Method for using phosphogypsum in mine goaf consolidated filling

Abstract

The invention discloses a method for cemented filling of phosphogypsum in a mine goaf. The method mainly comprises the following steps: mixing the following materials in weight ratio: 0.8 to 1.2 percent of cement, 1.2 to 0.8 percent of water quenched iron (steel) slag, 10 to 14 percent of the phosphogypsum, and 0.4 to 0.8 percent of lime; adding water to the mixture and stirring the mixture to form filling slurry with the weight concentration of between 55 and 65 percent; conveying the filling slurry to the mine goaf; and curing the filling slurry to form a high-strength filling material. The method can significantly reduce the curing time of the filling slurry taking the phosphogypsum as the main raw material, is suitable for various mining techniques and the cement filling for various types of mine goafs, and has strong economic and social benefits.

Description

Technical field [0001] The invention belongs to the field of comprehensive utilization of phosphogypsum, and specifically relates to a method for cementing and filling phosphogypsum in mine goafs. Background technique [0002] Phosphogypsum is a waste residue produced in the process of producing phosphoric acid. About 5 to 6 tons of phosphogypsum are discharged for every ton of phosphoric acid produced. my country's annual phosphogypsum output is more than 20 million tons, but its comprehensive utilization rate is only about 25%. . The calcium sulfate dihydrate content in phosphogypsum is generally between 80 and 95%, which is equivalent to the first and second grade natural gypsum. Since it contains a small amount of phosphoric acid, fluosilicate, and sulfuric acid, it is usually acidic and will occupy land. Environmental pollution problems. Although in areas with industrial by-product phosphogypsum, phosphogypsum has been used to replace natural gypsum to produce gypsum b...

AI Technical Summary

Problems solved by technology

Because the filling period is too long, it directly affects the mining efficiency and is limited by the mining method

Chinese patent CN101008316A discloses the phosphogypsum cementation followed by filling mining method and its pulping process. Its limitation is the same as that of the patent CN1821547A. It cannot be solidified within a week and achieve a compressive strength above 1.5MPa.