Introduction
Heavy calcium carbonate, referred to as heavy calcium carbonate, is made of calcite, marble, limestone, chalk, White Marble and other natural carbonate ores by crushing, grinding and grading. With the advantages of large reserves, low cost and adjustable performance, it has become an indispensable filler, constitutional pigment and functional chemical raw materials in all walks of life. Different downstream industries have vastly different demands for indicators such as purity, particle size, whiteness, oil absorption value, wear, and particle morphology of heavy calcium. Accurately matching terminal needs is a key lever for powder processing enterprises to optimize production lines, create differentiated products, and expand markets. This article combines the actual production conditions of the entire industry, systematically disassembles the nine mainstream application scenarios of heavy calcium, synchronously sorts out the material selection standards and product development points in various fields, and provides reference for industry practitioners.
1、 Papermaking: Paper fillers and core raw materials for coating pigments
In the papermaking industry chain, fibers are the base material, and heavy calcium is the second most important auxiliary material in terms of usage. It is divided into two major scenarios: paper fillers and paper surface coating pigments, optimizing the overall quality of paper in all aspects. After adding heavy calcium, the opacity and surface whiteness of the paper substrate are significantly improved, and the paper surface is delicate, uniform, and has a soft touch, which can effectively reduce the problems of moisture absorption, expansion, deformation, and warping of the paper; At the same time, the powder can adsorb ink, improve printing color clarity and adaptability, reduce the use of wood pulp fibers, and control paper production costs. At the maintenance level of paper machine equipment, powder wear value is the core assessment parameter. Low wear heavy calcium can reduce the wear of scrapers, filters, and rollers, and extend the equipment maintenance cycle. Overseas paper companies often use chalk with low impurities and excellent purity as raw materials; When domestic enterprises mine calcite and marble powder, they prioritize selecting mineral sources with high calcium carbonate content and low harmful impurities such as iron and silicon to meet the production requirements of high-end paper products.
2、 Plastic: the largest downstream market for heavy calcium consumption in China
The plastic processing industry covers the vast majority of common polymer materials such as PVC, PE, PP, ABS, etc., and is the core consumer market for heavy calcium. Powder filling can optimize plastic products from multiple dimensions such as molding, performance, and cost. In terms of physical properties, heavy calcium filling can reduce the shrinkage rate of plastics after injection molding and extrusion molding, and stabilize the size of finished products; Simultaneously improving the surface hardness and overall rigidity of the material, enhancing its ability to withstand heat deformation in high-temperature environments, and endowing the product with a matte and soft glossy appearance. At the processing level, the reasonable addition of heavy calcium can adjust the fluidity of the melt and simplify the forming process; The modified functional heavy calcium can also endow plastic with insulation and flame retardant properties. From the perspective of production cost, replacing high priced resin raw materials with a large amount of powder can significantly reduce the cost of plastic product raw materials, and is widely used in products such as pipes, profiles, plastic films, and home appliance casings.
3、 Coatings: Universal skeleton pigments, suitable for all types of coating products
The heavy calcium in the coating system belongs to the basic constitutional pigment, which plays a role in supporting the skeleton in the paint film, filling the fine gaps of the substrate, and adjusting the coating construction and film-forming performance. The addition ratio of different coating categories varies significantly. Putty powder is used as a basic leveling material for home decoration, with heavy calcium accounting for 70% -80% of the total raw material; The amount of industrial thick paint powder added exceeds 30%, and the range of water-based latex paint added for interior and exterior walls is between 20% and 60%; Matte finish paint relies on heavy calcium to achieve extinction effect, for example, the proportion of heavy calcium added in matte white latex paint is about 11.5%; Calcium carbonate can assist in enhancing rust prevention ability in metal anti-corrosion paint, with a conventional addition amount of 30%; Ordinary interior wall vinyl acetate lotion decorative paint, calcium carbonate is routinely mixed with about 10%. Ultra fine grinding of heavy calcium is suitable for high-end latex paint, which can shorten the time consumption of sanding and dispersing process, improve the coverage of paint film, reduce the amount of expensive titanium dioxide, and improve the feel of putty polishing; Low end economical latex paint uses coarse particle size, low oil absorption value, and heavy calcium compression formula cost. Hard standard for high-end latex paint powder for interior walls: particle size d97 is less than 10 μ m, median diameter d50 is controlled at around 1.5 μ m, powder whiteness is higher than 95, and effective calcium carbonate content is not less than 98%.
