Criteria for choice of a brand of activated carbon for hydrometallurgical recovery of gold from ore pulps in carbon-in-leaching and carbon-in-pulp processes

Ibragimova, R. I.; Mil'chenko, A. I.; Vorob'ev-Desyatovskii, N. V.

doi:10.1134/s1070427207060092

Cited by 10 publications

(8 citation statements)

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“…solubility, mobility, sorption, precipitation, formation of secondary minerals) compared to acidic conditions might change completely under alkaline conditions (especially in the presence of cyanide) and metal values might be recovered more easily, e.g. by sorption onto activated carbon (Ibragimova et al, 2007). Additionally, leachates might be less corrosive at alkaline pH.…”

Section: Resultsmentioning

confidence: 99%

Biomobilization of silver, gold, and platinum from solid waste materials by HCN-forming microorganisms

et al. 2008

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Biomobilization of silver, gold, and platinum from solid waste materials by HCN-forming microorganisms Biomobilization of silver, gold, and platinum from solid waste materials by HCN-forming microorganisms Abstract Cyanogenic Chromobacterium violaceum, Pseudomonas fluorescens, and P. plecoglossicida were able to mobilize silver, gold, and platinum when grown in the presence of various metalcontaining solids such as gold-containing electronic scrap, silver-containing jewelry waste, or platinum-containing automobile catalytic converters. Five percent of silver was microbially mobilized from powdered jewelry waste as dicyanoargentate after one day, although complete dissolution was obtained when non-biological cyanide leaching was applied. Dicyanoargentate inhibited growth at concentrations of >20 mg/L. Gold was bacterially solubilized from shredded printed circuit boards. Maximum dicyanoaurate concentration corresponded to 68.5% dissolution of the total gold added. Additionally, cyanide-complexed copper was detected during treatment of electronic scrap due to its high copper content of approximately 100 g/kg scrap. However, only small amounts of platinum (0.2%) were mobilized from spent automobile catalytic converter after 10 days probably due to passivation of the surface by an oxide film. In summary, all findings demonstrate the potential of microbial mobilization of metals as cyanide complex from solid materials and represent a novel type of microbial metal mobilization (termed "biocyanidation") which might find industrial application. ABSTRACT Cyanogenic Chromobacterium violaceum, Pseudomonas fluorescens, and P. plecoglossicida were able to mobilize silver, gold, and platinum when grown in the presence of various metalcontaining solids such as gold-containing electronic scrap, silver-containing jewelry waste, or platinum-containing automobile catalytic converters. Five percent of silver was microbially mobilized from powdered jewelry waste as dicyanoargentate after one day, although complete dissolution was obtained when non-biological cyanide leaching was applied. Dicyanoargentate inhibited growth at concentrations of >20 mg/L. Gold was bacterially solubilized from shredded printed circuit boards. Maximum dicyanoaurate concentration corresponded to 68.5% dissolution of the total gold added. Additionally, cyanide-complexed copper was detected during treatment of electronic scrap due to its high copper content of approximately 100 g/kg scrap. However, only small amounts of platinum (0.2%) were mobilized from spent automobile catalytic converter after 10 days probably due to passivation of the surface by an oxide film. In summary, all findings demonstrate the potential of microbial mobilization of metals as cyanide complex from solid materials and represent a novel type of microbial metal mobilization (termed "biocyanidation") which might find industrial application. Biomobilization of silver, gold, and platinum from solid waste materials by HCN-forming microorganisms

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Section: Resultsmentioning

confidence: 99%

Biomobilization of silver, gold, and platinum from solid waste materials by HCN-forming microorganisms

et al. 2008

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“…The effect of the physical properties of an AC such as pore size distribution, specific surface, pore average diameter, on the gold adsorption from cyanide solution (Au (CN) 2 − form), has been studied and it has been shown that the rate adsorption and the amount of adsorbed gold increased with the increase in macropores and with the increasing pore average diameter []. Criteria for choice of a brand of AC for hydrometallurgical recovery of gold from ore pulps in carbon‐in‐leaching and carbon‐in‐pulp processes have been elucidated [].…”

Section: Sorbentsmentioning

confidence: 99%

Solid‐phase extraction in the determination of gold, palladium, and platinum

Mladenova

Karadjova²,

Tsalev³

2012

J of Separation Science

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A simple classification of various sorbents and solid-phase extraction procedures used for preconcentration of trace levels of Au, Pd, and Pt from different sample types is proposed in this review article. The large variety of available sorbents/procedures has been organized according to expected mechanisms of sorption process (complex formation; ion exchange; adsorption; ion-imprinted or molecularly imprinted polymers); according to the kind of monomeric units of the polymer matrix as well as on the basis of the kind of functional group responsible for main performance characteristics (selectivity, capacity) of the sorbent. Advantages of chemically modified sorbents, sulfur-containing sorbent extractants, and ion-imprinted polymers, together with rational pretreatment by means of microwave treatments, scaling down of enrichment, and quantification by means of flow and flow injection approaches are given. Preferred instrumental techniques for quantification of ppb levels of Au, Pd, and Pt in prepared concentrates/column eluates are multielement instrumental techniques: inductively coupled plasma optical emission spectrometry (ICP-OES), and inductively coupled plasma mass spectrometry (ICPMS). Excellent limits of detection at picogram levels of these analytes are provided by electrothermal atomic absorption spectrometry (ETAAS), generally in single-element mode and the neutron activation analysis (NAA), while X-ray fluorescence spectrometry and flame AAS are rarely applied because of lack of sensitivity at sub-ppm levels of Au, Pd, and Pt. Some problems of atomic spectrometric quantification techniques and their representative limits of detection are given. Recent applications to geological, industrial, pharmaceutical, biological, and other materials are tabulated. References have been selected mostly from the period 1995 to 2010.

