Method for preparing lime by using byproduct calcium carbonate obtained from preparation of ammonium sulfate by phosphogypsum as raw material

Abstract

The invention relates to a method for preparing lime by using a byproduct calcium carbonate obtained from preparation of ammonium sulfate by phosphogypsum as a raw material. The method comprises the following steps that (1) the byproduct wet-based calcium carbonate obtained from preparation of ammonium sulfate by phosphogypsum is fed to a third-level cyclone preheater for heat transfer and drying with decomposed exhaust gases; (2) dried materials in the previous step enters a decomposing furnace, pulverized coal and air are sprayed to the decomposing furnace by a pulverized coal preparation system to combust in the decomposing furnace to generate high-temperature flue gas at 1200 DEG C, the materials are heated and decomposed to CaO and CO2, and the exhaust gases generated by the decomposing furnace are fed to the third-level cyclone preheater in the previous step; (3) lime generated by decomposition enters a third-level cyclone cooler; (4) lime discharged out of the cooler is fed to a limit finished product storeroom; (5) the exhaust gases after heat exchange in the first step are fed to a bag type dust collector to be dedusted, and purified qualified exhaust gases are discharged to a chimney. The method provided by the invention is simple, remarkable in effect and applicable to manufacturers with devices for preparation of ammonium sulfate by phosphogypsum and sewage treatment devices.

Description

technical field [0001] The invention relates to chemical production, in particular to a method for preparing lime by using calcium carbonate, a by-product of the production of ammonium sulfate from phosphogypsum, as a raw material. Background technique [0002] Phosphogypsum is the industrial waste residue produced when sulfuric acid is used to extract phosphate ore in the production of wet-process phosphoric acid. About 5 tons of phosphogypsum are discharged for every ton of phosphoric acid produced. An increase of more than 100 million tons; Most of the phosphogypsum residues are now disposed of in stockpiles and landfills, which not only wastes resources, occupies land, but also causes great harm to the environment. The effective use of phosphogypsum is an urgent problem to be solved by the phosphorus chemical industry. Wengfu (Group) Co., Ltd. developed a phosphogypsum ammonium sulfate plant to solve this problem. The phosphogypsum ammonium sulfate system uses chemical b...

AI Technical Summary

Problems solved by technology

[0003] The object of the present invention is to provide a method for preparing lime as a raw material for the production of ammonium sulfate from phosphogypsum by-product calcium carbonate, so as to recycle and utilize industrial by-product calcium carbonate and turn waste As a treasure, it solves the technical problem of secondary waste pollution, and the lime produced at the same time can increase the economic benefits of the enterprise