Development And Performance Study Of A New Type Of Compound Dust Suppressant For Mine

There is a serious fugitive dust pollution caused by wind disturbance and material handling in tunnel,coal bunkers,surface plants and open-air coal stocking yards of coal businesses.High concentration of coal dust(dust)threatens the safety of mine production and the physical and mental health of miners.In view of the shortcomings that chemical dust reducing agent existed at present are single and the effect of dust reduction is poor,a new type of compound environmental protection and efficient dust reducing agent has been developed in this paper.The study results can provide a new idea for the development of chemical dust suppressants.In this paper,the chemical modification experiment was adopted,the synthetic chitosan quaternary ammonium salt(HTCC)was synthesized by chemical modification of-NH2 with natural cheap substance chitosan(CTS)as the main raw material.The effect of the mass ratio WEC of quaternation reagent(CTA)and chitosan(CTS),the reaction temperature T,the reaction time H and the system pH on the degree of substitution(DS)of product were discussed,and the optimum process conditions are determined.The technique of Fourier transform infrared spectroscopy(FTIR)was employed to characterize the molecular structure of CTS and the product of modification.The optimum concentration range of the reagents and the permeable agent JFC were determined by the monomer experiment,then four optimum proportions of composite dust suppressants were designed by orthogonal test,finally,optimal ratio of the new type dust suppressants was determined by the simulation experiment of spray dust reduction.A scanning electron microscope(SEM)was used to observe the surface morphology of the coal powders that are suppressed by the new type suppressants.A wind erosion resistance experiment was conducted to analyze the wind erosion rate of the coal powders.Finally,the effect of the new dust suppressant on the coal quality was determined by the automatic industrial analyzer and the total sulfur analyzer.According to the experiment results:the hydrogen atom of the nucleophilic center of CTS molecule,-NH2 was replaced by-CH2CH(OH)CH2N+(CH3)CI-and a product HTCC was obtained.The optimum process conditions is maintained at the mass ratio WFC of 3:1,the reaction temperature of 70?,the reaction time of 9 h,the system pH value of 7.Based on the spray experiment results,the final formula is determined at concentration of chitosan quaternary ammonium salt solution 1.75:50,concentration of glycerol 0.9%,and concentration of permeable agent JFC 0.6%.After spray the dust suppressant,the average dust reduction rates of the total dust(respirable dust)at each point increase from 72.5%(70%),70.5%(61.7%),68.9%(62.5%),and 67.4%(67.1%)to 90.6%(88%),90.3%(87.0%),89.5%(87.2%),and 89.5%(87.3%),respectively.The coal particles suppressed by the dust suppressant as observed with a 50,000 X SEM are coagulated together,which indicated very good cohesion effect.In addition,even at a wind speed of 17 m/s the dust suppressant can effectively prevent fugitive dusts,which indicated an obviously improved wind erosion resistance compared with the scenario without any dust suppressants sprayed.