Product Insights | Production Processes and Applications of Nano-Calcium Carbonate
Nanoscale calcium carbonate is by no means "ordinary lime powder," nor is it a product that can be manufactured simply by picking up a random stone. Rather, it is a nanoscale powder material—characterized by uniform particle size and stable performance—produced from high-quality limestone containing over 53% calcium, processed through a series of precise, multi-stage procedures. Each step requires rigorous control over critical parameters—such as temperature, humidity, and reaction time—to ensure the final product possesses core attributes including a high specific surface area, strong dispersibility, and high whiteness.
01. Factory Design Features
The main production facilities comprise the Kiln Workshop, Power Workshop, Digestion Workshop, Aging Workshop, Post-processing Workshop, and Recycled Water Pond. The core raw materials consist of limestone, fuel coal, and water, supplemented by small quantities of additives and coating agents. The primary medium within the production workshops is calcium carbonate solution, which is a non-combustible substance. Compared to large-scale chemical projects, the raw materials utilized in this project present lower safety risks.
02. Nano-Calcium Carbonate Production Process Flow
Currently, the majority of domestic manufacturers employ the carbonation method to produce nano-calcium carbonate. This method offers the distinct advantages of utilizing widely available raw materials while ensuring controllable production costs. Its core principle lies in the carbonation reaction between Ca(OH)₂ and CO₂ to generate CaCO₃; the specific process is both concise and efficient. The production workflow is subdivided into the following stages: raw material preparation, calcination, digestion, aging, carbonation, surface coating, drying, de-agglomeration, and packaging.
Raw Material Preparation: Limestone transported from the mine to the plant's raw material yard is washed in a stone washer to remove soil and impurities, then held in readiness for use. Washed anthracite, transported to the facility from external sources, is deposited into the coal bins located within the plant's raw material yard, where it is kept in reserve.
Raw Material Calcination: High-purity limestone and anthracite are charged into the kiln in a specific ratio and calcined at 1100°C, undergoing decomposition to produce calcium oxide and kiln gas containing 30% CO₂. After cooling and purification, the kiln gas is conveyed to the carbonation section; the entire process features intelligent control of temperature and pressure.
Slaking and Aging: Lime is fed into a slaker via a vibrating feeder, where it reacts with metered hot water to produce Ca(OH)₂ (at temperatures exceeding 80°C, the water source switches to recycled water). Following a three-stage process of slag removal and impurity elimination, the refined lime slurry is stored in a holding tank.
Carbonation and Coating: The refined lime slurry is thickened and cooled before being pumped into a carbonation reactor, where it reacts with kiln gas for 60–90 minutes at 20–35°C under controlled gas flow. After the slurry has thickened, it undergoes a coating process at 80°C—followed by impurity removal and cooling—before being conveyed to the pressure filtration and drying section.
Pressure Filtration and Drying: Following the coating process, the refined slurry undergoes pressure filtration using a filter press. The resulting filter cake is stored in a filter cake bin; subsequently, it is sliced by a slicer located in the lower section of the bin and fed into a dryer for drying. The heating medium for the dryer consists of hot air supplied by a hot-air furnace, with the hot air temperature ranging from approximately 200°C to 300°C.
De-agglomeration and Packaging: The dried nano-calcium carbonate powder is fed into a de-agglomerator for processing; the de-agglomerated powder is then conveyed to the finished product silo. From the silo, the nano-calcium carbonate powder is packaged using a packaging machine and transported via a belt conveyor to the warehouse for storage.
03. Multifaceted Applications of Nanocalcium Carbonate
The value of nano-calcium carbonate extends far beyond mere "filling and weight reduction"; more importantly, through performance modification, it empowers and upgrades end products. Its application scenarios span every facet of both industrial production and daily life:
Industrial Papermaking Sectorhttps://www.useencalcium.com/industries/pulp-and-paper/
The papermaking industry is one of the foundational sectors of the national economy, inextricably linked to socioeconomic development and people's daily lives. As a key raw material for high-grade printing paper, coated paper, and tissue paper, nanocrystalline calcium carbonate enhances paper whiteness, stiffness, and scrub resistance; it reduces the consumption of premium pulp and lowers production costs while simultaneously optimizing printability.
Rubber and Plastics Sectorhttps://www.useencalcium.com/industries/rubber/
The industries where the application of nano-calcium is most mature are the plastics and rubber sectors. Surface-treated nano-calcium carbonate can improve the rheological properties of plastic melts and enhance their moldability; when used as a plastic filler, it provides toughening and reinforcing effects, thereby increasing the plastic's flexural strength and flexural modulus. When utilized as a rubber filler, its primary functions are to increase volume, reduce costs, or improve processing characteristics and vulcanization performance; it can also enhance the elongation, tensile strength, tear strength, and flexural resistance of rubber products. The specific plastic product categories involved mainly include light-weight polyolefin pipes (such as PVC, PE, and PP); artificial leather; wire and cable sheathing compounds; PVC films (including calendered films); automotive components; shoe soles; rubber hoses; adhesive tapes; and tires.
Paints and Inks Industryhttps://www.useencalcium.com/industries/ink/
In high-end coatings, nano-calcium carbonate serves as an extender pigment, offering advantages such as fine particle size, uniform distribution, high whiteness, and excellent optical properties. It significantly improves the thixotropy of the coating system and can substantially enhance adhesion, scrub resistance, and stain resistance, while also boosting mechanical strength and surface gloss. Furthermore, it acts as an effective anti-settling agent and can partially replace titanium dioxide to reduce costs. In ink formulations—where nano-calcium carbonate is predominantly utilized—its exceptional dispersibility facilitates the optimal color development of other pigments. It meets requirements for transparency and superior gloss, thereby enhancing the ink's printability. Due to its minute particle size, it yields printed products with smooth surfaces and crisp halftone dots; this improves the overall finish of the ink and makes it particularly suitable for high-speed offset printing applications.
Adhesive Productshttps://www.useencalcium.com/industries/adhesives-and-sealants/
Nanoscale calcium carbonate serves as a primary component in sealants, functioning to regulate the product's thixotropy. Its scope of application encompasses structural sealants such as silicone, polysulfide, polyurethane, and epoxy. In addition to nanoscale calcium carbonate, fumed silica also acts as a key functional filler in sealants. Application Characteristics: When incorporated into sealant and adhesive materials, it exhibits excellent affinity with the polymer matrix; it accelerates the cross-linking reaction, significantly enhances the system's thixotropy, improves dimensional stability, and boosts the mechanical properties of the sealant. Furthermore, it allows for high loading levels, thereby fulfilling the dual functions of both filling and reinforcement.
