Magnetic separation mainly uses the magnetic difference between gangue minerals and silica sand to remove these colored impurities. Magnetic separation is more effective for magnetite, ilmenite and other strong magnetic minerals or iron filings mixed in the processing process.
For weakly magnetic minerals, there are two main methods: one is roasting to turn the minerals into strong magnetic iron oxide, and then grinding; Another method is to use high gradient and strong magnetic field grinding method for grinding.
Because the silica sand grinding method does not need to use chemicals and will not pollute the environment, it is widely used in the process of non-metallic beneficiation.
The grinding method has effectively solved the problem of the development and utilization of low-grade silica sand that does not have commercial mining value due to the high content of iron ore.