[Introduction] As a basic raw material in chemical industry production, light calcium carbonate is widely used.
China Powder Network News As we all know, calcium carbonate is an important inorganic compound with wide sources, abundant reserves, low cost of industrialization and wide application. According to different industrial preparation methods, calcium carbonate is divided into three types: heavy, light and activated calcium carbonate. Among them, light calcium carbonate is formed by chemical methods, and its density is smaller than that of calcium, but in terms of sedimentation volume, the value of light calcium carbonate is larger, so it is also called precipitated calcium carbonate, usually expressed as PCC. The particle size of light calcium carbonate prepared by chemical method varies from nanometer to micrometer, and the particle morphology includes hollow sphere, square, flower, chain and multi-level structure. As a basic raw material in chemical industry production, light calcium carbonate is widely used.
papermaking
The paper industry is one of the largest markets for calcium carbonate. Heavy calcium carbonate fillers are mainly used for printing paper, advertising paper, office paper, writing paper, etc., except cigarette paper, filter paper and special low-quantity information paper. Compared with heavy calcium carbonate, light calcium carbonate has better quality and has the advantages of fine particle size, high whiteness, low price, low foaming and good printing adaptability. It is very suitable for papermaking filler and can basically meet the requirements of paper printing. and optical performance requirements.
Relevant analysis shows that spindle-shaped ultra-fine-grained calcium carbonate can improve the quality and wear resistance of high-grade paper without modification, and filling the pulp with spindle-shaped calcium carbonate can simulate fine fibers, and there will be a large number of small air cells. , thus obtaining excellent smoothness and printability.
rubber
Light calcium carbonate is widely used in rubber products, such as tires, conveyor belt hoses, adhesive tapes and medical rubber products. Light calcium carbonate filled rubber can obtain higher tensile strength, abrasion resistance and tear strength than pure rubber sulfide, and has a significant reinforcing effect in natural rubber and synthetic rubber, and can adjust the consistency.
Relatively speaking, the reinforcing and toughening properties of acicular calcium carbonate are stronger than those of ordinary fillers. After filling in the material, the properties of the material in terms of strength, hardness and wear resistance can be improved.
plastic
Light calcium carbonate can play a skeleton role in plastic products, which has a great effect on the dimensional stability of plastic products, can improve the hardness of products, and can also improve the surface gloss and surface smoothness of products. Adding calcium carbonate to general plastic products can improve the heat resistance. Since the whiteness of light calcium carbonate is above 90%, it can also replace expensive white pigments to play a certain whitening effect.
paint
Calcium carbonate is an important filler in paint production, and the fineness and particle distribution determine the clarity of the paint. Light calcium carbonate is used in a large amount in the paint industry and is an indispensable framework. The amount of light calcium carbonate is more than 30% in thick paint, 4-7% in phenolic enamel, and more than 39% in phenolic fine pattern wrinkle paint.
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coating
Compared with heavy calcium, because light calcium is artificially synthesized, the crystal form and composition are easy to control, so it can endow light calcium with various functions, and the relatively high specific surface area makes the powder's reinforcement effect in the coating obviously better. in heavy calcium. Ordinary light calcium is mainly used for anti-corrosion coatings (including ship coatings, container coatings, vehicle primers, bridge and steel structure anti-corrosion, etc.), except for architectural coatings, paper coatings, and powder coatings. In addition to fillers, it also has certain water resistance and corrosion inhibition.
ink
When light calcium carbonate is applied to ink, it can make the gloss of the paint film clear and durable; it makes the printing tone of the ink elegant and uniform, and its good translucency, gloss and fluidity can also reduce the cost of paint and ink. The spherical and cubic nano-calcium carbonates are superior to other fillers in properties such as dispersion, transparency, gloss, and hiding power, and are widely used in high-quality inks in the fields of rapid printing and laser typesetting.
medicine
Light calcium carbonate is used in pharmaceutical formulations as neutralizers, filter aids, buffers and solubilizers as well as fillers and calcium source supplements. And the calcium carbonate with hollow structure has better function in terms of biocompatibility and can be used as a drug delivery and diagnostic marker.
