从磷酸废砷渣中回收砷的碱浸工艺研究

根据目前广西区大量砷渣得不到有效利用的现状,以磷酸净化过程中产生的含砷废渣为原料,通过物相分析确定了碱浸出法回收砷的工艺,考察了浸出温度、摩尔比、液固比和反应时间等工艺条件对砷浸出率的影响。结果表明,n(NaOH)∶n(As2S3)是影响砷浸出率的主要因素,较适宜的碱浸工艺条件为:浸出温度为70℃,n(NaOH)∶n(As2S3)=6.0∶1,液固比=6.0∶1,反应时间为30 min,在此条件下砷浸出率可达97.1%。在现有基础上,该工艺为磷酸废砷渣的综合利用提供了一条简单高效的技术路线。

Technological study of arsenic recovery from arsenic-containing waste residue by alkali leaching

Aiming at effective use of the arsenic-containing waste residue in Guangxi,the alkali leaching process was used to recover arsenic from arsenic-containing waste residue generated in phosphoric acid purification process by phase analysis of the residue.The effects of leaching temperature,molar ratio of NaOH/As2S3,liquid to solid ratio and reaction time on arsenic leaching rate were investigated respectively.The results showed that molar ratio of NaOH/As2S3 mainly affected the arsenic leaching rate,and the optimum conditions of the alkaline leaching process were determined as leaching temperature at 70 oC,molar ratio of NaOH/As2S3 of 6.0∶ 1,liquid to solid ratio of 6.0∶ 1,reaction time in 30 min.Under these conditions,the arsenic leaching rate could reach 97.1%.On the basis of existing technologies,this process provides a simple and efficient technological route for comprehensive utilization of arsenic-containing waste residue generated in phosphoric acid purification.