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Source Lei tell you | what is unique about nano-kaolin? What is the application prospect?

Release time:

2024-01-29 09:35

 

Source Lei tell you | what is unique about nano-kaolin? What is the application prospect?

 

Nano-kaolin is a kind of powder material prepared by intercalation, peeling and surface treatment, which has the thickness of kaolinite wafer in the range of 1-100nm. It has the characteristics of small size effect and surface effect, and has good performance and value in application, which is the focus of current research.

 

 

1. Characteristics of nano-kaolin powder

 

The surface of kaolinite crystal layer is charge neutral, still has low viscosity and good fluidity at high concentration, and is usually higher purity and less impurity than montmorillonite clay deposit. According to these characteristics, kaolinite can be used to produce nano clay powder with excellent performance.

 

(1) Chemical composition

 

The chemical composition of nano kaolin is close to the theoretical value of kaolinite, especially the content of iron and titanium which affect the whiteness is relatively low.

 

(2) Particle size and shape characteristics

 

In general, the aspect ratio of kaolinite wafers is between 1:20 and 1:50, so it can be inferred that the thickness of kaolinite flakes is between 50 and 20nm. In the natural state, kaolinite particles are adsorbed and connected to each other to form aggregates or aggregates. Direct application is impossible to produce nano-effect. Appropriate methods must be used to separate the particles into individual nanoparticles to produce nano-mutation effect.

 

(3) Specific surface area

 

The specific surface area of kaolin is generally 10-15m.2Between/g. The specific surface area is closely related to the particle size of kaolinite, the smaller the particle size, the larger the specific surface area.

 

(4) Loose density

 

Generally, the finer the powder, the smaller the loose density. The bulk density of kaolin less than 2 microns is about 0.3 g/cm3while the bulk density of nano-kaolin is 0.06-0.07 g/cm3.

 

(5) Surface effect

 

Due to the small particle size, the number of surface atoms and specific surface area of nano-kaolin increases, which increases the surface energy and the atomic coordination is insufficient, so that the activity of atoms is enhanced and it is easy to combine with other atoms.

 

(6) Small size effect

 

Due to the nano-size of the particles, most of the atoms of nano-kaolin are surrounded by nano-grain boundaries, in which the atoms are randomly arranged and are easy to migrate when subjected to external forces, so that the material has a certain degree of ductility and good toughness. The small size of the particles also enhances the light absorption properties of the nano-kaolin and shifts the plasmon resonance frequency of the absorption peak.

 

2. Application prospect of nano-kaolin

 

(1) Ceramics

 

In the process of making ceramics, kaolin has two functions: first, it is the main raw material for building sanitary ceramics, daily ceramics, radio electric porcelain, electric porcelain, arts and crafts porcelain, special industrial ceramics and industrial ceramics; second, it is used as a binder to bond other mineral ingredients (such as feldspar, quartz, etc.) together to make porcelain blanks.

 

The use of nano-kaolin as a raw material for making ceramics can make its structure denser, and can also increase ductility and toughness, so that the product has high hardness, easy processing, and difficult to break.

 

In the ordinary ceramic glaze coated nano kaolin, increase the glaze activity and sterilization at the same time, but also make it more smooth, so as to facilitate cleaning. Nano kaolin price than nano TiO2Low, can replace it in ceramics as a functional filler, reduce costs, but also has far-infrared insulation and anti-ultraviolet functions.

 

(2) Rubber

 

Adding nano-kaolin to rubber products, because the nano-particles are aligned in the rubber, and the rubber macromolecules are closely combined with the nano-size, the mechanical and physical properties of the product such as flexibility, elasticity, elongation at break and barrier properties are significantly improved, and the cost can be reduced.

 

Nano kaolin has small size and good dispersion performance, which can improve the stress distribution inside the rubber, reduce the fragile surface, and make it have high reinforcement. It can be used instead of white carbon black in butadiene rubber, nitrile rubber, natural rubber and EPDM rubber.

 

Based on these excellent properties, nano-kaolin can be used inTire inner tube, sidewall rubber, golf ball rubber, rubber wire, sole rubber, nitrile sealing rubber, rubber stick, rubber roller, conveying rubberand other rubber products.

 

(3) Coating

 

Nano kaolin particles are small, surface activity, and most of the coatings, raw materials can be compatible, easy to evenly dispersed in the coating, can form a uniform and stable system, so that the coating brushing, adsorption, resistance to moisture absorption, fading resistance, dirt resistance and impact resistance and other properties have been significantly improved.

 

The use of nano-kaolin as an additive for coatings can meet the increasingly diverse requirements for coatings in use. In the coating industry, nano-kaolin can also be used as a body pigment to increase the whiteness of the product, and it does not produce precipitation for a long time, which improves the gloss, hiding power and drying of the product, and also has a reinforcing effect, which can replace titanium dioxide. The same effect can also reduce production costs.

 

In addition, the large specific surface area of nano-kaolin makes the atomic and electronic behavior of the surface change, so that the coating has some special performance in the optical effect.

 

(4) Concrete

 

Reinforced concrete structure with the extension of the use of time and the occurrence of steel corrosion phenomenon, this phenomenon makes the concrete and steel bond performance between the sharp deterioration, until the steel can not play a normal role, affecting the structure of the use and safety.

 

Nano-kaolin, as a kind of nano-material with excellent performance, can improve the resistivity and mechanical properties of concrete materials. By filling in the tiny holes inside the matrix, it can effectively prevent the penetration of concrete materials, thereby improving its compactness, preventing the entry of chloride ions inside the concrete, and slowing down the corrosion of steel bars.

 

(5) Agriculture

 

At present, there are some problems in the application of fertilizer in our country, such as the need to increase the application amount due to the low utilization rate of fertilizer, which pollutes the ecological environment and a series of problems [. Kaolin can effectively adsorb and desorb nitrogen, phosphorus, potassium and organic carbon, and improve the efficiency of fertilizer application, thereby reducing the amount of use and reducing environmental pollution.

 

Under the same conditions, the effect of adding nano-kaolin in fertilizer is much higher than that of natural kaolin, and it shows a broad application prospect in agriculture.

 

(6) Other

 

Adding nano-kaolin to the manufacturing materials of drinking fountains and refrigerators can play a role in antibacterial and disinfection; adding nano-kaolin to plastics can improve the heat resistance of products, enhance strength, and reduce density; nano-kaolin can also be used as Stealth materials also have good application prospects in the field of national defense. With the development of science and technology, the cost of nanomaterialsIt will gradually decrease, and the application range of nano-kaolin will be more extensive.

Place, nano, kaolin, rubber, material, can, application, ceramics, properties, kaolinite

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