Fly ash washing process for multistage reverse pulping of carbon dioxide tempering

Abstract

The invention discloses a fly ash washing process for multistage reverse pulping of carbon dioxide tempering. The fly ash washing process comprises the following steps that 1, fly ash and water are mixed according to the solid-to-liquid ratio of 1: (3-5) to prepare slurry, and meanwhile, carbon dioxide gas is introduced into the slurry to adjust the pH value to be 6-8; 2, suction filtration is conducted on the slurry to obtain high-concentration water washing liquid and solid residues; 3, the solid residues obtained in the previous step are mixed with water according to the solid-to-liquid ratio of 1: (3-5) to prepare slurry; 4, suction filtration is conducted on the slurry prepared in the step 3 to obtain high-concentration water washing liquid and solid residues; 5, the third step and the fourth step are sequentially repeated once, and high-concentration washing liquid and solid residues are obtained; 6, the solid residues obtained in the step 5 are mixed with water according to the solid-to-liquid ratio of 1: (5-8) to prepare slurry; and 7, the slurry prepared in the step 6 is subjected to suction filtration, low-concentration water washing liquid and solid residues are obtained, the low-concentration water washing liquid is concentrated through a DTRO membrane, concentrated water and fresh water are obtained, the concentrated water is reused in the step 1 for preparing the slurry, and the fresh water is reused in the step 6 for preparing the slurry.

Description

technical field [0001] The invention belongs to the technical field of harmless treatment of fly ash produced by garbage incineration, and in particular relates to a fly ash water washing process of carbon dioxide conditioning and multi-stage reverse pulping. Background technique [0002] The output of fly ash from waste incineration in my country is huge. With the increase in the volume of domestic waste removal and the increase in the proportion of incineration, the waste incineration industry will grow explosively. By the end of 2020, the total amount of waste incineration will reach 591,400 tons per day. During the process of waste incineration, many harmful substances will be produced, such as dioxins, acid gases (such as hydrogen chloride, sulfur dioxide), nitrogen oxides, heavy metal dust, etc. Most of these pollutants will be trapped by the dust removal system to form fly ash during flue gas purification, and the annual production of fly ash is about 10 million tons....

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a carbon dioxide tempered multi-stage reverse pulping fly ash washing process. The main technical problem to be solved is that the existing fly ash washing device method based on carbon dioxide It can solve the problem of high evaporation water and high energy consumption after washing, but fails to propose a subsequent treatment plan for washing liquid, which cannot improve the utilization rate of water resources, and cannot fully harmless and resourceful washing liquid

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