YuQuan Gypsum manufacturers, direct sales of raw gypsum powder and calcined gypsum powder

Gypsum typically appears white or colorless transparent. Containing impurities, it may be gray-brown, yellow, etc. 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; at 20°C, the solubility of the dihydrate gypsum in terms of CaO is 2.05 grams per liter. After hardening, gypsum has a large number of pores, with a porosity of up to 50% to 60%, thus it has a low density and lower strength. Building gypsum, after hardening, has strong hygroscopic properties; upon absorption of moisture, the bonding strength between crystals weakens, leading to a significant decrease in strength. When exposed to water, the crystals dissolve, causing damage. Freezing after absorbing water makes it more prone to cracking. Therefore, the water resistance and frost resistance of pure building gypsum are poor. Unlike lime or cement, gypsum does not shrink upon solidification but slightly expands (about 1%) and does not crack during hardening. This allows gypsum paste to be cast 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 to 46°C. When exposed to fire, the crystalline water in the dihydrate gypsum evaporates, absorbing heat, and the resulting anhydrous material forms a good thermal insulator, making gypsum fire-resistant.