锌冶炼次氧化锌烟灰微波脱砷结块试验研究

Experimental study on microwave arsenic removal and agglomeration from secondary zinc oxide dust in zinc smelting

微波脱砷具有升温快、不产生热源气体以及升温过程物料无需翻动利于物料于炉内烧结造块的技术优势。本文对锌冶炼次氧化锌烟灰开展砷物相化学分析、热力学计算分析以及微波脱砷结块试验研究。结果表明:锌冶炼次氧化锌中砷的主要物相为砷(Ⅲ)氧化物,还含有少量的高价砷(Ⅴ)氧化物、硫化砷以及砷酸盐;脱砷温度升高以及脱砷时间延长有利于次氧化锌中砷的脱除。热力学分析表明,在低温微波脱砷结块过程中,主要发生的脱砷反应为砷(Ⅲ)氧化物的挥发反应。低温微波脱砷结块试验的适宜反应条件为:微波脱砷温度580℃,脱砷时间60 min,结块温度750℃。在此条件下,脱砷结块的烟灰平均含砷0.87%,脱砷率89.29%,结块率72.41%。该研究对含砷固废资源化回收技术水平的提升具有重要意义。

Microwave arsenic removal has the technical advantages of fast temperature rise,no heat source gas and no turnover of materials during temperature rise,which is conducive to sintering agglomeration of materials in the furnace.The chemical arsenic phase analysis,thermodynamic calculation,and microwave arsenic-removal agglomeration test were carried out on the secondary zinc oxide dust from zinc smelting.The results showed that the main material phase of arsenic in zinc smelting secondary zinc oxide dust was arsenic(Ⅲ)oxide,and also contained a small amount of high valence arsenic(Ⅴ)oxide,arsenic sulfide and arsenate;and the increase of arsenic removal temperature and the prolongation of arsenic removal time were beneficial to the removal of arsenic from secondary zinc oxide.The thermodynamic analysis of arsenic removal by microwave showed that the arsenic removal reaction mainly occurred at low temperature.The suitable reaction conditions for low temperature microwave arsenic removal test were as follows:microwave arsenic removal temperature 580℃,arsenic removal time 60 min and agglomeration temperature 750℃.Under these conditions,the average arsenic content in the final dust agglomeration was 0.87%,the arsenic removal ratio was 89.29%,and the agglomeration ratio was 72.41%.The study is of great significance to improve the technical level of arsenic containing solid waste recycling.