Co-processing method of dioxins and heavy metals in fly ash based on steel slag and slag

Abstract

A cooperative treatment method for dioxin and heavy metal in flying ash on the basis of steel slag and mineral slag is characterized by comprising the following steps that (1) to-be-treated flying ashand a dehalogenation agent are mixed according to a mass ratio of 4:1-9:1, mixed milling is conducted by a planetary mill or a ball mill, and after 2-10 h of continuous ball milling, organochlorine degradation flying ash is obtained; (2) the organochlorine degradation flying ash and a curing agent are mixed according to the mass ratio of 4:1-9:1 and are stirred evenly, and a flying ash mixture isobtained; and (3) water or a reducing agent of the mass ratio of 15% is added into the flying ash mixture, the obtained mixture is put into a compaction die for compaction forming, pressure is 20-50kN, pressing time is 15-30 s, maintenance is conducted for 3-7 days, and a flying ash solidified body is obtained. Through the cooperative treatment method, dioxins and heavy metal pollutants can be treated simultaneously, steel slag serves as a main material of the dehalogenation agent and can be utilized efficiently, and the problem of a low comprehensive utilization rate of the steel slag is solved while the flying ash is treated.

Description

technical field [0001] The invention relates to the field of hazardous waste treatment, in particular to a method for synergistically treating dioxin and heavy metals in fly ash based on steel slag and slag. Background technique [0002] Waste incineration, medical waste incineration and industrial production will produce incineration fly ash, and fly ash will enrich trace heavy metals in the following two ways: 1) During incineration, volatile metal compounds condense on the surface of suspended particles; 2) Incineration Afterwards, vaporized metals also condense directly on other volatiles. In addition, due to the presence of chlorides, persistent pollutants such as chlorinated dibenzodioxins and polychlorfurans will be produced during the incineration process of garbage. Therefore, the fly ash of domestic waste incineration is hazardous waste and must be treated innocuously. [0003] Generally speaking, the harmless treatment of municipal waste incineration fly ash can...

AI Technical Summary

Problems solved by technology

However, the heat treatment technology consumes a lot of energy, the cost is too high, and it will increase the risk of pollutants entering the gas phase and causing secondary pollution.

Due to the huge difference in the properties of dioxins and heavy metals, it is difficult to treat dioxins and heavy metals in fly ash at the same time by other methods

However, the combination of multiple methods will greatly increase the processing cost and increase the difficulty of process control.

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