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Metal Extraction and Bioleaching

Works Count: 58216

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This cluster of papers focuses on biohydrometallurgical processes for extracting and recovering metals from ores and waste materials. It covers topics such as bioleaching, microbial communities in metal recovery, oxidation mechanisms of sulfide minerals, acid mine drainage, vanadium extraction, sulfur metabolism, and the application of microbial ecology in metallurgical processes.

Keywords

Bioleaching; Microbial Communities; Metal Recovery; Sulfide Minerals; Acid Mine Drainage; Metallurgy; Microbial Ecology; Oxidation Mechanism; Vanadium Extraction; Sulfur Metabolism

STUDIES ON THE CHEMOAUTOTROPHIC IRON BACTERIUM FERROBACILLUS FERROOXIDANS

1959-05-01

Melvin Silverman , D. G. Lundgren

Microbial mineral recovery

1990-11-01

Henry L. Ehrlich , Córale L. Brierley

Because certain microorganisms have the ability to metabolize metals and inorganic elements generally, they serve an important role in the leaching of valuable minerals. Now with the advent of genetic … Because certain microorganisms have the ability to metabolize metals and inorganic elements generally, they serve an important role in the leaching of valuable minerals. Now with the advent of genetic engineering and biotechnology, we possess the ability to increase the efficiency of biogenic extractive metallurgy and minimize the environmental effects of mine wastes, dump leachates, and inorganic wastes. This volume is an up-to-date review of advances in the field, many of great economic and environmental importance.

Microwave energy for mineral treatment processes—a brief review

1999-07-01

K. E. Haque

Solubility of gold in arsenian pyrite

2005-06-01

Martín Reich , Stephen E. Kesler , Satoshi Utsunomiya +3 more

Pyrite oxidation: a state-of-the-art assessment of the reaction mechanism

2003-02-17

J. Donald Rimstidt , David J. Vaughan

Thio complexes of gold and the transport of gold in hydrothermal ore solutions

1973-03-01

Terry M. Seward

Variations in the compositional, textural and electrical properties of natural pyrite: a review

2003-12-06

P. K. Abraitis , R. A. D. Pattrick , David J. Vaughan

Aqueous oxidation of pyrite by molecular oxygen

1982-10-01

Richard T. Lowson

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAqueous oxidation of pyrite by molecular oxygenRichard T. LowsonCite this: Chem. Rev. 1982, 82, 5, 461–497Publication Date (Print):October 1, 1982Publication History Published online1 May 2002Published inissue 1 … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAqueous oxidation of pyrite by molecular oxygenRichard T. LowsonCite this: Chem. Rev. 1982, 82, 5, 461–497Publication Date (Print):October 1, 1982Publication History Published online1 May 2002Published inissue 1 October 1982https://doi.org/10.1021/cr00051a001RIGHTS & PERMISSIONSArticle Views2558Altmetric-Citations448LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (5 MB) Get e-Alertsclose Get e-Alerts

Use of XPS in the determination of chemical environment and oxidation state of iron and sulfur samples: constitution of a data basis in binding energies for Fe and S reference compounds and applications to the evidence of surface species of an oxidized pyrite in a carbonate medium

2000-10-01

Michaël Descostes , F. Mercier , N. Thromat +2 more

The mechanisms of pyrite oxidation and leaching: A fundamental perspective

2010-09-01

Anand P. Chandra , Andrea R. Gerson

Progress in bioleaching: fundamentals and mechanisms of bacterial metal sulfide oxidation—part A

2013-05-29

Mario Vera , Axel Schippers , Wolfgang Sand

Thiosulfate leaching of gold—A review

2001-02-01

Mark Aylmore , D.M. Muir

Mineral weathering by bacteria: ecology, actors and mechanisms

2009-08-01

Stéphane Uroz , Christophe Calvaruso , Marie-Pierre Turpault +1 more

Iron disulfide for solar energy conversion

1993-05-01

A. Ennaoui , S. Fiechter , Ch. Pettenkofer +5 more

(Bio)chemistry of bacterial leaching—direct vs. indirect bioleaching

2001-02-01

Wolfgang Sand , Tilman Gehrke , P.-G. Jozsa +1 more

Ultrasound: a powerful tool for leaching

2003-01-01

José L. Luque-García , M. D. Luque de Castro

A thermodynamic study of pyrite and pyrrhotite

1964-05-01

Priestley Toulmin , Paul B. Barton

Prokaryotic sulfur oxidation

2005-05-06

Cornelius G. Friedrich , Frank Bardischewsky , Dagmar Röther +2 more

Community proteomics of a natural microbial biofilm.

2005-06-24

Rachna J. Ram , Nathan C. VerBerkmoes , Michael P. Thelen +6 more

Using genomic and mass spectrometry–based proteomic methods, we evaluated gene expression, identified key activities, and examined partitioning of metabolic functions in a natural acid mine drainage (AMD) microbial biofilm community. … Using genomic and mass spectrometry–based proteomic methods, we evaluated gene expression, identified key activities, and examined partitioning of metabolic functions in a natural acid mine drainage (AMD) microbial biofilm community. We detected 2033 proteins from the five most abundant species in the biofilm, including 48% of the predicted proteins from the dominant biofilm organism, Leptospirillum group II. Proteins involved in protein refolding and response to oxidative stress appeared to be highly expressed, which suggests that damage to biomolecules is a key challenge for survival. We validated and estimated the relative abundance and cellular localization of 357 unique and 215 conserved novel proteins and determined that one abundant novel protein is a cytochrome central to iron oxidation and AMD formation.

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Oxidation of Reduced Inorganic Sulfur Compounds by Bacteria: Emergence of a Common Mechanism?

