo eletroquímico, pois ocorre transferência de elétrons do mineral para o microrganismo; portanto a biolixiviação nada mais é que um processo de corrosão.Muitos estudos já foram feitos para se compreender o mecanismo da lixiviação de metais por bactérias [4][5][6][7][8][9][10] , no entanto, o mecanismo eletroquímico dos processos de biolixiviação, principalmente a lixiviação do cobre, pouco se conhece. O entendimento destes mecanismos utilizando-se técnicas eletroquímicas, é de fundamental importância para orientar os estudos de otimização dos processos de recuperação de metais, principalmente em escala industrial.…”

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Aplicação de técnicas eletroquímicas no estudo da dissolução oxidativa da covelita (CuS) por Thiobacillus ferrooxidans

Teixeira¹,

Ramires²,

Júnior³

et al. 2002

Quím. Nova

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Recebido em 26/9/00; aceito em 6/7/01 ELECTROCHEMICAL TECHNIQUES APPLIED TO STUDY THE OXIDATIVE DISSOLUTION OF THE COVELLITE -CuS by THIOBACILLUS FERROOXIDANS. Among the copper sulphides, chalcopyrite (CuFeS 2 ), covellite (CuS) and chalcocite (Cu 2 S) are the most important source of minerals for copper mining industry. The acknowledge of behaviour of these sulphides related with bacterial leaching process are essential for optimization procedures. Despite of its importance, covellite has not deserved much interest of researchers regarding this matter. In this work it was studied the oxidation of covellite by the chemolithotrophic bacterium Thiobacillus ferrooxidans by using electrochemical techniques, such as open circuit potentials with the time and cyclic voltammetry. The experiments were carried out in acid medium (pH 1.8), containing or not Fe 2+ as additional energy source, and in different periods of incubation; chemical controls were run in parallel. The results showed that a sulphur layer is formed spontaneously due the acid attack, covering the sulphide in the initial phase of incubation, blocking the sulphide oxidation. However, the bacterium was capable to oxidize this sulphur layer. In the presence of Fe 2+ as supplemental energy source, the corrosion process was facilitated, because ocurred an indirect oxidation of covellite by Fe 3+ , which was produced by T. ferrooxidans oxidation of the Fe 2+ added in the medium.Keywords: Thiobacillus ferrooxidans; bioleaching; electrochemical techniques. INTRODUÇÃODevido ao aumento da demanda mundial dos bens minerais, temse verificado um progressivo esgotamento das reservas contendo alto teores dos metais de interesse econômico. Dessa forma, torna-se importante o desenvolvimento de métodos alternativos para o tratamento de minérios contendo baixos teores desses materiais. Assim o uso de técnicas hidrometalúrgicas vem merecendo crescente atenção dos técnicos e empresários do setor mínero-metalúrgico.A Hidrometalurgia consiste na utilização de soluções ácidas ou básicas para o tratamento dos minérios e a recuperação desses metais de interesse. Entre os processos hidrometalúrgicos, há um processo biotecnológico denominado Biohidrometalurgia ou lixiviação bacteriana, que utiliza microrganismos capazes de promoverem a solubilização de metais pela oxidação de sulfetos metálicos. Esta técnica é reconhecida atualmente como uma alternativa ou processo complementar, para a recuperação e obtenção de metais de minérios de teores reduzidos. Estima-se um mercado de cerca de 10 bilhões de dólares para esse tipo de processo 1 . A lixiviação bacteriana é atualmente aplicada em escala industrial para recuperação de metais como cobre, urânio e ouro 2 , em países como: E.U.A., Rússia, Chile, Espanha, Canadá, África do Sul, Australia entre outros 3 . A lixiviação bacteriana do cobre tem sido muito estudada em minerais sulfetados. Apesar da calcopirita (CuFeS 2 ) ser o mineral sulfetado de cobre mais abundante na natureza, existem outros dois minerais sulfetados também importantes...

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“…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 (Nordstrom 1982;Taylor et al 1984a, b;Evangelou and Zhang 1995;Nordstrom and Alpers 1999;Descostes et al 2001;Schippers 2004;Blodau 2006;Balci et al 2007Balci et al , 2012. However, the details of the process causing and regulating AMD generation include complex geochemical and biogeochemical reactions involving acid generation and consumption (Nordstrom and Alpers 1999;Nordstrom 2003;Blowes et al 2003;Blodau 2006;Cravotta 2008a, b).…”

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confidence: 99%

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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A review: Pyrite oxidation mechanisms and acid mine drainage prevention

Cited by 491 publications

References 84 publications

Geochemical Characterization of Acid Mine Lakes in Northwest Turkey and Their Effect on the Environment

Geochemical Characterization of Acid Mine Lakes in Northwest Turkey and Their Effect on the Environment

Aplicação de técnicas eletroquímicas no estudo da dissolução oxidativa da covelita (CuS) por Thiobacillus ferrooxidans

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

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