次氧化锌火法脱氯制备高纯氧化锌的工艺研究

Study on preparation process of high⁃purity zinc oxide by dechlorination of zinc oxide dust

模拟研究了回转窑焙烧次氧化锌的火法脱氯工艺。通过热力学分析确定了焙烧温度范围,并采用高温煅烧工艺对次氧化锌粉进行热处理,探讨了焙烧过程中次氧化锌的氯脱除率、物相及形貌变化。对次氧化锌原料进行了X射线衍射分析(XRD)、X射线荧光分析(XRF)、扫描电子显微镜分析(SEM)。结果表明:次氧化锌主要成分为氧化锌,质量分数为76.14%,粒度为100~200 nm;其含氯杂质相主要为KCl和FeOCl,呈200~500 nm针状或树枝状团簇。热处理结果表明,在1 100℃、焙烧2 h条件下,氯脱除率达到97.63%,氧化锌纯度为94.81%,晶粒粒度从亚微米级增大至微米级,粒度为2~8μm。

The dechlorination process of sintering zinc oxide dust in rotary kiln was simulated and studied.The sintering temperature range was determined by thermodynamic analysis,and the zinc oxide dust was heat treated by a high-tempera-ture calcination process,and the changes of chlorine removal rate,phase and morphology of zinc oxide dust during the sin-tering process were discussed.The zinc oxide dust raw materials were characterized by X-ray diffraction analysis(XRD),X-ray fluorescence analysis(XRF)and scanning electron microscopy(SEM).The results showed that zinc oxide dust was an ultrafine powder of 100~200 nm,the main component was zinc oxide with mass fraction of 76.14%,and the main chlorine-containing compounds were KCl and FeOCl,which were needle-like or dendritic clusters of 200~500 nm.The heat treatment results showed that the chlorine removal rate reached 97.63%,the purity of zinc oxide was increased to 94.81%,and the grain size was increased significantly to 2~8μm at 1100°C for sintering 2 h.