Method for producing EDTA ferric sodium salt by recovering Fe<II>EDTA wet-process complexed denitrated waste-liquid

Abstract

The invention discloses a method for producing EDTA ferric sodium salt by recovering a Fe<II>EDTA wet-process complexed denitrated waste-liquid. The method comprises: performing dedusting and desulphurization on a flue gas by a Fe<II>EDTA wet-process complexing denitration method, making the to-be processed flue gas enter into an absorption reactor and fully contact an absorption liquid, fully oxidizing Fe<III>EDTA and nitrogen-sulfur compounds both contained in the denitrated waste liquid by hydrogen peroxide or ozone to generate EDTA ferric sodium salt, NO<3-> and SO4<2->; and calculating the volume of a saturated solution of the generated EDTA ferric sodium salt at 100 DEG C according to the content of Fe<II>EDTA in the absorption liquid, heating and evaporating the oxidized waste liquid to the volume, cooling to 33 DEG C, and gradually separating out a reddish brown precipitate of EDTA ferric sodium salt. The method is low in investment and operation cost, the regenerated products are higher-economic-value EDTA ferric sodium salt, NaNO3 and Na2SO4, and the method helps to realize recycling of denitrated products.

Description

technical field [0001] The invention belongs to the field of environmental protection, in particular to a reclaimed Fe II A method for generating EDTA iron sodium salt by wet complexation of denitrification waste liquid with EDTA. Background technique [0002] At present, my country's air pollution is serious. In order to protect the ecological environment, desulfurization and denitrification of coal-fired flue gas is imminent. Among them, wet flue gas purification technology has attracted much attention because of its simplicity and good effect. [0003] In various wet denitrification technologies, Fe II EDTA wet complexation denitrification has attracted much attention due to its high efficiency, but the defect of this method is that Fe II EDTA absorption solution is easily oxidized to Fe III EDTA fails, resulting in higher absorption costs and difficult practical engineering applications. In the past 20 years, the United States, Japan and Europe have been devoting th...

AI Technical Summary

Problems solved by technology

Japan's Ashahi company concentrated the waste liquid after denitrification and sent it to the condenser, and recovered part of the dithionite, etc. generated during the crystallization, separation and complexation process, but the recovery cost was very high, and EDTA was discharged into the water body, causing other adverse effects

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