Preparation and characterization of porous ceramics prepared by kaolinite gangue and Al（OH）₃ with double addition of MgCO₃ and CaCO₃

Wen Yan,Nan Li,and Bing-qiang HanThe Key State Laboratory Breeding Base of Refractories and Ceramics,Wuhan University of Science and Technology,Wuhan 430081,China

摘 要：Porous ceramics were prepared from kaolinite gangue and Al（OH）3 with double addition of MgCO3 and CaCO3 by the pore-forming in-situ technique.The characterizations of porous ceramics were investigated by X-ray diffractometry,scanning electron microscopy,and mercury porosimetry measurements,etc.It is found that although the decomposition of MgCO3 and CaCO3 has little contribution to the porosity,the double addition of MgCO3 and CaCO3 strongly affects the formation of liquid phase,and then changes the phase compositions,pore characterization,and strength.The appropriate mode is the sample containing 1.17wt% MgCO3 and 1.17wt% CaCO3,which has high apparent porosity（41.0%）,high crushing strength（53.5 MPa）,high mullite content（76wt%）,and small average pore size（3.24 μm）.

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