| Coal dust pollution has always been an important issue in coal mine safety,and dust suppressants are one of the most common methods used today to reduce the damage caused by coal dust to operators and equipment.However,so far,there have been more studies on the dust-reducing effects of dust suppressants and fewer tests on the eco-friendliness and degradability of dust suppressants.Therefore,the preparation of non-toxic and non-hazardous dust suppressants is a key issue that needs to be addressed.This paper uses theoretical analysis and laboratory experiments to carry out experimental research on pectin modification,compound dust suppressant preparation,dust suppressant properties and dust reduction effect testing research,to prepare an eco-friendly dust suppressant and study its wetting,bonding and settling effects on coal dust.The main conclusions obtained are as follows.The pectin was modified by graft copolymerization,using acrylamide as the grafting monomer,to develop a modified pectin(Pectin-PAM,PPAM)with better wetting properties and viscosity suitable for use in underground coal mine spraying.The optimum process conditions for the modification of pectin were determined by single-factor experiments as 4 g of acrylamide addition,0.1 g of potassium persulphate addition,2 h of modification time and 90°C of modification temperature.XPS and FTIR tests were carried out on the modified PPAM to analyse the changes in elemental structure and functional groups of pectin and PPAM,which proved that the modified PPAM had more hydrophilic groups compared to the premodified PPAM.Therefore,the modified PPAM is more hydrophilic and has better wetting effect on coal dust compared to the pre-modified PPAM.An eco-friendly dust suppressant with both bonding and wetting effects was prepared by using modified pectin(PPAM)as a binder and adding a non-toxic and non-corrosive surfactant as a wetting agent.By using surface tension and contact angle as the basis for selection,anionic+nonionic complex surfactant combinations of alkyl polysaccharide(APG)+ sodium sec-alkyl sulfonate(SAS-60),SAS-60 + isomeric alcohol polyoxyethylene ether(XL-70),longchain carboxylate polyoxyethylene sulfonate(LMES)+ XL-70 with excellent wetting properties were obtained,and synergistic effects with PPAM were found of XL-70,LMES and dodecyl dimethylamine ethylene lactone(BS-12),the study determined the dust suppressant formulation.The optimum ratio to determine the dust suppressant was determined by orthogonal experiments as 0.08% LMES + 0.2% XL-70 + 0.2% PPAM.The correctness of the ratio was verified by testing the surface tension of the dust suppressant at 27.75 m N/m,the contact angle at 22.01° and the settling time at 9s.Through a series of performance tests conducted on the eco-friendly dust suppressant,it was determined that the dust suppressant has excellent wetting properties and is more effective in wetting coal dust with larger particle sizes when the contact time is very short.The dust suppressant has good water retention,the water loss rate of coal dust sprayed with dust suppressant is reduced by 34.46% compared to that of coal dust sprayed with water;the bonding effect of dust suppressant on coal dust observed under scanning electron microscope proves that the dust suppressant acts on coal dust with good film-forming property,making the surface of coal dust smooth and the particles closely connected;the dust suppressant is not toxic to plants and has good degradation performance;the spray dust reduction test reveals that the ecofriendly dust suppressant has an excellent dust reduction effect,with an average dust reduction rate of 45.07% higher than that of water spraying,effectively reducing the dust concentration in the space.Figure54 Table18 Reference108... |
PDF Full Text Request