Key Functions of Calcium Carbonate Surface Modification

Surface modification is a core method for transforming mineral fillers from ordinary extender fillers into functional fillers. Its primary goal is to optimize surface properties and address application pain points, while achieving dispersion, viscosity reduction, filling enhancement, and interfacial mechanical strengthening. The commonly used modification methods include chemical modification, coating modification, and mechanochemical modification.

Enhance Compatibility and Adaptability

Surface modification improves the affinity between calcium carbonate and organic materials such as rubber and plastics, enabling better integration. For example, after treatment with titanate coupling agents, its compatibility with polymer molecules is significantly enhanced, which can remarkably improve the mechanical properties of thermoplastic composites, including impact strength, tensile strength, flexural strength, and elongation at break.

Improve Dispersion Uniformity

The finer the particle size of calcium carbonate, the higher its quality. However, fine particles have high surface energy and are prone to adsorption and agglomeration. After surface modification, modifiers adsorb on the particle surface and impart charge characteristics, reducing agglomeration and ensuring uniform dispersion of calcium carbonate in the matrix material, thus stabilizing product performance.

Reduce Oil Absorption Loss

Modified calcium carbonate exhibits more uniform dispersion, with reduced gaps between and within particles. Meanwhile, modified molecules cover the surface, weakening polarity and reducing friction between particles, leading to denser particle packing. This effectively lowers the oil absorption value and reduces the consumption of matrix materials in applications.

Expand High-End Application Fields

With good affinity and low oil absorption, modified calcium carbonate can be widely used in high-end scenarios such as plastics, coatings, rubber, papermaking, sealants, and breathable films. It not only improves the quality of end products but also helps downstream enterprises reduce costs, breaking the application limitations of ordinary calcium carbonate.

Increase Product Added Value

The market for ordinary calcium carbonate suffers from overcapacity and fierce low-price competition. Surface-modified calcium carbonate offers significantly improved usability and user experience, leading to higher product prices and added value. This helps enterprises break away from low-price competition and expand profit margins.

Endow Diversified Functions

Surface modification enables calcium carbonate to gain new functions: coating with silica can partially replace fumed silica; coating with metals enhances the special properties of rubber products; coating with titanium dioxide can substitute part of titanium dioxide; treatment with phosphates or other substances can produce acid-resistant calcium carbonate, expanding application boundaries.

Basic Process Conditions for Surface Modification

The process and equipment for surface modification need to be flexibly adjusted according to the modification purpose, method, and type of modifier. The core principle is to achieve the highest coating rate and optimal modification effect with the minimum consumption of coating materials and cost. The process design must meet three core requirements: adapting to the application characteristics of the modifier to ensure its uniform dispersion; realizing uniform and firm coating of the modifier on the powder surface; and guaranteeing controllable process parameters and stable product quality.
01

The modifier shall be pretreated by dilution, emulsification, spraying, or other methods to improve its own dispersion, laying a foundation for subsequent coating.

02

Prioritize the continuous spraying or dripping mode linked with the continuous feeding of powder to ensure the synchronization and adaptation between modifier addition and material transportation.

03

Accurately regulate the system temperature and reaction time to match the modification mechanism and the modifier’s requirements for process conditions, ensuring the full progress of the modification reaction or coating process.

04

Precisely measure the modifier and materials separately to achieve uniform addition and feeding, ensuring the instantaneous accuracy of their proportioning ratio.

05

Pay attention to auxiliary supporting facilities and environmental factors: rationally use supporting equipment such as dispersers and classifiers, and control external conditions including ambient temperature and humidity.

06

Optimize equipment operating parameters and conduct regular maintenance of equipment status to ensure stable equipment operation and maintain process consistency.

Three Mainstream Modification Production Processes

Continuous Modification Production Process

The continuous modification production process is mostly connected after the dry powder preparation process, focusing on large-scale continuous production of non-metallic mineral active powders. Such powders are widely used as inorganic fillers or pigments in polymer-based composites such as plastics, rubber, and adhesives.

The core of this process is to realize continuous powder feeding and continuous modifier addition. Therefore, in addition to the main modification equipment, it is necessary to match continuous feeding devices and precise modifier addition devices. Its production equipment is significantly different from batch-type equipment, which can meet the large-scale production needs of large enterprises and adapt to high-yield scenarios.

Batch Modification Production Process

The batch modification production process allows wide adjustment of time and temperature, and has strong adaptability to different modifiers and composite formulas. It is especially suitable for the surface chemical modification of small and medium-batch powders, such as silane coupling agent modification scenarios.

Key parameters including rotation speed, temperature, processing time, material filling rate and modifier addition method need to be controlled during operation. The specific process is: put the measured powder raw materials and prepared modifier into the modification equipment together, complete modification at a set temperature for a specified time, unload the finished product, and then reload for the next batch. It is usually used with an air classifier to separate agglomerated particles and improve product uniformity.

Composite Modification Production Process

The composite modification production process is an integrated modification scheme with multiple equipment linkage. The core is to add surface modifiers synchronously during mechanical force action or fine grinding and ultra-fine grinding processes. While reducing the powder particle size, the chemical coating modification of the particle surface is completed.

This process combines the advantages of continuous and batch processes, with uniform and strong adhesion of modifiers, high process controllability, and stable product quality. In practical applications, it is often matched with a depolymerizer or classifier to further optimize product dispersibility and particle size distribution.

Equipment and Processes We Can Provide

Cyclone Mill Modification Process

This calcium carbonate modification process using a cyclone mill boasts prominent advantages. Its strong airflow cyclone effect ensures full contact between modifiers and calcium carbonate particles, enabling efficient and uniform dispersion and coating. Equipped with an adjustable classification structure, it has a wide particle size adaptability range. Combined with variable frequency temperature control design, it guarantees stable product quality. The automatic feeding system reduces costs and improves efficiency. The flexible process is compatible with upstream and downstream procedures, integrating multiple functions for energy conservation and easy maintenance.

Turbo Mill Modification Process

When the equipment operates at high speed, it will strongly drive the airflow inside the chamber to form a powerful air flow field, accurately guiding and retaining the originally agglomerated and adhered calcium carbonate powder particles in the specially designed grooved stator structure inside the equipment. The air pressure and wind speed of the airflow are coupled and synergistically act...

Three-roller Mill Modification Process

The three-roll mill calcium carbonate modification process relies on the relative motion of three rotors. By regulating the action mode of cyclones and eddies inside the equipment, it achieves surface coating modification of calcium carbonate particles synchronously during the powder dispersion process. This process is compatible with mainstream calcium carbonate types such as precipitated calcium carbonate (PCC) and ground calcium...

Pin Mill Modification Process

The pin mill is a high-efficiency ultrafine grinding and **integrated modification equipment**. Its core consists of two grinding discs that can rotate independently at high speed (or one rotating and one stationary), with needle-shaped/tooth-shaped elements evenly distributed on the disc surfaces. For calcium carbonate powder processing requirements, during operation, the relative high-speed movement of the two discs generates intense shearing,...

Mechanical Fusion Machine Modification Process

This equipment adopts a batch operation mode, making it particularly suitable for the modification scenarios of calcium carbonate powder with additives such as silanes that require high temperature and long reaction time. It is equipped with built-in heating and timing devices to precisely control the temperature and reaction duration of calcium carbonate modification. The inner lining can be made of optional ceramic materials to achieve zero metal contamination of calcium carbonate powder. It drives the full mixing and integration of calcium carbonate materials and modifiers through mechanical force, enhancing the coating modification effect.