Study On The Effect Of Dolomite And Bauxite On The Properties Of Loess-based Ceramic Membrane Support

The inorganic ceramic membrane support was prepared by rolling forming using loess as a raw material.Alumina bauxite was selected as the aluminum source additive and dolomite was used as the pore-forming agent.The influence of sintering system on the performance of the support were studied when the silicon-aluminum ratio is best.Select the amount of bauxite added,the amount of loess added and the amount of talc added as three factors and design a three-factor three-level response surface methodology to study the effects of various factors on the performance of the support by the Design Expert v8.0.6.The effect of graphite as a pore former on the performance of the support was investigated.The performance of the support was tested and characterized by universal material testing machine,self-made device,mercury porosimeter,SEM and XRD.The results show that the sintering temperature and soaking time are positively correlated with the water flux and mechanical strength.of the support.Bauxite,loess and dolomite in the proportion of 56.8 wt%,39.2 wt%and 4 wt%can be made into ceramic membrane support with water flux of 4023.73 L.m^-2.h^-1.bar^-1,average pore size of 2.466?m,porosity of 28.09%,mechanical strength of 30.24 MPa,acid?alkali?corrosion rate of2.27%?0.1%?when the sintering temperature was 1140?and soaking time for 9hours.The optimum proportion of bauxite 40 wt%,dolomite 10 wt%and talcum 8 wt%was determined by BBD model optimization.At this time,the mechanical strength of the support was 45.37 MPa,the water flux was 8482.781 L.m^-2.h^-1.bar^-1,the average pore size was 5.154?m,and the porosity was 8.8%.The main crystal phases of XRD were determined to be quartz,corundum,mullite,albite,?-quartz,cordierite,and alumina chrome.The SEM images showed that the number of small holes on the surface of the support was large and uniformly distributed.The SEM-EDS was used to determine the crystals observed by as slender needle-like and radial clustered mullite crystals.Graphite can improved the pore structure and water flux of the support.When thesintering temperature was 1080?,1100?and 1120?,the water flux of the support increased with the increase of the amount of graphite added,but the trend of mechanical strength was opposite.Chemical stability showed acid tolerance and alkali intolerance.The optimum technological conditions were determined as graphite content 6 wt%and sintering temperature 1100?At this time,the mechanical strength of the support was 43.503 MPa,the water flux was 847.203 L.m^-2.h^-1.bar^-1,the porosity was 16%,the average pore size was2.388?m,and the acid?alkali?corrosion rate was 1.0773%?0.361%?.Diopside crystals,quartz crystals,mayenite crystals and anorthite crystals were observed in the SEM image,which was consistent with the phase of XRD.