Light calcium carbonate is also called precipitated calcium carbonate, referred to as light calcium, with a molecular formula of CaCO3 and a molecular weight of 100.09. Light calcium is calcined limestone and other raw materials to produce lime (the main component is calcium oxide) and carbon dioxide, then add water to digest the lime to produce milk of lime (the main component is calcium hydroxide), and then pass in carbon dioxide to carbonize the milk of lime to form calcium carbonate precipitation, and finally It is obtained by dehydration, drying and crushing. Or use sodium carbonate and calcium chloride to carry out metathesis reaction to generate calcium carbonate precipitate, then dehydrate, dry and pulverize. Because the sedimentation volume of light calcium carbonate (2.4-2.8mL/g) is larger than that of heavy calcium carbonate (1.1-1.4mL/g), it is called light calcium carbonate.
Light calcium properties
White powder, tasteless, odorless, specific gravity about 2.71. It decomposes at 825~896.6ºC, and its melting point is 1339ºC. There are two forms of amorphous and crystalline forms, and the crystalline forms can be divided into orthorhombic and hexagonal systems, which are columnar or rhomboid. Insoluble in water and alcohol. Soluble in acid, while releasing carbon dioxide, showing exothermic reaction. Also soluble in ammonium chloride solution. It is stable in the air and has a slight moisture absorption capacity.
Light calcium use
It can be used as a filler in industries such as rubber, plastics, paper, coatings and inks. Widely used in organic synthesis, metallurgy, glass and asbestos production. It can also be used as a seeding agent for industrial wastewater, an antacid for gastric and duodenal ulcer disease, an antidote for acidosis, an SO2 scavenger in waste gas containing SO2, a dairy cow feed additive, and an anti-sticking agent for linoleum . It can also be used as a raw material for tooth powder, toothpaste and other cosmetics.
Powder characteristics of light calcium carbonate
1. The shape of the particles is regular, which can be regarded as monodisperse powder, but it can be in various shapes, such as spindle, cube, needle, chain, spherical, sheet and square column. These different shapes of calcium carbonate can be prepared by controlling the reaction conditions.
2. The particle size distribution is narrow.
3. The particle size is small, the average particle size is generally 1-3μm. To determine the average particle size of light calcium carbonate, the short-axis particle size in the triaxial particle size can be used as the apparent particle size, and then the median particle size can be used as the average particle size. Hereinafter, unless otherwise specified, the average particle diameter refers to the average minor-axis particle diameter.