Process method for converting dry-method desulfurized fly ash into desulfurized gypsum

Abstract

The invention belongs to the technical field of solid waste treatment, and particularly relates to a process method for converting dry-method desulfurized fly ash into desulfurized gypsum. The processmethod comprises the following steps: step 1, adding water and dry-method desulfurized fly ash into an oxidation tower, and stirring to obtain a dry-method desulfurized fly ash solution; step 2, introducing the dry-method desulfurized fly ash solution into sintering machine flue gas under a stirring condition for reaction; 3, after the reaction is completed, carrying out solid-liquid separation on the solution; step 4, returning the solution prepared by solid-liquid separation to an oxidation tower, and feeding a separated solid into a distillation device; step 5, carrying out solid-liquid separation in a distillation device, returning distilled water vapor to the oxidation tower, and taking the left solid as desulfurized gypsum; a precipitation method can be adopted to remove calcium chloride and calcium nitrite in the solution prepared through solid-liquid separation further. According to the method, the temperature of the flue gas of a sintering machine head and the sulfur dioxidemedium in the flue gas are fully utilized to realize conversion of calcium sulfite in the dry-method desulfurization fly ash, and meanwhile, the problem of secondary pollution caused by calcium chloride and calcium nitrite is solved.

Description

technical field [0001] The invention belongs to the technical field of solid waste treatment, and in particular relates to a process method for converting desulfurized ash into desulfurized gypsum by dry method. Background technique [0002] In the process of industrial production such as iron and steel, the generated flue gas contains powder (smoke) dust, sulfur oxides (SO X ), nitrogen oxides (NO X ) and CO 2 Among them, the semi-dry desulfurization process adopted by the sulfur oxide emission control equipment, its by-product is dry desulfurization ash, the main components of dry desulfurization ash are calcium sulfite, calcium carbonate, etc., due to calcium sulfite It is easy to decompose, so it is not used as a raw material for building materials, and the country has no standards for using dry desulfurization ash as building materials. At present, the more common treatment methods are stacking or landfilling, which does not meet the national requirements for solid wa...

AI Technical Summary

Problems solved by technology

However, in the actual application process, there is calcium nitrite in the desulfurization ash. If it is not treated, the precipitated calcium nitrite will cause secondary pollution.

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