Method for dearsenization of arsenic containing waste water generated in regeneration process of vanadium, tungsten and titanium denitration catalyst

Abstract

The invention relates to a method for removing arsenic from arsenic-containing wastewater produced in the regeneration process of a vanadium-tungsten-titanium denitrification catalyst, and belongs to the technical field of chemical engineering. The method is to carry out arsenic-containing catalyst and sodium hydroxide solution for alkali leaching dearsenic reaction. After the reaction, the catalyst and arsenic-containing wastewater after alkali leaching are obtained, and the arsenic-containing wastewater needs to be further treated for arsenic removal; Oxidation reaction is carried out by adding oxidizing agent hydrogen peroxide, then adding iron salt to adjust the pH of the solution>9, then adding CaO at 50-100° C., and continuing the reaction for 0.5-3 hours. After the reaction is finished, liquid-solid separation is carried out. The liquid phase is the liquid after de-arsenic, which can be prepared by adding sodium hydroxide to a solution containing sodium hydroxide, and then returns to participate in the alkali leaching de-arsenic reaction, which is recycled in the entire catalyst regeneration system; the solid phase It is harmless waste and can be piled up directly. The content of As in the waste water after arsenic removal treatment is less than or equal to 0.5 mg / l. This method not only reduces the cost, but also does not cause any pollution to the environment.

Description

technical field [0001] The invention belongs to the technical field of chemical engineering, and in particular relates to a method for removing arsenic from arsenic-containing wastewater produced in the regeneration process of a vanadium-tungsten-titanium denitrification catalyst. The method can meet the requirements of high efficiency, safety and environmental protection for arsenic removal, and the waste water after arsenic removal can be recycled in the whole system. Background technique [0002] Most thermal power plants use honeycomb catalysts for flue gas denitrification treatment. Since coal-fired boilers contain a small amount of arsenic, gaseous As in high-temperature flue gas 2 o 3 , It is easy to enter the pores of the catalyst, causing arsenic poisoning of the catalyst and deactivation, thereby reducing the service life of the catalyst. At present, more and more catalyst manufacturers are concerned about catalyst regeneration. However, arsenic-containing wastew...

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Problems solved by technology

[0002] Most thermal power plants use honeycomb catalysts for flue gas denitrification treatment. Since coal-fired boilers contain a small amount of arsenic, gaseous As in high-temperature flue gas 2 o 3 , easy to enter the pores of the catalyst, causing arsenic poisoning of the catalyst and deactivation, thereby reducing the service life of the catalyst

At present, more and more catalyst manufacturers are concerned about catalyst regeneration. However, arsenic-containing wastewater will inevitably be generated during the catalyst regeneration process. If it is not treated, it will undoubtedly cause secondary pollution to the environment.

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