Calcium carbonate (heavy)

Heavy calcium carbonate, referred to as heavy calcium, is ground from natural carbonate minerals such as calcite, marble, and limestone.It is a commonly used powdery inorganic filler with high chemical purity, high inertness, not easy to chemical reaction, good thermal stability, no decomposition under 400 ° C, high whiteness, low oil absorption, low refractive index, soft, dry, No crystal water, low hardness, low wear value, ~, tasteless, odorless, good dispersibility, etc.

Physical and chemical properties

The chemical formula of calcium carbonate is caco3, and its crystals mainly include calcite of complex trigonal trihedral crystal and aragonite of orthorhombic crystal. At normal temperature and pressure, calcite is stable, and aragonite is quasi-stable. At present, calcite is mainly used. main.

Under normal pressure, calcite is heated to 898 ℃ and aragonite is heated to 825 ℃, and it will be decomposed into calcium oxide and carbon dioxide; calcium carbonate reacts with all strong acids to generate water and corresponding calcium salts (such as calcium chloride CaCl2), At the same time, carbon dioxide is released; at normal temperature (25 ℃), the concentration product of calcium carbonate in water is 8.7 × 1029, the solubility is 0.0014, the pH value of calcium carbonate aqueous solution is 9.5~10.2, and the air is saturated with carbonic acid. The pH value of the calcium aqueous solution is 8.0~8.6.Calcium carbonate~, odorless, non-irritating, usually white, with a relative density of 2.7~2.9.The Mohs hardness is 3 for calcite and 3.5 to 4 for aragonite.Calcite has three groups of rhombohedral complete cleavage, and aragonite also has cleavage.The sedimentation volume of heavy calcium carbonate: 1.2~1.9ml/g, and the specific surface area is about 1m2/g; the heavy calcium carbonate has a low oil absorption value due to its large particle size, smooth surface and small specific surface area, which is 48ml/ 100g or so.

Granularity

The shape of ground calcium carbonate is irregular, the particle size varies greatly, and the particles have certain edges and corners, the surface is rough, the particle size distribution is wide, the particle size is large, and the average particle size is generally 1~10μm.Ground calcium carbonate is divided into: coarse ground calcium carbonate (> 3μm), fine ground calcium carbonate (1~3μm), superfine calcium carbonate (0.5~1μm ground calcium carbonate) according to its original average particle size (d). Powder characteristics: a. The particle shape is irregular; b. The particle size distribution is wider; c. The particle size is larger.

Application field

At present, calcium carbonate has been widely used in papermaking, plastics, plastic films, chemical fibers, rubber, adhesives, sealants, daily chemicals, cosmetics, building materials, coatings, paints, inks, putties, sealing wax, putty, felt packaging, medicine , food (such as chewing gum, chocolate), feed, its functions are: increase product volume, reduce cost, improve processing properties (such as adjusting viscosity, rheological properties, vulcanization properties), improve dimensional stability, reinforce or semi-reinforcement , Improve printing performance, improve physical properties (such as heat resistance, extinction, abrasion resistance, flame retardancy, whiteness, gloss) and so on.