The Use and Consumption of Wollastonite
Wollastonite is widely used in sectors such as ceramics, plastics, asbestos substitutes, metallurgy, coatings, etc. due to its low water absorption, thermal stability, conductivity, and chemical inertness. At present, the annual consumption of wollastonite in the world is about 600000 tons, with ceramics accounting for about 40-50%, plastics 20-25%, asbestos substitutes 20-25%, metallurgy accounting for 10%, and pigments and others accounting for 5%. High aspect ratio wollastonite (15:1~20:1) is mainly used as a reinforcing functional filler in coatings, plastics, and rubber to improve hardness, bending strength, and impact resistance. It can also improve the electrical properties of plastics, enhance their thermal stability, enhance corrosion resistance, and improve wear resistance; It can also replace asbestos for manufacturing friction materials, insulation materials, and flame retardants. Grinding grade wollastonite (low aspect ratio wollastonite 3:1-5:1) is mainly used as a raw material for CaO and SiO2 in the manufacturing process of ceramics and glass, as well as a low-temperature flux in the metallurgical industry.
From the above table, it can be seen that the main uses of wollastonite in the world today are in the ceramic industry, as functional fillers in plastic rubber paint coatings, and so on. Ceramics, as the largest consumer of wollastonite, accounts for nearly half of the world's annual production in this field. Wollastonite as a ceramic raw material can increase the strength of ceramic bodies and ceramic products, reduce ceramic fragmentation and glaze spots, increase the surface gloss of the glaze, and also reduce fuel consumption (which can save 60% of fuel). Therefore, wollastonite is a highly promising energy-saving ceramic raw material. Experts predict that the demand for wollastonite in the ceramic industry will increase year by year at a rate of around 5%. Needle shaped wollastonite powder is used for special ceramics.
Needle shaped wollastonite powder, due to its needle like structure and non-toxic and harmless properties, can partially replace asbestos, glass fiber, pulp, etc., and is relatively inexpensive. Due to the environmental pollution caused by long-term exposure to asbestos in the air, many countries around the world have enacted laws and regulations to restrict or prohibit the use of asbestos. And wollastonite, due to its thermal stability, various enhancing properties, and non-toxic and harmless properties, naturally becomes the best substitute for asbestos. In recent years, the use of wollastonite as a substitute for short fiber asbestos has grown rapidly, with 35000 to 40000 tons of high aspect ratio wollastonite consumed annually in industries such as building materials and insulators. It is mainly used for firewall boards, cement materials, and friction materials. Other applications include indoor wall panels, roof tiles, high-temperature insulation bricks, and panels. The friction material originally made of asbestos has been replaced with needle shaped wollastonite with high friction levels, mainly including brake pads, valve plugs, and automotive clutches. Currently, this market is steadily growing in many regions around the world.
The fastest growing consumer sector for wollastonite is the plastic industry. Adding wollastonite powder to plastics can improve the tensile and flexural strength of plastic products, reduce resin dosage, and improve the thermal stability and shape stability of plastics at high temperatures. The surface treatment of needle shaped wollastonite powder can increase the adsorption strength of wollastonite and organic polymers, improve the properties of formed products, and is widely used in plastic products such as automotive plastics, PP, PV, PVC, etc. Currently, The automotive plastic market has become the fastest-growing consumer sector for wollastonite.
High purity silica fume, as an inorganic white pigment, is widely used in coatings and can replace expensive titanium dioxide powder; In light colored rubber products, it can also replace a portion of anatase titanium dioxide at a price of only one tenth of titanium dioxide.
The main consumer countries and regions of wollastonite in the world include Europe, the United States, Japan, India, Mexico, China, etc. Wollastonite in North America is mainly consumed in the ceramic industry, but the per capita consumption of ceramic tiles is lower than in Asia and Europe. The consumption of wollastonite in Europe is mainly used in the ceramic and metallurgical industries, while in India, wollastonite is mainly used in the ceramic and coating industries. China's wollastonite is mainly consumed in glazed tiles and ceramic billets, accounting for over 50% of the total consumption of wollastonite; Other consumer areas include plastics, rubber, coatings, metallurgy, construction, and asbestos substitutes. At present, the annual consumption of wollastonite in China is about 100000 tons. The main consumer area is ceramics, accounting for approximately 55%; Metallurgy, accounting for approximately 30%; Others (plastics, rubber, paper, coatings, welding electrodes, etc.) account for approximately 15%.
The United States is an important consumer of wollastonite in the world, and the domestic sales of wollastonite in 2002 were basically the same as in 2001. The sales volume in the plastic consumer sector has increased, while the sales volume in other consumer sectors has remained basically unchanged or slightly decreased. From the perspective of product types, due to the slowing economic growth in the United States and competition in foreign wollastonite prices, the sales volume of low value wollastonite products in the United States decreased in 2002. Although the sales volume of high value wollastonite products increased, the total volume was very small, and the impact on the total domestic wollastonite sales was minimal. The main consumer sectors of wollastonite in the United States are industries such as ceramics, metallurgy, coatings, and plastics. In recent years, the main consumption structure of wollastonite is roughly as follows: plastic 37%, ceramics 28%, metallurgy 10%, coatings 10%, friction products 9%, and other 6%.