7 Application Fields and Characteristics of Sericite
Feb. 25, 2021
Sericite is a silicate mineral with a fine scaly structure. It has fine particles and is easy to hydrate. The structure has less cation replacement. The amount of K+ filled in between the layers is less than that of muscovite, so the potassium content in the chemical composition is slightly lower than that of muscovite. , But the water content is higher than that of muscovite, so some people call it a kind of clay mica that is more silicon, poor in potassium, and rich in water.
1.The application of sericite in the field of coatings
Superfine sericite powder is a new type of functional filler, which is widely used in paints and coatings. Because sericite powder has fine scaly, smooth crystal surface, large diameter-to-thickness ratio, high whiteness, stable chemical properties, light weight, smoothness, insulation, and radiation resistance, it is a variety of high-grade paints, rust-proof, fire-proof, and anti-corrosion coatings. Good pigments and fillers. Due to the layered structure of sericite, the dye particles can keep the paint film from fading for a long time after entering the interlayer of the sericite lattice.
The chemical nature of sericite is similar to the traditional coating filler talc, kaolin, wollastonite, etc. It is a silicate mineral, but its unique structure and special properties make it affect the relevant performance of the coating in the application, for example, The coating has a plane enhancement effect. The use of ultrafine sericite powder to replace traditional inorganic fillers in the coating formulation can significantly enhance the strength of the coating film and the adhesion between the coating film and the substrate, improve the integrity of the coating coating, weather resistance, acid and alkali resistance, and improve the paint Smoothness of the film. Applied to exterior wall coatings, it can improve its heat resistance, antifouling, radiation resistance and other properties.
Wet-milled sericite powder can be added to high-grade paint to replace zinc powder, aluminum powder, titanium powder, etc. Wet-milled sericite powder has been widely used in standard linseed oil civil paint, butadiene milk, vinyl propylene, and polyvinyl acetate. Interior wall paints such as fat emulsion and acrylic emulsion, as well as paints for automobiles, motorcycles, and ships.
After adding superfine sericite powder to steel structure fire-retardant coatings, its related properties are greatly improved. Adding titanate coupling agent-modified sericite powder can increase the heat resistance limit of the fire-retardant coating by 25℃ and water resistance. The limit is increased from 28h to 47h, and the bond strength is increased from 0.45MPa to 1.44MPa.
Adding an appropriate amount of superfine sericite powder to the rust conversion coating can enhance the heat resistance, weather resistance, water resistance, corrosion resistance and comprehensive mechanical properties of the coating film.
After adding ultra-fine sericite powder to the anticorrosive coating, the surface hardness, flexibility, adhesion, and impact resistance of the coating film are improved; at the same time, it can replace or partially replace the titanium dioxide in the coating formulation to reduce the cost without affecting the coating. Performance.
2. Application of sericite in rubber industry
In the rubber industry, sericite is a good filler or extender, which can reduce the rubber content of the material, thereby reducing production costs. Sericite has a unique sheet structure, which can effectively improve the damping performance of rubber. Its good compression resistance, tensile resistance, light resistance, flame resistance, weather resistance, heat resistance, acid resistance, and electrical insulation physical and chemical properties can improve the mechanical properties, heat resistance, and aging resistance of sericite-added rubber products. Used in the development of special rubber products.
Application studies of superfine sericite powder added to natural rubber, styrene butadiene rubber, neoprene and other rubbers show that under the same conditions, the reinforcing performance of sericite powder is significantly better than common inorganic reinforcing fillers such as calcium carbonate and clay. , Active silicon powder, etc., its reinforcing performance is second only to semi-reinforcing carbon black. The application research of rubber products with sericite powder has shown that its mechanical properties such as tensile strength, impact strength, and tearing force have been greatly improved.
Chen Jianwen added wet-ground sericite powder to natural rubber and styrene-butadiene rubber. The results showed that it not only enhanced the reinforcement performance of the product, but also had a smooth appearance and good hand feeling, and could partially replace carbon black or white carbon black.
3. Application of sericite in the field of plastics
Sericite has a unique fine scale structure and silky luster. When it is used as a reinforcing filler in the plastic industry, it can significantly improve the optical properties of plastic products, and improve the air tightness, rigidity, heat resistance and dimensional stability of plastic products. , Which is exactly the difference between it and other inorganic fillers.
