LOESCHE Vertical Roller Mills for the Comminution of Ores and Minerals

摘要

Vertical roller mills follow the principle of interparticle comminution. The feed material is dropped onto the center of a rotating table and moves to the edge of it due to centrifugal On the outer part of the table 2, 3, 4 or even 6 concial rollers are installed. The material is nipped by these rollers which are attached to hydraulic cylinders providing the grinding pressure. Comminution takes place in the material bed under high pressure between the rollers and the grinding table. LOESCHE mills are very famous for grinding of raw materials for the cement industry, and for the production of pulverized coal for power plants and blast furnaces. They are available with capacities up to 840 t/h cement raw material with a fineness of 99 percent passing 200 pm and with an installed power of up to 6 MW. After these mills have been applied very successfully in the field of production of cement and ground granulated blast furnace slag since 1994 it was a consequent step to use this technology for the processing of ores and minerals as well. The results from trials in pilot plants showed, that dry grinding in a LOESCHE mill can improve the efficiency of the downstream processes significantly and lead to higher grades and better recovery. A first large-scale installation is in operation since 2000 for processing a phosphate carrying pyroxenite ore with a capacity of 825 t/h at 80 percent P 480 mu m.