Heavy calcium carbonate is a powder material obtained by mechanical grinding of natural minerals such as calcite, marble, limestone, chalk, and white marble. It is an important industrial filler, pigment, and chemical product.
1. Papermaking
For the papermaking industry, heavy calcium carbonate is an important raw material second only to fiber. As a filler and coating pigment, heavy calcium carbonate improves the performance of paper mainly in the following aspects:
(1) Improve opacity and brightness;
(2) Improve smoothness, uniformity and softness;
(3) Reduce hygroscopicity and deformation;
(4) Enhance ink absorption and printability;
(5) Reduce paper costs.
2. Plastics
The plastics industry is the largest consumer of calcium carbonate in China. Calcium carbonate is widely used to fill polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), acrylonitrile butadiene-styrene copolymer (ABS), etc.
3. Coatings
Calcium carbonate is the most widely used physical pigment in coatings. It plays a role in filling the skeleton and base material in the paint film, and improves the performance of the coating at the same time.
4. Rubber
Heavy calcium carbonate is mainly used as a filler in the rubber industry. It can also be used with other reinforcing agents to improve the process performance of rubber compounds and the performance of products. It is suitable for heels, soles, floors, hoses, molded, extruded and foamed rubber products.
5. Breathable film
Breathable film is made by adding about 50% of special calcium carbonate to PE or PP carriers for blending, extruding and stretching at a certain ratio after film formation. It is widely used in the packaging of medical and health products (such as medicinal films, surgical gowns, medical gloves, sanitary napkins, baby diapers and disposable sheets and other clinical medical consumables), food packaging (such as cling film, composite film, cooked food packaging bags) and daily products (such as warm clothing interlayers, disposable lightweight raincoats) and other fields.
6. Food additives
In the food industry, heavy calcium carbonate can be used as an alkaline agent, nutritional supplement, dough regulator, curing agent, yeast nutrient, anti-caking agent, loosening agent, gum additive and modifier, etc. It can also be added to calcium nutrition fortified health foods, gum bases, leavening agents, flour products, cereal breakfasts, biscuits, dairy products, soft capsules and other products. It is even an ideal reaction raw material for high-purity pharmaceutical grade calcium citrate, calcium lactate, calcium citrate-malate, calcium gluconate and other organic calcium salts.
7. Medicine
Calcium carbonate is often used as a filler for certain drugs (such as tablets). By using its anti-acid effect, it can neutralize part of the gastric acid after taking it to maintain the stability of the drug.
8. Toothpaste
In the toothpaste industry, calcium carbonate is a commonly used abrasive. It is cheap and the raw materials are easy to obtain (limestone or calcite as raw materials). It is widely used in medium and low-end toothpaste.
9. Feed
Heavy calcium carbonate is a feed-type mineral raw material used as a calcium source. The general feed addition amount is 0.5~1%. Egg-laying poultry such as chickens, ducks, and geese need to add an appropriate amount of calcium carbonate to their feed. During the peak egg-laying period of egg-laying poultry, it can be added to 8~9%.
10. Artificial stone
Heavy calcium carbonate powder is the main filler of resin-based artificial stone, generally accounting for more than 75% of the quality of artificial stone. Moreover, the larger the filling amount, the less resin is used, the lower the production cost, and the more environmentally friendly it is.
11. Sealant
Calcium carbonate is one of the most commonly used functional fillers in the sealant industry. Its addition accounts for 10% to 70% of the entire sealant formula system. It can increase the volume of the sealant and improve its tensile strength, wear resistance, tear resistance, hardness and other properties.
12. Building materials
Heavy calcium carbonate has relatively stable chemical properties and a complete crystal structure in the basic magnesium sulfate cement system. The square rhombohedral heavy calcium carbonate is filled between the needle-shaped crystals, acting as a filler and forming a structural skeleton, making the basic magnesium sulfate cement structure more compact. Therefore, the addition of heavy calcium carbonate can still maintain the compressive strength of cement.
13. Chemical raw materials
(1) Sodium citrate
The one-step extraction process for producing sodium citrate mainly includes neutralization reaction, double decomposition reaction, deironization and decolorization, evaporation concentration, crystallization and drying.
(2) Calcium hydrogen phosphate
Heavy calcium carbonate is the only starting material for producing food-grade calcium hydrogen phosphate, and its quality characteristics are closely related to the final product phosphate.