The mechanical strength of the plastic products filled with sericite is improved to a certain extent, and the plastic will not be warped and deformed, which can endow the product with excellent dimensional stability; it has the functions of shielding ultraviolet rays, resisting infrared heat radiation, and blocking micro-electromagnetic waves; improving the product The properties of aging resistance, corrosion resistance, heat resistance, insulation, etc.; reduce the flammability, abrasion and permeability of products; improve the dielectric properties of thermosetting plastics, etc.
When 50% sericite powder is added to polypropylene, the breakdown resistance of the product is increased by 1.3 times, and the dielectric constant is increased by more than 40%. When sericite powder is used in nylon 6, it can improve the rigidity and heat resistance of nylon 6, reduce its molding shrinkage, etc., and at the same time can greatly reduce the production cost of nylon 6, and enhance market competitiveness.
The performance of hard polyvinyl chloride products added with wet-ground sericite powder is better than that of common fillers such as activated calcium carbonate, calcined kaolin, talc, etc. The quality is in full compliance with national standards, and it is also conducive to plastic processing enterprises to reduce production costs And improve product quality.
4. Application of sericite powder in the field of cosmetics
Sericite powder has strong smoothness, stable chemical properties, strong adhesion, good dispersibility, evenly mixed with water and glycerin, silky luster, UV resistance and other excellent characteristics. It is a high-quality cosmetics industry in the beauty and cosmetics industry. raw material. Because of its fine texture, elasticity, appropriate gloss, high whiteness, and little or no heavy metal elements such as lead and mercury, it can meet the special requirements of some high-end cosmetics.
The powder cake test shows that the superfine sericite powder is soft, smooth and full of elasticity, and the skin has a velvety smooth feeling after applying the powder; the fine scale structure of sericite has the function of reflecting ultraviolet rays, and it can prevent the skin from tanning when added to the sunscreen The role of.
Young Hoon Yun and others have greatly improved the whiteness by coating TiO2 on the surface of sericite, replacing titanium dioxide as a high-end cosmetic filler, reducing production costs and improving market competitiveness.
5. Application of sericite in potash fertilizer manufacturing
At present, there are many domestic and foreign researches on the extraction of potassium from insoluble potassium ore. The methods for extracting potassium from insoluble potash can be roughly divided into five categories: direct method, calcining method, volatilization method, wet chemical method and biological method. At present, potassium feldspar is the main research object, and the research of potassium extraction technology is carried out.
There are few reports on the extraction of potassium from mica minerals. Foreign scholars such as Reichenbach and Varadachari have conducted a series of basic research on the extraction of potassium from mica minerals. Domestic scholars Han Yuexin, Yin Wanzhong and others have conducted potassium extraction research on the potassium-rich shale rich in sericite, using methods such as adding NaOH roasting and sulfur-fluorine mixed acid leaching. The research results show that the potassium leaching rate is as high as 94.03%; Wang Deqiang, Wang Fuya and others have studied the potassium release performance of muscovite, sericite and illite. The results show that the potassium release of illite is the largest under natural conditions; the potassium release effect of sericite is the best after activation at 650℃, and the available potassium Increased from 237.8µg/g to 417.3µg/g, and slow-acting potassium from 761.5µg/g to 4859.3µg/g.
6. Application of sericite powder in the field of papermaking
In the paper industry, adding sericite powder can increase the color brightness of the paper, improve the ability of the paper to reflect ultraviolet rays and the corrosion resistance, and the paper that is stored for a long time is not easy to yellow.
A Japanese study found that the particle size of the added sericite has a significant effect on the breakage, smoothness and tightness of the paper. When sericite powder is used as a filler, packaging paper and printing paper with excellent performance can be produced.
7. Application of sericite powder in electrode coating
In the production of welding electrodes, sericite powder is used as the electrode coating material, which can prevent the problem of electrode coating cracking, and give the electrode coating good slippage and viscosity, and improve the process performance, pressure coating performance and external quality of the electrode. At the same time, it can replace titanium dioxide and reduce the production cost of welding rods.
In addition, sericite can also be used in ceramics, pearlescent mica titanium, electrical insulating materials, etc. In addition, the company also provides biotite and mica powder, please feel free to contact us if necessary
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