Method for harmless treatment of waste incineration fly ash through hydrothermal technology

Abstract

The invention discloses a method for harmless treatment of waste incineration fly ash through a hydrothermal technology. The method comprises the following steps of (1) adding a hydroxyapatite precursor liquid into fly ash, and then performing first-step hydrothermal reaction under normal pressure at 40 to 50 DEG C to stabilize heavy metals in the fly ash; and (2) adding magnetic hydroxyapatite powder and hydrogen peroxide into a mixture obtained by the reaction of the step (1), and then performing second-step microwave hydrothermal reaction under a high pressure at 20 to 150 DEG C to furtherstabilize the heavy metals in the fly ash and degrade polyaromatic hydrocarbons. According to the method, stabilization of the heavy metals and degradation and detoxification of the polyaromatic hydrocarbons in the waste incineration fly ash can be realized efficiently and synchronously; the leaching toxicity of the heavy metals is lower than identification standards for hazardous wastes and can meet domestic waste landfill pollution control standards; the heavy metals are actually stabilized in the fly ash rather than being transferred to a hydrothermal waste liquid on a large scale; the toxic equivalent degradation rate of sixteen polyaromatic hydrocarbons is up to 95.06 percent; and secondary pollution is prevented.

Description

technical field [0001] The invention belongs to the technical field of chemical industry and environmental protection, and in particular relates to a method for harmless treatment of waste incineration fly ash by hydrothermal treatment. Background technique [0002] Waste incineration treatment technology has the characteristics of short treatment cycle, good reduction effect, small footprint, etc., and can use the heat generated by it for power generation and heat supply as resources, so it has become a waste treatment technology commonly used in countries all over the world. According to the latest statistics, as of the end of 2018, my country has built 331 waste incineration plants, accounting for 45.1% of the amount of harmless waste (China Statistical Yearbook 2019), and the harmless rate of incineration has increased by 4.9% compared with the previous year. The scale of waste incineration in my country is showing a momentum of rapid development. In the process of secon...

AI Technical Summary

Problems solved by technology

Although this method achieves the detoxification of heavy metals and polycyclic aromatic hydrocarbons to a certain extent, the method is based on inducing the formation of tobermorite at 150-200 °C to stabilize the heavy metals and affect the ratio of silicon-aluminum elements in the fly ash reaction system. The precision control requirements are extremely high, and the treatment effect needs to be further improved (for example, the heavy metal leaching toxicity of the stabilized fly ash has not yet reached the entry standard for landfills (GB16889-2008), the toxic equivalent degradation rate of polycyclic aromatic hydrocarbons not exceeding 95%)

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