Beneficiation of wollastonite ores from swedish, greek and spanish deposits

Wollastonite is used for ceramics, special paints and plastics, while there is also an increasing demand for the mineral as a substitute for asbestos. Annual consumption within the EU amounts to about third of the world market. There have been no recent instances of development of any of the European deposits which occur in Spain, Greece, Germany, Sweden and Finland. Only the Finnish deposits are worked on any substantial scale. The others are reported to be small or too low grade for exploitation. The development of viable techniques for the treatment of wollastonite ores is thus a matter of importance, identify sufficient wollastonite resources in Europe to form the basis of the mining and mineral processing industry supplying between 30% and 50% of the total european demand. In this study dry and wet techniques have been elaborated for the economical beneficiation of wollastonite ores from Swedish, Greek and Spanish deposits containing wollastonite, epidote, calcite, pyroxenes, vesuvianite, Na-K feldspars, quartz and garnets in different quantities and grade of intergrow. The processes developed provide commercial grade concentrates of wollastonite with a recovery of about 70% suitable for general filling, metallurgical, ceramics, paints, paper, plastics and asbestos replecement applications. Commercial grade concentrates of calcite, feldspar and garnet can be also obtained as by-products with recoveries in excess of 70%.