Analysis And Token Of Guizhou Phosphogypsum's Physical And Chemic Property

The physical and chemical property of phosphogypsum specimens that came from three companies in Guizhou was studied, at the same time, we made a compare between phosphogypsum and naturegypsum. The experiments show that they almost had the same content of CaSO₄.2H₂O. The great discrepancy between phosphogypsum and naturegypsum is that there are a few impurities in phosphogypsum, for example F, P, and organic matter, which can make a great effect on the utilization of phosphogypsum. In addition, grading in phosphogypsum approximately is taken on normal distribution, while the naturegypsum is not. The grain which the size is between 105～80um can reach to over 33%(WT%), and the contents of impurities increase with increasing phosphogypsum size, while the P₂O₅ in crystal lattice decrease. In order to decrease the content of P₂O₅ in crystal lattice, we tried to wash phosphogypsum with water or the solution of vitriol, ammonia, lime, the effect was not availability, but experiments result showed that washing with the solution of vitriol or lime can decreased the temperature when trying to remove the P₂O₅ in crystal lattice by calcining phosphogypsum. In addition, we tried to make gypsum for building from phosphogypsum, we found that the content of impurities made great effect, and we could not attain eligible product because of too much impurities in one phosphogypsum, on the contrast, we could get better gypsum for building when the content of impurities was lower.