Method for preparing sulphoaluminate cement and co-producing sulfuric acid by virtue of segmented calcination of desulfurized gypsum

Abstract

The invention relates to a method for preparing sulphoaluminate cement and co-producing sulfuric acid by virtue of segmented calcination of desulfurized gypsum. The method comprises the following steps: completely replacing limestone and natural gypsum with desulfurized gypsum, mixing bauxite, silica and anthracite with the gypsum to prepare blocks, and then carrying out segmented calcination to prepare the sulphoaluminate cement. According to the method, the utilization rate of the desulfurized gypsum can be greatly improved, and the high-concentration sulfur dioxide tail gas can be used for preparing sulfuric acid through absorption. The prepared sulphoaluminate cement clinker has high hardening speed, the early strength is high, the later strength is also improved stably, and the performance test shows that the mechanical strength of the sulphoaluminate cement prepared by the method conforms to the standard of the fast-hardening sulphoaluminate cement.

Description

technical field [0001] The invention relates to a method for preparing sulfoaluminate cement and co-producing sulfuric acid by segmental calcination of desulfurized gypsum, belonging 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 we...

AI Technical Summary

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.

Images