2001-07-01

Cornelius G. Friedrich , Dagmar Röther , Frank Bardischewsky +2 more

Biological oxidation of hydrogen sulfide to sulfate is one of the major reactions of the global sulfur cycle. Reduced inorganic sulfur compounds (referred to below as sulfur) are exclusively oxidized … Biological oxidation of hydrogen sulfide to sulfate is one of the major reactions of the global sulfur cycle. Reduced inorganic sulfur compounds (referred to below as sulfur) are exclusively oxidized by prokaryotes, and sulfate is the major oxidation product. Sulfur oxidation in members of the

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The bioleaching of sulphide minerals with emphasis on copper sulphides — A review

2006-06-24

H.R. Watling

Bioleaching review part B:

2003-12-01

G. J. Olson , James A. Brierley , Córale L. Brierley

Etude par spectroscopie de photoelectrons de la degradation superficielle de FeS2, CuFeS2, ZnS et PbS a l'air et dans l'eau

1980-06-01

D. Brion

Bioleaching review part A:

2003-12-01

Thore Rohwerder , T. Gehrke , Kenneth W. Kinzler +1 more

Chemistry of Iron Sulfides

2007-01-30

David Rickard , George W. Luther

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemistry of Iron SulfidesDavid Rickard and George W. LutherView Author Information 1School of Earth, Ocean and Planetary Sciences, Cardiff University, Cardiff CF103YE, Wales, U.K., and College of … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemistry of Iron SulfidesDavid Rickard and George W. LutherView Author Information 1School of Earth, Ocean and Planetary Sciences, Cardiff University, Cardiff CF103YE, Wales, U.K., and College of Marine and Earth Studies, University of Delaware, Lewes, Delaware 19958 Cite this: Chem. Rev. 2007, 107, 2, 514–562Publication Date (Web):January 30, 2007Publication History Received22 June 2006Published online30 January 2007Published inissue 1 February 2007https://pubs.acs.org/doi/10.1021/cr0503658https://doi.org/10.1021/cr0503658research-articleACS PublicationsCopyright © 2007 American Chemical SocietyRequest reuse permissionsArticle Views14876Altmetric-Citations1146LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Iron,Pyrite,Stability,Sulfides,Sulfur Get e-Alerts

Does a rhizospheric microorganism enhance K+ availability in agricultural soils?

2013-12-05

Vijay Singh Meena , B. R. Maurya , Jay Prakash Verma

Acidithiobacillus ferrooxidans metabolism: from genome sequence to industrial applications

2008-12-01

Jorge Valdés , Inti Pedroso , Raquel Quatrini +5 more

Abstract Background Acidithiobacillus ferrooxidans is a major participant in consortia of microorganisms used for the industrial recovery of copper (bioleaching or biomining). It is a chemolithoautrophic, γ-proteobacterium using energy from … Abstract Background Acidithiobacillus ferrooxidans is a major participant in consortia of microorganisms used for the industrial recovery of copper (bioleaching or biomining). It is a chemolithoautrophic, γ-proteobacterium using energy from the oxidation of iron- and sulfur-containing minerals for growth. It thrives at extremely low pH (pH 1–2) and fixes both carbon and nitrogen from the atmosphere. It solubilizes copper and other metals from rocks and plays an important role in nutrient and metal biogeochemical cycling in acid environments. The lack of a well-developed system for genetic manipulation has prevented thorough exploration of its physiology. Also, confusion has been caused by prior metabolic models constructed based upon the examination of multiple, and sometimes distantly related, strains of the microorganism. Results The genome of the type strain A. ferrooxidans ATCC 23270 was sequenced and annotated to identify general features and provide a framework for in silico metabolic reconstruction. Earlier models of iron and sulfur oxidation, biofilm formation, quorum sensing, inorganic ion uptake, and amino acid metabolism are confirmed and extended. Initial models are presented for central carbon metabolism, anaerobic metabolism (including sulfur reduction, hydrogen metabolism and nitrogen fixation), stress responses, DNA repair, and metal and toxic compound fluxes. Conclusion Bioinformatics analysis provides a valuable platform for gene discovery and functional prediction that helps explain the activity of A. ferrooxidans in industrial bioleaching and its role as a primary producer in acidic environments. An analysis of the genome of the type strain provides a coherent view of its gene content and metabolic potential.

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The kinetics and electrochemical rate-determining step of aqueous pyrite oxidation

1994-12-01

Mark A. Williamson , J. Donald Rimstidt

The microbiology of acidic mine waters

2003-05-28

D. Barrie Johnson , Kevin B. Hallberg

Sulfolobus: A new genus of sulfur-oxidizing bacteria living at low pH and high temperature

1972-01-01

Thomas D. Brock , Katherine M. Brock , R. T. Belly +1 more

Acidic Mine Drainage: The Rate-Determining Step

1970-02-20

Philip C. Singer , Werner Stumm

The rate-determining step in the oxidation of iron pyrite and the formation of acidity in streams associated with coal and copper mines is the oxidation of ferrous iron. Effective pollution … The rate-determining step in the oxidation of iron pyrite and the formation of acidity in streams associated with coal and copper mines is the oxidation of ferrous iron. Effective pollution abatement necessitates control ling this reaction.

Aqueous pyrite oxidation by dissolved oxygen and by ferric iron

1987-06-01

Carl O. Moses , D. Kirk Nordstrom , Janet S. Herman +1 more

Processing of vanadium: a review

2003-07-22

R.R. Moskalyk , Akram Alfantazi

Microbial communities in acid mine drainage

2003-04-25

Brett J. Baker , Jillian F. Banfield

The dissolution of sulfide minerals such as pyrite (FeS2), arsenopyrite (FeAsS), chalcopyrite (CuFeS2), sphalerite (ZnS), and marcasite (FeS2) yields hot, sulfuric acid-rich solutions that contain high concentrations of toxic metals. … The dissolution of sulfide minerals such as pyrite (FeS2), arsenopyrite (FeAsS), chalcopyrite (CuFeS2), sphalerite (ZnS), and marcasite (FeS2) yields hot, sulfuric acid-rich solutions that contain high concentrations of toxic metals. In locations where access of oxidants to sulfide mineral surfaces is increased by mining, the resulting acid mine drainage (AMD) may contaminate surrounding ecosystems. Communities of autotrophic and heterotrophic archaea and bacteria catalyze iron and sulfur oxidation, thus may ultimately determine the rate of release of metals and sulfur to the environment. AMD communities contain fewer prokaryotic lineages than many other environments. However, it is notable that at least two archaeal and eight bacterial divisions have representatives able to thrive under the extreme conditions typical of AMD. AMD communities are characterized by a very limited number of distinct species, probably due to the small number of metabolically beneficial reactions available. The metabolisms that underpin these communities include organoheterotrophy and autotrophic iron and sulfur oxidation. Other metabolic activity is based on anaerobic sulfur oxidation and ferric iron reduction. Evidence for physiological synergy in iron, sulfur, and carbon flow in these communities is reviewed. The microbial and geochemical simplicity of these systems makes them ideal targets for quantitative, genomic-based analyses of microbial ecology and evolution and community function.

