Solidification of sulfur and arsenic in gold concentrate and leaching of the gold by thiosulfate. Issue 1 (19th January 2020)

• Record Type: Journal Article
• Authors: He, Yi; Hu, Xianzhi; Zi, Futing; Yang, Baomin; Cheng, Huiling
• Is Part Of: Asia-Pacific journal of chemical engineering. Volume 15:Issue 1(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-01-19
• Subjects: gold leaching -- refractory gold concentrate -- solidification of sulfur and arsenic -- thiosulfate; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/apj.2396
• Languages: English
• ISSNs: 1932-2135

Abstract

Abstract: The processing of refractory minerals rich in arsenic and sulfur often causes give off arsenic and sulfur contamination during roasting and oxidation pretreatments. In this paper, the solidification of elemental arsenic and sulfur by adding calcium‐containing compounds (calcium oxide, calcium carbonate, and calcium hydroxide) during roasting and oxidation was investigated with the aim of reducing environmental pollution. At the same time, the gold leaching from residues produced by solidification roasting and oxidation using nontoxic and environmentally friendly green copper‐ammonia‐thiosulfate method was also studied. The results indicated that a relatively better solidification effect of SO2 and As2 O3 was achieved by adding Ca (OH)2, with a solidification efficiency for sulfur and arsenic as 84.67% and 50%, respectively. When copper‐ammonia‐thiosulfate leaching was carried out on the residues after solidification roasting, it was found that a 90% gold leaching percentage was obtained. Via characterization using Brunauer–Emmett–Teller surface area, scanning electron microscope, X‐ray diffraction, and X‐ray photoelectron spectroscopy, it was also found that the arsenic and sulfur in arsenopyrite were oxidized into stable and safe sulfates and arsenates after solidification. The results show that solidification roasting oxidation is an efficient and environmentally friendly pretreatment method, and the gold in the calcine can be effectively leached out via the green copper‐ammonia‐thiosulfate system.