中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 13 No. 1 February 2003 |
zinc residues by thiourea leaching method with
pressurized preoxidation process
（Department of Environmental Science and Engineering,
Hunan University, Changsha 410082, China）
Abstract:As for the leaching-resistant zinc residues, the silver leaching rate can be over 98% through the process of pressurized preoxidation and thiourea leaching. Compared with the method of extracting the silver directly from the leaching-resistant zinc residues, the silver leaching rate is greatly improved. The optimum preoxidation conditions are: particle size range 40-60μm, oxygen partial pressure 106 Pa, temperature 80-90℃, pH=1.0, and leaching time 5h. After pretreatment, the time of thiourea leaching silver is shortened to 1.5h, and the thiourea consumption is reduced greatly. The oxidation mechanism and the thiourea leaching kinetics were also explored.
Key words: zinc residue; pressurized preoxidation; thiourea leaching; shrinking core model
