Effects of Na2SiF6 on Preparing Mullite Material with Sludge from the Aluminum Profile Factory and P

In this research,the mullite material with sludge from aluminum profile factory and pyrophyllite as primary raw materials was prepared.Based on the optimal formula,optimal calcining temperature and holding time determined in the research,effects of Na2SiF6 mineralizer on crystal structure,microstructure and properties of mullite were discussed to determine the optimal addition of Na2SiF6 mineralizer.With XRD and SEM methods,crystal structure and microstructure of the test samples were characterized; with Rietveld Quantification method,contents of various crystal phases in the test samples were determined; properties of the test samples were tested.In combination with the structural and property analysis results,the optimal Na2SiF6 addition was determined to be 2%.Correspondingly,the content of solid solution of mullite-Al4.59Si1.41O9.7 was96.9wt%,the bulk density was 2.10 g/cm3,the degree of porosity was 27.0%,the water absorption rate was 12.8%,the rupture strength was 24.30 MPa and primary thermal-shock rupture strength retention rate was 87.4%.