Gangue

Coal gangue is a kind of 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. It includes the excavation gangue in the process of roadway excavation, the gangue extracted from the roof, floor and interlayer in the process of excavation, and the gangue extracted in the process of coal washing. It is mainly composed of Al2O3 and SiO2. In addition, it contains Fe2O3, Cao, MgO, Na2O, K2O, P2O5, SO3 and trace rare elements (gallium, vanadium, titanium and cobalt).

Application:

① Recovery of coal and pyrite: through simple process, good coal is washed from coal gangue, inferior coal is selected through screening, and pyrite is picked out at the same time.

② (2) for power generation: it mainly uses coal washing and gangue washing for power generation. In China, fluidized bed boilers have been used to burn the mixture of coal washing and gangue washing (calorific value is about 2000 kcal / kg) for power generation.

③ Manufacturing building materials: instead of clay as raw materials for brick making, less good land can be dug. When firing bricks, coal can be saved by using the combustibles of coal gangue itself.

④ Coal gangue can partly or completely replace clay component to produce ordinary cement.

⑤ Coal gangue can be used to sinter lightweight aggregate.

⑥ In addition, coal gangue can also be used to produce low calorific value gas, make ceramics, make soil amendments, or for road paving, underground filling and ground filling. After spontaneous combustion, grass can be planted on the waste dump to beautify the environment.