heavy calcium carbonateIt is a calcium carbonate powder material made of calcite, chalk, marble and other ores as raw materials by mechanical crushing. It has the characteristics of wide source of raw materials, high whiteness, low oil absorption value, good applicability and low price. It is a widely used inorganic non-metallic mineral powder.

　　1.heavy calcium carbonateperformance characteristics. Although the main chemical composition is the same as light calcium carbonate, heavy calcium carbonate has the characteristics of high bulk density, small sedimentation volume, small specific surface area and small oil absorption value compared with light calcium carbonate. In addition, the degree of aggregation of heavy calcium carbonate is less than that of light calcium carbonate (the primary particle size of light calcium carbonate is small, and the degree of aggregation is large). The pH of the aqueous solution: light calcium carbonate is 9-10; heavy calcium (GCC) is 8-9. In the grinding process of ground calcium carbonate, although it can affect the particle shape to a certain extent, it cannot control the particle crystal form through the carbonization process like light calcium carbonate, and produce products with different crystal forms.

Due to the above performance differences, the application performance of heavy calcium carbonate and light calcium carbonate also have their own characteristics:

Due to the large sedimentation volume or small bulk density of light calcium carbonate, the volume of the product can be increased under the same filling amount. The original particle size is small, and the mechanical properties of the filling material are better under the same filling amount. However, due to the large specific surface area, large oil absorption value and large resistance when mixed with resin, light calcium carbonate has poor processability.

Under the same filling amount, the heavy calcium carbonate filling material has small volume and high density, and is easy to mix with resin due to its small specific surface area and small oil absorption value. However, different impurities in different raw materials have different effects on the color of the product.

　　2.heavy calcium carbonateThe impact of product metrics on application performance.

　　 (1) The chemical composition of CaO, hydrochloric acid insolubles, iron, manganese and heavy metal content of heavy calcium carbonate mainly affect the whiteness, abrasion value, color and chemical stability of filling materials and the safety of application in toothpaste and food.

(2) Particle size and its distribution affect whiteness, brightness or gloss, abrasion value, bulk density, mechanical properties (strength, elongation at break, modulus, etc.).) and the cost of the filling material.

(3) Sedimentation volume or bulk density mainly affects the density of the filler.

(4) Whiteness mainly affects the color and brightness of the product.

(5) The oil absorption value affects the dispersion of heavy calcium carbonate in filling materials or products and the processing performance (mixing difficulty) of the filling resin system, and affects the dispersion stability or sedimentation performance of coatings and inks.

(6) Moisture content mainly affects the apparent performance of filling materials or products. Excessive moisture content not only affects the surface modification effect, but also may change the apparent quality of the filling material or product.

(7) The degree of surface activity or activation mainly affects the dispersion of heavy calcium carbonate in the resin and its interaction with the polymer substrate, which in turn affects the mechanical properties, aging resistance and apparent properties of the filling material or product.

(8) The specific surface area mainly affects the oil absorption value of ground calcium carbonate.

(9)pH mainly characterizes the acidity and alkalinity of heavy calcium carbonate products, and is one of the main factors affecting the chemical stability of filling materials or products.

In general, at present our countryheavy calcium carbonateThe application of the main primary products, the surplus of ordinary products, high value-added products, can not meet the needs of the world market and China's high-end market, resulting in a large number of imported ultra-fine heavy calcium carbonate products are expensive.