(1) dry process, usually the ore will be broken through the crusher to about 25mm, to the cage crusher, the particle size reduced to about 6mm. The crushed ore is further ground by a blown Raymond Mill equipped with a centrifuge and cyclone dust collector. The process can remove most of the sand and gravel, and is suitable for processing ores with high whiteness, low sand content and suitable particle size distribution. Dry processing is of low cost and is usually used as a low filler for rubber, plastics, and paper making industries.