Coal gangue is a kind of solid waste produced in the process of coal mining, and for a long time, the stacking and discarding of coal gangue not only occupies a lot of land resources, but also causes serious pollution to the environment.
1. Analysis of physical and chemical properties of coal gangue.
1.Physical.
The appearance of coal gangue is black or dark brown, the hardness is large, and the density is generally 15-2.0g cm. The particle size of coal gangue is unevenly distributed, and the particle size can vary from a few millimeters to tens of centimeters. Coal gangue has good physical stability and is not easy to break, but it is easy to weathered after being wet.
2.Chemical properties.
The chemical composition of gangue mainly includes minerals such as silicate, aluminate, ferrite, etc., as well as a small amount of organic matter. The silicate content in coal gangue is high, generally between 50%-70%, mainly quartz and plagioclase. The aluminate content is low, and kaolin is dominant. Ferrites are mainly magnetite and hematite. In addition, coal gangue also contains a small amount of sulfur, phosphorus and other elements.
3.Thermodynamic properties.
The heat of combustion of coal gangue is generally between 500-800 cal g, and the calorific value is low. The pyrolysis temperature of coal gangue is relatively high, generally around 800-1000. The thermal conductivity of coal gangue is low and the thermal insulation performance is good.
2. Resource utilization of coal gangue**.
1.Coal gangue power generation.
Coal gangue can be used as a resource by burning for power generation. The construction and technology of coal gangue power plants have been relatively mature, and coal gangue power generation can not only reduce the amount of coal gangue stacked, but also save coal resources and reduce environmental pollution.
2.Coal gangue for building materials.
Coal gangue can be used to prepare building materials such as cement, concrete, bricks, etc. The use of coal gangue to prepare building materials can not only reduce environmental pollution, but also save land resources and improve resource utilization.
3.Coal gangue extracts trace elements.
Coal gangue contains a certain amount of trace elements, such as gallium, vanadium, rare earths, etc. Through chemical extraction methods, these valuable elements can be extracted from coal gangue to achieve resource reuse.
4.Coal gangue biological treatment.
The use of microorganisms to treat coal gangue can convert the organic matter into fertilizer, biomass energy, etc. The biological treatment technology of coal gangue is still in the research stage, but it has a good application prospect.