| Dust in storage and transportation of bulk coal has always been an important link in the governance of the country and the coal industry.Based on this,it is an important method to develop a chemical dust suppressant which can effectively restrain the flying of coal dust.A new type of dust suppressant was prepared by microwave polymerization combined with traditional solution polymerization,and inorganic mineral bentonite was selected as the composite agent.And its physical and chemical properties and indoor and outdoor application properties were characterized.The material integrates wetting,binding,water absorption and moisture retention.It is easy to be degraded under natural conditions,has a wide source of materials,and has a good dust suppression effect.At the same time,it lays a foundation for the further application and promotion of dust suppressant and broadens new research ideas.The main conclusions of this paper are as follows:(1)With the mass loss rate,coal dust settling time,moisture absorption rate and grafting rate as the experimental indicators,the monomer experimental range of film forming component,wetting component,cross-linking component and reaction temperature were obtained.With filtration rate,moisture absorption rate and pH value as the experimental index,identified the best prescription of dust suppression agent by visual analysis and variance analysis: 1.0% film-forming components,0.7% wetting components,1.0% crosslinking components,and reaction temperature for 35 ℃.Through comparative analysis,the optimal solid content of dust suppressant was determined to be 3%.(2)The solid content of dust suppressant should be at least 5%;when placing temperature was 25~30 ℃,the viscosity value was between 9 to 10 mPa·s;the average grafting rate of dust suppressant was 82.04%;the SEM results showed that the network-like polymer molecules were generated;in the XRD pattern,the characteristic diffraction peaks of the end products widened obviously,the crystallinity increased,and amorphous peaks with strong intensity were generated at some peaks;the characteristic stretching vibration peaks of-OH and Si-O in the FTIR spectrum changed obviously before and after the reaction,all of which indicated the success of graft copolymerization;by comparing the changes of SEM,XRD and FTIR before and after microwave radiation,it could be seen that microwave radiation further promoted the complete reaction;according to the TG-DTG experimental results,the maximum pyrolysis of dust suppression agent temperature was 217 ℃.(3)The effective dust suppression time of the dust suppressant was 3 days;the number of effective rain-erosion resistance of dust suppressant was 3 times;when the blowing wind speed was 10 m/s,the wind erosion rate of the curing layer sprayed with dust suppressant was only 5.84%;after spraying the dust suppressant for 30 days,the degradation rate increased significantly;the infiltration of dust suppressant to coal dust mainly occurred in the first 15 minutes after spraying;after freeze-thaw experiments for 15 times,the wind erosion rate of the solidified layer was relatively being stable,proving that the dust suppressant has the ability to survive in the repeated freeze-thaw environment.(4)The dust suppression effect of dust suppressant is much higher than that of clear water in both total dust concentration and respirable dust concentration;under the same condition,after spraying clean water on the surface of the scattered coal piles,the decrease rate of total dust concentration was 60.09%,and the decrease rate of respiratory dust concentration was 46.15%;after dust-inhibiting agent was sprayed on the surface of the scattered coal piles,the decrease rate of total dust concentration was 92.96% and the decrease rate of respiratory dust concentration was 84.62%;the curing layer formed in the open air for 30 days was being stable. |
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