Harmless disposal method of waste incineration fly ash

Abstract

The invention relates to a harmless disposal method of waste incineration fly ash. The method comprises the steps that the waste incineration fly ash is added into molten-state sodium chloride to react, and fly ash molten salt residues and volatile gas are generated in the reaction process; the fly ash molten salt residues generated in the reaction process are sedimentated to the bottom of the molten-state sodium chloride from the molten-state sodium chloride, and the fly ash molten salt residues at the bottom are collected and then subjected to landfilling; heavy metal in the volatile gas generated in the reaction process is collected through condensation, and the rest of gas is discharged; and a molten salt auxiliary is added into the waste incineration fly ash. The disposal method is simple in process, the size of fly ash is reduced by 50%, the weight of the fly ash molten salt residues is reduced by 50%, and the volume reduction rate of the size and weight is remarkable.

Description

technical field [0001] The invention belongs to the field of environmental protection for the disposal and comprehensive utilization of hazardous solid waste, in particular to a harmless disposal method for waste incineration fly ash. Background technique [0002] There are many disposal techniques for traditional waste incineration fly ash. Specifically, it is divided into four categories: separation and extraction technology; heat treatment technology, solidification and stabilization technology and other technologies. However, none of them can meet the actual requirements of recycling, harmlessness, reduction, economical rationality, safety and high efficiency at the same time. [0003] Solidification and stabilization technology not only increases capacity, but also the price of solidification and stabilization materials is high, and the comprehensive cost of landfill storage is also high; [0004] Separation and extraction technology is complex, expensive equipment an...

AI Technical Summary

Problems solved by technology

[0006] With the improvement of people's living standards and environmental awareness, the chemical composition of waste incineration fly ash has also undergone significant changes. The prominent features are high salt content and high calcium oxide content, which makes traditional melting technology encounter difficulties. Without the addition of co-solvent, the melting temperature of waste incineration fly ash exceeds 1500°C, coupled with secondary fly ash treatment, extremely high energy consumption, unprecedented technical difficulties in the melting process

However, even if the sintering technology is adopted, the sintering temperature is very high, and the salt in the fly ash directly affects the quality of the sintered product. Water washing and desalting treatment is required before sintering, which increases the cost and complicates the process, and the risk of heavy metal leaching of the sintered product still exists

[0007] With the cement mixed firing process after washing, the cement production capacity is excessive, the amount of cement clinker fired is small, the concentration of chloride ions at the kiln tail increases, and the hidden danger of the kiln tail preheater skinning increases, and many technologies such as chloride salt recovery, filter hardening, etc. Problems make cement blending also face many difficulties

[0008] Separation of heavy metals and decomposition of dioxins are the key technologies for the harmlessness of waste incineration fly ash. The lack of economical and effective technical methods is a prominent problem at home and abroad.

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