Technical method of phosphoric acid waste slag treatment to form calcification gypsum powder

Abstract

A process for preparing the calcified gypsum powder from the waste phosphoric acid dregs includes proportionally mixing said waste phosphoric acid dregs (pH 2-5, water content below 15-30%) with calcium carbonate substance containing CaCO3 (35-70%), stirring, calcining and grinding. Its advantages are high quality and low cost.

Description

technical field [0001] The invention relates to a calcified gypsum powder used for regeneration and utilization of phosphoric acid waste slag or building materials, and a process for the calcified gypsum powder. Background technique [0002] At present, the waste residue discharged from the production of phosphoric acid in chemical plants, also known as phosphogypsum, is a wet powder with a fineness of 100 mesh, 5%-10% of the sieved residue, 10%-30% of absorbed water, and a large amount of impurities. From Chemical analysis compared with natural gypsum, mainly there is 0.3%-1.5% P 2 o 5 , these P 2 o 5 Soluble in water to make phosphoric acid waste residue into an acidic substance containing a small amount of phosphoric acid and free acid. Its pH value is 2-5. It not only affects the setting time of gypsum, but also affects the flexural and compressive strength of gypsum. If they are not treated properly , and carry out the preparation of science, just can't produce the ...

AI Technical Summary

Problems solved by technology

[0002] At present, the waste residue discharged from the production of phosphoric acid in chemical plants, also known as phosphogypsum, is a wet powder with a fineness of 100 mesh, 5%-10% of the sieved residue, 10%-30% of absorbed water, and a large amount of impurities. From Chemical analysis compared with natural gypsum, mainly there is 0.3%-1.5% P 2 o 5 , these P 2 o 5 Soluble in water to make phosphoric acid waste residue into an acidic substance containing a small amount of phosphoric acid and free acid. Its pH value is 2-5. It not only affects the setting time of gypsum, but also affects the flexural and compressive strength of gypsum. If they are not treated properly , and carry out scientific preparation, it is impossible to produce qualified building gypsum powder

In order to utilize this waste residue, the current technical treatment production method is the water method (every ton of phosphoric acid waste residue needs 5 tons of clear water to be turned into sewage), and the harmful substances in the phosphoric acid waste residue, especially P 2 o 5 Wash off most of it and neutralize it with lime to make its PH value reach 6 to produce building gypsum powder, which has high production cost, high heat consumption, difficult sewage treatment, difficult control of pH, and unstable quality