Roasting temperature effect on the recovery of refractory gold and silver in pyrite concentrates
J. Min. Metall. Sect. B-Metall., 57 (2) (2021) 235-243 DOI:10.2298/JMMB200911019Z
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Available online 18 February 2021
(Received 11 September 2020; Accepted 17 February 2021)
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Abstract
Pyrite concentrates with refractory gold and silver were roasted at different temperatures to improve the recovery of the metals by cyanide leaching. Scanning Electron Microscope characterization of the calcine revealed that the gold occluded in the pyrite less than one micron, and roasting produced channels in the concentrate, exposing the gold particles to the leaching solution. Gold and silver recoveries were maximum in the temperature range of 500-600°C due to the calcine high surface area and porosity. The Au and Ag recovery improved from 25 to 86% and 50 to 73%, respectively. The Au secondary encapsulation due to the sintering, the formation of the Ag-Fe-S species (Fe1−xS + Ag2S + Ag) and Ag ferrite in higher roasting temperatures hence Au and Ag recoveries decreased.
Keywords: Gold recovery; Silver recovery; Roasting; Gold refractory; Cyanide leaching
Correspondence Address:
A. Lopez-Valdivieso *; C.-S. Peng **,
a Instituto de Metalurgia, Universidad Autónoma de San Luis Potosí,
San Luis Potosí, Mexico; b School of Environmental and
Chemical Engineering, Zhaoqing University, Zhaoqing, China;,
email: alopez@uaslp.mx *; cspeng@ouc.edu.cn **;
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