Although heavy medium beneficiation , photo-selection, flotation, electro-election, etc. can be used for gypsum beneficiation, in China, these methods have not been widely used in industrial production. Most mines simply pick the gypsum ore that is mined and pick up the stone. Some mines with more complex ore types are selected by hand to extract fiber gypsum, plaster, ordinary gypsum and a small amount of anhydrite . 3D Folding Face Mask,3D Folding Protective Mask,3D Foldable Ffp2 Respirator,3D Folding 5 Layer Disposable Respirator Henan Aklly Filter Engineering Co., Ltd , https://www.akllyfilte.com
　　 The calcination process of raw gypsum is divided into dry process and wet process. Dry calcination is the heating and dehydration of raw gypsum under normal pressure (or low partial pressure of water vapor), and β-type hemihydrate gypsum, type II anhydrite or burnt gypsum are formed depending on the temperature. This product is a plaster, cast gypsum or pre-product gypsum commonly used in construction. The wet calcination is to heat the raw gypsum under the pressure of water vapor in the autoclave or in a salt solution having a boiling point higher than 100 ° C at a low pressure, and the product is α-type hemihydrate gypsum, which can be used as a special gypsum base material for pouring. .