Co - Solubility Of Chalcopyrite In Thiosulfate Leaching System And Its Effect On Leaching Process

Thiosulfate leaching gold method is regarded as the most promising leaching gold technology to alternate cyanidation due to the quality of quick leaching speed, high leaching rate, non-toxic, proper to deal with gold ore containing copper, arsenic, carbonaceous, etc. But it is not clear and definite for associated mineral about the dissolution of the metal and reagent consumption and the influence of leaching gold in this process. This paper have studied chalcopyrite, one of the most common associated minerals, which is including the cupreous co-dissolution, the consumption of thiosulfate and the influence of gold dissolution in the thiosulfate leaching gold system.The chalcopyrite leaching experiments show that:the copper can be leached from chalcopyrite in the present of ammonia or ethanediamine. Pumping oxygen can promote the copper extraction while inlet nitrogen restrains this process. Additional copper ions in the lixivium could hold-up the dissolution of copper, the addition of annexing agent such as EDTA, ammonium oxalate, sodium phosphate, CMC can improve copper leaching, especially for EDTA. The dynamics study indicates that the process of the dissolution of copper is controled by inner diffusion model in the system of "NH3-S2O32-" while it is controled by external diffusion model in the system of "en-S2O32-".The consumption of thiosulfate experiments show that:the consumption of thiosulfate all have done along with the dissolution of copper in the leaching gold system of "NH3-S2O32-" and "en-S2O32-" separately, But in the ethanediamine leaching system, the consumption of thiosulfate is low. the addition of EDTA, ammonium oxalate, sodium phosphate, CMC can decrease the consumption of thiosulfate agent. EDTA is the most efficiency annexing agent in these annexing agents.Pure gold leaching experiments show that:in the exist of chalcopyrite "NH3-S2O32-" leaching gold system, the gold leaching quantity is increased with the addition of ammonium concentration, and is decreased with the addition of thiosulfate concentration. While in the "en-S2O32-" leaching gold system, the gold leaching quantity is decreased with the addition of ethanediamine concentration, and is increased with the addition of thiosulfate concentration. The addition of annexing agent such as EDTA, ammonium oxalate, sodium phosphate, CMC can promote leaching gold from gold foil. From these, EDTA is the most efficiently annexing agent.The actual gold ore contains copper leaching experiments show that:the leaching rate of copper in the system of ammonium hydroxide and ethanediamine is 33.2%　and 9.7%　separately, while the gold is 79.9%　and 50.1%　separately. Compared with ammonium hydroxide, ethanediamine leaching system is low. The addition of annexing agent such as EDTA, ammonium oxalate, sodium phosphate, CMC can promote the leaching quality of gold and copper from ore and restrain the consumption of thiosulfate, especially for EDTA; After adding EDTA, the gold leaching rate in ammonium hydroxide and ethanediamine is 91.9%　and 70.8% separately.