Study On Not Sintering Phosphogypsum Bricks

Phosphogypsum is the industrial waste that expelled from phosphate acid plant. Because there is a little impurity in phosphogypsum, it affect the efficient use of phosphogypsum, bring about the rate of use is very low, the use of phosphogypsum is a very regardful problem of researchers. At the same time, along with the practice of the national wall reformation policy, the use of clay bricks is restricted, the requirement of new wall materials that can replace clay brick is very large, it provides a large space for empoldering phosphogypsum wall materials. Whether in environment protection or in the efficient use of resources, they also have important meanings to empolder phosphogypsum wall materials.This dissertation regards phosphogypsum as the basic materials, in the condition of no pretreatment, adopting pressing technics to manufacture wall materials directly. It bases the theory of gelatification material subject, regarding calces as alkaline excitated medicament first, on the one hand, it can neutralize the acidic substance in phosphogypsum; on the other hand, it also can be regarded as the efficient excitated medicament of slag, moreover, the additive that selected can occur chemical reaction with the other components of the system, it can enhance the forepart strength efficiently, it can benefit the final intensity of phosphogypsum bricks at the same time.Confirming the components of the system and the best component rate through single factor experiment and orthogonal experiment, discussing the main technical parameters that affect the performance of phosphogypsum bricks, analysing the hydrate products and its microcosmic structure of phosphogypsum bricks by XRD and SEM etc. modern testing means, discussing the process that cement, slag and additive occur chemical reaction to produce C-S-H and AFt, and primarily explaining the reason of strength forming of phosphogypsum bricks.Experiments indicating, it is feasible that using phosphogypsum to produce building bricks, phosphogypsum, cement, slag and sand are mixed by certain rate, adding a little additive at the same time, milling to uniformity and then pressing to mold, after conserving for a period of time, it can get the products whose compressive strength is no less than 15MPa.