两步针铁矿除铁法在氧化锌烟尘回收中的探索实践

Exploration and practice on two-step goethite Fe removal process used in zinc oxide dust recovery

针对水解除铁工序存在的后液Fe^(2+)浓度波动大、锌损失率高、双氧水及碳酸钙单耗高等问题,某锌冶炼厂结合生产实际情况及现场地域条件,采用连续加间断的组合式两步针铁矿除铁工艺,通过氧气替代双氧水、双氧水加入方式优化及浮渣替代碳酸钙作为中和剂等手段,取得了较好的生产指标:溶液Fe^(2+)小于25 mg/L,溶液锌浓度从110 g/L~120 g/L提高至130 g/L~140 g/L,锌损从6%~8%降低至2%~3%,双氧水单耗降低70%以上,不再使用碳酸钙。

The hydrolysis process for Fe removal exists such problems as large fluctuation of Fe^(2+) concentration in resulting solution,high Zn loss rate,high unit consumption of hydrogen peroxide and calcium carbonate,etc. Under this background,the continuous and intermittent combined goethite Fe removal process is proposed,while considering the actual production conditions and site conditions. In this process,oxygen is used to replace hydrogen peroxide,the dosing method of hydrogen peroxide is optimized,dross is used as neutralizer to replace calcium carbonate,by these methods the Fe^(2+) in the resulting solution is reduced below 25 mg/L,Zn concentration in the resulting solution improved from 110 g/L ~ 120 g/L to 130 g/L ~ 140 g/L,Zn loss reduced from 6% ~ 8% to 2% ~3%,the unit consumption of hydrogen peroxide reduced by more than 70%,and no calcium carbonate is used.