Study on effect of wet magnetic separation on distribution of Fe and heavy metal in fly ash
A wet magnetic separation process was used for pulverized coal boiler fly ash(FA1 ash)and circulating fluidized bed boiler fly ash(FA2 ash)to reduce their heavy metal content.Scanning electron microscope,laser particle sizer and X-ray diffractometer were used to characterize the morphology,particle size distribution and physical phase analysis of the highly magnetic and weakly magnetic parts of the two types of fly ash before and after magnetic separation under the condi-tions of different magnetic induction strengths and different concentrations of magnetic separation solutions,and to deter-mine the changes in the contents of iron and five heavy metal elements(Hg,Pb,As,Cr,Cd).It was found that the iron recov-ery rate of the two types of fly ash after magnetic separation was increased gradually with the increase of magnetic induction strength,and the content of heavy metal elements in the high magnetic group was significantly different from that in the weak magnetic group.The results showed that the Fe recovery of FA1 was 71.2%and that of FA2 was 47.0%at the magnetic induction intensity of 8000 Gs and the magnetic separation solution concentration of 20%.At this time,the difference of Pb content,Cr content and As content after magnetic separation of FA1 was 0.2 mg/kg,9.2 mg/kg and 1.1 mg/kg,respectively.The difference of Pb content,Cr content and As content after magnetic separation of FA2 was 18.1 mg/kg,25.0 mg/kg and 9.1 mg/kg,respectively.
magnetic separationfly ashheavy metal elementscirculating fluidized bed
万方数据
维普
