Solubility of gypsum powder: slightly soluble in water, soluble in acid, ammonium salt, sodium thiosulfate and glycerin

石膏粉的稳定性：加热至150℃时失去1.5H2O而成半水物(熟石膏)，继续加热至163℃失去全部结晶水变成无水物

The stability of gypsum powder: when heated to 150 ℃, it will lose 1.5H2O and become hemihydrate (anhydrous gypsum). If heated to 163 ℃, it will lose all crystal water and become anhydrous

石膏粉的毒性：无毒

Toxicity of gypsum powder: non toxic

石膏粉的应用：用作密封胶的填充剂或用于配置无机胶黏剂

Application of gypsum powder: used as filling agent of sealant or preparing inorganic adhesive

加热时存在3个排出结晶水阶段：105~180℃，首先排出1个水分子，随后立即排出半个水分子，转变为烧石膏，也称熟石膏或半水石膏。200~220℃，排出剩余的半个水分子，转变为Ⅲ型硬石膏。约350℃，转变为Ⅱ型石膏Ca[SO4]。1120℃时进一步转变为Ⅰ型硬石膏。熔融温度1450℃。

During heating, there are three stages of discharging crystal water: 105 ~ 180 ℃, first one water molecule is discharged, and then half water molecule is discharged immediately, and then it is transformed into calcined gypsum, also known as anhydrite or hemihydrate gypsum. At 200 ~ 220 ℃, the remaining half water molecules are discharged and transformed into type III anhydrite. At about 350 ℃, it is transformed into type II gypsum CA [SO4]. At 1120 ℃, it is further transformed into type I anhydrite. The melting temperature is 1450 ℃.

石膏及其制品的微孔结构和加热脱水性，使之具优良的隔音、隔热和防火性能。

The microporous structure and heating dehydration property of gypsum and its products make it have excellent sound insulation, heat insulation and fireproof performance.

凝结硬化快，凝固时体积微膨胀，这一特性使石膏制品的表面光滑、尺寸精确、形体饱满、装饰性好，干燥时不产生收缩裂缝，加之石膏制品洁白、细腻，特别适合制作建筑装饰制品。孔隙率大，由于硬化体孔结构的特点，使建筑石膏制品具有表观密度小、质轻，保温隔热性能好和吸声性强等优点，还具有一定的调温湿性 。

This characteristic makes the surface of gypsum products smooth, accurate in size, plump in shape, good in decoration, and does not produce shrinkage cracks when drying. In addition, gypsum products are white and delicate, so it is especially suitable for building decoration products. Due to the characteristics of the pore structure of hardened body, building gypsum products have the advantages of small apparent density, light weight, good heat insulation performance and sound absorption, and also have certain temperature and humidity regulation.