Study On Treatment And Utilization Of Mswi Fly Ash By Electric Current Sintering

The MSWI fly ash is enriched with pollutants such as chloride salts,heavy metals and dioxins,which are hazardous solid wastes.There are many technical problems in harmless treatment and resource utilization.In this paper,for the first time,a new type of electric current sintering technology was used to conduct experimental research on the disposal and utilization of MSWI fly ash.Firstly,the experiment of change temperature and electric current sintering of MSWI fly ash was carried out.The MSWI fly ash was sintered by adjusting the electric field strength and the chloride salt content,and the changes of the electric current sintering starting temperature,power dissipation and sample temperature during the electric current sintering process were investigated.The microstructure and heavy metal properties of the sintered body were analyzed.The results show that the initial temperature of electric current sintering decreases with the increase of the electric field strength and the increase of the chloride salt content.In the original MSWI fly ash sintering experiment,when the electric field strength is 400V/cm,the initial temperature of electric current sintering is 420℃,the sintering time is less than 5min,heavy metal leaching is less than the limit of relevant standards.At steady state,the power consumption and sample temperature decrease with th e increase of the electric field strength and the increase of the chloride salt content.Subsequently,the experiment of isothermal and electric current sintering of MSWI fly ash was carried out.The MSWI fly ash was sintered by adjusting furnace temperature,chloride salt content,additives,set current,etc.,and the changes of the power dissipation and sample temperature changes during the electric current sintering process were investigated.The microstructure,heavy metal characteristics and properties of the sintered body were analyzed.The results show that the power dissipation and sample temperature decrease with the increase of furnace temperature,the increase of chloride salt content,the decrease of additives and the increase of set current,and isothermal electric current sintering MSWI fly ash can significantly reduce peak power consumption during electric current sintering;The quality ratio of washed MSWI fly ash and original MSWI fly ash is 7:3,doped with 5 wt% fly ash,420℃ furnace temperature,400V/cm electric field,900 m A current,heat preservation for 10 min,its compressive strength reached 24.57 MPa,heavy metal leaching is far below the National standard,and the curing rates of Cr,Ni,Cu,Zn,Pb are 98.99%,99.01%,97.43%,89.05%,8 0.97%,respectively.Finally,the isothermal electric current sintering experiment was carried out by simplifying the process and mixing the original MSWI fly ash with fly ash The results show that the original MSWI fly ash is doped with 15wt% fly ash at 600℃ furnace temperature,400V/cm electric field,900 m A current,heat preservation for 10 min,its compressive strength reaches 23.83 MPa,heavy metal leaching is far below the National standard,and the curing rates of Cr,Ni,Cu,Zn,Pb are 94.37%,94.25%,99.39%,98.09%,72.56%,respectively.