HomeNewsCaCO3 powder surface modification machine-What is the difference between modified calcium carbonate

CaCO3 powder surface modification machine-What is the difference between modified calcium carbonate

Posted: 2020-06-24

  • What is the difference between modified calcium carbonate and ordinary calcium carbonate?


    Calcium carbonate is a very commonly used mineral industrial raw material and is widely used. In the production process of heavy calcium and light calcium, certain modifiers are used, and the surface modification through the powder modifier can improve the application performance and applicability of calcium carbonate, broaden its application market, and also promote calcium carbonate products. A method of market competitiveness.

    Heavy calcium carbonate processed with calcite and chalk is currently the largest amount of inorganic filler in organic polymer-based materials. However, the non-surface-treated heavy calcium carbonate has poor compatibility with polymers, and it is easy to cause uneven dispersion in the polymer matrix, resulting in interfacial defects in the composite material and reducing the mechanical strength of the material. As the dosage increases, these shortcomings become more obvious. Therefore, in order to improve the application performance of the heavy calcium carbonate filler, it must be surface-modified to improve its compatibility or affinity with the polymer base.  

    After surface modification, calcium carbonate has the following specific functions:



    1. Improve calcium carbonate dispersibility   

    Ultrafine is an important way to improve the quality of calcium carbonate, but the smaller the particle size of calcium carbonate, the higher the surface energy, the stronger the adsorption, and the more serious the agglomeration phenomenon. Through surface modification, the modifier can be adsorbed on the surface of calcium carbonate to make the surface have charge characteristics. Due to the repulsion of the same charge, calcium carbonate is not easy to agglomerate, thereby achieving good dispersion in the matrix.  

    2. Improve calcium carbonate compatibility

    Through surface modification, the interface compatibility and affinity of calcium carbonate and organisms can be increased, thereby improving the product performance of composite materials with rubber or plastics. For example, calcium carbonate treated with titanate coupling agent has good compatibility with polymer molecules. At the same time, because the titanate coupling agent can form a molecular bridge between the calcium carbonate molecule and the polymer molecule, the interaction between the organic polymer or resin and the calcium carbonate is enhanced, and the thermoplastic composite material can be significantly improved. Mechanical properties.

    3. Give calcium carbonate functionality

    Through surface modification, calcium carbonate can be changed from a common filler to a multifunctional modifier, such as calcium carbonate coated with silica on the surface, which can partially replace white carbon black and supplement white carbon black in certain properties Deficiencies. Light calcium carbonate coated with metal on the surface can improve some special properties of rubber products. Calcium carbonate composite material coated with titanium dioxide on the surface can replace titanium dioxide to a certain extent. 

    4. Lower the oil absorption value of calcium carbonate

    Surface modification is an important means to reduce the oil absorption value of powder. After surface modification of calcium carbonate, the degree of dispersion is increased, and the gap between particles is reduced. At the same time, the coverage of the surface of the calcium carbonate by the modified molecules reduces the gap in the particles, and this coverage reduces the polarity of the surface of calcium carbonate, and the particles The friction becomes smaller and the lubricity becomes better, so the bulk density can be increased and the oil absorption value can be reduced.

    5. Increase the added value of calcium carbonate

    At present, ordinary calcium carbonate has overcapacity and low price competition is fierce. The surface-modified calcium carbonate significantly improves the use effect, the user experience is good, and the value naturally increases accordingly. Of course, the modified prices of calcium carbonate with different meshes are also different.


    Calcium carbonate powder surface modification machine


    The surface modification of heavy calcium carbonate is mainly by adding surface modifiers to the surface chemical treatment. The surface modifiers used are: stearic acid (salt), titanate coupling agent, aluminate coupling agent, zirconium aluminate coupling agent, random polypropylene, polyethylene wax, etc.

    Surface modification should be carried out with the aid of equipment. The usual surface modification equipment is SLG continuous powder surface modification machine, high-speed heating mixer , vortex mill and fluidization modification machine.

    Calcium carbonate is dried (dry powder with lower water content can also be dried) and then fed into the surface modifier, and a certain amount of surface modifier is added at the same time. After a certain period of time, the surface modified active heavy carbonic acid is obtained calcium.

    The main factors affecting the surface modification effect of heavy calcium carbonate are: the variety, dosage and usage of surface modifiers (the so-called surface modifier formula); surface modification temperature and residence time (that is, surface modification process); surface The degree of dispersion of modifiers and materials. Among them, the degree of dispersion of surface modifiers and materials mainly depends on the surface modification machine.

    Surface modifier formulation is the key technology for surface modification of ground calcium carbonate. The selection of the surface modifier formulation must first consider the application system of modified heavy calcium carbonate, and secondly, the particle size, distribution characteristics and specific surface area of ​​the heavy calcium carbonate, as well as the cost of the surface modifier.

    After the formulation is determined, the surface modification equipment should also be selected. Good surface modification equipment should have the following basic process characteristics:

    ①Good dispersion of powder and surface modifier

    ②Equal chance of contact or action between powder and surface modifier

    ③ Modification temperature is adjustable

    ④Low energy consumption per unit product

    ⑤No dust pollution

    ⑥ Easy operation and stable operation
     
    calcium carbonate powder SLG modification machine
    Figure 1 SLG continuous powder surface modification machine

    1- thermometer; 2- discharge door; 3- air inlet; 4- air pipe; 5- host; 6- feed inlet; 7- metering pump; 8- feeder
     
    calcium carbonate powder surface SLG modification machine
    Figure 2 High-speed heating mixer

    1-Revolving cover; 2-Mixer; 3-Baffle plate; 4-Agitating impeller; 6-Drive motor; 7-Base


    Shanghai Clirik Machinery Co., Ltd. is the ideal choice for calcium carbonate processing and grinding. It can process heavy calcium of different fineness, high-quality light calcium, calcium oxide, calcium hydroxide and other products. The equipment runs smoothly, the output is high, and the environmental protection effect is good. In addition, there is a special powder modification machine that can be used on the surface of calcium carbonate. Modified production.
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