Meanwhile, the crushing effect and saving energy of the equipment working in process of grinding ironstone are researched, all these lay a foundation for the further study of the technology.

The semi-industrial test on fine products by Meishan Dressing Plant was carried out with the RP80/25 type high pressure roller mill produced by Homburg Corporation of Germany.

The high pressure roller mill brings still high pressure to bear on the particle beds and makes them destroy inside to numerous tiny cracks.