Study On Preparation Of Sanitary Ceramics Using Waste Porcelain

Waste porcelain resources are vital to the ceramic industry’s sustainable development. Aseries of negative effects have become increasingly prominent with low utilizationrate,increasing waste porcelain and pollution of the environment.In this thesis, the physicochemical properties of the ceramic sanitary waste porcelain wasanalyzed.The results showed: adding waste porcelain presented none adverse effects on theporcelain body with clay which had fine particles, good plasticity and water retention. theporcelain whiteness was low because of the high Fe,Ti content of the waste porcelain,so highhiding capacity opacified glaze was needed to obtain good appearance and high products’grade.The influence of waste porcelain, albite, black mud,ball clay on the properties of slurryand porcelain body was studied. The basic formula of porcelain body （wt%）was identified:waste porcelain29.7,albite7.9, black mud7.9, west pit mud22.8, ball clay29.7,fired talc2.0.Samples’ performance under various process factors was studied, The resultsshowed:sequence of impact on strength respectively was:firing temperature＞milling time＞holding time.The optimization process was: firing temperature1200℃,milling time45min,holding time60min. Porcelain made with the optimization process had high densitywith no obvious pores.Crystal growth was good with high bending strength （70MPa）andlow water absorption rate（0.30）.In this thesis, SiO2、Al2O3content of glaze was adjusted by four angle experiment, CaO,MgO, ZnO content of glaze by three angle experiment, the results showed: Sample17,18,19had smooth glaze layer,their opacifying particles were zirconium silicate,part of theopacifying particles was zirconium silicate residue particles,the rest part was fromprecipitated zirconium silicate crystals of the melt.The two parts contributed to the glazeopaque.The opacifying particles of sample18were small,much and even with whiteness92.17,gloss88.3.Glaze18,19as positive glaze,their thermal stability were good because theirthermal expansion coefficient was less than the porcelain body.High content of Mg2+and Zn2+could increase the high temperature melt viscosity,causing pinhole or orange glaze,while too much ZnO lead to glazed crack.This was probably related to the partial crystallization of ZnO.Appropriate increase of ZnO raised the content of zirconium silicate and enhancedgloss.When content of MgO was high,zirconium silicate content and glaze layer glossinessreduce,melt surface tension increased.CaO could react with the porcelain as well as theglaze,so it could improve the adaptability and thermal stability of glaze.The final glaze was asfollows: n(SiO2)3.69mol、n(Al2O3)0.34mol、n(CaO)0.35mol、n(MgO)0.18mol、n(ZnO)0.18mol,whitenes93.43,gloss89.6with good suitability and thermal stability.