Thiosulfate as an alternative lixiviant to cyanide for gold ores

Thiosulfate is generally considered to be an attractive alternative reagent to cyanide for processing gold. It is relatively inexpensive and nontoxic, forms strong gold and silver complexes, and readily leaches gold ores when catalyzed by Cu(II). Research over the past 30 years has focused mostly on...

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Main Author: Aylmore, Mark
Format: Book Chapter
Published: Elsevier 2016
Online Access:http://hdl.handle.net/20.500.11937/10985
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author Aylmore, Mark
author_facet Aylmore, Mark
author_sort Aylmore, Mark
building Curtin Institutional Repository
collection Online Access
description Thiosulfate is generally considered to be an attractive alternative reagent to cyanide for processing gold. It is relatively inexpensive and nontoxic, forms strong gold and silver complexes, and readily leaches gold ores when catalyzed by Cu(II). Research over the past 30 years has focused mostly on the understanding and applying the copper-catalyzed ammoniacal thiosulfate system to carbonaceous ores and copper–gold ores where gold recovery is poor when using cyanide or where cyanide consumption is high. Researchers have also investigated ammonia-free and alternative oxidant systems to mitigate environmental issues associated with the use of ammonia. Barrick Gold Corporation developed and commercialized a copper-calcium thiosulfate process, which is currently in use at Goldstrike, Nevada, USA. This chapter reviews recent advances in understanding of the chemistry and mechanism of gold dissolution, influence of mineralogy, certain cations and anions, as well as gold recovery options. The speciation and stability of the thiosulfate system are considered under typical leaching conditions, together with examples of leaching various gold ores that have been reported in the literature. Further work by the industry is required to continue developing robust overall process flow sheets incorporating gold recovery, reagent recycling, and impurity control for a wider range of ore applications.
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spelling curtin-20.500.11937-109852017-09-13T14:53:52Z Thiosulfate as an alternative lixiviant to cyanide for gold ores Aylmore, Mark Thiosulfate is generally considered to be an attractive alternative reagent to cyanide for processing gold. It is relatively inexpensive and nontoxic, forms strong gold and silver complexes, and readily leaches gold ores when catalyzed by Cu(II). Research over the past 30 years has focused mostly on the understanding and applying the copper-catalyzed ammoniacal thiosulfate system to carbonaceous ores and copper–gold ores where gold recovery is poor when using cyanide or where cyanide consumption is high. Researchers have also investigated ammonia-free and alternative oxidant systems to mitigate environmental issues associated with the use of ammonia. Barrick Gold Corporation developed and commercialized a copper-calcium thiosulfate process, which is currently in use at Goldstrike, Nevada, USA. This chapter reviews recent advances in understanding of the chemistry and mechanism of gold dissolution, influence of mineralogy, certain cations and anions, as well as gold recovery options. The speciation and stability of the thiosulfate system are considered under typical leaching conditions, together with examples of leaching various gold ores that have been reported in the literature. Further work by the industry is required to continue developing robust overall process flow sheets incorporating gold recovery, reagent recycling, and impurity control for a wider range of ore applications. 2016 Book Chapter http://hdl.handle.net/20.500.11937/10985 10.1016/B978-0-444-63658-4.00028-1 Elsevier restricted
spellingShingle Aylmore, Mark
Thiosulfate as an alternative lixiviant to cyanide for gold ores
title Thiosulfate as an alternative lixiviant to cyanide for gold ores
title_full Thiosulfate as an alternative lixiviant to cyanide for gold ores
title_fullStr Thiosulfate as an alternative lixiviant to cyanide for gold ores
title_full_unstemmed Thiosulfate as an alternative lixiviant to cyanide for gold ores
title_short Thiosulfate as an alternative lixiviant to cyanide for gold ores
title_sort thiosulfate as an alternative lixiviant to cyanide for gold ores
url http://hdl.handle.net/20.500.11937/10985