Calcium carbonate is an important inorganic chemical product and functional powder material. Due to its excellent and unique physical and chemical properties, it is widely used in industries such as roads, building materials, metallurgy, rubber, plastics, papermaking, and coatings. This article will answer for you what heavy calcium is. What is light calcium? What is nano calcium? What is activated calcium?

Calcium carbonate is an important inorganic chemical product and functional powder material. Due to its excellent and unique physical and chemical properties, it is widely used in industries such as roads, building materials, metallurgy, rubber, plastics, papermaking, and coatings.

Types of calcium carbonate

Light calcium carbonate (precipitated calcium carbonate), abbreviated as light calcium, is produced by calcining limestone to generate lime (calcium oxide) and carbon dioxide, then adding water for digestion to form lime milk (calcium hydroxide), followed by the introduction of carbon dioxide to form calcium carbonate precipitate. Finally, it is obtained through dehydration, drying and grinding. The sedimentation volume of light calcium carbonate is 2.4 to 2.8mL/g.

Heavy calcium carbonate, abbreviated as heavy calcium, is a product obtained by mechanically processing natural calcium carbonate minerals such as calcite, limestone, chalk, and shells through grinding and ultrafine ring rollers to an appropriate particle size. The sedimentation volume of heavy calcium carbonate is 1.1 to 1.4mL/g.

Active calcium carbonate, also known as modified calcium carbonate or gelatinous calcium carbonate, is simply called active calcium. It is produced by surface modification of light calcium carbonate or heavy calcium carbonate particles with surface modifiers (such as coupling agents, stearic acid, etc.). The surface-modified calcium carbonate has a reinforcing effect, which is called "activity". Therefore, the modified calcium carbonate is also conventionally referred to as active calcium carbonate. The activation rate of the Shanhe activation and modification machine can reach 98%, with low consumption of modifiers and advanced modification principles. It is the preferred equipment for increasing the added value of powder.

Nano calcium carbonate, abbreviated as nano calcium, is produced by calcining selected limestone through carbonization to obtain calcium oxide. The calcium hydroxide generated by digestion is then crushed under high shear force to remove impurities. Carbon dioxide is then introduced to obtain calcium carbonate slurry, which is then dehydrated, dried and subjected to surface treatment.

 

The difference between heavy calcium and light calcium

Bulk density: The most significant difference between heavy calcium and light calcium lies in their bulk density. Heavy calcium has a higher bulk density, typically ranging from 0.8 to 1.3g/cm ³, while light calcium has a lower bulk density, usually from 0.5 to 0.7g/cm ³.

Whiteness: Heavy calcium carbonate has relatively more impurities. The whiteness of the product is generally 89% to 93%, and it is rare to reach 95%. Light calcium is a chemically synthesized product. Many impurities have been removed, resulting in a product with high purity. Its whiteness is mostly 92% to 95%, and some can reach 96% to 97%, or even higher.

Flowability: Considering the flowability, the microstructure of light calcium is spindle-shaped and its oil absorption value is relatively high. Therefore, its flowability is significantly inferior to that of heavy calcium. Generally, adding more than 25 parts to the formula will affect the flowability of the mixture. In contrast, heavy calcium carbonate is in an irregular granular form and promotes the fluidity of the mixture. Under the condition that certain physical properties of the product are relaxed, the addition amount of heavy calcium carbonate can be significantly increased.

Moisture content: The moisture content of heavy calcium products is relatively low and stable, generally ranging from 0.2% to 0.3%. The moisture content of light calcium is generally between 0.3% and 0.8%.

The difference between active calcium and non-active calcium

Hydrophobicity: After the surface of active calcium is coated with an activator, it exhibits obvious hydrophobic properties. The situation of active calcium and non-active calcium dissolving in water can be used for identification.

Fluidity: The surface of active calcium is coated with organic active agent molecules with lower surface tension, and its surface energy is lower than that of non-activated calcium. The viscous resistance between particles is reduced, which significantly improves the fluidity of active calcium powder and also marks the difference in product dispersibility (compared under the same conditions).

Particle size: Due to the reduction of the surface energy of the particles by the active calcium surfactant, the particle agglomeration force is significantly weakened, and the particle size is obviously reduced. The differences between the two products were distinguished by electron microscopy.

Oil absorption value: Due to the reduction in the particle size of active calcium, the void ratio between particles also decreases accordingly, making the microscopic surface of the particles smooth and flat. Therefore, the oil absorption value of active calcium is lower than that of non-active calcium