| Mining faces a serious problem of dust pollution,especially for ultra-fine metal mineral dust.Its chemical composition is complex and its hazards are diverse.It is easy to suspend and diffuse in the atmosphere,which poses a serious threat to occupational health and safety and the surrounding environment of the mine.This paper analyzes the dust suppression mechanism of nano fluid,combines it with traditional dust suppressors,obtains the optimal proportioning process of new nano-composite dust suppressants through orthogonal experiments,and determines its dust suppression performance.The main research contents and conclusions are as follows:(1)The basic principle of the application of nanofluid suppressant in the field of dust suppression is analyzed.According to the size and surface effect of nanoparticles,as well as their high-efficiency adsorption,caulking and other related dust suppression mechanisms,combined with the properties and prevention difficulties of ultra-fine metal mineral dust,the coupling law of nano fluid and ultra-fine metal mineral dust is analyzed,which lays a foundation for the preparation of new nanocomposite dust suppressant.(2)The size and preparation method of Al2O3 nanoparticles were optimized.This paper expounds the preparation method of nanofluid suppressant and the correlation between the principle of dispersion stability and dust suppression effect.Through the dispersion measurement experiment of Al2O3 nanofluid,the best proportion of nanoparticles and dispersant is selected.At the same time,the cracks caused by nanofluid suppressant spraying on the dust surface are measured,and different sizes of Al2O3 nanoparticles are selected,the nanofluid with nanoparticles to dispersant ratio of 5:1 and 30nmAl2O3 was selected as a suitable nanocomposite dust suppressant material.(3)The optimum concentration range of the compound components of nano-composite dust suppressant was optimized.By analyzing the relevant dust suppression mechanism of traditional wetting,water retention and other dust suppressants and the dust suppression defects of nanofluid suppressant,SAP,CMS and PAM are added to further improve the wetting,water retention and bonding effects of dust suppressants.At the same time,the relevant dust suppression indicators of each reagent are measured to optimize its optimal concentration range.(4)The optimum ratio of new nano-composite dust suppression was optimized.According to the orthogonal test table of four factors and three levels,Al2O3 nanofluids,SAP,CMS and PAM of different components are compounded to measure the dust suppression performance of nanocomposite dust suppressants in each experimental group.Visual analysis and variance analysis are carried out according to the experimental results to obtain the influence degree and significance of each factor on the dust suppression performance index.The F value of each factor is analyzed through comprehensive balance,The optimal proportion of nanocomposite dust suppressant was obtained.The specific formula was 2%Al2O3 nano fluid,1.5%CMS,0.006%PAM and 0.2%SAP.(5)The dust suppression performance of nano-composite dust suppressant with the best ratio was analyzed.Through comparison and inspection experiments,it is proved that the nano-composite dust suppressant with the best process ratio has good dispersion and wettability,and its dust suppression performance indexes are improved after spraying on the dust surface.At the same time,it is proved that its solid content meets the actual use standard.In addition,the surface morphology and structure of ultra-fine sulfide mineral dust after spraying nano-composite dust suppressant and water are compared and analyzed.It is proved from the micro point of view that nano-composite dust suppressant can effectively bond and cover dust particles to form a network binder with certain strength,so as to prevent dust from flying. |
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