Effect Of Micro Component On The Performance Of Cement Clinker Be Produced By Phosphogypsum

Phosphogypsum is a solid waste generated in the manufacture of phosphoric acid by wet process. About 10 million tons of PG is produced every year in China,and the quantity is increasing at a rate of 15% per year.With the development of phosphorus chemical industry, phosphogypsum emissions year by year.Untreated phosphogypsum is not onlyoccupation the land, pollution of surface water, waste a lot of resources, but also bringingmore serious environmental pollution and security risks.Utilization of PG is therefore one of the key issues for the continuing development of the phosphate fertilizer industry. It is one of important influential utilization approaches for the technology with the highest potential to produce cement clinker and sulfuric acid by phosphogypsum decomposition.The influence of microelements F,P,Al,Fe on composition and performance of cement clinker has been studied in this paper. The clinker was sintered by using phosphogypsum as the raw material. The burning mechanism and mechanical performance, component and structure of the clinker and hydration process were studied with the help of DTA—TG, XRD, and SEM. Main research conclusions are as follows:(1) the influence of calcining temperatureChange the content of microelements F,P,Al,Fe on the phosphogypsum system, the basic shapes of thermal analysis curve was unchanged. As the increases of F,P,Fe content, the decomposition of the phosphogypsum reaction temperature reduction, weightlessness rate increases, and Al content increases, can make the weightlessness rate to decrease.(2) the influence of clinker performanceMixing CaF2 into the phosphogypsum system can debase the decomposable temperature of CaSO4, is benefit to sinter the clinker. CaF2 act as the mineralizer and the optimum proportion of CaF2 in the raw materials is 2%. At the optimtlrn level, the compressive seength of minerals at each hydration age increased. The optimum proportion of P2O5 mixed into the phosphogypsum system is0%-0.6%,and the optimum proportion of CaF2 in the raw materials is 0.6%. Mixing a fit proportion of Fe203 into the phosphogypsum system can debase the viscosity, is benefit to sinter the clinker,and the compressive strength was increased.As the increase of aluminum content, the compressive strength of at 1 d increased obviously and that of 3d,28d improved appreciably.(3) Characterization of solid productsAnalysis the solid products by XRD and SEM, it shows that the appearance of sintered phosphogypsum has been changed. Dihydrate gypsum crystal in the phosphogypsum has been destroyed, and there exists a collection of mineralization reaction that contribute to increase the strength of phosphogypsum solidified.