Chang Jun, Zhang Er-Dong, Zhang Li-Bo, Peng Jin-Hui, Zhou Jun-Wen, Srinivasakannan C, Yang Chang-Jiang
State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming, Yunnan 650093, China; Kunming University of Science and Technology, Faculty of Metallurgical and Energy Engineering, Kunming, Yunnan 650093, China.
Kunming University of Science and Technology, Faculty of Metallurgical and Energy Engineering, Kunming, Yunnan 650093, China; Yunnan Minzu University, Kunming, Yunnan 650031, China.
Ultrason Sonochem. 2017 Jan;34:222-231. doi: 10.1016/j.ultsonch.2016.05.038. Epub 2016 May 24.
In the process of steel manufacture, up to ten millions of tons of sintering dust (SD) are produced annually in China, which contain noble metals such as Ag. Therefore, recovery of silver (Ag) from SD could be a potential economic and environmental activity. The purpose of this article is to generate information about reaction kinetics of silver leaching with thiourea from SD, comparing the conventional and ultrasonic-augment leaching. The effects of various control parameters such as the ultrasound power, particle size, leaching temperature and thiourea concentration on leaching rate of silver were studied. The results showed 89% silver recovery for conventional process against 95% for ultrasound assisted leaching. The ultrasonic wave increased the leaching rate and shorten the reaction time. The rate controlling step was analyzed using shrinking core model and the rate controlling step is identified to be the diffusion through the product layer in both conventional and ultrasonic-augment leaching processes. The activation energies were estimated to be 28.01kJ/mol and 18.19kJ/mol, and the reaction order were 0.89 and 0.71, respectively.
在钢铁制造过程中，中国每年产生多达数千万吨的烧结粉尘（SD），其中含有银等贵金属。因此，从烧结粉尘中回收银可能是一项具有潜在经济和环境效益的活动。本文的目的是获取有关从烧结粉尘中用硫脲浸出银的反应动力学信息，比较传统浸出和超声强化浸出。研究了超声功率、粒度、浸出温度和硫脲浓度等各种控制参数对银浸出率的影响。结果表明，传统工艺的银回收率为89%，而超声辅助浸出的回收率为95%。超声波提高了浸出率并缩短了反应时间。使用收缩核模型分析了速率控制步骤，确定在传统浸出和超声强化浸出过程中，速率控制步骤均为通过产物层的扩散。估计活化能分别为28.01kJ/mol和18.19kJ/mol，反应级数分别为0.89和0.71。