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Bioleaching: metal solubilization by microorganisms

1997-07-01

Klaus Bosecker

Bioleaching is a simple and effective technology for metal extraction from low-grade ores and mineral concentrates. Metal recovery from sulfide minerals is based on the activity of chemolithotrophic bacteria, mainly … Bioleaching is a simple and effective technology for metal extraction from low-grade ores and mineral concentrates. Metal recovery from sulfide minerals is based on the activity of chemolithotrophic bacteria, mainly Thiobacillus ferrooxidans and T. thiooxidans, which convert insoluble metal sulfides into soluble metal sulfates. Non-sulfide ores and minerals can be treated by heterotrophic bacteria and by fungi. In these cases metal extraction is due to the production of organic acids and chelating and complexing compounds excreted into the environment. At present bioleaching is used essentially for the recovery of copper, uranium and gold, and the main techniques employed are heap, dump and in situ leaching. Tank leaching is practised for the treatment of refractory gold ores. Bioleaching has also some potential for metal recovery and detoxification of industrial waste products, sewage sludge and soil contaminated with heavy metals.

Reclassification of some species of Thiobacillus to the newly designated genera Acidithiobacillus gen. nov., Halothiobacillus gen. nov. and Thermithiobacillus gen. nov.

2000-03-01

D. P. Kelly , Ann P. Wood

The species of the genus 'Thiobacillus' fall into the alpha-, beta- and gamma-subclasses of the Proteobacteria, the type species Thiobacillus thioparus being located in the beta-subclass. 'Thiobacillus' species exhibit almost … The species of the genus 'Thiobacillus' fall into the alpha-, beta- and gamma-subclasses of the Proteobacteria, the type species Thiobacillus thioparus being located in the beta-subclass. 'Thiobacillus' species exhibit almost as much diversity in DNA composition and physiology as is found collectively in all other proteobacterial groups. On the basis of physiological characters and 16S rRNA gene sequence comparisons, eight of the existing Thiobacillus species are proposed for reassignment to three newly designated genera within the gamma-subclass of the Proteobacteria, namely Acidithiobacillus, Halothiobacillus and Thermithiobacillus.

Bacterial Leaching of Metal Sulfides Proceeds by Two Indirect Mechanisms via Thiosulfate or via Polysulfides and Sulfur

1999-01-01

Axel Schippers , Wolfgang Sand

ABSTRACT The acid-insoluble metal sulfides FeS 2 , MoS 2 , and WS 2 are chemically attacked by iron(III) hexahydrate ions, generating thiosulfate, which is oxidized to sulfuric acid. Other … ABSTRACT The acid-insoluble metal sulfides FeS 2 , MoS 2 , and WS 2 are chemically attacked by iron(III) hexahydrate ions, generating thiosulfate, which is oxidized to sulfuric acid. Other metal sulfides are attacked by iron(III) ions and by protons, resulting in the formation of elemental sulfur via intermediary polysulfides. Sulfur is biooxidized to sulfuric acid. This explains leaching of metal sulfides by Thiobacillus thiooxidans .

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Biodiversity and ecology of acidophilic microorganisms

1998-12-01

D. Barrie Johnson

Microbial life in extremely low pH (<3) natural and man-made environments may be considerably diverse. Prokaryotic acidophiles (eubacteria and archaea) have been the focus of much of the research activity … Microbial life in extremely low pH (<3) natural and man-made environments may be considerably diverse. Prokaryotic acidophiles (eubacteria and archaea) have been the focus of much of the research activity in this area, primarily because of the importance of these microorganisms in biotechnology (predominantly the commercial biological processing of metal ores) and in environmental pollution (genesis of 'acid mine drainage'); however, obligately acidophilic eukaryotes (fungi, yeasts, algae and protozoa) are also known, and may form stable microbial communities with prokaryotes, particularly in lower temperature (<35°C) environments. Primary production in acidophilic environments is mediated by chemolitho-autotrophic prokaryotes (iron and sulfur oxidisers), and may be supplemented by phototrophic acidophiles (predominantly eukaryotic microalgae) in illuminated sites. The most thermophilic acidophiles are archaea (Crenarchaeota) whilst in moderately thermal (40–60°C) acidic environments archaea (Euryarchaeota) and bacteria (mostly Gram-positives) may co-exist. Lower temperature (mesophilic) extremely acidic environments tend to be dominated by Gram-negative bacteria, and there is recent evidence that mineral oxidation may be accelerated by acidophilic bacteria at very low (ca. 0°C) environments. Whilst most acidophiles have conventionally been considered to be obligately aerobic, there is increasing evidence that many isolates are facultative anaerobes, and are able to couple the oxidation of organic or inorganic electron donors to the reduction of ferric iron. A variety of interactions have been demonstrated to occur between acidophilic microorganisms, as in other environments; these include competition, predation, mutualism and synergy. Mixed cultures of acidophiles are frequently more robust and efficient (e.g. in oxidising sulfide minerals) than corresponding pure cultures. In view of the continuing expansion of microbial mineral processing ('biomining') as a cost-effective and environmentally sensitive method of metal extraction, and the ongoing concern of pollution from abandoned mine sites, acidophilic microbiology will continue to be of considerable research interest well into the new millennium.

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Community structure and metabolism through reconstruction of microbial genomes from the environment

2004-02-01

Gene W. Tyson , Jarrod Chapman , Philip Hugenholtz +7 more

Heavy Metal Mining Using Microbes

2002-09-04

Douglas E. Rawlings

The use of acidiphilic, chemolithotrophic iron- and sulfur-oxidizing microbes in processes to recover metals from certain types of copper, uranium, and gold-bearing minerals or mineral concentrates is now well established. … The use of acidiphilic, chemolithotrophic iron- and sulfur-oxidizing microbes in processes to recover metals from certain types of copper, uranium, and gold-bearing minerals or mineral concentrates is now well established. During these processes insoluble metal sulfides are oxidized to soluble metal sulfates. Mineral decomposition is believed to be mostly due to chemical attack by ferric iron, with the main role of the microorganisms being to reoxidize the resultant ferrous iron back to ferric iron. Currently operating industrial biomining processes have used bacteria that grow optimally from ambient to 50 degrees C, but thermophilic microbes have been isolated that have the potential to enable mineral biooxidation to be carried out at temperatures of 80 degrees C or higher. The development of higher-temperature processes will extend the variety of minerals that can be commercially processed.

