真空热解工艺脱除金矿石中的砷铅研究

Study on the Arsenic and Lead Removal in Gold Ore by Vacuum Pyrolysis

金矿含砷、铅对提金会产生不利影响,在提金前需要降低砷、铅含量。为确定适宜的工艺流程,采用真空脱砷、碳热还原铅的方法进行了预先脱除砷、铅研究。理论计算表明,毒砂及黄铁矿均易分解,分别产生砷和硫;真空条件下金矿石中的白云石分解生成氧化钙,硫化铅在有氧化钙参与时可还原生成金属铅。试验结果表明,在真空度为20 Pa、600℃、保温30 min情况下,可脱除99%以上的砷、26%左右的硫;在20 Pa、900℃、保温30 min情况下,铅回收率达到95%以上。

The bearing of arsenic and lead in the gold ore will have an adverse impact on gold extraction.It is necessary to reduce the content of arsenic and lead before gold extraction.In order to determine the appropriate process flow,the methods of vacuum for arsenic removal and carbothermal reduction for lead were used to study the pre-removal of arsenic and lead.Theoretical calculation shows that arsenopyrite and pyrite are easy to decompose and produce arsenic and sulfur respectively.Under the vacuum conditions,dolomite in gold ore decomposes into calcium oxide,and lead sulfide can be reduced to metal lead with the participation of calcium oxide.The test results showed that more than 99%arsenic and about 26%sulfur can be removed under the condition of vacuum degree of 20 Pa,600℃and holding for 30 min.Under the condition of 20 Pa,900℃and holding for 30 min,the lead recovery rate is more than 95%.