The Effect of Additive on Solidification of MSWI Fly Ash by Fuel Furnace

The experiments were carried out to test the additive(glass dust as a substitute for SiO_2) on the melting and solidification condition of fly ash from municipal solid waste incinerator(MSWI) for more than 6 months with a total daily treatment capacity of 500 kilograms by diesel oil furnace in a pilot scale,intending to clarify the effects of the additive on the melting temperature,volume reduction and the concentration of leaching heavy metals in molten slag.The results show that the additive can effectively reduce the melting temperature of fly ash,and the remaining levels of heavy metals in molten slag that meets the standard limit of Toxicity Characteristic Leaching Procedure of United States.The additive addition can increase the fixed rate of Cu and Zn remarkably,but almost have not effects on the fixed rates of Pb,Cd and Cr.When the temperature reaches melting point of fly ash samples,the volume reduction rate of all fly ash samples is over 80%,with the order as follows: fly ash with 20% additive fly ash with 10% additive fly ash with 5% additive original fly ash.The total toxic levels of dioxin in flue gas is 0.053 ng-TEQ/m~3,which is apparently lower than the national management guideline of total dioxin emissions,and the other pollutants in flue gas meet the national emissions.The whole molten system runs stably and is maneuverable to operate in the experimental periods.