Biochemistry and molecular biology of lithotrophic sulfur oxidation by taxonomically and ecologically diverse bacteria and archaea

2009-06-10

Wriddhiman Ghosh , Bomba Dam

Lithotrophic sulfur oxidation is an ancient metabolic process. Ecologically and taxonomically diverged prokaryotes have differential abilities to utilize different reduced sulfur compounds as lithotrophic substrates. Different phototrophic or chemotrophic species … Lithotrophic sulfur oxidation is an ancient metabolic process. Ecologically and taxonomically diverged prokaryotes have differential abilities to utilize different reduced sulfur compounds as lithotrophic substrates. Different phototrophic or chemotrophic species use different enzymes, pathways and mechanisms of electron transport and energy conservation for the oxidation of any given substrate. While the mechanisms of sulfur oxidation in obligately chemolithotrophic bacteria, predominantly belonging to Beta- (e.g. Thiobacillus) and Gammaproteobacteria (e.g. Thiomicrospira), are not well established, the Sox system is the central pathway in the facultative bacteria from Alphaproteobacteria (e.g. Paracoccus). Interestingly, photolithotrophs such as Rhodovulum belonging to Alphaproteobacteria also use the Sox system, whereas those from Chromatiaceae and Chlorobi use a truncated Sox complex alongside reverse-acting sulfate-reducing systems. Certain chemotrophic magnetotactic Alphaproteobacteria allegedly utilize such a combined mechanism. Sulfur-chemolithotrophic metabolism in Archaea, largely restricted to Sulfolobales, is distinct from those in Bacteria. Phylogenetic and biomolecular fossil data suggest that the ubiquity of sox genes could be due to horizontal transfer, and coupled sulfate reduction/sulfide oxidation pathways, originating in planktonic ancestors of Chromatiaceae or Chlorobi, could be ancestral to all sulfur-lithotrophic processes. However, the possibility that chemolithotrophy, originating in deep sea, is the actual ancestral form of sulfur oxidation cannot be ruled out.

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Cytoplasmic pH Measurement and Homeostasis in Bacteria and Archaea

2009-01-01

Joan L. Slonczewski , Makoto Fujisawa , Mark Dopson +1 more

The iron-oxidizing proteobacteria

2011-04-22

Sabrina Hedrich , Michael Schlömann , D. Barrie Johnson

The ‘iron bacteria’ are a collection of morphologically and phylogenetically heterogeneous prokaryotes. They include some of the first micro-organisms to be observed and described, and continue to be the subject … The ‘iron bacteria’ are a collection of morphologically and phylogenetically heterogeneous prokaryotes. They include some of the first micro-organisms to be observed and described, and continue to be the subject of a considerable body of fundamental and applied microbiological research. While species of iron-oxidizing bacteria can be found in many different phyla, most are affiliated with the Proteobacteria. The latter can be subdivided into four main physiological groups: (i) acidophilic, aerobic iron oxidizers; (ii) neutrophilic, aerobic iron oxidizers; (iii) neutrophilic, anaerobic (nitrate-dependent) iron oxidizers; and (iv) anaerobic photosynthetic iron oxidizers. Some species (mostly acidophiles) can reduce ferric iron as well as oxidize ferrous iron, depending on prevailing environmental conditions. This review describes what is currently known about the phylogenetic and physiological diversity of the iron-oxidizing proteobacteria, their significance in the environment (on the global and micro scales), and their increasing importance in biotechnology.

Aqueous Pyrite Oxidation and the Consequent Formation of Secondary Iron Minerals

2015-10-26

D. Kirk Nordstrom

The oxidation of pyrite in aqueous systems is a complex biogeochemical process involving several redox reactions and microbial catalysis. This paper reviews the kinetic data on pyrite oxidation, compares available … The oxidation of pyrite in aqueous systems is a complex biogeochemical process involving several redox reactions and microbial catalysis. This paper reviews the kinetic data on pyrite oxidation, compares available data on the inorganic vs. microbial oxidative mechanisms and describes the occurrence of mineral products resulting from pyrite oxidation. Although oxygen is the overall oxidant, kinetic data suggests that ferric iron is the direct oxidant in acid systems and that temperature, pH, surface area, and the presence of iron and sulfur-oxidizing bacteria can greatly affect the rate of reaction. The vast amount of literature on the microbial and geochemical investigations on this subject have limited usefulness for understanding natural systems. Additional research is needed on the hydrologic, geologic and microbiologic characteristics of field sites where oxidation occurs. The acid water resulting from pyrite oxidation may precipitate a large suite of soluble and insoluble iron minerals depending on pH, degree of oxidation, moisture content, and solution composition.

Earth-Abundant Metal Pyrites (FeS2, CoS2, NiS2, and Their Alloys) for Highly Efficient Hydrogen Evolution and Polysulfide Reduction Electrocatalysis

2014-08-26

Matthew S. Faber , Mark A. Lukowski , Qi Ding +2 more

Many materials have been explored as potential hydrogen evolution reaction (HER) electrocatalysts to generate clean hydrogen fuel via water electrolysis, but none so far compete with the highly efficient and … Many materials have been explored as potential hydrogen evolution reaction (HER) electrocatalysts to generate clean hydrogen fuel via water electrolysis, but none so far compete with the highly efficient and stable (but cost prohibitive) noble metals. Similarly, noble metals often excel as electrocatalytic counter electrode materials in regenerative liquid-junction photoelectrochemical solar cells, such as quantum dot-sensitized solar cells (QDSSCs) that employ the sulfide/polysulfide redox electrolyte as the hole mediator. Here, we systematically investigate thin films of the earth-abundant pyrite-phase transition metal disulfides (FeS2, CoS2, NiS2, and their alloys) as promising alternative electrocatalysts for both the HER and polysulfide reduction. Their electrocatalytic activity toward the HER is correlated to their composition and morphology. The emergent trends in their performance suggest that cobalt plays an important role in facilitating the HER, with CoS2 exhibiting highest overall performance. Additionally, we demonstrate the high activity of the transition metal pyrites toward polysulfide reduction and highlight the particularly high intrinsic activity of NiS2, which could enable improved QDSSC performance. Furthermore, structural disorder introduced by alloying different transition metal pyrites could increase their areal density of active sites for catalysis, leading to enhanced performance.

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The Chemistry of gold extraction

1992-09-01

R.A. Williams

The chemistry of gold extraction

1992-11-01

J. O. Marsden , Iain House

Historical developments process mineralogy process selection metallurgical development principles of gold hydrometallurgy oxidative pretreatment leaching solution purification and concentration recovery surface chemical methods refining effluent treatment industrial applications. Historical developments process mineralogy process selection metallurgical development principles of gold hydrometallurgy oxidative pretreatment leaching solution purification and concentration recovery surface chemical methods refining effluent treatment industrial applications.

