4.14.3.1 Availability and Demand

The available amount of wollastonite ores in China in 1997 was about 0.25 million tons, while demestic consumption was about 0.11 million tons, accounting for around 44% of the total output. 

Recently, wollastonite products applied mainly consist of two categories: high L/D ratio wollastonite and ground wollastonite. The high L/D ratio wollastonite has a L/D ratio of 10~20:1 and is usually used as reinforced fillers in the fields of plastics and rubber (accoun-

Table 4.14.3 Major wollastonite production enterprises in China

ting for 19%~20% of gross consumption), asbestos substitutes (taking up 20%), and dye and paint (taking up 2%~8%). Adding this kind of wollastonite can improve the hardness, rigidity and bending strength of products, and at the same time, can improve the electrical properties of plastics and raise the heat stability. The ground wollastonite is used as fillers in ceramics and metallurgy, and their consumption accounts for 40% and 12% of the total consumption respectively.

Wollastonite is dominantly consumed as glazed ceramic tile and ceramic batch mix, of which, the consumption for ceramics accounts for 50%, that of plastics, rubber and painting takes up 30%, and that of metallurgical protective slag, building materials and asbestos substitutes takes up 20%. In recent years, the amount of wollastonite used in the dye and pain-ting industries increase steadily, accounting for around 10% of the gross consumption. At present, the supply of wollastonite exceeds demand in the demestic market, and the annual consumption is only around 0.1 million tons and the remaining is exported to overseas. 

The annual export volume of wollastonite in China ranks first in the world, and accounts for one-third of the world trade volume now. Export of wollastonite in China during 1994~1997 is given in Table 4.14.4.

Table 4.14.4 Export of wollastonite in China during 1994~1997

4.14.3.2 Supply and Demand 

Wollastonite is a multifunctional material with unique physical and chemical properties, and is widely used in the fields of metallurgical casting, architectural ceramics, painting and plastics. With popularized application of the low-temperature rapid burning technology, the consumption of wollastonite in ceramic industry will continuously increase. Since wollastonite possesses the characteristics of reinforcement of performance, low absorbability, heat stability, and conduction and chemical purity, the amount of wollastonite used as filers in the plastics industry are quickly increased and its application fields will be widened more and more in the future. Recently, in foreign countries it is already used for production of thermoinsulation building materials and others instead of asbestos, and used as substitutes for such mineral materials as talc, asbestos, clay, diatomite, and feldspar. The super-fine powder of acicular wollastonite is consumed in the production of plastic films in agriculture, prolonging greatly the life of the plastic films. China has rich wollsatonite resources and reserves, which can meet the needs of development of the wollastonite mining industry in the years to come. 

Because the development of the wollastonite mining industry in China is later, the production and application technology is not ripe yet. Many application fields are remained to be developed. The production intensity of enterprises is still very low. Their products are cannot meet internationalized requirements. This is unfavourable for being compatible with the international practices. Nevertheless, an analysis of the wollastonite markets shows vast prospects for the use of wollastonite.