Combined production method for preparing sulphoaluminate cement and sulfuric acid from flue gas desulfurization gypsum

Abstract

The invention relates to a combined production method for preparing sulphoaluminate cement and sulfuric acid from flue gas desulfurization gypsum. According to the method, flue gas desulfurization gypsum which replaces limestone and natural gypsum completely is mixed with bauxite, silica and anthracite, and the sulphoaluminate cement is obtained after calcinations. The method can improve the utilization rate of flue gas desulfurization gypsum by a large margin, and the tail gas containing sulfur dioxide with a higher concentration can be absorbed to prepare sulfuric acid; the prepared sulphoaluminate cement clinker is fast in rate of hardening, high in early strength and further promotes the stability of later strength; through the performance tests, it is indicated that the mechanical strength of the sulphoaluminate cement prepared by the method meets the standard of rapid hardening sulphoaluminate cement.

Description

technical field [0001] The invention relates to a method for preparing sulphoaluminate cement to co-produce sulfuric acid from desulfurized gypsum, and belongs to the technical field of cement preparation. Background technique [0002] With the modernization of engineering technology, the technical requirements for special cement are getting higher and higher. These include the special requirements for the speed of rapid setting and hardening and the hardness of each stage during the construction of special projects, such as the connection construction of cement pipelines, and the construction of foundation sites for large-scale equipment. However, although the application and the sales market are constantly expanding, they are limited due to the high cost of the product, making more users out of reach. On the other hand, my country's flue gas desulfurization technology is mainly wet desulfurization process. The consequence of this limestone-gypsum wet desulfurization proce...

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Problems solved by technology

[0003] Chinese patent document CN103979810A discloses a method for comprehensively utilizing papermaking lime mud, bauxite and desulfurized gypsum to prepare sulphoaluminate cement clinker. This process uses papermaking lime mud, bauxite and desulfurized gypsum as raw materials. It is obtained by raising the temperature at 20-30°C / min to 1200-1300°C and keeping it warm for 1.5-2.5h; it is taken out and cooled to room temperature, and the clinker is ground to 400m2 / kg to obtain the desired product; The formula of acid salt raw meal is: papermaking lime mud 40wt%-50wt%, bauxite 35wt%-45wt%, and the rest is desulfurized gypsum. This method cleverly uses papermaking lime mud and desulfurized gypsum as the main raw materials. Sulphoaluminate cement can not only effectively utilize solid waste, but also reduce the cost of sulphoaluminate, but the amount of desulfurized gypsum used in the process only accounts for 5-25% of the raw material ratio, and the utilization rate of desulfurized gypsum is low , and calcining desulfurized gypsum in the invention will produce sulfur dioxide, which will cause environmental pollution if not handled properly

However, the amount of desulfurization gypsum in this method is only about 10%, and a large amount of limestone is still needed, and the sulfur dioxide contained in the tail gas obtained will cause environmental pollution if not handled properly

[0005] After searching, there is no report that fully utilizes desulfurized gypsum to prepare stable sulfoaluminate cement with fast hardening speed, high early strength and enhanced later strength.

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