铅银渣焙烧脱硫动力学研究

针对各种方法处理铅银渣回收率低的问题，采用火法冶金技术破坏铅银渣的物相结构是提高金属回收率的有效方法，但火法冶金处理铅银渣过程其中的化合物热分解机理及脱硫动力学尚不明晰。采用卧式高温管式炉对铅银渣进行焙烧脱硫处理，利用TG-DSC和XRD等相结合研究铅银渣热分解反应历程。结果表明：铅银渣热分解分为脱水、KFe3(SO4)2(OH)6分解、Fe3(SO4)2分解和难分解MeSO4的分解四个阶段，及脱羟基化和释放硫两个亚稳态质量损失过程。采用Kissinger-Akahira-Sunose微分法和Flynn-Wall-Ozawa积分法计算了热分解反应表观活化能，表明反应由易到难依次为Fe2(SO4)3分解、ZnFe2O4生成和难分解MeSO4的分解。铅银渣通过脱硫有效改变了其物相结构，提高了有价金属和稀贵金属的品位，脱硫铅银渣中硫降到了0.44%，为火法或湿法处理铅银渣提供理论和数据支撑。

Study on melting desulfurization kinetics of lead silver slag

In view of the low recovery rate of lead-silver slag treated by various methods. The pyrometallurgical technology is an effective method to destroy the phase structure of lead-silver slag to improve the metal recovery rate. However, the thermal decomposition mechanism of various compounds during pyrometallurgical treatment and the desulfurization kinetics of lead-silver slag are still unclear.In this paper, a horizontal high temperature tube-furnace was used for roasting and desulfurization of lead-silver slag. TG-DSC and XRD were used to study the thermal decomposition reaction mechanism of lead-silver slag. The results show that the thermal decomposition of lead-silver slag can be divided into four stages, namely dehydration, decomposition of KFe3(SO4)2(OH)6, decomposition of Fe3(SO4)2 and decomposition of refractory MeSO4, respectively. And two metastable mass loss processes,dehydroxylation and sulfur release, respectively. The apparent activation energy of thermal decomposition reaction was calculated by Kissinger Akahira Sunose differential method and Flynn Wall Ozawa integral method. It show that the reaction from easy to difficult is Fe2(SO4)3 decomposition, ZnFe2O4 generation and MeSO4 decomposition. Through desulfurization of lead-silver slag, its phase structure is effectively improved, and the grade of valuable metals and rare precious metals is increased. The sulfur in the lead-silver slag is reduced to 0.44%, providing theoretical and data support for pyro or hydrometallurgical treatment of lead-silver slag.