Wollastonite is an inorganic acicular mineral with non-toxic, chemical resistance, good thermal stability and dimensional stability, glass and pearl luster, low water absorption and oil absorption, excellent mechanical and electrical properties, and a certain amount of supplementation. strong effect, etc. Wollastonite products can be divided into two categories: high aspect ratio wollastonite (10:1) and ground wollastonite. Its performance varies from application to application.
High aspect ratio wollastonite mainly uses its needle-like physical and mechanical properties, and is widely used in plastics, rubber, asbestos substitutes, paints and other fields, which can increase the hardness, flexural strength, impact resistance of products, and improve the electrical properties of materials , improve thermal stability and dimensional stability.
The ground wollastonite powder is mainly used in the ceramic and metallurgical industries. The SiO2 and CaO components in wollastonite provide low expansion rate and good thermal shock resistance.
Application status of wollastonite
as ceramic raw material
Wollastonite can densify the ceramic structure, improve the mechanical strength, reduce the coefficient of wet expansion, improve the strength and quality of the green body, reduce the sintering temperature, realize rapid sintering at low temperature, and achieve the purpose of energy saving and efficiency. In the glaze industry, wollastonite can improve the whiteness of the glaze, improve the flow performance, and reduce the defects of the products.
Wollastonite can be used to prepare various electric porcelain, architectural porcelain, daily-use ceramics and brake pads. China's wollastonite is mainly consumed in glazed tiles and ceramic blanks, accounting for more than 50% of the total wollastonite consumption.
as plastic reinforcing filler
Wollastonite has unique needle-like fibers, good insulation, wear resistance, and high refractive index, which can improve impact strength, enhance fluidity, and improve tensile strength, impact strength, linear tensile and mold shrinkage , is a better filling material for plastic and rubber products.
Wollastonite, as a filler and reinforcing agent in the plastics and rubber industry, is the application field with the most potential, the highest added value and the fastest growth. At present, this field accounts for 19-25% of the total world consumption of wollastonite. Demand for metal components is increasingly being replaced in manufactured goods, and the market demand is growing rapidly.
as asbestos substitute
Wollastonite has needle-like properties, low thermal expansion and excellent thermal shock resistance, and is an ideal substitute for short-fiber asbestos. At present, the total amount of wollastonite used as a substitute for asbestos accounts for 20-25% of the world's wollastonite consumption.
In terms of construction, wollastonite can still maintain its unique needle-like structure after special processing technology, so that the impact resistance, bending strength, The wear resistance is greatly improved. And because wollastonite has the advantages of non-toxic, odorless, non-radioactive, etc., it gradually replaces asbestos, which is harmful to human health, and becomes a new raw material for environmental protection building materials in the new century; in terms of friction materials, wollastonite with high friction coefficient is partially replaced. The friction materials prepared from asbestos have good comprehensive properties and are mainly used in brake pads, valve plugs, automobile clutches and other fields.
as paint filler
Wollastonite is used as a filler for paint coatings, which can improve the physical and chemical properties, durability and weather resistance of products, and reduce problems such as paint breakage and aging. At the same time, high-purity wollastonite can also replace expensive titanium dioxide as a white pigment, which is widely used in coatings to reduce the oil absorption of coatings, maintain alkalinity, and enhance corrosion resistance.
At present, wollastonite is rarely used in coatings, and wollastonite for coatings only accounts for 2-5% of the world's total consumption of wollastonite.
as metallurgical aid
Wollastonite has low temperature fluxing properties, stable chemical composition, high purity and neutral alkalinity. This excellent characteristic provides an ideal raw material for the protective castables of metallurgical steelmaking, especially wollastonite contains very little Al2O3, so the metallurgical mold slag made has a very strong ability to adsorb harmful inclusions of Al2O3 in molten steel, so it is widely used. in the metallurgical industry. At present, about 12-15% of the world's wollastonite is used in the metallurgical industry.
From ordinary carbon steel, manganese steel to stainless steel continuous casting, slag types from billet, bloom, slab to out-of-furnace refining, etc., wollastonite-based mold slag is widely used, replacing expensive imported Molding slag has played a role in promoting the development of metallurgical steelmaking industry.
as paper filler
The papermaking-grade wollastonite powder can still maintain its unique needle-like structure after special processing technology, so that the white board paper added with wollastonite powder can improve its whiteness, opacity (surface covering degree), flatness, smoothness , Adaptability, reduce the difference in the quantification of the profile and the wet deformation of the cardboard, improve the printing adaptability, and can greatly reduce the use of various other raw materials, and reduce the cost of paper products in general.
Due to the improvement of processing methods and the acquisition of ultra-fine particles, potential new uses are being discovered one after another, making wollastonite more and more widely used. Some experts predict that the demand for wollastonite in the ceramic industry will increase year by year at a rate of about 5%. The fastest growing is the rubber and plastics industry, especially the engineering plastics industry.