Gold and silver extraction from Hellyer lead-zinc flotation middlings using pressure oxidation and thiourea leaching

Bruckard, Warren J.; Sparrow, Graham J.; Woodcock, J.T.

doi:10.1016/0304-386x(93)90003-v

Cited by 25 publications

(7 citation statements)

References 14 publications

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“…For silver, the aqueous system gives a very poor result with a maximum extraction of less than 20%. The concentration of silver in the aqueous system reaches a maximum before slowly decreasing over time, as was also noted by Bruckard et al 8 and indicates the precipitation of an insoluble silver species. The bmim + HSO 4 2 leaching system proved to be more promising for the recovery of silver from the Perseverance ore, with high selectivity for silver giving a 60% extraction at 50 hours.…”

Section: Resultssupporting

confidence: 76%

“…Thiourea has been recently examined as an alternative leaching agent, but only offers similar extraction capacity for gold and a lower capacity for silver. 8,9 Here, we report the first study with an ionic liquid as the core of 'green' leach liquors, and the observation in the presence of bmim + HSO 4 2 of significantly enhanced extraction of silver by thiourea and the same high yielding extraction of gold compared with an aqueous sulfuric acid liquor. Further, we demonstrate the ability of the bmim + HSO 4 2 liquor to be recycled without decomposition or significant change in extraction outcome.…”

Section: Introductionmentioning

confidence: 87%

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‘Green’ leaching: recyclable and selective leaching of gold-bearing ore in an ionic liquid

2004

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The recovery of gold and silver from ore in an ionic liquid is reported for the first time. The 1-butyl-3-methyl-imidazolium hydrogen sulfate ionic liquid (bmim + HSO 4 2 ) was employed, with iron(III) sulfate oxidant and thiourea added. Selective extraction of gold (485%) and silver (460%) from powdered ore (of dominantly chalcopyrite/pyrite/pyrrhotite/sphalerite mineralogy) was achieved at room temperature in 50 h, with other lower-value metals present in the ore (Cu, Zn, Pb, Fe) extracted to only low percentages. Gold extraction was similar to that achieved in aqueous H 2 SO 4 /thiourea/Fe 2 (SO 4 ) 3 , and silver extraction was significantly better. Moreover, the ionic liquid can be recycled following selective stripping of gold and silver on activated charcoal, with reuse in at least four successive treatments leading to neither ionic liquid degradation nor any loss in extraction efficiency.

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Section: Resultssupporting

confidence: 76%

Section: Introductionmentioning

confidence: 87%

‘Green’ leaching: recyclable and selective leaching of gold-bearing ore in an ionic liquid

2004

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“…Thus, thioureation is one of the most widely used leaching techniques for recovering precious metals from industrial waste sources. The following equation, which utilizes thiourea as the leaching agent and Fe(III) ions as the oxidant, represents the complexation of Ag from Ag2S using thiourea (Bernaola-Flores et al, 2019;Bruckard et al, 1993):…”

Section: Thiourea Leachingmentioning

confidence: 99%

Hydrometallurgical processes for heavy metals recovery from industrial sludges

Gunarathne

Rajapaksha

Vithanage

et al. 2020

Critical Reviews in Environmental Science and Technology

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Hydrometallurgical processes for heavy metal recovery from industrial sludgesHydrometallurgical approaches have been successfully employed for metal separation and recovery from various types of waste materials. Therefore, hydrometallurgy is a promising technology for metal recovery and the removal of potentially toxic heavy metals found in industrial sludge.However, a comprehensive review that focuses on the heavy metal recovery from industrial sludge using hydrometallurgical approaches has not been conducted in the recent past. The present review discusses the capacity of hydrometallurgical techniques in recovering heavy metals sourced from different types of industrial sludges, highlighting recent scientific findings. Hydrometallurgical approaches primarily consist of three process stages: metal dissolution, concentration and purification, and metal recovery. The chemical characteristics of industrial sludge, including the type, concentration and speciation of heavy metals, directly impact selection of the best recovery method. Solvent extraction, ion-exchange, and adsorption are the major techniques employed in concentration and purification, whereas electrodeposition and precipitation are the main methods used in metals recovery. Future research should focus on the development of more efficient and environmentally-friendly methods for metal dissolution from industrial sludges contaminated with multiple metals, while increasing selectivity and energy use efficiency in the concentration and purification, and recovery steps.

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“…Bruckard [14] suggested the equations for gold and silver dissolution in the presence of Fe 3+ ions as:…”

Section: Thiourea Leaching Of Au-ag Wastesmentioning

confidence: 99%

Leaching of Gold and Silver from Crushed Au-Ag Wastes

Ficeriová¹,

Baláž²,

Dutková³

et al. 2008

TOCENGJ

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Au-Ag noble metal wastes represent a wide range of waste types and forms with various ballast elements and components. The thiourea process of gold and silver extraction from ores, concentrates or secondary raw materials consists of gold and silver leaching into the thiourea solution and the consequent precipitation of these metals from the solution. Due to the non-toxic character of thiourea it is the perspective alternative to the up to now most frequently used cyanide method. The thiourea leaching of gold and silver from electronic waste, goldsmith's waste and ceramic waste using crushing as the pretreatment step was investigated. For electronic waste, it was possible to achieve 97 % gold and 94 % silver recovery within 120 minutes of thiourea leaching. Up to 98 % of gold and 96 % of silver were recovered from goldsmith's waste after 60 minutes of leaching. In the case of ceramic waste, we achieved up to 98 % gold and 97 % silver extraction efficiency after only 45 minutes of leaching. In comparison with the classical cyanide leaching, thiourea leaching acts faster and without a harmful environmental impact.

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Gold and silver extraction from Hellyer lead-zinc flotation middlings using pressure oxidation and thiourea leaching

Cited by 25 publications

References 14 publications

‘Green’ leaching: recyclable and selective leaching of gold-bearing ore in an ionic liquid

‘Green’ leaching: recyclable and selective leaching of gold-bearing ore in an ionic liquid

Hydrometallurgical processes for heavy metals recovery from industrial sludges

Leaching of Gold and Silver from Crushed Au-Ag Wastes

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