Efficient strategies to enhance gold leaching during cyanidation of multi‐sulfidic ores

Azizi, Abdelaziz; Olsen, Caroline; Larachi, Faı̈çal

doi:10.1002/cjce.22039

Cited by 10 publications

(7 citation statements)

References 18 publications

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“…The silica layer as depicted in the above arrangement consists of chemically and electrochemically inert quartz particles (P 80 149 mm, Sigma-Aldrich, Canada) consequently having no effect on the leaching of gold in aerated cyanide solutions. [24,25,26] The dissolution of gold for a bilayer arrangement of sulphidic minerals was also carried out. In this study, the sulphide minerals taken were 4 g of pyrite mineral and 2 g of one of the subsequent minerals, chalcopyrite, sphalerite, or stibnite.…”

Section: Equipment and Proceduresmentioning

confidence: 99%

Effect of silver on gold cyanidation in mixed and segregated sulphidic minerals

Muhammad

Larachi

2016

Can J Chem Eng

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Gold is mostly found in nature in metallic form and is associated with sulphide minerals and other precious metals, most often silver. Pyrite, chalcopyrite, sphalerite, and stibnite are the sulphidic minerals investigated in the present gold‐silver cyanidation study by adopting the metal‐sulphide multi‐layer packed‐bed reactor approach. Gold leaching kinetics was enhanced remarkably for the pyrite and chalcopyrite sulphide minerals, with 94.5 % and 85 % recovery respectively. The influence of a bilayer sulphidic mineral system on the dissolution of gold was also investigated with a maximum gold dissolution of 87 % for the pyrite‐chalcopyrite bilayer system. The effect of silver on the dissolution of gold was investigated with the gold associated with sulphidic minerals in an arrangement of mixed as well as segregated mineral layers. Three sets of mineral systems were established: pyrite‐chalcopyrite‐silica, pyrite‐sphalerite‐silica, and pyrite‐stibnite‐silica systems. The addition of silver enhanced the gold dissolution for the pyrite‐sphalerite‐silica system, slightly lessened the gold dissolution with the pyrite‐stibnite‐silica system, and retarded gold dissolution severely in the case of the pyrite‐chalcopyrite‐silica system, irrespective of the dispersion of gold and silver in the same as well as in the segregated mineral layers.

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Section: Equipment and Proceduresmentioning

confidence: 99%

Effect of silver on gold cyanidation in mixed and segregated sulphidic minerals

Muhammad

Larachi

2016

Can J Chem Eng

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“…The sulphide minerals exhibiting electrical conductivity allow charge transfer at their surfaces. In the presence of gold‐sulphide contacts, galvanic interactions were previously shown to considerably influence the gold leaching behaviour …”

Section: Introductionmentioning

confidence: 99%

“…In the presence of gold-sulphide contacts, galvanic interactions were previously shown to considerably influence the gold leaching behaviour. [2,3,[5][6][7][8][9][10] The sulphide minerals are readily soluble in cyanide solution and the species resulting from the dissolution of sulphide minerals influence the gold cyanidation in various ways, rendering the gold cyanidation process difficult to optimize. The selectivity of cyanide for gold is poor over the enclosing sulphide mineral matrix, and these parasitic reactions inflict extra utility costs and profit losses resulting from high levels of cyanide and dissolved oxygen consumption.…”

Section: Introductionmentioning

confidence: 99%

Impact of silver sulphide on gold cyanidation with conductive sulphide minerals

2017

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Gold is mostly found in metallic form, while silver exists in various mineral forms. Pyrite, chalcopyrite, sphalerite, and stibnite were the sulphidic minerals investigated for the effect of silver sulphide on gold cyanidation. Four sets of mineral systems, pyrite‐silica, chalcopyrite‐silica, sphalerite‐silica, and stibnite‐silica, were established to investigate the effect of silver sulphide. Silver sulphide addition promoted gold dissolution for the pyrite‐silica and sphalerite‐silica systems. The gold dissolution was retarded with the chalcopyrite‐silica and stibnite‐silica systems, irrespective of the dispersion of gold and silver sulphide in the mineral as well as in the quartz layer. The surface characterization of the gold particles was attempted by using X‐ray photoelectron spectroscopy (XPS) in order to identify the surface obstructing species. XPS analysis showed that the passivation layers of silver sulphide (Ag2S), Cu2O/Cu(OH)2, and antimony oxide (Sb2O5) might form on the surface of goldparticles by the simultaneous dissolution of silver sulphide as well as sulphide minerals, resulting in the retardation of gold dissolution.

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“…Because the gold is usually associated with or encapsulated in sulfide minerals, such as pyrite, arsenopyrite, and chalcopyrite, a reaction of gold-containing arsenopyrite dissolution is shown below (2). In these cyanide solutions, mainly thiocyanate (SCN -), sulfite (SO 3 2-), and thiosulfate (S 2 O 3 2-) ions are formed (Azizi et al 2014).…”

Section: Supergene Enrichment Mechanism Of Gold and Silvermentioning

confidence: 99%

Authigenic gold formation in the cyanidation tailings of gold–arsenopyrite–quartz ore of Komsomolsk deposit (Kuznetski Alatau, Russia)

2016

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In this study, we assess the link between morphologies and composition of gold grains and supergene processes of Au migration and redeposition by aqueous solutions in the aggressive environment of cyanidation tailings. High concentrations of both dissolved (10 lg/L) and solid (0.97 ppm) native gold in the upper horizons of the Komsomolsk tailings profile formed as the result of the long-term oxidation of the cyanidation waste. These horizons stand out due to contrasting changes in pH, Eh and the concentration of the elements in solutions (from 0.8 9 10 -4 to 72 g/L iron, from 1.5 9 10 -5 to 30 g/L arsenic and from 0 to 37 g/L aluminum). One of the main findings of this study is that the Au and Ag contained in tailings as impurities in the residual sulfide minerals are almost completely redeposited in the top few centimeters of the cross-section. Gold dissolves into pore solution in thiosulfate complexes in the reducing environment of the lower part of tailings and mainly in hydroxide complexes in the acidic environment of the upper horizons. Native gold is found only in the upper few centimeters and presents as irregular grains and crystals of an Au-Ag alloy and as microcrystalline and flat growths of pure Au. The surface morphologies of gold grains are the result of its supergene dissolution, redeposition and crystallization in tailings.

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Efficient strategies to enhance gold leaching during cyanidation of multi‐sulfidic ores

Cited by 10 publications

References 18 publications

Effect of silver on gold cyanidation in mixed and segregated sulphidic minerals

Effect of silver on gold cyanidation in mixed and segregated sulphidic minerals

Impact of silver sulphide on gold cyanidation with conductive sulphide minerals

Authigenic gold formation in the cyanidation tailings of gold–arsenopyrite–quartz ore of Komsomolsk deposit (Kuznetski Alatau, Russia)

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