Foamed Ceramic Insulation Building Materials Were Prepared From Gasification Ash And Slag

Fly ash and bottom slag are the by-product material of chemical plants generated during a gasification process of coal.Generally,the disposal methods are stacking and landfill,which may cause s a series of environmental problems.Thus,the resource utilization of fly ash and bottom slag is of particular importance.Since the components of fly ash and bottom slag are similar to that of foamed ceramics,it would be a significant research topic to prepare foamed ceramics with gasification ash and slag.In this study,the bottom slag and fly ash obtained from a commercial Shell gasification unit located in Anqing Petrochemical were selected,and the basic properties,chemical composition,mineral composition,physical properties and thermal properties were systematically analyzed.The orthogonal test was used to investigate the primary and secondary factors affecting the preparation of foam ceramic insulation materials by the gasification ash and slag.On this basis,the effects of sintering temperature,heating rate,holding time and adding amount of blowing agent on the bulk density,porosity,compressive strength and water absorption of foamed ceramic materials were studied.Moreover,the crystal mineral composition and microscopic morphology of the foamed ceramic materials were investigated by means of XRD and SEM,and the formation and thermal insulation mechanism of the foamed ceramic materials were explored.According to the research on the physical and chemical properties of the bottom slag and fly ash,the main components are SiO2,Al2O3,Fe2O3 and CaO which are in line with the composition requirements of the preparation of foam ceramic materials.At the same time,the contents of F,Cl,As,Hg and heavy metal elements are all lower than the national building materials standard.Thus,the fly ash and bottom slag can be used as the raw materials for preparing foam ceramics.The results of orthogonal tests show that the sintering temperature,holding time and adding amount of foaming agent(SiC)are the main factors affecting the performance of ceramics,while the heating rate is the secondary factors.Besides,the influence of single factor on the properties of foam ceramics was explored,and the result show that the porosity,bulk density,water absorption and compressive strength of foam ceramics are improved with the increase of sintering temperature,holding time and adding amount of SiC,while the change of heating rate has less influence on the performance of the foam ceramics.Combine the research results of orthogonal tests and single factor experiments,an optimum process for preparing foam ceramics is established:sintering temperature is 1180?,heating rate is 3?/min,holding time is 20 min and adding amount of SiC is 5%,and the foam ceramics with volume density of 0.81 g/cm3,porosity of 39.23%,water absorption rate of 6.23%and compressive strength of 8.68Mpa is prepared.It was found that the formation of anorthite improves the compressive strength and thermal stability of foam ceramics.The reason is that anorthite has the advantages of low thermal expansion coefficient,small volume density,high specific strength,low sintering temperature and so on.Figure[37]Table[15]Reference[94]...