YuQuan Gypsum Raw Gypsum Powder Industrial Gypsum Powder Custom Direct Sale

Gypsum typically appears white or colorless transparent. Containing impurities, it can turn gray-brown, yellow, etc. Its specific gravity ranges between 2.31~2.33, with a Mohs hardness of 1.5~2. 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%~60%, making it less dense and less strong. Building gypsum has a strong hygroscopic property after hardening; when it absorbs moisture, the bonding force between crystals weakens, resulting in a significant drop 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 and cement, gypsum does not shrink upon solidification but slightly expands (about 1%), and no cracks appear during hardening. Thus, gypsum slurry can be cast into components with accurate 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~46°C. When exposed to fire, the crystalline water in the dihydrate gypsum evaporates, absorbing heat. The resulting anhydrous material forms a good thermal insulator, making gypsum fire-resistant.