After extracted from quarries and underground mines, gypsum ore will be processed by gypsum powder raymond grinder. First it will be crushed and stockpiled near a plant. According to specific applications, the stockpiled ore is further crushed and screened to about 2 inches in diameter. If the moisture content of the mined ore is greater than about 0.5 weight percent, the ore must be dried in a rotary dryer or a heated roller mill.
Ore dried in a rotary dryer is conveyed to a roller mill, where it is ground to the extent that 90 percent of it is less 100 mesh. The ground gypsum exits the mill in a gas stream and is collected in a product cyclone. Ore is sometimes dried in the roller mill by heating the gas stream, so that drying and grinding are accomplished meantime and no rotary dryer is needed.