What are the properties of building gypsum?
Release Time:
2020-05-12
Building stone has certain sound insulation and fire prevention functions, can meet the needs of many users, is an indispensable material for building decoration! Below we introduce what is building gypsum and its function!
Building stone has certain sound insulation and fire prevention effects, can meet many user needs, is an indispensable material for building decoration! Below we introduce what is building gypsum and its functions!
Building Gypsum
The raw materials for producing gypsum are mainly natural gypsum containing calcium sulfate (also known as gypsum) or chemical by-products containing calcium sulfate and waste slag such as phosphogypsum, fluorogypsum, and borogypsum, with the chemical formula CaSO4.2H2O, also known as dihydrate gypsum. Different types of gypsum can be obtained by calcining natural dihydrate gypsum at different temperatures. For example, heating natural dihydrate gypsum under dry conditions at 107~1700°C can yield building gypsum.
After adding water to the building gypsum, it mainly dissolves in water, and then dihydrate gypsum is generated and separated. As the hydration continues, the generated dihydrate gypsum colloidal particles increase continuously. These particles are finer than before, with a large specific surface area, adsorbing a lot of water; at the same time, the free water in the slurry continuously decreases due to hydration and evaporation, the consistency of the slurry continuously increases, the bonding between colloidal particles gradually strengthens, friction and bonding forces are generated between particles, causing the slurry to gradually lose plasticity, that is, the slurry gradually coagulates. Continuous hydration, the colloid transforms into crystals. The crystal particles gradually grow, causing the slurry to completely lose plasticity, generating strength, that is, the slurry hardens. This process continues until the slurry is completely dry, and the strength no longer increases. At this time, the slurry has hardened into stone.
Main functions of building gypsum
(1) Fast coagulation and hardening. After adding water and mixing building gypsum, the slurry begins to lose plasticity within a few minutes and completely loses plasticity and generates strength within 30 minutes.
(2) Slight volume expansion during coagulation and hardening. Gypsum slurry will experience slight expansion in the initial stage of coagulation and hardening. This property makes the surface of gypsum products smooth, delicate, accurate in size, full in shape, and good in decoration.
(3) High porosity. When mixing building gypsum, in order to make the slurry have the plasticity required for construction, 60% of the water content needs to be added, while the theoretical water requirement for building gypsum hydration is 18.6%, so a lot of free water forms many capillary pores inside the building gypsum products during evaporation. The thermal conductivity is low, the sound absorption is good, and it belongs to a lightweight heat-insulating material.
(4) It has a certain humidity regulation property. Because the numerous capillary pores inside gypsum products have a strong adsorption capacity for water vapor in the air, they have a certain regulating effect on the indoor air humidity.
(5) Good fire resistance, poor durability, water resistance, impermeability, and frost resistance.
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Dream Brand
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