Preparation And Properties Of Porous Ceramics Based On Porous Hollow Microspheres

Porous ceramics are a type of functional materials that combine the performance of porous materials and ceramic materials.They have the advantages of high porosity,large specific surface area,high temperature corrosion resistance,thermal insulation,uniform pore structure distribution and long service life.Manufacture of materials such as separation and filtration,sound absorption and heat insulation,catalytic carrier,and sensitive components.In this study,silicon hollow powder and glass powder were used as raw materials to make porous hollow microspheres through patented technology;Then porous silicon microporous hollow microspheres were used as aggregates,and glass powder porous microspheres were used as adhesives to prepare porous ceramic materials by dry pressing.The effects of the ratio of aggregate to binder on the porosity,specific surface area,median pore diameter and compressive strength of porous ceramics were discussed.Using the particle-stabilized foam technology,the structure of the silicon micropowder porous hollow microspheres optimized by adding organic dispersant and foaming agent to the slurry was explored;the effects of the sintering temperature and the ratio of aggregate and binder on the properties of the porous ceramics;Based on the above experience exploration,in this study,in the follow-up experiment,the raw material silicon micropowder was replaced with diatomite.The effects of process parameters such as foaming agent content,sintering temperature,aggregate to binder ratio,and holding time on the cross-sectional morphology,phase change,open porosity,median pore size,specific surface area and compressive strength of diatomite-based porous ceramics were systematically studied.At the same time,an orthogonal experiment was designed to optimize the process parameters.Finally,the effect of the foamed diatomite-based porous material on the decontamination of river water is discussed.The conclusions are as follows:(1)The porous ceramic material prepared by dry press molding using porous silica microporous hollow microspheres as the aggregate and porous glass microporous microspheres as the adhesive has a pore size close to 16μm,and a small porosity and specific surface area of 57.3%and 0.69 m~2/g,respectively,unable to meet the basic requirements of the experimental filter material.(2)After the introduction of particle-stabilized foam technology in the slurry preparation process,the ceramic aggregate structure improved significantly.The pore size of the foamed silicon micropowder-based porous ceramic prepared by this method is reduced to 10.5μm,the open porosity and specific surface area were 69%,1.92 m~2/g.(3)In the process study of foamed diatomite-based porous ceramics,it is find that when the amount of foaming agent is 140m L per 3kg of ceramic powder,the ratio of aggregate and binder is 7:3,and the sintering temperature is 800℃and the holding time is 2h,the performance of the porous ceramic reaches its best.The open porosity is up to 75%,the median pore diameter is 7.40μm,the specific surface area is 2.91m~2/g,and the compressive strength is 1.91±0.09MPa.(4)By comparing foamed diatomaceous earth-based porous ceramics and foamed silica micropowder-based porous ceramics,we chose foamed diatomaceous earth-based porous ceramics with better performance parameters to carry out bacterial,turbidity and color The results of the filtration test showed that the diatomite-based porous material prepared by the experiment had an interception efficiency of more than 99%for the total number of bacteria,and the turbidity and color of the river water after filtration reached the sanitary standards for drinking water.In view of this,the technology and its products have good application prospects.