磷酸工业硫化砷渣氧化浸出及浸出动力学

Oxidative Leaching and Kinetics of Arsenic Sulfide Slag from Phosphoric Acid Industry

磷酸生产过程中磷酸净化脱砷工艺产生的硫化砷渣属于危险固体废物,环境危害大,但因其含砷量高,同时也是一种具有较高回收价值的砷资源。采用过氧化氢作为氧化剂在酸性条件下对磷酸厂硫化砷渣进行氧化浸出,考察了浸出温度、过氧化氢用量、浸出时间在氧化浸出实验中对砷浸出的影响,实验结果表明:控制浸出温度为95℃,V(过氧化氢,mL):m(硫化砷渣,g)为1.5:1,浸出时间为2 400 s的条件下,砷浸出率达到99.20%。通过对不同浸出温度下硫化砷渣浸出动力学的研究,结果表明:在酸性条件下,过氧化氢浸出硫化砷过程符合未反应收缩核模型,浸出反应的表观活化能为22.82 kJ/mol,浸出过程受扩散控制。

Arsenic sulfide slag from phosphoric acid industry is a kind of hazardous waste,which is harmful to the environment.However,the slag is also a kind of arsenic resource due to its high arsenic content.This study worked on the leaching of arsenic sulfide slag with hydrogen peroxide as oxidant.The effects of leaching temperature,hydrogen peroxide dosage and leaching time on the leaching of arsenic were investigated.The results show that arsenic leaching rate of 99.20%was obtained,as the leaching temperature was 95℃,the ratio of hydrogen peroxide(solution,mL)and arsenic sulfide residue(solid,g)was 1.5:1,and leaching time was 2 400 s.The kinetics study shows that the leaching process was applicable to the shrinking core model and the apparent active energy was 22.82 kJ/mol,that means the leaching process was controlled by mass diffusion.