4、 Rubber: Incremental filling material, suitable for various rubber molded products
In rubber production, heavy calcium belongs to the economical filling powder, which is often used in combination with reinforcing powders such as carbon black and white carbon black to optimize the processing performance of the rubber material and the effectiveness of the finished product. It is suitable for shoe soles, rubber floors, water hoses, as well as rubber products with full process of molding, extrusion, and foaming. After filling, the volume of the adhesive material can be greatly expanded, reducing the cost of raw materials; Improve the stiffness of rubber blanks, reduce the shrinkage amplitude of extrusion molding, and enhance the insulation performance of finished products. In addition, ultrafine heavy calcium can also serve as a production isolation agent, mold release agent, or coloring filler for white rubber products.
5、 Breathable functional film: modified calcium carbonate track for sanitary packaging
The breathable film is made of PE and PP plastic resin as the matrix, mixed with about 50% special modified heavy calcium blend granulation. After extruding the film, it is oriented and stretched to form a large number of micropores, with dual characteristics of waterproof and breathable. Its downstream applications span across three major fields: medical, food, and daily use. In the field of healthcare: surgical protective clothing, disposable medical gloves, medicinal packaging film, sanitary napkins, baby diapers, disposable bed sheets for diagnosis and treatment; Food packaging field: cling wrap film, cooked food composite packaging bags; Daily consumer goods: waterproof and breathable clothing interlayer, lightweight disposable raincoat. The quality and processing stability of breathable film products rely entirely on the properties of calcium carbonate powder: high-quality heavy calcium can avoid material coking and pinhole defects during extrusion, and is suitable for mass production of ultra-thin films; At the same time, it directly determines the permeability rate, water pressure resistance, thermal stability, and tensile mechanical strength of the film, and belongs to customized powders specifically designed for segmented tracks.
6、 Food industry: compliant food calcium additives and raw materials for organic calcium preparation
Food grade heavy calcium is a multifunctional food additive allowed by the state to act as an acidity regulator, calcium nutrient fortifier, dough improver, anti caking agent, leavening agent, and chewing gum specific additive. It is widely added to products such as biscuits, breakfast cereals, dairy products, soft capsules, and gum based fruits. High purity food grade heavy calcium is still the core raw material for preparing organic calcium nutritional fortifiers such as calcium citrate, calcium lactate, and calcium gluconate. The production threshold for food grade powders is higher: the mineral source must be selected from heavy metal free, high-purity natural calcite; The entire process of crushing, grinding, grading, and packaging is sealed and dust-proof, completely eliminating pollution from heavy metals and impurities of different colors, ensuring food safety.
7、 Daily chemical toothpaste: mainstream cleaning and friction agent for mid to low end toothpaste
Friction agent is the core cleaning component in toothpaste formula, and heavy calcium has become the mainstream choice for mid to low end toothpaste due to its abundant raw material reserves and low production costs. Limestone and calcite powder are often used as raw materials. Calcium carbonate used in toothpaste has strict physical and chemical requirements: moderate particle hardness, uniform particle size distribution, extremely low solubility in water, and stable chemical properties; The appearance of the powder is pure white without any impurities or odors. It has a mild and non irritating taste, fully complying with the non-toxic safety standards of daily chemical products. It relies on particle friction to remove surface stains on teeth.
8、 Livestock and poultry feed: animal specific calcium source mineral supplement
Heavy calcium, as a specialized mineral calcium source for feed, meets the calcium needs of livestock and poultry bones and eggshells. The addition ratio of conventional livestock and poultry compound feed is 0.5% -1%; Egg laying hens, ducks, and geese enter the peak period of egg production, and the amount of calcium added increases to 8% -9%. Egg and poultry feed has special requirements for the particle size of calcium carbonate: ultra-fine powder has a short residence time in the muscle and stomach, low calcium absorption and utilization rate, and is prone to causing thin shell eggs and broken eggs. The industry's optimal compounding solution adopts multi-stage particle mixing: 75% 6-8 mesh coarse particles, 12.5% 10-12 mesh medium particles with 12.5% 50 mesh fine powder. The combination of coarse and fine particles can achieve a continuous and balanced supply of calcium, improve the density of eggshells, and reduce the rate of damage; At the same time, coarse particles can assist in grinding grass in the muscle stomach, improving the digestion and absorption efficiency of livestock and poultry.
9、 Artificial stone: resin based artificial stone core filling powder
The mainstream resin artificial stone on the market can be filled with over 75% heavy calcium powder. The higher the powder filling amount, the less resin binder is used, which can effectively control the production cost of artificial stone, reduce the use of chemical resin, and improve the environmental protection properties of the product. The two core indicators of artificial stone powder are: first, low oil absorption value, which directly affects resin consumption. The industry generally reduces oil absorption through powder surface activation modification process; The second is high whiteness. The white artificial stone in the kitchen and bathroom has strict requirements for whiteness, and the mature specialized heavy calcium on the market can achieve a whiteness of over 95. The product granularity covers a full range of specifications from 20 mesh to 1250 mesh, suitable for the production of artificial stones with different textures and processes.