Electrochemistry of Silicon and Its Oxide

2004-01-01

Xiaoge Gregory Zhang

Pyrite Oxidation and Its Control

2018-04-27

V. P. Evangelou

Pyrite Oxidation and its Control is the single available text on the market that presents the latest findings on pyrite oxidation and acid mine drainage (AMD). This new information is … Pyrite Oxidation and its Control is the single available text on the market that presents the latest findings on pyrite oxidation and acid mine drainage (AMD). This new information is an indispensable reference for generating new concepts and technologies for controlling pyrite oxidation.This book focuses on pyrite oxidation theory, experimental findings on oxidation mechanisms, as well as applications and limitations of amelioration technologies. The text also includes discussions on the theory and potential application of novel pyrite microencapsulation technologies for controlling pyrite oxidation currently under investigation in the author's laboratory.

Reduction of Electric Arc Furnace Dust (EAFD) Using Biochar Towards Sustainable Ironmaking

2025-06-24

B. Prasad Kumar , Gour Gopal Roy | Transactions of the Indian Institute of Metals

Leaching of complex copper concentrates in alkaline monosodium glutamate solutions

2025-06-24

C.G. Perea , Christian F. Ihle , Laurence Dyer +3 more | Minerals Engineering

A Single-Step Roasting Strategy for Vanadium Slag: Enhancing Vanadium Extraction Efficiency via Particle Size Reduction and Optimized Crystallinity

2025-06-24

Yuguo Ma , Tianyou Zhai , Ling Wang +3 more | JOM

Characterization and formation mechanism of clinkers and ring deposits in rotary kiln furnace during calcination of spodumene lithium ore

2025-06-24

Sung Hwan Park , Seung Seok Lee , Joo Hyun Park | Minerals Engineering

Removal of Organic and Inorganic Contaminants from Titanium Turning Scrap via Alkali and Acid Two-Step Cleaning

2025-06-24

Siwen An , Raj Narayan Hajra , Chan Hee Park +4 more | MATERIALS TRANSACTIONS

Petroleum refinery wastewater treatment through the successive process of electrocoagulation and electrooxidation

2025-06-24

Laith Louay , Shahriyar Bahar | Al-Qadisiyah Journal for Engineering Sciences

Water pollution and scarcity are problems of the current time due to the industrial and biological wastes that are thrown into the aquatic environment, especially the water produced from petroleum … Water pollution and scarcity are problems of the current time due to the industrial and biological wastes that are thrown into the aquatic environment, especially the water produced from petroleum refineries, because it contains organic and inorganic pollutants. In this study, work was done to reduce the chemical oxygen demand (COD), which represents some major pollutants such as organic materials in real wastewater collected from the Najaf refinery in Iraq, using successive electrocoagulation (EC) and electrooxidation (EO) processes. Graphite and aluminum (Al) electrodes were used as the anode, and a stainless-steel electrode (SS) as the cathode. The Box-Behnken design (BBD) of experiments was used. Starting from COD (1250 ppm), the effect of current density, time, NaCl concentration, and pH on the removal efficiency was studied. The results indicate that the removal efficiency is directly proportional to the increase in current density, time, and NaCl conc, whereas it is inversely proportional to the increase in pH, as the optimal conditions for removal were at current density, time, NaCl concentration, and pH in this case. Conditions: About 97.5% COD removal was achieved. Through the results of the ANOVA analysis, it was found that current density and time have a high effect on removal, while NaCl concentration and pH have a lower effect on removal.

Reduction Disintegration Behavior and Mechanism of Vanadium–Titanium Magnetite Pellets During Hydrogen-Based Reduction

2025-06-24

Feng Chen , Hao Li , Shuai Wang +5 more | Metals

Hydrogen-based reduction followed by the electric furnace smelting of vanadium–titanium magnetite pellets offers notable advantages, including high reduction efficiency, reduced energy consumption, lower CO2 emissions, and improved titanium recovery. However, … Hydrogen-based reduction followed by the electric furnace smelting of vanadium–titanium magnetite pellets offers notable advantages, including high reduction efficiency, reduced energy consumption, lower CO2 emissions, and improved titanium recovery. However, the disintegration of pellets during the reduction process presents a major barrier to industrial application. In this study, the reduction disintegration behavior and underlying mechanisms under hydrogen-based conditions were systematically investigated. The most severe disintegration was observed at 500 °C in an atmosphere of H2/(H2 + CO) = 0.25, where titano–magnetite [(Fe,Ti)3O4] was identified as the dominant phase. The complete transformation from titano–hematite [(Fe,Ti)2O3] to titano–magnetite occurred within 30 min of reduction. Extended reduction (60 min) further intensified disintegration (RDI−0.5mm = 81.75%) without the formation of metallic iron. Microstructural analysis revealed that the disintegration was primarily driven by volumetric expansion resulting from the significant increase in the titanium–iron oxide unit cell volume. Raising the reduction temperature facilitated the formation of metallic iron and suppressed disintegration. These findings provide essential guidance for optimizing reduction parameters to minimize structural degradation during the hydrogen-based reduction of vanadium–titanium magnetite pellets.

Recovery of Titanium and Aluminum from Secondary Waste Solutions via Ultrasonic Spray Pyrolysis

2025-06-24

Sreċko Stopić , Duško Kostić , Vladimir Damjanović +4 more | Metals

The synthesis of oxide nanopowders through ultrasonic spray pyrolysis (USP) represents a sustainable method for producing high-purity, spherical particles tailored for advanced material applications. Recent developments in USP synthesis leverage … The synthesis of oxide nanopowders through ultrasonic spray pyrolysis (USP) represents a sustainable method for producing high-purity, spherical particles tailored for advanced material applications. Recent developments in USP synthesis leverage the continuous transport of aerosols from an ultrasonic generator to a high-temperature furnace, with nanopowders collected efficiently using an electrostatic precipitator. This study explored the use of USP for titanium oxysulfate and aluminum nitrate solutions derived from the aluminum industry, focusing on resource recovery and waste reduction. Titanium oxysulfate was synthesized by leaching slag, generated during the reduction of red mud, with sulfuric acid under oxidizing, high-pressure conditions. After purification, the titanium oxysulfate solution was processed using USP in a hydrogen reduction atmosphere to yield spherical titanium dioxide (TiO2) nanopowders. The hydrogen atmosphere enabled precise control over the nanoparticles’ morphology and crystallinity, enhancing their suitability for use in applications such as photocatalysis, pigments, and advanced coatings. In parallel, both synthetic and laboratory solutions of aluminum nitrate [Al(NO3)3] were prepared. The laboratory solution was prepared by leaching aluminum hydroxide oxide (AlOOH) with hydrochloric acid to form aluminum chloride (AlCl3), followed by a conversion to aluminum nitrate through the addition of nitric acid. The resulting aluminum nitrate solution was subjected to USP, producing highly uniform, spherical alumina (Al2O3) nanopowders with a narrow size distribution. The resulting nanopowders, characterized by their controlled properties and potential applicability, represent an advancement in oxide powder synthesis and resource-efficient manufacturing techniques.

