Study On The Preparation Of Phosphogypsum-bricks

Phosphogypsum is by-product that is formed in the production of phosphoric acid and phosphoric fertilizers. On the average, 5 tons phosphogypsum are discharged for producing one ton phosphoric acid. As the wasted dregs contain nocuous ingredients, it has been increasing cost, occupying land, polluting environment, endangering human health because phosphogypsum is discharged randomly. The research showed that the composition of phosphogypsum are similar with nature gypsum, in spite of containing a little of P2O5, F- and other substances, as well as contents of radioactive element that is less than the requirement of national standard. So phosphogypsum can be used as raw materials of construction. Along with the implementation of the national policy of innovating the wall materials, clay bricks is limited for using, and the need of new wall materials is increased. For resolving the two problems, this article put forward a new thinking of preparing the new wall materials-- phosphogypsum bricks.By a series of orthogonal and contrastive experiments, the suitable condition of production is obtained. The parameters of the processes thatare suitable for industrialization production are designed. And hydrating mechanism of phosphogypsum bricks is discussed. The two relations, y=2. 6331n(x)+1. 7951 and N=6. 622X0.407Y0.201Z-0.174, fit the experiment data. Basing of the laboratory work, the trial success in a pilot plant are thus obtained. The results indicate that the compressive strength of the phosphogypsum bricks is beyond 10MPa. This phosphogypsum construction product possesses many benefit characteristics, such as light weight, anti-seismic ability, heat-preservation and air humidity-accommodation.