含铜难处理金矿石混合氯浸试验研究

Experimental research on mixed chloride leaching of copper-containing refractory gold ores

某难处理金矿石中含有大量铜,如果直接氰化浸出,除了消耗大量氰化物外,还会在金表面形成一层薄膜,减慢金的溶解速度,金回收率低于30%;如果预氧化处理后再氰化提金,操作复杂、过程冗长、有污染、成本高,而且回收率并无实质性提高。为提高金回收率,降低生产成本,试验将该难处理金矿石破碎细磨后采用低浓度的NH4Cl和氨水混合浸出,利用氯离子与金形成稳定的配合物进行提金,矿石中的铜离子起氧化作用,促进金的反应,金浸出率可达87%以上。该方法无需进行预氧化处理,避免添加有毒有害药剂,消除对环境的污染。

The refractory gold ore contains large amount of copper and will consume a great deal of cyanide if goes through direct cyanidation process. Besides,a thin film will form on the surface of gold that can slow the dissolution rate,making the overall recovery rate below 30 %. If a pretreatment process of oxidation is employed before cyanidation,the recovery rate is not evidently increased,not mentioning the complicated operation,the lengthy process,the pollution and the high cost. To increase gold recovery rate and lower production cost,the experiment finely grinded the refractory ores and then leached them with low concentration NH_4Cl and NH_3·H_2O. Chlorine ion and gold form stable complexes,copper ions in ores work as oxidation to catalyze gold reaction,and the gold recovery rate can reach over87 %. The process needs no oxidation pretreatment,avoids the use of poisonous chemicals and does no harm to the environment.