Resource utilization method of semi-dry desulfurization ash

Abstract

The invention discloses a resource utilization method of semi-dry desulfurization ash, comprising the following steps: 1) oxidizing the semi-dry desulfurization ash to make the CaSO 3 Fully converted to CaSO 4 ; 2) add water to make the desulfurized ash after the oxidation into a desulfurized ash slurry, then fill the desulfurized ash slurry with CO 2 , so that CO 2 and Ca(OH) in desulfurization ash slurry 2 Fully react to form CaCO 3 , where, by CO 2 with Ca(OH) 2 The molar ratio is 1.2~1.5:1 and filled with CO 2 ; 3) press NH in step 3) gained slurry 4 HCO 3 Add NH at a molar ratio of 1.2 to 1.5:1 to calcium 4 HCO 3 , and adjust the pH to be 7-9, so that the sulfur-containing calcium is fully converted into calcium carbonate precipitation; 4) the slurry obtained in step 3) is used to obtain calcium oxide and ammonium sulfate solids. The method of the present invention makes full use of the characteristics of high calcium and high sulfur in the semi-dry desulfurization ash, and converts the desulfurization ash into ammonium sulfate and calcium carbonate, so that the conversion rates of calcium and sulfur elements can reach more than 95% respectively, and then the resources of desulfurization ash The value of transformation can be fully realized.

Description

technical field [0001] The invention relates to solid waste recycling technology, in particular to a semi-dry desulfurization ash recycling method. Background technique [0002] The semi-dry desulfurization process has been widely used in recent years due to its advantages of small investment, low land occupation, and no waste water generation. The desulfurization ash produced in the semi-dry desulfurization process has not yet been well utilized, and it is mainly stockpiled, which has brought about land occupation and environmental problems. [0003] In the process of research on the resource utilization of semi-dry desulfurization ash, due to the unstable properties of calcium sulfite in semi-dry flue gas desulfurization ash, problems such as pyrolysis and prolonged cement setting time are prone to occur in the process of resource utilization, so In recent years, desulfurization enterprises and scientific research institutes have focused on how to improve the oxidation ef...

AI Technical Summary

Problems solved by technology

[0003] In the process of research on the resource utilization of semi-dry desulfurization ash, due to the unstable properties of calcium sulfite in semi-dry flue gas desulfurization ash, problems such as pyrolysis and prolonged cement setting time are prone to occur in the process of resource utilization, so In recent years, desulfurization enterprises and scientific research institutes have focused on how to improve the oxidation efficiency of calcium sulfite in semi-dry desulfurization ash. The main components of oxidized desulfurization ash are calcium sulfate, calcium carbonate and hydroxide Calcium is currently mainly used to replace gypsum as a raw material for the production of mineral powder or cement. However, this method of utilization does not give full play to the high calcium and high sulfur characteristics of desulfurization ash; moreover, gypsum is relatively cheap and easy to obtain As a raw material, it is of little practical significance to replace gypsum with desulfurization ash