氨法浸出锌冶金渣尘提锌工艺及动力学研究

锌冶金渣尘作为一种重要的锌二次资源,来源广、储量大、具有较高的综合回收利用价值。以NH₃-CH₃COONH₄-H₂O为浸出体系,考察粒度、反应时间、搅拌速度、液固比、总氨浓度、NH₃与NH₄⁺物质的量比和温度对锌浸出率的影响,结果表明：控制浸出温度为25 ℃、总氨浓度为5 mol/L、液固体积质量比为5 mL/g、n（NH₃）/n（NH₄⁺）=1:1、搅拌速度为300 r/min、浸出时间为60 min,在此条件下锌的浸出率可达84%。含锌冶金渣尘浸出动力学分析显示,浸出反应表观活化能为22.66 kJ/mol,锌浸出过程的浸出速率受固体膜层扩散及界面化学反应共同控制,并获得了浸出锌的动力学速率方程。

Study on leaching process and kinetics of zinc extraction from metallurgical slag and dust with ammonia

Zinc metallurgical slag and dust is an important secondary resource,it has the advantages of wide source,large re-serves and high comprehensive recycling value.The influence of particle size,reaction time,stirring speed,liquid-solid ratio,total ammonia concentration,amount-of-substance ratio of NH₃ to NH₄⁺ and temperature on the zinc leaching rate were investi-gated in NH₃-CH₃COONH₄-H₂O system.The results showed that the control leaching temperature of 25 ℃,total ammonia co-ncentration of 5 mol/L,liquid-solid volume-mass ratio of 5 mL/g,amount-of-substance ratio of n（NH₃）/n（NH₄⁺）=1:1,stirring speed of 300 r/min and leaching time for 60 min,then the zinc leaching rate reached 84%.The leaching kinetic analysis of metallurgical slag and dust indicated that the apparent activation energy of the reaction was 22.66 kJ/mol.The leaching rate of zinc was controlled by both solid film diffusion and interfacial chemical reaction,and the kinetic rate equation of zinc leaching was obtained.