Heap leaching of gold with in-situ bacterial formation of the leach lixiviant. The case for the bio-formation of (1) cyanide lixiviant, and (2) thiosulfate lixiviant

通过原位细菌形成浸出液来堆浸金。

• 批准号: 523048-2017
• 负责人: Ghahreman, Ahmad
• 金额: $ 3.5万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=697756
• 关键词: Heap; leaching; gold; situ; bacterial

The conventional method for gold leaching and extraction relies on the use of cyanide (or thiosulfate) as the gold leaching lixiviant. In this process gold from the ore is leached in a cyanide (or highly concentrated thiosulfate) solution, and later is recovered from the solution as impure gold, and finally purified to 99.99% gold. Cyanide is known to be an extremely toxic reagent; however, it is highly selective for gold leaching with very attractive leaching efficiency. Thus the replacement of cyanide with alternative lixiviants is very difficult in the gold industry. Nonetheless, the shipping and handling of cyanide salts to the gold operations have always raised concerns. This proposed project pertains to the development of an alternative route for the in-situ generation of cyanide for gold leaching thus eliminating the use of cyanide as a "purchased-reagent" in the gold industry. Herein, it is proposed to use cyanide producing bacteria in gold heap leaching operations to produce cyanide. The in-situ formation of cyanide in the gold heap leaching operations would eliminate the need for the purchase and shipping of cyanide from the cyanide production facilities to the gold mines sites around the world. As a secondary objective, the proposed research will also investigate the option for the in-situ production of thiosulfate, which is known to be a very attractive lixiviant for gold leaching, similar to cyanide. The challenge with the thiosulfate gold leaching process is the high cost of the thiosulfate reagent (the process requires large volumes of thiosulfate salt for gold leaching). In this research project we will also investigate the possibility of the in-situ thiosulfate production from the sulfide ores in the gold heap leaching operations, thus providing a very low cost lixiviant for gold leaching.

传统的金浸出和提取方法依赖于使用氰化物（或硫代硫酸盐）作为金浸出剂。在这个过程中，矿石中的金在氰化物（或高浓度硫代硫酸盐）溶液中浸出，然后从溶液中回收为不纯金，最后纯化为99.99%的金。