YuQuan plaster gypsum models, industrial plaster powder, long-term supply

Gypsum is generally 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 and 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 converted to 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%, making it lightweight and less strong. Building gypsum has strong hygroscopic properties after hardening; when it absorbs moisture, the bond between crystals weakens, leading to a significant drop in strength. Upon contact with water, the crystals dissolve, causing damage. When frozen after absorbing water, it is 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 setting but slightly expands (about 1%), and no cracks appear during hardening. Thus, gypsum paste can 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·hr between 16°C and 46°C. When exposed to fire, the crystalline water in the dihydrate gypsum evaporates, absorbing heat. The resulting anhydrous substance forms a good thermal insulator, making gypsum fire-resistant.