Study On Preparation And Proerties Of Porous Ceramic For Filter

With the development of industry, discharge of waste water is growing both in amount and in kind. How to efficiently treat polluted water is a world puzzle. The development of novel filtration material for sewage disposal is of significant importance.In this experiment, sand was used as main material, and water glass was used as binder. The method of particle stacking and pore-forming agent appending was adopted to produce porous ceramic for filter material in sewage disposal. The obtained porous ceramic had stable chemical performance, good corrosion resistance and long service life, thus having wide application prospects.With emphasis on the preparation of porous ceramics and performance testing, this paper reached the main conclusions as follows:(1) Through the investigation of the process for porous ceramic sintering, it was found that the porosity of the porous ceramic was affected by sintering temperature, heat holding time, pore-forming agent and the size of sand particle. The porosity decreased with the increase of sintering temperature and time, and increased with the amount of pore-forming agent and the particle size. The compressive strength showed opposite tendency. The comparative analysis of the factors indicates that the optimum conditions were: temperature 1150℃, heat holding time 30 min, the dose of pore-forming agent 10 percent, and the particle size of sand 60-80mesh.(2) The porosity, water absorption, bulk density, compressive strength, basic/acid resistance and microstructure of the porous ceramics were investigated. The porosity was in the range of 17.28～44.57%; the compressive strength was 10.52-27.65MPa; the acid resistance was 96.64 -98.14%; the basic resistance was 97.94-99.09%. The microstructure observation revealed the 3-demensional interconnected pore channels in the porous ceramic and high special surface area, which fully meet the requirements on ceramic-filter performance for water treatment.(3) The sintering thermodynamics and kinetics were also analyzed. The models and theories for initial, intermediate and final stages of sintering were discussed, with the emphasis on the mass transfer mechanism in the initial stage of sintering. According to the calculation by the kinetic equations for the initial stage, the main sintering mechanism included both Surface-proliferation and interface diffusion. The kinetic analysis on the experimental data for the final stage of sintering meeted Coble's model.