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“…Thus, whereas acid-wash removes inorganic pollutants by dissolving them, thermal reactivation eliminates organic waste by thermal decomposition [15][16][17][18][19][20][21][22][23][24][25][26][27].The variation in some properties of activated carbon after reactivation has been investigated in previous studies. Compared with SAC, the moisture and the ash content of AC subjected to a reactivation process decreased [28,29]. In order to be reused in the CIP process, reactivated carbon should have a value of ash content between 2% and 4% [29].…”

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confidence: 99%

“…Compared with SAC, the moisture and the ash content of AC subjected to a reactivation process decreased [28,29]. In order to be reused in the CIP process, reactivated carbon should have a value of ash content between 2% and 4% [29]. After reactivation, the iodine number and the Brunauer-Emmett-Teller (BET) specific surface area of AC increased significantly [13,15,28,29].…”

mentioning

confidence: 99%

“…In order to be reused in the CIP process, reactivated carbon should have a value of ash content between 2% and 4% [29]. After reactivation, the iodine number and the Brunauer-Emmett-Teller (BET) specific surface area of AC increased significantly [13,15,28,29]. For instance, a carbon subjected to a chemical-thermal reactivation increased the iodine number from 534 mg I 2 /g CA before the treatment to 1070 mg I 2 /g CA after the reactivation [15].…”

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Reactivation Process of Activated Carbons: Effect on the Mechanical and Adsorptive Properties

et al. 2020

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Carbon reactivation is a strategy to reduce waste and cost in many industrial processes, for example, effluent treatment, food industry, and hydrometallurgy. In this work, the effect of physical and chemical reactivation of granular activated carbon (AC) was studied. Spent activated carbon (SAC) was obtained from a carbon in pulp (CIP) leaching process for gold extraction. Chemical and physical reactivations were evaluated using several acid-wash procedures (HCl, HNO 3 , H 2 SO 4 ) and thermal treatment (650-950 • C) methods, respectively. The effect of the reactivation processes on the mechanical properties was evaluated determining ball pan hardness and normal abrasion in pulp resistance. The effect on the adsorptive properties was evaluated via the iodine number, the gold adsorption value (k expressed in mg Au/g AC), and Brunauer-Emmett-Teller (BET) surface area. Initial characterization of the SAC showed an iodine number of 734 mg I 2 /g AC, a k value of 1.37 mg Au/g AC, and a BET surface area of 869 m 2 /g. The best reactivation results of the SAC were achieved via acid washing with HNO 3 at 20% v/v and 50 • C over 30 min, and a subsequent thermal reactivation at 850 • C over 1 h. The final reactivated carbon had an iodine number of 1199 mg I 2 /g AC, a k value of 14.9 mg Au/g AC, and a BET surface area of 1079 m 2 /g. Acid wash prior to thermal treatment was critical to reactivate the SAC. The reactivation process had a minor impact (<1% change) on the mechanical properties of the AC.Molecules 2020, 25, 1681 2 of 18 refining [10,11]. Leaching is achieved typically with a solution of NaCN; the CN − ion complexes gold to form an aurocyanide complex, which remains dissolved in the solution. Subsequently, AC in the carbon in pulp process (CIP) absorbs and concentrates the aurocyanide complex. The gold is desorbed from the loaded AC by an elution process, and it is recovered as metal via electrolysis. Once the elution is over, AC goes to a reactivation process that regenerates its adsorptive capabilities, and this regenerated AC is reused in the CIP process [1,10,11].The gold extraction industry is a very profitable business worldwide. It involves the use of large amounts of activated carbon, especially in medium and large capacity operations. AC is used owing to the high gold recovery reached during the CIP process. However, the gold adsorption capacity of AC decreases after several batch cycles owing to the blockage of the carbon pores caused by the progressive deposition of clays, oxides, and hydroxides of calcium and magnesium on the AC surface. Consequently, the reactivation process is not only essential to restore the adsorption capacities of the carbon, but also it could improve the economy of the process by reducing the amount of virgin carbon needed [10,[12][13][14].Some of the most used reactivation procedures include the following: acid-wash, treatment with supercritical fluids, microwave reactivation, electrochemical process, and thermal reactivation. Previous studies concluded that, in order to achi...

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Criteria for choice of a brand of activated carbon for hydrometallurgical recovery of gold from ore pulps in carbon-in-leaching and carbon-in-pulp processes

Cited by 10 publications

References 14 publications

Biomobilization of silver, gold, and platinum from solid waste materials by HCN-forming microorganisms

Biomobilization of silver, gold, and platinum from solid waste materials by HCN-forming microorganisms

Solid‐phase extraction in the determination of gold, palladium, and platinum

Reactivation Process of Activated Carbons: Effect on the Mechanical and Adsorptive Properties

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