High-temperature chlorination of gold with transformation of iron phase

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• 作者：Zheng-Yao Li ; Wei-Wei Wang ; Kun Yue ; Ming-Xing Chen
• 关键词：Cyanide tailings ; Chlorination–reduction one ; step roasting ; Transformation of iron phase ; Gold
• 刊名：Rare Metals
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：35
• 期：11
• 页码：881-886
• 全文大小：973 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Metallic Materials
  Chinese Library of Science
  
• 出版者：Journal Publishing Center of University of Science and Technology Beijing, in co-publication with Sp
• ISSN：1867-7185
• 卷排序：35

文摘

Gold in cyanide tailings from Shandong Province is mainly encapsulated by hematite and magnetite at distribution rates of 76.49 % and 10.88 %, respectively. Chlorination–reduction one-step roasting of cyanide tailings was conducted under the following conditions: calcium chloride dosage of 6 %, bituminous coal dosage of 30 %, calcium oxide dosage of 10 % (all dosages are vs. the mass of cyanide tailings) at 1000 °C of roasting temperature. X-ray diffraction (XRD), scanning electron microscopy (SEM), and chemical-phase analysis were performed to investigate the effects of iron phase transformation on the high-temperature chlorination of gold. Results indicate that the lattice structure of hematite undergoes expansion, pulverization, and reorganization when hematite is reduced to magnetite, which leads to 42.03 % gold exposure, and the high-temperature chlorination rate of gold is 41.17 % at the same time. The structure of wustite formed by the reduction in magnetite is porous and loose, and thus 44.02 % of gold is exposed. The high-temperature chlorination rate of gold is increased by 41.98 percentage points. When wustite is reduced to metallic iron, 4.42 % of gold is exposed, and the high-temperature chlorination rate of gold is increased by 3.38 percentage points. Accordingly, the high-temperature chlorination of gold mainly occurs in two stages, in which Fe₂O₃ is reduced to Fe₃O₄, and Fe₃O₄ is reduced to Fe_xO finally.