Coal gangue is a solid waste discharged in the process of coal mining and coal washing, It is a kind of black gray rock with low carbon content and harder than coal that is associated with coal seams in the process of coal formation. It includes the driving gangue in the roadway driving process, the gangue extracted from the roof, floor and interlayer in the mining process, and the washing gangue picked out in the coal washing process. Its main components are Al2O3 and SiO2. In addition, it also contains varying amounts of Fe2O3, CaO, MgO, Na2O, K2O, P2O5, SO3 and trace rare elements (gallium, vanadium, titanium, cobalt). How to comprehensively utilize coal gangue is related to environmental protection and comprehensive utilization of resources.
Coal gangue instead of fuel: iron melting, boiler burning, lime burning, recycling coal. Production of cement: production of ordinary portland cement, production of special cement, production of clinker free cement. Production of building materials: coal gangue sintered bricks are of good quality and uniform color. Coal gangue produces light aggregate. Light aggregate is a kind of porous aggregate selected to produce coal gangue asbestos for the purpose of reducing the relative density of concrete. It is a kind of building material made of coal gangue and lime after melting and blowing at high temperature.
Production of chemical products: crystalline aluminum trichloride is made from coal gangue and hydrochloric acid, a by-product of the chemical industry, through crushing, burning, grinding, acid leaching, precipitation, concentration, crystallization and dehydration. It is a new type of water purification agent, which produces sodium silicate and ammonium sulfate. The iron sulfide in coal gangue produces SO2 at high temperature, then oxidizes to produce SO3, meets water to produce sulfuric acid, and produces ammonium sulfate with ammonia compounds.
