(1) Hydration of building gypsum After the construction gypsum is mixed with water, the process of hydration reaction with water to form calcium sulfate dihydrate is called hydration. The produced calcium sulfate dihydrate has the same molecular formula as the raw gypsum, but the physical and mechanical properties are different due to the difference in crystallinity and crystal form. The hydration and coagulation hardening mechanism can be simply described as: since the solubility of dihydrate gypsum is smaller than that of hemihydrate gypsum, the dihydrate gypsum first precipitates from the saturated solution to promote the dissolution of the hemihydrate gypsum, and the reaction process continues continuously. It is carried out until the hemihydrate gypsum is completely hydrated to form dihydrate gypsum. (2) Condensation hardening of building gypsum As the hydration reaction continues, the free water is continuously reduced by hydration and evaporation. In addition, the generated dihydrate gypsum particles are finer than the hemihydrate gypsum, have a large specific surface area, and absorb more water, so that the gypsum slurry is quickly formed. Loss of plasticity and condensation; as the crystals of dihydrate gypsum crystals grow, the crystal particles gradually overlap, intertwin, and symbiosis, resulting in strength, that is, hardening. In fact, the above-described hydration and condensation hardening processes are continuously performed while crossing each other. The most notable features of the building gypsum hardening process are: 1. high speed. The hydration process is generally 7 to 12 minutes, and the entire condensation and hardening process takes only 20 to 30 minutes. 2. The volume is slightly expanded. The building gypsum hardening process produces a volume expansion of about 1%. This is a characteristic that other cementitious materials do not have. Hollow Shaft Hybrid Stepper Motor Hollow Shaft Stepper Motor,Stepper Servo Motor,High Torque Stepper Motor,4 Phase Stepper Motor Changzhou Hebe Interantional Trade Co., Ltd , https://www.hebe-motion.com