Preparation Of Polished Slag Lightweight Ceramic Tiles And Its Pore Structure Regulation Study

With the rapid development of China’s ceramic industry in recent years,the annual production of about 10 million tons of ceramic polishing slag,but only 5%is used.In this paper,in response to the problems of the complex composition of ceramic polishing slag,low utilization rate,and uneven foaming at high temperatures,we carried out the preparation of lightweight ceramic bricks with ceramic polishing slag as the research object,supplemented with raw materials such as spherical clay,porcelain tile sand and medium temperature sand,and SiC as the pore structure regulator,and discussed the firing preparation process and pore structure control method of high-strength lightweight ceramic bricks.The effects of the sintering regime,sintering temperature,and ball milling time on the pore structure,microstructure,and properties were investigated with the help of XRD,SEM,X-CT,and TG-DSC.The conclusions are as follows:(1)The effect of the amount of ball clay and the ratio of two ceramic sands on the performance of lightweight ceramic tiles was investigated.It was found that the volume density and compressive strength of lightweight ceramic tiles were both negatively correlated with the ratio of two ceramic sands when the amount of ceramic polishing slag was 60 wt%and the amount of ball clay was certain.And the sintering system was optimized by orthogonal experiments for lightweight ceramic tiles with volume density of 0.63 g/cm~3,water absorption of 21.99%,apparent porosity of11.85%,and compressive strength of 14.02 MPa.(2)The effects of process parameters on the pore structure and properties of lightweight ceramic tiles were investigated.Controlling the holding time in the high-temperature phase results in a material with uniform porosity,with decreasing volume density,water absorption,apparent porosity,and compressive strength as the holding time increases from 10 min to 30 min;The volume density of the material was 0.68g/cm~3,water absorption was 27.33%,apparent porosity was 15.49%,and compressive strength was 13.07 MPa at 30 min of holding time.The holding time exceeds 30 min,the internal formation of connected pores and large pores,uniform stomata,volume density,apparent porosity,and water absorption rate increase,and strength decreases.When the sintering temperature increases from 1160℃to 1210℃,the liquid phase increases,the viscosity is large,the gas increases,and the pores become larger while the connectivity and uniformity of the specimen pores are improved,the compressive strength,volume density,and apparent porosity decrease at this stage,and the water absorption first increases and then decreases and then increases.With the extension of slurry ball milling time,the particle size decreases,and the surface energy increases,resulting in a more liquid phase in the sintering process,large foaming,and stomatal changes,while making the pore size large and improving the uniformity of connected pores and stomata,also resulting in lower volume density and compressive strength of the material,water absorption and apparent stomata are the first to increase and then decrease.(3)To investigate the effect of external doping with different particle sizes of SiC and the doping amount on the regulation of the pore structure of lightweight ceramic tiles.When SiC doping from 0.25 wt%to 1.5 wt%,resulting in large foaming volume,large pores,thin pore walls,and uneven formation of connected pores,resulting in changes in performance;And the best performance was achieved when the doping amount was 1.0 wt%.The particle size of SiC will affect the pore structure;the smaller the particle size of SiC,the more foaming it causes and the easier it is to form open and connected pores,which affects the volume density of the material;The larger the particle size,the incomplete oxidation,less foaming,and smaller pore size,where the bulk density is the smallest(0.6007 g/cm~3)when doped with a particle size of 18μm SiC.By doping different proportions of SiC with different particle sizes it was found that fine SiC made the material more porous and reduced the bulk density;Then the coarse SiC makes the material bulk density increase and the pore size become smaller.This can effectively regulate the pore structure and properties of lightweight ceramic tiles.