The factors affecting the setting speed of gypsum do not include the properties of plaster of Paris.
Because gypsum needs to react chemically with water in water before solidification to form calcium gypsum hydrate, while gypsum plaster itself has already reacted with water to form a certain amount of calcium gypsum hydrate, so the solidification speed is basically unaffected. The factors affecting the solidification rate of gypsum include:
1. The fineness of gypsum powder: the finer the gypsum powder, the larger its surface area, and the easier it is for water molecules to penetrate into the powder to react, and the faster the solidification rate of gypsum.
2. Quality and temperature of water: The quality and temperature of water are also important factors affecting the setting speed of gypsum. Poor water quality and low water temperature will reduce the setting speed of gypsum.
3. Proportion of gypsum and water: The proportion of gypsum and water will also affect the setting speed of gypsum, which is usually expressed by the ratio of the weight of gypsum to the weight of water. Improper proportion will lead to too slow or too fast setting speed.
4. ambient temperature and humidity: ambient temperature and humidity are also one of the factors that affect the setting speed of gypsum. when the temperature is low and the humidity is high, the setting speed of gypsum will slow down.
5. dosage and mixing method: the dosage and mixing method of gypsum will also affect the setting speed of gypsum, and excessive or uneven addition of gypsum will reduce or uneven the setting speed of gypsum.
methods of gypsum solidification
1. manually add water and stir: pour a proper amount of gypsum powder into a certain amount of clear water, let it stand for a while and then stir until the mixture becomes uniform. This method has the advantages of simplicity and low cost, but it needs manual mixing and a certain amount of labor and time.
2. Automatic mixing by machines: gypsum solidification machines widely used in medical industry at present can automatically control the proportion of gypsum and water and automatically mix, so that the gypsum mixture is uniform, fast and efficient, which is suitable for large-scale production or experimental needs.
3. Oscillator: The particles of gypsum mixture are arranged more neatly and compactly by vibration, which promotes solidification.
4. Vacuum suction equipment: It can remove bubbles in the mixture and improve the density and uniformity of the mixture, which plays an important role in the manufacture of high-precision gypsum products.