选择性硫化法有效分离高砷锑烟尘中的砷和锑

摘要

The separation of arsenic and antimony from dust with high content of arsenic was conducted via a selective sulfidation roasting process. The factors such as roasting temperature, roasting time, sulfur content and nitrogen flow rate were investigated using XRD, EPMA and SEM?EDS. In a certain range, the sulfur addition has an active effect on the arsenic volatilization because the solid solution phase ((Sb,As)2O3) in the dust can be destroyed after the Sb component in it being vulcanized to Sb2S3and this generated As2O3continues to volatile. In addition, an amorphization reaction between As2O3and Sb2O3is hindered through the sulfidation of Sb2O3, which is also beneficial to increasing arsenic volatilization rate. The results show that volatilization rates of arsenic and antimony reach 95.36% and only 9.07%, respectively, under the optimum condition of roasting temperature of 350 ℃, roasting time of 90 min, sulfur content of 22% and N2flow rate of 70 mL/min. In addition, the antimony in the residues can be reclaimed through a reverberatory process.%以硫磺为添加剂对高砷锑烟尘进行硫化焙烧,可实现物料中砷、锑的高效分离.借助 XRD、EPMA 和SEM?EDS 等表征手段,对焙烧温度、焙烧时间、硫磺添加量和氮气流量对物料中砷、锑分离效率的影响进行研究.结果表明,在一定添加范围内,硫磺对高砷锑烟尘中砷的挥发脱除具有显著促进作用,原因是硫磺可将高砷锑烟尘中固熔体(Sb, As)2O3结构中的Sb组元硫化转变为Sb2S3,使As2O3组分得以解离释放,促进砷挥发率的提高;同时,高砷锑烟尘中Sb2O3物相可硫化生成Sb2S3,对As2O3和Sb2O3之间的非晶反应形成阻碍,亦有利于砷的挥发.在焙烧温度350 ℃、焙烧时间90 min、硫磺添加量22%和N2流量 70 mL/min的试验条件下,砷挥发率可达95.36%,锑挥发损失率仅9.07%,实现砷锑烟尘中砷、锑的高效分离.