Research On The Classification And Purification Techniques For β-SiC Micropowder

Due to the various excellent performances of high strength,high rigidity\resist high temperature oxidation,high chemical stability,high temperature conductivity and low expansion coefficient,β-SiC had been abroad researched by scientists of apiece nation. With the theory and experimentation research, one new patented techonlogy of preparingβ-SiC micropowder and whisker was invented by professor wang xiao gang in Xi An university of science and technology. Using the new technology,β-SiC micropowder could be manufactureed on an industrialized scale. However, theβ-SiC micropowder raw producation can not be satisfied market require because of wise granularity range and all grains stowing together, and coataining SiO2,graphite,amorphism carbon and iron,magnesium,calcium etc.So we hope to get a lot of high qualityβ-SiC micropowder with sharp granularity range which can be used in industry by using Classification and Purification Techniques in reason .First, for the sake of actualizing Classification and Purification Techniques well forβ-SiC micropowder , the effect factors of micropowder reunite,compound particles and impurities was studied.We made sure that V1 was the best dispersant by studying many dispersant ofβ-SiC micropowder; and undone the compound particles through abrading experiment; get rid of some impurities passing screen.Second, A new filtration enrichment classifier was designed by combining uprightness ascend,liquid-solid phase level floding,centrifugal sedimentation and wet sieving theory. It was shown that the design of filtration enrichment classifier was right , and that can grade bigger than 14μm ofβ-SiC micropowder. Though three legs centrifugal machine, The grading experiment was shown that the grader can separate thin grain. So we could gradeβ-SiC micropowder by combining filtration enrichment classifier and three legs centrifugal machine, and the class craftwork was made. Through purification experiment, we made sure an efficient technique of getting rid of impurities. The measure of removing carbon was made by comparing static state calcine divisor,functionality purification furnace and floatation. The impurities of silicon dioxide,dissociate silicon,ferric oxide,calcium and alumina ect were removed by combining acid and water cleanout. We chose hydrofluoric acid,reagent A and B,tap and distilled water as regent.Through drying and second abrade technics,we got the final micropowder. The conduct was tested by grain size and XRD,SEM,energy chart and chymical analysis, it was shown that the purification technique was an effective process toβ-SiC micropowder.The content ofβ-SiC is to 99.9%. Using the Classification and Purification Techniques, someβ-SiC micropowder product with high content more than 99.9% has been ploughed into market that with sharp granularity range of 0~1μm,0~2.5μm,0~5μm and so on.