Yuquan Gypsum - Raw Gypsum Powder, Industrial Gypsum Powder - In Stock Supply

Gypsum is generally colorless or white transparent, but can take on shades of gray-brown, yellow, etc., when impurities are present. Its specific gravity ranges between 2.31 to 2.33, with a Mohs hardness of 1.5 to 2. Its solubility in water is relatively low, with a solubility of 2.05 grams per liter of CaO dihydrate at 20°C. Once hardened, gypsum has a high porosity, up to 50% to 60%, resulting in a low density and strength. Construction gypsum has a strong hygroscopic nature after hardening, which weakens the bonding between crystals, significantly reducing its strength upon absorption of moisture. When exposed to water, the crystals dissolve, causing damage. Freezing after absorption of water makes it more prone to cracking. Therefore, pure construction gypsum has poor water resistance and frost resistance. Unlike lime and cement, gypsum does not shrink upon setting but expands slightly (about 1%), preventing cracks during hardening. This allows for casting into components with precise dimensions and smooth, fine surfaces. Gypsum is a poor conductor of heat, with a thermal conductivity of 0.259 kcal/m·°C·h between 16°C and 46°C. When exposed to fire, the crystalline water in the dihydrate evaporates, absorbing heat, and the resulting anhydrous material forms a good thermal insulator, making gypsum highly fire-resistant.