food
Light calcium carbonate is widely used in the modern life calcium-supplementing nutritional food industry, and is a high-quality nutritional fortification additive for dairy products, meat products and flour products, dairy milk powder, milk flakes and other industries. In the process of preparing penicillin, streptomycin, and oxytetracycline, a large amount of calcium carbonate is required. It is used as an additive in food to ensure the necessary calcium intake of the human body, such as chewing gum, chocolate and yogurt, calcium tablets, jelly and other beverages as a fortifier to meet the human body's demand for calcium. Light calcium carbonate is used as alkaline agent, nutritional supplement, dough conditioner, solidifying agent, yeast nutrition, anti-caking agent, bulking agent, gum adjuvant and modifier in food processing. Food grade CaCO3 content is high, impurities are low, Pb, As, Hg, Fe and other indicators are particularly low.
feed
Light calcium carbonate is used in feed as a calcium supplement in feed processing. Feed grade light calcium carbonate must meet the following standards: calcium carbonate (CaCO3) content ≥ 98%; calcium carbonate (Ca) content ≥ 39.2%; moisture content ≤ 1%; hydrochloric acid content ≤ 0.2%; heavy metal content (Pb) ≤ 0.003%; Arsenic (As)≤0.0002%; Barium salt (Ba)≤0.030%.
toothpaste
Light calcium carbonate can be used in daily chemical products such as tooth powder, toothpaste, and cosmetics. Light calcium carbonate is used as a friction agent in toothpaste, which can not only remove dental plaque and material residues, but also polish the teeth without damaging the enamel, and has good permeability to aroma and paste diffusion. It can neutralize the acidic metabolites of dental plaque bacteria such as citric acid and reduce the pH value of the oral cavity, which has multiple functions such as removing acidic plaque and neutralizing acidic metabolites in the oral cavity.
Sealants and Adhesives
Calcium carbonate is used as a semi-reinforcing filler in adhesives, which can change the properties of the adhesive layer and reduce the cost of the adhesive, and basically does not react with the base material. Adding a certain amount of calcium carbonate to the adhesive can increase its bonding strength, hardness, heat resistance, dimensional stability, reduce curing shrinkage and linear expansion coefficient. For example, the commonly used glass glue, without the use of reinforcing fillers, has poor adhesion. Adding industrial calcium carbonate can improve the strength of the bonded joint, increase the surface hardness, increase the viscosity and thermal conductivity, and increase the impact toughness and wear resistance. , Improve the medium resistance of the adhesive and reduce the cost. Light calcium, especially nano-scale light calcium, has good particle size stability and uniform dispersion, and can provide sealants with good elasticity, water resistance, air tightness and rheology, and is an ideal sealing material.
ceramics
The development of cubic calcium carbonate with uniform particle distribution can be used for densified ceramics manufactured at low temperature of 600 °C.
cable
In cable products, light calcium carbonate can improve electrical insulation performance, moderate pH, good compatibility with resin, can increase filling amount and reduce cost, especially suitable for filling PVC wire and cable materials.
other
Light calcium carbonate is also widely used in organic synthesis, metallurgy, glass and asbestos production. It can also be used as a seed agent for industrial wastewater, a SO2 remover in SO2-containing waste gas, etc.
summary
With the rapid development of the national economy, the demand for light calcium carbonate is still on the rise. In the future, functionalization and specialization will become the development trend of light calcium carbonate, and the product structure will also undergo great changes. High-end products such as nano-scale calcium carbonate, ultra-fine calcium carbonate, medical-grade and food-grade calcium carbonate; various surface-modified special calcium carbonates, such as natural rubber special, synthetic rubber special, and light calcium carbonate special for coatings, will surely be sold in large quantities. put on the market to meet market demand.
References:
Han Jinrong. Application and development prospect of light calcium carbonate
Chen Yiwen. Study on the preparation technology of light calcium carbonate with different morphologies
Official websites of Guangxi Huana, Tianshi Nano, Huaca New Materials, etc.