Effect of boric acid–sodium sulfate mixture on the selective reduction process of saprolitic nickel laterite

2025-06-22

Bambang Suharno , Rekso Adi Makayasa , Donanta Dhaneswara +4 more | Ironmaking & Steelmaking Processes Products and Applications

In selective reduction of nickel laterite process, sulphur-bearing materials as the sole additive have been studied to improve the nickel grade by inhibiting the metallisation of iron. However, the sulphidation … In selective reduction of nickel laterite process, sulphur-bearing materials as the sole additive have been studied to improve the nickel grade by inhibiting the metallisation of iron. However, the sulphidation reaction lowers the recovery of nickel. Therefore, the selection of proper additives carried out. Combining boric acid and sodium sulphate as additives, in selective reduction of saprolitic nickel ore has been investigated clearly in this work. Nickel saprolite, additives and coal were mixed and pelletised into 10–15 mm of diameter. The pellets were heated in a muffle furnace and before the wet magnetic separation process. The selective reduction process of saprolite with the mixture of boric acid and sodium sulphate at 20 wt% dosages (with 75–25 ratio), reductant amount of 0.4 stoichiometry of carbon, and temperature reduction of 1250°C has produced ferronickel contains nickel grade and recovery of 18.29% and 74.87%, respectively.

Application of corn stalk waste in direct reduction of vanadium titanium magnetite: Phase composition, microstructure evolution, reduction behavior and mechanism analyses

2025-06-21

Xin Shen , Yingyi Zhang , Laihao Yu +4 more | Bioresource Technology

Advancing circular economy in the pulp and paper sector with novel routes for microbial sulfur recovery

2025-06-20

Elifnaz Unay , Dogukan Tunay , Bestami Özkaya | International Journal of Hydrogen Energy

Characteristics study and process optimization of direct reduction of natural hematite with ammonia

2025-06-19

Li Li , Pengyu Li , Hongwu Li +2 more | Ironmaking & Steelmaking Processes Products and Applications

The ironmaking process in the steel industry is characterized by high energy consumption and environmental pollution. To address these issues, this study explored direct reduction ironmaking technology utilizing ammonia (NH … The ironmaking process in the steel industry is characterized by high energy consumption and environmental pollution. To address these issues, this study explored direct reduction ironmaking technology utilizing ammonia (NH 3 ) as a hydrogen carrier. NH 3 surpassed H 2 in technical maturity for liquefaction and transport, offering significantly lower transportation costs. In this study, NH 3 served as a reducing agent in the treatment of natural hematite using a horizontal high-temperature heat treatment electric furnace. The study investigated the effects of reduction temperature, gas concentration, and reduction time on the reduction process. The experimental results indicated that NH 3 exhibited superior reducibility toward natural hematite under specific conditions. An elevation in temperature and an increase in NH 3 concentration substantially enhance the reduction efficacy of hematite. Higher temperatures facilitate the forward progression of the reaction and diminish the requisite critical NH 3 concentration. At 900°C, a flow rate of 500 mL·min −1 , and 30% ammonia concentration, complete reduction of hematite powder was achieved in 12 min. Scanning electron microscopy (SEM) characterization revealed gradual precipitation and coarsening of spherical iron (Fe) particles, forming a porous and loose structure.The ammonia reduction of iron oxide process is divided into three stages, sequentially controlled by surface chemical reactions, diffusion, and the shrinking core model. The third stage is the rate-controlling step with an activation energy of 69.67 kJ/mol.

Authigenic iron oxyhydroxide rims attenuate deleterious element fluxes during sulphide oxidation in historical gold mine tailings

2025-06-19

Steve Jason Chingwaru , Bjorn P. von der Heyden , Margreth Tadie | Research Square (Research Square)

<title>Abstract</title> Historical gold tailings pose environmental hazards globally, leading to acid mine drainage and the release of harmful elements due to the oxidation of unrecovered sulphides. The metastable secondary iron … <title>Abstract</title> Historical gold tailings pose environmental hazards globally, leading to acid mine drainage and the release of harmful elements due to the oxidation of unrecovered sulphides. The metastable secondary iron oxyhydroxides formed during this process influence the mobility of these elements, although the specific mass flows between the sulphide cores, iron oxyhydroxide rims and the environment remain poorly understood. Using a gold tailings storage facility in the Klerksdorp goldfields (South Africa) as a natural laboratory, this study investigates the role of secondary iron oxyhydroxide rims in controlling the mobility of Co, Ni, As, Pb, Zn, Au, and Cu after prolonged exposure of tailings to surface conditions. The release versus retention of these deleterious elements is characterised and quantified using a multi-method approach including LA ICP-MS, automated mineralogy, and wet chemistry. Although iron oxyhydroxide rims make up less than 1% of the mineralogy, they strongly retain As, Ni, Cu, and Zn fluxes that emanate from the precursor sulphides. In contrast, Co, Au, and Pb show limited compatibility (< 3% deportment) with these rims, suggesting their preferential mobilisation into the environment. The measured immobilisation of some of these elements is insufficient to meet environmental standards, highlighting the need for direct remedial measures, including metallurgical reprocessing and effective capture mechanisms for deleterious elements. These strategies are essential for reducing environmental risks and can simultaneously recover valuable (and critical) metals such as Au, Cu, Co, and Ni.

Metals Recovery from RO Brine

2025-06-18

Muayad Al-Shaeli , Raed A. Al-Juboori , Basheer Hashem Hlihl +3 more | CRC Press eBooks

Chlorobaculum tepidum outer membrane vesicles may transport biogenic elemental sulfur

2025-06-18

Vadesse Lhilhi Noundou , Amalie Levy , Shannon Modla +3 more | Applied and Environmental Microbiology

