Method for processing special anhydrite cementitious material made from phosphogypsum with tunnel kiln equipment

Abstract

The method for processing special anhydrite cementitious material made of phosphogypsum with tunnel kiln equipment comprises the following steps: (1) batching and homogenization: by weight, 48-75 parts of phosphogypsum, 8-25 parts of stone coal and 15- 50 parts of waste rock slag are used for batching, grinding to make powder, adding 8 to 18 parts of water, and mixing and homogenizing into plastic materials; (2) Forming: forming plastic materials into molding materials; (3) Tunnel kiln calcination: Send it into the tunnel kiln, calcine at 980-1300°C for 20-60 minutes, and quench to obtain special anhydrite slag; (4) Preparation of special anhydrite cementitious material: grinding to obtain special anhydrite glue condensate material. The special anhydrite cementitious material obtained according to the method of the present invention contains a variety of hydration active minerals, can be widely used in the cement industry, has high strength when used, and is used as masonry cement or cement bricks, etc., without cracking and good strength; using this method The inventive method has the advantages of small investment, no generation of waste water and waste residue, and good economic efficiency.

Description

technical field [0001] The invention relates to a method for preparing a special anhydrite cementitious material from phosphogypsum, in particular to a method for processing the special anhydrite cementitious material from phosphogypsum with tunnel kiln equipment. Background technique [0002] Phosphogypsum is the waste residue discharged from phosphoric acid or phosphate fertilizer in the phosphating chemical industry. The main component is gypsum-based sulfate, with a content of 78-96%, followed by quartz SiO containing 4-22%. 2 , Soluble phosphate and fluorophosphate and insoluble phosphate, fluorophosphate and aluminosilicate minerals, and contain a small amount of harmful heavy metal elements such as cobalt, strontium, lead, cadmium, etc. [0003] The newly discharged phosphogypsum is a granular material, and it is easy to raise dust when it is disposed of and stored. However, under the action of an appropriate amount of water, the gypsum can be slowly recrystallized an...

AI Technical Summary

Problems solved by technology

A large amount of discarded phosphogypsum has objectively caused serious pollution and damage to the environment, groundwater and soil

[0004] At present, the research and application of phosphogypsum are mainly focused on four aspects. One is to modify phosphogypsum with lime, that is, add lime to neutralize the soluble phosphate and fluorophosphate in it, and replace natural gypsum for cement production. However, the application effect is not ideal objectively, and the actual consumption is very limited; the second is to convert phosphogypsum into hemihydrate gypsum or a compound of hemihydrate gypsum and soluble anhydrite, that is, 250-500 ℃ Low-temperature heat treatment of building gypsum powder, used to produce gypsum powder, gypsum board, gypsum block and other products, but because the grade and color of phosphogypsum are far inferior to natural gypsum, and contain a certain amount of harmful elements and harmful impurities, and building gypsum products are water-resistant Poor, its actual application consumption is still limited; third, phosphogypsum and lime, cinder, fly ash are mixed and pressed to make bricks after curing, but due to the influence of harmful impurities and harmful elements and the autoclaved curing process can be compared It is good to ensure the volume stability of brick products, but its popularization and application is not ideal; fourth, it is the by-product cement of sulfuric acid production, which leads to popularization and application due to large investment, low sulfuric acid grade, poor economy, and large secondary pollution. obstructed