How Is Gypsum Processed?

Open-Pit Quarrying

• In some areas of the world, gypsum deposits exist near the ground's surface. These surface deposits are extracted most efficiently via open-pit quarrying. Quarry workers remove the soil and any rock cover to reach the gypsum deposit. The workers then blast or drill the gypsum loose.

Underground Mining

• Mining allows procurement of gypsum far underground. Miners drill shafts into the ground until they reach a gypsum deposit. Then, the miners extract the gypsum, creating a "room" in the process. Finally, miners remove the gypsum from the mine with the help of machinery.

Transported to Processing Plant

• Upon removal, trucks transport gypsum to the processing plant. The plant produces unformed gypsum material for product manufacturers or produces the end-product on-site. Trucks dump loads of raw gypsum rock at the plant in piles until the plant is ready for them.

Crushing

• A vibrating pan feeder moves the raw gypsum material into the processing plant. The vibrating pan feeder consists of a conveyor belt that shakes to evenly distribute the gypsum rock onto the conveyor surface. The conveyor feeds the rock into a crusher. The crusher machine pulverizes the rock into pieces measuring 2 inches or less.

Partial Drying

• The small gypsum rocks enter a drying receptacle. The receptacle spins and heats the rocks evenly. The rock dryer transforms the gypsum into what is called a "hemi-hydrate."

Milling

• A machine with rotating rollers crushes the gypsum rock. Plaster of Paris is composed of this hemi-hydrate crushed material.

Calcination

• The calcination process heats the gypsum to high temperatures. This transforms the hemi-hydrate into an anhydrite. The anhydrite form of gypsum provides further strength in plaster usage. In some processing, the manufacturer adds water to reshape the gypsum into a desired form.