Study On The Process And Burning Mechanism Of Coal Gasification Slag For Preparing Sintered Wall Materials

Coal gasification slag is a solid waste produced by the new coal chemical industry,which can reach more than 40 million tons per year.These Coal gasification slag not only occupy land,but also pollute the environment.Therefore,it is necessary to find a way to harmlessly consume coal gasification slag.Imminent.Based on the study of the physical and chemical properties of coal gasification slag,this paper adopts the press molding method to prepare high-strength sintered bricks with the main crystal phase of mullite and calcium as the main crystal phase by changing the content of coal gasification slag and additives.Lightweight porous foam material of feldspar.And through XRD,SEM,TG-DSC,photothermal measurement system and other analytical testing methods to explore the sintering mechanism.On the basis of studying the physical and chemical properties of coal gasification slag,binders and additives are added to adjust the formula,so that the batch material meets the requirements for preparing sintered bricks.Through the controlled variable method,the change law of the compressive strength,density and water absorption rate of sintered bricks under the process conditions of 30?45wt%of coal gasification slag and sintering temperature of 1050-1250?was systematically studied.The results show that when the coal gasification slag content is 45 wt%,when the sintering temperature is 1150?,a sintered brick with a compressive strength of 49.71 MPa,a density of 1.5 g/cm~3,and a water absorption rate of 21.66%can be obtained;Design L9(3~3)orthogonal experiment to explore the influence of heating rate,sintering temperature and holding time on the performance of sintered bricks when the coal gasification slag content is 35 wt%,and find that the degree of influence on the compressive strength,density and water absorption of the product is:Sintering temperature>heating time>heating rate,the degree of influence on the thermal conductivity of the product is sintering temperature>heating rate>heating time,and the best combination based on the above performance indicators is obtained.During the sintering process,as the sintering temperature rises,the molten liquid inside the green body gradually fills the pores under the action of liquid viscous flow and surface tension,and crystals such as mullite,anorthite,quartz,etc.The skeleton of the green body is interlaced with the liquid phase to form an interwoven network structure in the green body to form a dense sintered body,which gives the green body a certain mechanical strength.When the content of coal gasification slag continues to increase,the characteristic of high residual carbon content in coal gasification slag is used to prepare foaming materials as a foaming agent.The foaming temperature is preliminarily determined through TG-DSC and photothermal measurement system.When the sintering temperature is 1200?and the coal gasification slag content is 60 wt%,a foamed product with a compressive strength of 4.17 MPa,a density of 0.75g/cm~3 and a porosity of 71.16%can be obtained.Using the VFT model,the relationship between the content of coal gasification slag and the temperature-viscosity curve of the billet at high temperature and the shrinkage of the billet was studied.The XRD test shows that the mineral crystal phases of the foamed material mainly include anorthite and hematite.