一种从硫化砷渣中回收砷的新方法

A new way of recycling arsenic from arsenic sulphide residue

介绍了采用质量分数30%的双氧水氧化浸出-氯化亚锡还原法处理硫化砷渣以制备单质砷的方法。比较研究了双氧水用量、反应温度、反应时间在氧化浸出试验中对砷浸出率的影响及浓盐酸用量、Sn Cl2与As摩尔比在还原试验中对砷回收率的影响。结果表明:当固液比为1∶7(固体质量与双氧水体积比),反应温度为75℃,反应时间为6 h时,砷的浸出率达到99.70%;将滤液加热浓缩至As质量浓度约1 450 g/L后,常温下,当浓盐酸与浓缩液体积比为1∶1,Sn Cl2与As摩尔比为1.2∶1时,反应8 h后,砷的回收率达到99.14%。最终产物于105℃烘箱中干燥6 h,经检测其单质砷质量分数为98.26%。

In this experiment, elemental arsenic was produced by pre-oxidation leaching arsenic sulphide residue with H2O： solution（30 mass%） ,and then reduced by SnC12 in an acid medium. Comparative study was conducted on the effects of the dosage of H2O2,reaction temperature and time on the leaching rate of arsenic,while those of the dosage of HCl,the molar ratio of SnC12 to arsenic on the recovery rate of arsenic were also investigated. Results showed that arsenic leaching rate of 99. 70% was obtained, as the ratio of solid to liquid was 1：7（ mass Of arsenic sulphide residue to the dosage of H2O2 ）,leaching temperature was 75 ℃, and leaching time was 6 hours. After heating concentrating process, the concentration of arsenic in the filtrate was about 1 450 g/L. The recovery rate of arsenic was 99. 14% after 8 hours of reaction time at normal atmospheric temperature, when the volume ratio of concentrated hydrochloric acid to concentrated solution was 1 ： 1, the molar ratio of SnC12 to arsenic was 1.2 ： 1. It was tested that the mass fraction of elemental arsenic in the end product reached 98.26% after dried for 6 hours at 105 qC of dry oven.