ABSTRACT Outer membrane-derived vesicles (OMVs) have been studied in different phyla of gram-negative bacteria, most extensively in the Pseudomonadota, where they have been shown to participate in diverse biological and … ABSTRACT Outer membrane-derived vesicles (OMVs) have been studied in different phyla of gram-negative bacteria, most extensively in the Pseudomonadota, where they have been shown to participate in diverse biological and environmental processes. To date, the production of OMVs has not been reported in the Chlorobiaceae within the phylum Chlorobiota. Chlorobaculum tepidum is the model organism for the Chlorobiaceae that synthesizes and consumes insoluble extracellular sulfur (S(0)) globules by an unknown mechanism. Here, we report evidence implicating outer membrane vesicles in biogenic S(0) globule synthesis. We demonstrate that Cba. tepidum secretes OMVs in the extracellular milieu and that OMV concentration and size vary with growth conditions, particularly sulfide concentration. A core of 31 proteins involved in diverse biological processes such as cell wall biogenesis, inorganic ion transport, and metabolism was found to be shared between OMVs, extracellular S(0) globules, and Cba. tepidum -intact cells. Multiple analytical methods indicated that OMVs contain S(0) and that OMVs and biogenic S(0) globules share protein and polysaccharide signatures, including lipooligosaccharides. Together, these lines of evidence indicate that Cba. tepidum ’s OMVs are one component of sulfur transport between cells and extracellular sulfur globules. IMPORTANCE All living cells must exchange material with their environment while maintaining cellular integrity. This is a particular challenge for materials that are not water-soluble; however, many bacteria utilize insoluble materials for energy conservation and as nutrients for growth. Here, we show that Cba. tepidum makes outer membrane vesicles, and these vesicles are likely involved in the exchange of material with extracellular elemental sulfur globules formed and consumed by Cba. tepidum as part of its energy metabolism based on oxidizing reduced sulfur compounds like hydrogen sulfide. These data expand our basic understanding of Cba. tepidum ’s metabolism. As elemental sulfur is an industrial by-product with a limited number of uses, the information here may help enable the use of additional sulfur compounds by Cba. tepidum to drive the synthesis of biomass and/or specialty biochemicals from waste elemental sulfur by this autotrophic bacterium.

Gold Recovery in Heap Leaching of Old Mine Tailings Using Chloride Solution

2025-06-18

Kupakwashe Mahamba , John Malbenia Masamvu , Nancy Mabwe +2 more | JOM

Evolution of Solid Products Formed During the Cathodic Decomposition of Chalcopyrite at Different Energetic Conditions in Acetic Acid

2025-06-17

Laura Recio , J.C. Fuentes-Aceituno , R. Pérez‐Garibay +3 more | Metals

This paper presents a systematic analysis of the solid products formed during the cathodic decomposition of chalcopyrite using the acetic acid system. The reduction of chalcopyrite was assessed using different … This paper presents a systematic analysis of the solid products formed during the cathodic decomposition of chalcopyrite using the acetic acid system. The reduction of chalcopyrite was assessed using different electrochemical and surface characterization techniques. The effect of multiple cathodic polarizations of chalcopyrite immersed in acetic acid was evaluated on the formation of less refractory copper species through the interaction of chalcopyrite with monoatomic hydrogen. The reduction products obtained were characterized by the FESEM/EDS techniques. The results revealed that the iron content in the chalcopyrite lattice was continuously decreased and released into the acetic acid solution when the polarization cycles were increased from 1 to 11 starting from OCP to −2.2 V vs. SHE. The chemical analyses revealed that iron released into the solution corresponds to 0.085 and 1.95 mg/L for 1 and 11 cycles, respectively. The open circuit potential (OCP) measurements of the solid products were shifted to more cathodic potentials than that of chalcopyrite, confirming the possibility to form less refractory species in this weak organic acid. Finally, the FESEM-EDS and XRD analyses showed that chalcopyrite refractoriness decreased, producing Cu, Cu2S, CuS, CuO, and C4H6CuO4H2O species depending on the applied energetic condition.

Mechanism of Iron Powder to Enhance Solid-State Reduction of Chromite Ore

2025-06-17

Xiaohong Jiang , Feng Zhang , Yaodong Cen +1 more | Minerals

This study investigated the solid-state reduction characteristics of natural chromite ore and the effect of iron powder on the solid-state reduction characteristics of natural chromite ore under isothermal conditions below … This study investigated the solid-state reduction characteristics of natural chromite ore and the effect of iron powder on the solid-state reduction characteristics of natural chromite ore under isothermal conditions below 1200 °C. The enhancement mechanism of iron powder on the solid-state reduction of natural chromite ore was revealed using optical microscopy, X-ray diffraction (XRD), and scanning electron microscopy–energy dispersive spectroscopy (SEM-EDS). The iron metallization rate of chromite ore exhibited a trend of increasing first and then decreasing with the addition of iron powder, and the optimal iron powder addition was determined to be 30%. The multi-step reaction gradually transforms into a single-step reaction with the increase in the dosage of iron powder. Iron powder facilitates the generation of a low-melting Fe-C alloy liquid phase and accelerates the speed of the solid-state reduction reaction of chromite ore and the disintegration of chromite spinel particles. When the iron powder dosage exceeds 30%, most of the multi-step reduction reaction of chromite ore is transformed into the single-step reduction reaction, which reduces the disintegration of chromite spinel particles and weakens the enhancement effect of iron powder on the solid-state reduction of chromite ore.

Separation and recovery of vanadium from leaching solution of calcium roasting vanadium slag by extraction with P204 extractant

2025-06-17

D.P. Wang , Lin Zhang , Jingwei Li +7 more | Minerals Engineering

A systematic approach for the characterisation of potential elemental risks associated with sulphide-bearing mine waste: A gold waste rock case study

2025-06-17

Alexander K.B. Opitz , Susan T.L. Harrison , Jennifer L. Broadhurst +1 more | Minerals Engineering

Appraisal on local manufacturing of grinding plates used in food processing in Ghana: The use of local plant extract for surface optimization

2025-06-16

Divine Ishimwe , Sullaiman Alhassan , Acheampong Antwi Afari +3 more | MRS Advances

Influence of Different Organic Loading Rates on the Stability and Operational Performance of a UASB Reactor Treating Industrial Slaughterhouse Effluent

2025-06-16

Carlos Daniel Davi de Souza , Allan Bruno Dantas Gonçalves , Antonia Gisele Bezerra Simeão +4 more | Revista de Gestão Social e Ambiental

Objective: The objective of this study is to investigate the influence of different organic loading rates on the stability and operational performance of a UASB reactor treating industrial slaughterhouse effluent. … Objective: The objective of this study is to investigate the influence of different organic loading rates on the stability and operational performance of a UASB reactor treating industrial slaughterhouse effluent. Theoretical Framework: Wastewater from industrial slaughterhouses contains high levels of organic matter and solids with significant polluting potential. Anaerobic digestion in UASB reactors has emerged as an effective treatment alternative, contributing to energy generation and reducing greenhouse gas emissions. Methodology: The methodology involved operating a scaled-down UASB reactor subjected to organic loading rates ranging from 2.44 to 23.77 kgCOD/m³.d. Monitoring included analyses of organic matter, solids, pH, temperature, alkalinity (and its fractions), volatile fatty acids, and biogas production and composition. Results and Discussion: The results indicated adequate stability of anaerobic digestion. However, higher organic loading rates led to increased sludge production and operational challenges, reducing methane production and the efficiency of organic matter and solids removal. Research Implications: The correlations between organic loading rates, organic matter indicators, and methane gas production influence the operation and treatment efficiency of UASB reactors. Originality/Value: This study contributes to the literature by providing insights to enhance UASB reactors as an efficient and environmentally sustainable solution for treating industrial slaughterhouse effluents.

