Preparation Of Coal Mine Spraying Material By Removing-Carbon Fly Ash

Gas disasters and water inrush accident caused by electrostatic in the safety production of coal mining enterprises are still most dangerous, restrict healthy and sustainable development of coal industry,.Shanxi University and Shanxi Lu’an Environmental Energy Development Co.Ltd develop a kind of coal mine roadway spray material which had waterproof, fireproof, antistatic, air tightness characteristics. Spraying on the surface of roadway prevents water seepage and gas blocking. But the impermeability, durability and antistatic properties of this coating are deficient. Abandoned fly ash from power plant through the carbon removal treatment can be used as the filler of coating, this is not only a new direction for fly ash utilization, but also improves the impermeability durability and other properties of coal mine roadway coating, reduces the cost.In this paper, according to existing problems of the coating and the status of Lu’an fly ash piling, develop the experimental study of decarbonzation by flotation method, the effect of fly ash and conductive filler on the performance of coal mine roadway coating, and pilot test in Changcun coal mine.(1)Study of decarbonization from fly ash by flotation methodThe particle size of fly ash is centralized in-0.075mm, and the various particles of fly ash ignition loss are over10%, it must be decarbonized by flotation. The best flotation reagent and condition are:The effect of MR-1emulsion is better than OP-10emulsion. Best collector agent is kerosene, its optimum amount is2000g/t, the optimal amount of frother2pine oil is2000g/t.(2) Performance improvements of coal mine spraying material by fly ashContrast to coating apparent situation of high-carbon and removing carbon fly ash, we can see:The coating of adding20-30%high-carbon fly ash has cracks, but the coating apparent situation of removing carbon fly ash is better. So fly ash must be decarbonized.By measuring the bond strength, no treatment, alkali treatment and heat treatment tensile properties, impermeability and water absorption of removing carbon fly ash coating, the optimal dosage of the removing carbon fly ash is40%.(3) Effect of conductive filler on the performance of coal mine spraying materialThe effect of conductive mica powder, graphite, carbon black and various ratio of mixed filler on the performance of drying time, surface resistance and water absorption of the sealing material were investigated. The results showed that:Considering the antistatic and water proof performance of coatings,the best of the conductive filler was a mixture of graphite and carbon black, and the best mass ratio of graphite and carbon black was2:3.From results above, the formula is adjusted:Removing carbon fly ash replaces quartz, a mixture of graphite and carbon black (2:3) replaces graphite, the amount drops from15-18%to5%. Next the improved formula will be tested in underground roadway.(4)Pilot test of coal mine spraying materialsImproved formulation for coal mine spraying material is sprayed in Changcun Coal Mine pedestrians channel,+470m roadway of East Wing and water storage chamber. Through on-scene test, compare the curve before and after spraying, the minimum gas concentration reduced by0.07%, maximum1.2%, average can be reduced0.09%. Through the detection of the gas emission intensity before and after spraying, before spraying the roadway gas emission intensity changes obviously with the distance increase away from the working face, but the general trend is that the gas emission intensity tends to decrease with the extension of the roadway length. Consequently, after coating spraying, a decreasing trend. Visible after the sealant spray tunnel, sealing off the cracks of the coal wall surface, reducing the permeability coefficient of the roadway around the delay of gas emission, the blocking effect is more obvious. Through the results above, we not only research on removing carbon fly ash mixed conductive filler and carbon black graphite coating material formulations for coal mine roadway improvements, but also provide a new way of using high-carbon fly ash.