| In recent years,people's demand for a better environment has become increasingly urgent,and the state has therefore issued stricter environmental standards.A large part of the pressure caused by all these falls on the production-oriented enterprises.Industries such as carbon black,cement and garbage incineration need to bear high costs for the treatment of high-temperature flue gas.Because the maximum working temperature of the existing filter material is only about 200?,enterprises must first conduct cooling treatment for high temperature dust filtration,which raises the cost of production.Especially in the case of SCR denitrification process commonly used in flue dust treatment,due to the insufficient temperature resistance of filter materials,enterprises must sacrifice the service life of denitrification catalyst to ensure good catalytic denitrification efficiency.The only way to solve the above problems is to develop a filter material whose working temperature is above 300?.Basalt fiber,as a kind of high cost-effective fiber,has the characteristics of high strength,good high-temperature resistance,environment friendly,pollution-free production process,and degradable,which accords with the development direction of high-temperature filter materials.In this paper,the basalt fibers were made into needle punching felt filter material,and the basalt fibers were impregnated and covered with the developed high-temperature resistant coating agent.At the same time,the mechanical properties and filtration properties of the film-coated basalt fiber needle-punched felt were tested.The conclusions are as follows:(1)Through orthogonal test,single factor test and film-forming test,the optimum proportion of Film-covering agent was determined as follows:w[PTFE]=11%,w[A151]=1.5%,w[acrylate]=5%,w[silicic acid polymer]=12%,w[cross-linking agent]=5%,and the other components were water-soluble.(2)In the performance test of the film,it was found that the initial decomposition temperature of the film was 220?,which was 70? higher than that of the pure acrylic emulsion film.At 380?,the retention rate of fluorosilicone emulsion film is 75%,25%higher than that of pure acrylic emulsion film.The results show that the developed film has good temperature resistance.At the same time,the results of particle size distribution and FT-IT analysis show that there is no general agglomeration between silicic acid polymers.The nano-silicic acid polymers have good bonding properties with organic components and form Si-O-C bonds.(3)It is found that the theoretical breaking strength of basalt fibers coated with film is 276.99 N after high temperature treatment(340?,30 min),while that of basalt fibers without film is 253.99 N.It shows that the film coating can promote the high temperature resistance of basalt fibers.(4)It was found that the tensile strength of coated basalt fibers was 87.2%after soaking in 2 mol/L HCl solution for 3 h,while that of uncoated basalt fibers was 65.3%.It shows that the presence of the film can enhance the acid resistance of basalt fibers.(5)In alkali resistance test of basalt fibers coated with film,it was found that after soaking in NaOH solution of 2 mol/L for 3 h,the tensile strength retention rate of basalt fibers coated with film was 20.4%,while that of basalt fibers without film was 24.3%.Coating basalt fibers is not conducive to their alkali resistance.(6)In the performance test of pure basalt fiber needle felt and composite basalt fiber needle felt containing P84,it was found that the tensile strength retention rate of pure basalt fiber covered needle felt was 53.77%after high temperature treatment(320?,24 h),while that of composite basalt fiber needle felt containing P84 was 47.89%.It shows that pure basalt fibers have more advantages in temperature resistance. |
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