Applications and Future Trends of Nano Calcium Carbonate
Overview of Calcium Carbonate Properties
Calcium carbonate is an important inorganic compound widely used in many industries such as papermaking and pharmaceuticals. As a cornerstone of the 21st-century industrial revolution, nanomaterials have become an important research field and a focus of attention for manufacturers. Among them, cost-effective and efficient nano calcium carbonate has attracted much attention and is expected to become a key new material for modern industry.
In recent years, significant progress has been made in the refining technology of ultrafine calcium carbonate. Coupled with the complexity of its structure and the ongoing research into surface modification, its application potential has been greatly enhanced. For example, ultrafine calcium carbonate powder with a particle size of less than 100 nanometers exhibits significant reinforcing properties, while the reinforcing ability of ultrafine calcium carbonate powder with a particle size of less than 20 nanometers is comparable to that of silica. This allows them to partially or completely replace more expensive fillers such as carbon black and silica.
Nano calcium carbonate exhibits superior performance compared to traditional precipitated calcium carbonate in various applications, which has sparked global interest in developing innovative preparation methods for nanomaterials.
Preparation steps of calcium carbonate
In the preparation of calcium carbonate, carbon dioxide gas is first passed into a calcium hydroxide suspension to continuously carry out the carbonization process until the carbonization rate reaches 5% to 40%. Then, a crystal regulator is added to promote further carbonization until the pH value stabilizes between 8.0 and 9.0. Subsequently, a surface charge regulator and a steric hindrance regulator are added to continue the carbonization process until the pH value drops to between 6 and 7.5, ultimately forming nanoscale cubic calcium carbonate.
Crystal form modifiers can be one of a variety of compounds, including phosphates, sulfates, acetates, citrates, monosaccharides or polysaccharides, or combinations thereof, added in an amount of 0.05% to 3.0% of the slurry weight. Surface charge and steric hindrance modifiers can include one or more of phosphates, sulfates, chlorides, triethanolamine, and sodium dodecylbenzenesulfonate, with a recommended addition amount of 0.1% to 4.0% of CaCO3 weight.
Next, an aqueous coating agent solution is prepared by adding a fatty acid or a water-soluble titanium ester coupling agent (or both). The carbon chain length of the fatty acid should be in the C12-C18 range.
The nano calcium carbonate slurry is heated to 45°C to 95°C, and then a coating agent is added. The amount of coating agent should be 0.5% to 3.5% of the weight of calcium carbonate, and the coating treatment time is 0.5 to 3.5 hours. Finally, the slurry is filtered and dried to obtain nano-activated calcium carbonate.
Specific Applications of Calcium Carbonate
Due to its unique properties, nano calcium carbonate has a wide range of applications in various industries:
01 Rubber and Plastics Industry
Rubber: Nano calcium carbonate can be used as a reinforcing filler in products such as tires, hoses, and belts. It can partially replace silica, thereby improving tensile strength, tear resistance, and abrasion resistance.
Plastics: In materials such as PVC, PP, and PE, it improves rigidity, hardness, heat resistance, and dimensional stability, while also improving surface smoothness. Furthermore, it enhances the toughness of flexible PVC formulations.
02 Coatings Industry
Nano calcium carbonate, as a functional filler, can enhance the coverage, adhesion, anti-settling properties, and scrub resistance of coatings. Its translucent nature makes it ideal for high-end automotive and furniture coatings, ensuring that color performance is not affected.
03 Ink Industry
In resin inks, nano calcium carbonate exhibits excellent dispersibility, gloss, and transparency, as well as effective absorption and rapid drying properties.
04 Adhesives and Sealants
As an important thickener and thixotropic agent, it helps prevent sagging during application and imparts stability and mechanical strength to the final product. It is commonly used in silicone and polyurethane sealants.
05 Paper Industry
Nano calcium carbonate, used as a filler and pigment in coatings, can significantly improve the opacity, whiteness, smoothness, and ink absorption of paper, while reducing the need for fiber raw materials.
06 High-end Applications
Pharmaceuticals and Food: Can be used as a calcium source fortifier or pharmaceutical excipient.
Personal care products: In toothpaste and cosmetics, it is used as an abrasive or thickener.
Building Material: Adding it to cement can improve overall performance.
Market and Development Trends
The nano calcium carbonate market is experiencing significant growth due to the development of downstream industries and the increasing demand for high-performance materials. This growth is driven by the growing need for advanced materials across various sectors.
Sustainability and Environmental Considerations: A noteworthy trend is the use of carbon dioxide from industrial waste gases (such as those emitted by power plants) to produce nano calcium carbonate. This method not only addresses environmental issues but also embodies the concept of "turning waste into treasure," paving a promising path for future development.
Nano calcium carbonate is a crucial inorganic nanomaterial in modern industry and materials science. Through advanced chemical synthesis and innovative surface engineering design, it effectively transforms inexpensive raw materials such as limestone into high-value functional products. This process marks a significant shift in market sales models, moving from traditional bulk sales by the ton to more refined sales methods by the kilogram or even gram. As a key raw material, nano calcium carbonate plays a vital role in the transformation and upgrading of traditional industries and the development of high-tech industries.