YuQuan Gypsum Powder - Construction Gypsum Powder - Custom Processing

Gypsum generally appears white or colorless transparent. When impurities are present, it can take on shades of 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 anhydrous calcium oxide in dihydrate gypsum is 2.05 grams per liter. Once hardened, gypsum has a high porosity, reaching 50% to 60%, resulting in low density and strength. Building gypsum has a strong hygroscopic nature after hardening; when it absorbs moisture, the bond strength between crystals weakens, significantly reducing its strength. Upon contact with water, crystals dissolve, leading to destruction. 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 no cracks appear 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 heat is absorbed due to the evaporation of crystalline water in dihydrate gypsum, and the resulting anhydrous substance is a good thermal insulator, making gypsum fire-resistant.