H_(2)O_(2)氧化联合化学复合淋洗去除煤气化细渣中重金属

Removal of heavy metal in coal gasification fine slag by H_(2)O_(2) oxidation combined with chemical composite leaching

以内蒙古某煤化工企业煤气化细渣为对象,研究了H_(2)O_(2)氧化联合化学复合淋洗对煤气化细渣中Cu、Pb和Cr的去除效果,优化了淋洗工艺条件,并采用XRD和SEM技术对煤气化细渣进行了表征。实验结果表明:以柠檬酸(CA)和草酸(OA)配制复合淋洗剂,在复合淋洗剂浓度为0.05 mol/L、淋洗液固比为10∶1、淋洗剂pH为3,淋洗时间为1.0 h、淋洗次数为3的条件下,煤气化细渣中Cu、Pb和Cr的去除率分别达到73.1%、70.1%和79.4%;H_(2)O_(2)氧化联合化学复合淋洗可促进煤气化细渣中Cu、Pb和Cr形态的转变,并有效降低易迁移态占比。表征结果显示,H_(2)O_(2)氧化联合化学复合淋洗不会破坏煤气化细渣的结构。

Taking coal gasification fine slag from a coal chemical enterprise in Inner Mongolia as the object,the removal effect of Cu,Pb,and Cr from coal gasification fine slag by H_(2)O_(2) oxidation combined with chemical composite leaching was studied.The leaching process conditions were optimized and the coal gasification fine slag was characterized by XRD and SEM.The experimental results show that:When the composite eluent is prepared with citric(CA)and oxalic acid(OA),and under the conditions of eluent concentration 0.05 mol/L,liquid-solid ratio 10∶1,eluent pH 3,leaching time 1.0 h and leaching times 3,the removing rate of Cu,Pb and Cr from coal gasification fine slag reaches 73.1%,70.1% and 79.4%,respectively;The process of H_(2)O_(2) oxidation combined with chemical composite leaching can promote the transformation of Cu,Pb and Cr forms in coal gasification slag,and effectively reduce the proportion of migratable state.The characterization results show that H_(2)O_(2) oxidation combined with chemical composite leaching does not damage the structure of coal gasification fine slag.