Light calcium carbonate, which is also called precipitated calcium carbonate, or light calcium for short, is made by the following processes: burn limestone and other raw material to produce lime and carbon dioxide, add water to digest lime to produce lime milk (the main ingredient is calcium hydroxide), then feed carbon dioxide to carbonize the lime milk for producing calcium carbonate precipitation, and light calcium carbonate is prepared by the dehydration, drying and grinding of calcium carbonate precipitation; Or it can be made by drying, dehydrating and grinding the calcium carbonate precipitation produced by the double decomposition reaction of sodium carbonate and calcium chloride. The sediment volume of light calcium carbonate is 2.4-2.8mL/g. The shape of ordinary light calcium looks like a jujube pit when the particles are fully dispersed, and the particle size of it is 5 - 12 μm in long diameter, 1-3 μm in short diameter, and 2 - 3 μm in average powder diameter. However, without the surface treatment, many particles tend to condense together to form a grape-like lump after the formation, dehydration, and drying of light calcium carbonate, so the quality requirements for light calcium carbonate in the national standard are only judged from the sieve residue of 125μ m and 45 μm, which does not directly reflect the true size and the distribution of particles.
The functions of light calcium carbonate：
The particle size of light calcium carbonate is smaller than that of ground calcium carbonate, the oil absorption is larger than that of ground calcium carbonate, and the price is higher than that of ground calcium carbonate. It is better to use them together because they are both commonly used fillers in latex paint. Light calcium carbonate has advantages in the settlement, but its oil absorption is greater than heavy calcium carbonate, and the price is generally higher than heavy calcium carbonate.
Light calcium carbonate is usually used as fillers in artificial floor tile, rubber, plastic, papermaking, coating, paint, ink, cable, building supplies, food, medicine, textile, feed, toothpaste, and other daily-use chemical industries, which can increase the volume of products and reduce the production cost.
The functions and applications of light calcium carbonate：
Light calcium carbonate has a wide range of functions and uses, which can be applied in the following industries:
Rubber industry: calcium carbonate is one of the earliest fillers with the largest usage amount in the rubber industry. With a lot of calcium carbonate in rubber, it can increase the volume of products, thus saving the usage of expensive natural rubber to reduce the cost. The filling of calcium carbonate in rubber will obtain higher tensile strength, abrasive resistance, and tear strength than pure rubber sulfide, have a significant reinforcing effect in natural rubber and synthetic rubber and adjust the consistency.
Paint industry: the usage amount of calcium carbonate in the paint industry is quite large, and it is an indispensable skeleton in the paint. The usage amount is more than 30% in thick paint, 4-7% in phenolic enamel, and more than 39% in phenolic fine pattern wrinkle paint.
Waterborne coatings industry: the application of calcium carbonate is wider in the waterborne coatings industry. It can make the coating does not settle, easy to disperse, glossy, and have other characteristics, and the usage amount in waterborne coatings is 20-60%.
In addition, calcium carbonate plays an important role in the papermaking industry, which can ensure the strength and whiteness of paper with low costs. In the cable industry, it can also play a certain role in insulation.