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: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=689688
• 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）作为金浸出浸出剂。在此过程中，矿石中的金在氰化物（或高浓度硫代硫酸盐）溶液中浸出，然后从溶液中以不纯金的形式回收，最后纯化至 99.99% 的金。氰化物已知是一种剧毒试剂；然而，它对金的浸出具有高度选择性，并且浸出效率非常有吸引力。因此，在黄金工业中用替代浸滤剂替代氰化物是非常困难的。尽管如此，向黄金作业运送和处理氰化物盐始终引起担忧。 该拟议项目涉及开发一种用于金浸出的原位产生氰化物的替代路线，从而消除在黄金工业中使用氰化物作为“购买试剂”的情况。 本文提出在金堆浸作业中利用产氰菌来生产氰化物。在金堆浸作业中原位形成氰化物将消除从氰化物生产设施购买和运输氰化物到世界各地金矿的需要。作为次要目标，拟议的研究还将调查硫代硫酸盐是原位生产的选择，硫代硫酸盐与氰化物类似，对于金浸出来说是一种非常有吸引力的浸滤剂。硫代硫酸盐浸金工艺面临的挑战是硫代硫酸盐试剂的成本较高（该工艺需要大量硫代硫酸盐用于浸金）。在本研究项目中，我们还将研究在金堆浸作业中从硫化矿石中原位生产硫代硫酸盐的可能性，从而为金浸出提供一种成本非常低的浸滤剂。