抄録
Nippon Mining & Metals has operated a hydrometallurgical process of copper anode slime treatment for two and half years. The process is based on the conception that was proposed by Mr. James E. Hoffmann. Nippon Mining & Metals modefied and advanced some stages of the original one to be suitable for producing precious metals in its acceptable qualities.
The original process treats copper anode slimes fully in aqueous solutions and has the main flow consisted of de-copperizing stage, wet chlorination stage, gold solvent extraction and reduction stages and silver chloride conversion and reduction stages. It also includes de-tellurizing stage and gold extraction raffinate treating stage.
Nippon Mining & Metals examined the original process and improved some stages with its former and recent experiment. The modefied process employs the aeration and the ferric leaching for de-copperizing instead of pressure leaching and pyrometallurgical processing of crude silver from silver chloride reduction with iron instead of silver chloride refining in aqueous solutions. The process is able to recover raw materials of platinum group metals, selenium and telurium, separately. Continuous operation of gold extraction stage is acheived with mixer-settlers and a further refining system for gold loading organic extractent.
The plant of the modefied process started in 1997 and has been succesfuly operated since then. The plant has its capacity of processing 172 t / M of copper anode slimes and producing 2,500 kg / M of gold, 32,000 kg / M of silver, 40 kg / M of platinum and 400 kg / M of palludium.
