Preparation Of Foam Concrete Block With Ceramic Polishing Sludge

Ceramic polish sludge is waste slag powder produced in the process of producing porcelain polished tiles and glazed brick,the main component is composed of SiO2 66.8%,18.6% Al2O3,1.47% CaO,3.16% MgO,2.62% K2 O,and 2.56% Na2 O.The size distribution of ceramic polish sludge is in the range of 0~100 ?m,the average particle size is 12.08 ?m.Besides,ceramic polish sludge has certain pozzolanic and cementitious activity.In this study,the ceramic polish sludge was used as the raw material,the Portland cement clinker,granulated blast furnace slag,lime and gypsum as cementitious materials,and animal protein foaming agent was used for foaming.The ceramic polished sludge foam concrete blocks were prepared according to the raw material mixing-grinding-bubbling-stirring-injection-static stop-stripping-curing process.The compressive strength,dry density,thermal conductivity and other properties were tested according to JC/T 1062-2007.Univariate method and orthogonal method were used to investigate the influence of mixture grinding fineness,ratio of water to material,contents of polish sludge,cement clinker,granulated blast furnace slag,lime and gypsum on the preparation process and properties of the block,the ratio of the raw materials was determined,and XRD,SEM and other measuring methods were used to study setting and hardening mechanism and strength formation mechanism.The results indicated that the specific surface of mixture of Portland cement clinker and granulated blast furnace slag after ball milling reached to 2200 cm2/g,showing slag micro ball polishing effect and sludge powder micro aggregate effect.Compared with conventional preparation process,the cementitious activity was greatly improved,foam gel system stability was improved.Ceramic green body was prepared using 50% Ceramic polishing sludge,30% cement clinker,8% granulated blast furnace,and 4% lime and 4% gypsum after curing 28 d in standard conditions.The dry density was 518 kg/m3,compressive strength was 2.31 MPa,while the thermal conductivity was 0.0830 W/(m·K).After 25 freezing and thawing cycles,the freeze-thaw strength loss rate was less than 20%,the mass loss rate was lower than 5%,The properties of the ceramic green body meet the JC/T 1062-2007 index requirements.XRD results showed that the main crystal phases were silica,ettringite and tobermorite,some gel-like amorphous phase was also detected.The SEM images showed that the productshad gas-solid two-phase structure,most of the pores diameter were closed pores,which were less than 1 mm.The dense walls of the pores were composed of crystal phases and gel phase particulates,resulting in high strength and good heat insulation performance of samples.By using the micro grinding ball and the micro aggregate effect,ceramic polished sludge foam concrete blocks with good properties were successfully prepared using ceramic polish sludge,which opens a new way for the utilization of the silicon rich solid waste materials.