Preparation And Research Of Wear-resistant Coating For Cement Kiln

With the improvement of cement kiln equipment and fuel,the use environment of cement kiln is more stringent,so there are higher requirements for refractory materials for cement kiln.Silicon mullite brick has excellent wear resistance and corrosion resistance is applied to cement kiln tertiary air duct and other parts,but in the working environment for a long time by dust particles,high temperature alkali gas erosion wear and erosion hazards,so that the refractory material damage caused by the shutdown,production reduction.In order to improve the wear resistance and corrosion resistance of silicon mullite bricks in cement kilns,an inorganic wear-resistant coating suitable for the use of tertiary air ducts in cement kilns is studied.In this thesis,the effects of binder,filler composition,potassium feldspar addition,surface modifier type and content,alumina content and aluminum source on the wear resistance and corrosion resistance of the coating were studied by XRD,SEM and other detection methods.The following conclusions are drawn:（1）The coating prepared by silica sol has better coating performance than the aluminum sol coating.After heat treatment,the nano-silica sol is immersed in the pores of the silicon-mortar brick substrate to play a’pinning’role,so that the coating and the substrate silicon mullite brick have good bonding,and there are no defects such as protrusions in the coating.（2）In the low aluminum coating,with the increase of potassium feldspar addition,the liquid phase content of the coating increases,which can improve the high temperature film forming performance of the coating.When the potassium feldspar addition is 70%,it has the best high temperature film forming performance.The addition of metal aluminum powder in the high aluminum coating can improve the high temperature film forming performance of the coating,and the optimum addition amount is 10%.（3）In the high alumina coating,when the content of Al₂O₃is 50%-70%,the coating with white corundum as the aluminum source has good high temperature film-forming properties,and the coating with 70%white corundum powder has the best high temperature wear resistance.At 1450°C erosion environment,high aluminum wear-resistant coating blocks the erosion effect of erosion medium on the matrix silicon mullite brick aggregate and improves the corrosion resistance of silicon mullite brick.（4）Adding defoamer and attapulgite to the coating can reduce the surface tension of the coating,improve the dispersion and suspension of the filler in the coating,improve the viscosity of the coating and the shrinkage/needle phenomenon that occurs when the film is formed at room temperature.At the same time,the defoamer and attapulgite have a certain sintering effect at high temperature,reduce the“orange peel”phenomenon formed by high temperature film formation,and improve the wear resistance of the coating.In contrast,the best defoaming agent is Df-150,adding amount is 0.3%,attapulgite adding amount is 0.3%.（5）The best ratio of low aluminum coating filler is:potassium feldspar 70%,alumina 20%,boron oxide 10%,plus 0.3%Df-150 defoamer,0.3%attapulgite thickener.At this time,the coating and the substrate silicon Mo brick are tightly bonded,and the wear resistance is 6.2cm³,which can play a wear-resistant protective effect on the substrate silicon mullite brick.（6）The best proportion of high alumina coating filler is:white corundum powder 70%,potassium feldspar 20%,metal aluminum powder 10%,0.3%Df-150defoamer,0.3%attapulgite thickener.At this time,the coating has the best wear resistance of 5.22cm³,which can protect the matrix silicon mullite brick from wear and corrosion.