| Due to the rapid development of China's ceramic industry in recent years,reserves of high-quality bauxite have rapidly declined.With the gradual deterioration of the ecological environment of bauxite mining areas,the problem of imbalance between supply and demand of bauxite gradually emerged.Based on the development status of the ceramic industry and the development concept of national environmental protection,our research focuses on two aspects.On the one hand,we make effective use of limited bauxite resources by improving the performance of ceramic materials.On the other hand,we reduce the use of bauxite by using solid waste such as ferrochrome tailings,bauxite tailings instead of bauxite as raw materials to prepare high-strength ceramic materials.Finally,ceramic materials are classified by chemical composition and mineral composition.Ceramic proppants were prepared with the best performance of ceramic materials in different systems as the final formulation.86 MPa corundum ceramic proppants,52 MPa MgO-Al2O3-SiO2 system ceramic proppants and 52 MPa K2O-Fe2O3-FeO-Al2O3-SiO2 system ceramic proppants were successfully prepared.(1)Corundum ceramics were successfully prepared with secondary bauxite as the main raw material.The corundum ceramics flexural strength reached 265.37 MPa with 2 wt%pyrolusite and 4 wt%dolomite at 1350? for 30 min.The mechanism of pyrolusite and dolomite as composite additives on the corundum ceramics was studied.At the same time,the corundum ceramics flexural strength reached 291.64 MPa with 7 wt%magnesium ore at 1350? for 30 min.The mechanism of magnesium ore as an additive on the corundum ceramics was studied.The formulation with the highest flexural strength(92 wt%bauxite,1 wt%clay,and 7 wt%magnesium ore)was selected to prepare the ceramic proppants.The performances were 4.88%of breakage ratio(under the closed pressure of 86 MPa)and 1.86 g/cm3 of bulk density,which has reached the national standard of 12.5K.The prepared high-strength bauxite-based corundum ceramics can replace alumina ceramics in some fields and achieve the purpose of reducing the production cost of alumina ceramics.(2)MgO-Al2O3-SiO2 system ceramics were successfully prepared with high-temperature sintering using ferrochromium slag and secondary bauxite as main raw materials.Pyrolusite was used as an additive.The ceramic material with a flexural strength of 177.7 MPa was successfully prepared at 1320?.The sintering mechanism was systematically studied.The enhance mechanism of pyrolusite as an additive on this system ceramics was also studied.The formula with the highest flexural strength(45 wt%ferrochromium slag,52 wt%secondary bauxite,2 wt%clay,and 1 wt%pyrolusite)was selected to prepare the ceramic proppants.The performances were 5.08%of breakage ratio(under the closed pressure of 52 MPa)and 3.03 g/cm3 of apparent density,which reaches the national standard of 7.5K.The leaching concentration of chromium was only 0.0198 mg/L.High-strength MgO-Al2O3-SiO2 system ceramics have broad application prospects,and provide a simple method for the efficient utilization of solid waste ferrochromium slag.(3)K2O-Fe2O3-FeO-Al2O3-SiO2 system ceramics were successfully prepared with high-temperature sintering using bauxite tailings as the main raw material and a small amount of secondary bauxite.The ceramic material with a flexural strength of 197.41 MPa was successfully prepared at 1130?.The ultra-low temperature sintering mechanism was systematically studied.The formula with the highest flexural strength(85 wt%bauxite tailings,14 wt%secondary bauxite,and 1 wt%clay)was selected to prepare the ceramic proppants.The performances of ceramic proppants were 4.65%of breakage ratio(under the closed pressure of 52 MPa)and 2.78 g/cm3 of apparent density,which reaches the national standard of 7.5K.The K2O-Fe2O3-FeO-Al2O3-SiO2 system ceramics with high-strength and ultra-low sintering temperature have broad application prospects,and provide a simple method for the efficient utilization of solid waste bauxite tailings. |
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