Study On The Preparation Of Phosphogypsum Lightweight Wall-bricks

Phosphogypsum is by—product that is formed in the production of phosphoric acid and phosphoric fertilizers. Generally it would yield to extra five tons phosphogypsum (according to P2O5) per producing one-ton phosphoric acid. As the wasted dregs contain nocuous ingredients, it has been occupying land, polluting environment because phosphogypsum is discharged randomly. Its being recycled and reused is always being researched. The main composition of the phosphogypsum is CaSO₄·2H₂O and some impurities. Through appropriate methods and technique, the phosphogypsum may be used as the useful resources of the chemical engineering, building materials areas etc.The paper research on phosphogypsum lightweight wall-bricks. We discuss strength, water resistance, processing technology condition of the lightweight wall-bricks. We analyse the affection of phosphogypsum pretreatmeat way and adding water repellent compound and hydrate reactive mechanism of phosphogypsum lightweight wall-bricks.The results show that phosphogypsum can be used for preparing lightweight wall-bricks after being properly pretreated. But the lime-neutralization method is simple. With this method, we succeeded in making the phosphogypsum lightweight wall-bricks. It has been satisfactorily the standard of intensity level.By a series of single factor and orthogonal experiments of compression resistance, softening coefficient, water absorption. The suitable condition of production is obtained. This system is contain of phosphogypsum, mine refuse, silica sand, cement, calcium lime. We can get the phosphogypsum lightweight wall-bricks which attain the standard of JC422-91.The paper's innovations are that prepare phosphogypsum lightweight wall-bricks including the approach of pretreatment of lime-neutralization phosphogypsum and the method of casting moulding. The technique equipment is relatively simple, and it's easy to control. According to the method, it can be used to manufacture the product on industry scale. Therefore the way has application and value.