2016-Sustainable Industrial Processing Summit
SIPS 2016 Volume 5: Starkey Intl. Symp. / Mineral Processing
| Editors: | Kongoli F, Kumar P, Senchenko A, Klein B, Silva A.C., Sun C, Mingan W |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2016 |
| Pages: | 270 pages |
| ISBN: | 978-1-987820-44-7 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Recovery of Gold from Tailings of Al-Amar Mine in Saudi Arabia
Mohamed Hesham Hassan Mahmoud1; Hesham Awad2;1COLLEGE OF SCIENCE, CHEMISTRY DEPARTMENT, Taif, Saudi Arabia (Kingdom of Saudi Arabia); 2TAIF UNIVERSITY, Taif, Saudi Arabia (Kingdom of Saudi Arabia);
Type of Paper: Regular
Id Paper: 211
Topic: 5
Abstract:
The leaching efficiency of gold from some Saudi ores by the toxic cyanidation process is as low as 60-80%. Mining tailings of these ores contain considerable amounts of residual gold and toxic cyanide ion. These tailings are stored in massive ponds (tailing dam) containing considerable amounts of gold and pose environmental hazards. Utilization of these materials thus remains a challenging task for the gold ore industry in Saudi Arabia. This paper is aiming to recover gold from tailings of Al-Amar mine using the harmless thiosulfate process. Petrography of mineral constituents and XRD analysis showed that the rock samples consisted mainly of the following minerals in decreasing order of abundance: sphalerite (ZnS), chalcopyrite (CuFeS2), pyrite (FeS2) and galena (PbS). The elemental distribution map showed that gold is distributed mainly in sphalerite with gold content ranged from nil up to 0.04% in the tested sample. However, fine gold is found also in chalcopyrite and pyrite. Cyanidation of Carbon in Leach (CIL) feed samples gave about 60% extraction of gold at CN- ion concentration of 0.2% for 24 hours. We supposed that fine dispersion of gold in sulfide minerals could be the main reason for the limited gold recovery. Therefore, the encapsulated gold could be released after oxidation of sulfide minerals by calcination at open air. Chemical analysis of tailings showed that it contained 1.1 ppm gold. Maximum possible gold extraction reached 45% at 0.2 M ammonium thiosulfate (ATS), 0.3 M ammonium hydroxide (AH) with solid to liquid ratio of ˝, and calcination for two hours at 400 ○C. The addition of Cu2+ or thiourea (TU) has no big influence on extraction efficiency. Replacing AH with TU gave almost similar results.
Keywords:
Extraction; Hydrometallurgical; Ore; Recovery; Tailings;References:
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