Coal gangue is the solid waste produced by vertical roller mill. It is the main waste of coal mining and is regarded as harmful substances and harmful gases. In the mining of coal gangue, the use of grinding equipment is indispensable.
In the development strategy of mills, we should adhere to the principle of clean and environmentally friendly resource saving, recycling and turning waste into available resources.
The inorganic components of coal gangue are mainly oxides of silicon, aluminum, calcium, magnesium, iron and some rare metals. The main useful minerals in high sulfur gangue are pyrite and coal. The relative density difference between pure pyrite and gangue is 2-2.3, while the relative density difference between paragenetic pyrite and gangue is 0.5-1.