Hydrothermal Harmless Treatment of Waste Incineration Fly Ash

Abstract

The invention discloses a method for hydrothermal harmless treatment of waste incineration fly ash, which comprises the following steps: (1) adding hydroxyapatite precursor liquid to the fly ash, and then performing the first step at 40-50°C Pressurized hydrothermal reaction to stabilize heavy metals in fly ash; (2) Add magnetic hydroxyapatite powder and hydrogen peroxide to the mixture obtained in step (1), and then carry out the second step of microwave high-pressure hydrothermal heating at 120-150°C reaction, further stabilizing heavy metals in fly ash and degrading polycyclic aromatic hydrocarbons. The invention can efficiently and synchronously realize the stabilization of heavy metals in waste incineration fly ash and the degradation and detoxification of polycyclic aromatic hydrocarbons. Not only the leaching toxicity of heavy metals is lower than the identification standard of hazardous waste, but also can be reduced to meet the "Standards for Pollution Control of Domestic Waste Landfill Sites", The heavy metals are really stable in the fly ash instead of being transferred to the hydrothermal waste liquid on a large scale, and the toxic equivalent degradation rate of 16 kinds of polycyclic aromatic hydrocarbons is over 95.06%, 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 more than 95%)

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