Preparation Of Porous Ceramics In The System Of CaO-Al₂O₃-SiO₂

In the paper, porous ceramics in the system CaO-Al₂O₃-SiO₂were prepared bysemi-forming and isostatic cool press forming, silicon power, carbonate and Kaolinwere main raw materials, kyanite as admixtures and carbon black as pore-formingagent, CLS as binder. X-ray diffraction analysis and scanning electron microscope（SEM） were used to characterize phase compositions and the microstructures, apparentporosity, bulk density and compression strength were tested and characterized.Calcium carbonate, kyanite and carbon black were added to prepare porous ceramicand study systematically. The results showed that:（1） When Kaolin and silica powder were added in a proportion of1:1, calciumcarbonate was added in an amount10%to20%, better performances with apparentporosity of37.9%⁴5.5%and compression strength of60.32MPa⁵0.63MPa wereachieved.（2） When Kaolin and silica powder were added in a proportion of1:1, calciumcarbonate was added in an amount10%, used cold isostatic molding and moldingpressure was75MPa, th sintering temperature was1000℃for1h. The main mineralphases were quartz, cristobalite, wollastonite and anorthite, the microstructures showedthat most of pore diameter were less than7μm, and the distribution of pores were nothomogeneous, apparent porosity of37.9%and compressive strength of64.41MPawere tested.（3） When Kaolin and silica powder were added in a proportion of1:1, calciumcarbonate was added in an amount10%, kyanite was added45%, the sinteringtemperature was1200℃. The main mineral phases were cristobalite, quartz, anorthite and mullite, the microstructure with a large number of micro pores and the sizes wereless than2μm, the pores dispersed in the mineral phase uniform completely, mullitecrystal presented fibrillar or needle and dispersively distributed, compression strengthof74.96MPa was obtained.（4） When Kaolin and silica powder were added in a proportion of1:1, calciumcarbonate was added in an amount of10%, carbon black was added in an amount of6%⁹%, the sintering temperature was1000℃for1h, cold isostatic pressing, moldingpressure of75MPa, the pore sizes were less than3μm, and the shape was irregularlyperfectly round, which distributed in the solid uniformly, and abtained porosity of42.4%⁴6.2%, compression strength of49.56MPa⁴6.36MPa.