Study of Copper Leaching Technology from Copper Ores by Biochemical Method

2025-06-16

Bagdaulet Kenzhaliyev , Aigul Koizhanova , М.Б. Ерденова +4 more | Kompleksnoe Ispolzovanie Mineralnogo Syra = Complex Use of Mineral Resources

The article presents the research results on the processing of dump ores of copper production from one of the deposits of Kazakhstan. The copper content in various rock formation samples … The article presents the research results on the processing of dump ores of copper production from one of the deposits of Kazakhstan. The copper content in various rock formation samples and from different sampling points varies from 0.2 to 0.9%. On average, the calculated copper content on the southern side of the dump was 0.3%, and on the northern side, 0.28%. Phase analysis of the dump samples revealed that the bulk of the rock is represented by quartz, albite, muscovite, clinochlorite, and noticeable amounts of malachite and atacamite were noted from copper dumps in many areas. Detailed mineralogical analysis, in addition to oxidized forms of minerals, also recorded fragments of sulfide mineral formations such as pyrite, chalcopyrite, chalcosine, etc. For this type of deposit, the most effective method of processing will be the use of biohydrometallurgical heap leaching technology. According to percolation leaching, the use of trichloroisocyanuric acid (TСCА) as a chemical oxidant was considered, and an adapted culture of A.Ferrooxidans was also used as a biooxidant. According to percolation leaching, the use of trichloroisocyanuric acid (TСCА) as a chemical oxidant was considered, and an adapted culture of A.Ferrooxidans was also used as a biooxidant. Standard sulfuric acid leaching served as a control option. As a result of the application of the chemical oxidation method using TСCА, an increase in copper extraction into solution compared with other options was observed only during the first 7 cycles. The highest efficiency was observed in the variant of preliminary bacterial oxidation, 76.08% copper was extracted into the productive solution over 28 irrigation cycles. The resulting productive solutions of all variants were subjected to a full technological cycle of hydrometallurgical copper production. As a result of the extraction and re-extraction processes, electrolyte solutions were developed that fully correspond to the qualitative parameters necessary for electrolysis. At the electrolysis stage, 30.8 g of copper was deposited on the cathode from the accumulated electrolyte solutions, which gives a current recovery equal to 94.6%.

Microbial Community Dynamics and Elemental Speciation in Antimony-Contaminated Mining Areas

2025-06-16

Can Wang , Ruiyong Zhang , Jin‐lan Xia +6 more | Journal of Sustainable Metallurgy

Silver Extraction from Jarositic Waste: Effect of Sodium Silicate on Cyanidation and Alkaline Decomposition as a Path to Revalorization

2025-06-16

G.I. Dávila-Pulido , Blanca R. González-Bonilla , Danay A. Charles +3 more | Journal of Sustainable Metallurgy

Dissolution kinetics of a low-grade oxide-sulfide copper ore with high silica content: Laboratory studies and statistical modeling

2025-06-15

Hamed Farhadi , Faramarz Doulati Ardejani , Sied Ziaedin Shafaei Tonkaboni +5 more | Acta Geochimica

Abstract In this study, copper extraction from low-grade oxide-sulfide ores was investigated using a leaching method combined with response surface methodology (RSM) to optimize operational conditions and assess leaching kinetics. … Abstract In this study, copper extraction from low-grade oxide-sulfide ores was investigated using a leaching method combined with response surface methodology (RSM) to optimize operational conditions and assess leaching kinetics. Given copper’s extensive industrial applications, sustainable recovery from low-grade ores is critical. Five key parameters-acid concentration, leaching time, particle size, temperature, and solids percentage-were identified as major influences on copper recovery. The results revealed that leaching time and solids percentage, along with interactions between temperature-time and temperature-solids percentage, had the most significant effects. Optimal conditions for 80% copper recovery while minimizing iron recovery below 3% included an acid concentration of 1.21 mol $$\text {L}^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mtext>L</mml:mtext> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math> , a leaching time of 108 min, a particle size of 438 $$\upmu$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>μ</mml:mi> </mml:math> m, a temperature of 45 $$^{\circ }\text {C}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mo>∘</mml:mo> </mml:mmultiscripts> <mml:mtext>C</mml:mtext> </mml:mrow> </mml:math> , and a solids percentage of 18.2%. Leaching kinetics were analyzed using shrinking core models, with the Dickinson model best describing the process, showing an activation energy of 32.63 kJ $$\text {mol}^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mtext>mol</mml:mtext> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math> , indicative of mixed diffusion and chemical reaction control. The final kinetic model effectively predicted the influence of key parameters. These findings highlight the importance of optimizing process variables and selecting suitable kinetic models to enhance extraction efficiency, reduce costs, and improve sustainability in copper recovery.

An experimental and computational study of the role of cytochrome 2 in the adhesion of Acidithiobacillus ferrooxidans to pyrite in fresh and saline water

2025-06-14

Christopher D. Cooper , Benjamín Rojas Yauri , Estefania García González +1 more | Minerals Engineering

Application research status and prospect of biomachining in the manufacturing

2025-06-13

Fei Ma , Meie Zheng , Hui Huang +3 more | The International Journal of Advanced Manufacturing Technology

Sulfidation of Saprolite Nickel Laterite Ore with Sodium Sulfate as Sulfur Resource

2025-06-12

Marwah Ayad Abbas , Cao Shu-Heng , Xia Long-gong | Mining Metallurgy & Exploration

The influential mechanisms of solution chemistry on the stability and transport of vanadium-titanium magnetite tailing colloids

2025-06-12

Qidi Zhao , Dan Zhou , Haoran Xiong +7 more | Journal of Hazardous Materials

Immobilization of hazardous components in zinc leaching residue by autothermal roasting with pyrite

2025-06-04

Binchuan Li , Xi Luan , Xiaoge Wang +7 more | Chemical Engineering and Processing - Process Intensification