A method for preparing sulphoaluminate cement from phosphogypsum

Abstract

The invention relates to a method for preparing sulphate aluminium cement through phosphogypsum. The method includes the steps that limestone and natural gypsum are completely replaced with the phosphogypsum, the phosphogypsum is subjected to powder grinding and homogenized through bauxite, solid waste steel residues and anthracite and calcined at the temperature of 1,250 DEG C to 1,300 DEG C to prepare the sulphate aluminium cement. By means of the method, the using rate of the phosphogypsum can be greatly increased, and high-concentration sulfur-dioxide tail gas can be prepared into sulfuric acid through absorption. The hardening speed of sulphate aluminium cement clinker prepared with the method is high, the earlier-stage strength is high, the later strength is also enhanced to be stable, and performance testing indicates that the mechanical strength of the sulphate aluminium cement prepared with the method meets the standard of the sulphate aluminium cement.

Description

technical field [0001] The invention belongs to the technical field of cement materials, and relates to a method for preparing sulphoaluminate cement by using phosphogypsum, which is waste from phosphorus chemical industry, as a raw material. 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 continue to expand, they are limited due to the high cost of the product, making more users out of reach. On the other hand, as one of the world's three major phosphate fertilizer producers, it is difficult to realize mass utilization due to the re...

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Problems solved by technology

[0003] Chinese patent document CN1401604A discloses a manufacturing process of fast-hardening sulfoaluminate cement. The raw material ratio of this process is 17-20% of dehydrated phosphogypsum, 45-52% of limestone, and 31-35% of bauxite. The successful use of waste phosphogypsum to replace the natural gypsum in the raw meal mix can partially reduce the cost of sulphoaluminate cement, but the amount of phosphogypsum used in the process only accounts for 17-20% of the raw meal mix. 45-52% of limestone is needed, which fails to achieve the purpose of effective utilization of phosphogypsum. In addition, the decomposition of phosphogypsum in the process will release sulfur dioxide, which will cause environmental pollution if not handled properly

However, this process needs to convert phosphogypsum into calcium carbonate first, and then proceed to raw material proportioning and calcination. The required equipment and process are relatively complicated, and the production cost is high.

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