Wollastonite is a metasilicate mineral of calcium and a new industrial mineral raw material that is mainly used in ceramic industry. Its secondary applications include metallurgical protection slag and coatings as well as welding rod coatings, asbestos substitutes, grinding adhesives, glass ingredients and fillings for producing rubber, plastic, insulation materials and paper. Some wollastonite rock can also be used as finish materials for buildings and ingredients for producing white cement。
Characteristics of ore and mineral raw materials:
The chemical formula of wollastonite is CaSiO3. Its structural formula is Ca3[Si3O9]. Its theoretical chemical composition is CaO 48.25% and SiO2 51.75%. In Nature, pure wollastonite is rarely seen. As its Ca is sometimes replaced by the ionic portions of Fe, Mn, Ti or Sr during its formation, it becomes an isomorphic system with lesser amount of Al and micro K and Na。
Depending on the temperature and pressure at which wollastonite is formed, there may be 3 isomorphic systems: (1) Triclinic chain structure Tc wollastonite, normally called low temperature triclinic wollastonite (α-CaSiO3); (2) Monoclinic chain structure ZM parawollastonite, normally called parawollastonite (α′-CaSiO3); (3) Triclinic ternary cyclic structure pseudo wollastonite, normally called pseudo wollastonite (β-CaSiO3). So far, low temperature triclinic wollastonite is the most widely used as industrial mineral raw material。
Low temperature three oblique wollastonite is three triclinic, mostly acicular, fibrous or flaky, often in clusters, fan-shaped radial aggregates, some with small particles. White microstrip gray, red, shiny glass, cleavage is pearl luster, cleavage parallel medium, two groups of the cleavage plane is 74 ° angle. Density of 2.78 ~ 2.91 g/cm3, hardness 4.5 ~ 5, melting point 1540 ℃. The thermal expansion coefficient is low, at 25 ~ 800 ℃ thermal expansion coefficient is 6.5 × 10-6 mm/ (mm ℃); in the 1125 ℃ can be transformed into pseudo wollastonite, and thermal expansion coefficient increased, and the release of Fe, Sr and other impurities, therefore the color from white to cream, red or brown.
Wollastonite ore natural type usually have skarn ore and wollastonite quartz - calcite ore two. The former mainly occurs in the skarn deposit, mineral component is complex, often associated with quartz, calcite and pyroxene, garnet skarn minerals; the latter mainly in metamorphism and metamorphic type contact deposit, mineral component is simple, and can be divided into: wollastonite quartz, silicon limestone calcite and wollastonite quartz - calcite types and 3 subtypes. Structure of wollastonite usually has two kinds: massive ore with fine-grained granoblastic or fiber become crystal structure, dense massive structure, wollastonite is small, columnar or fibrous aggregates, individual extremely fine-grained dense is jade shape; coarse wollastonite with fiber become crystal structure like, massive, brecciated, porphyritic or banded structure, wollastonite crystal size, in a plate column, fasciculate or radial (Chrysanthemum).
Applied science of wollastonite:
The acicular or fiber crystalline shape, high whiteness and unique physical and chemical properties of wollastonite have enabled it to be widely applied to ceramics, coatings, rubber, metallurgical protection slag, chemical, papermaking, electric welding rods as well as asbestos substitute, grinding adhesive and ingredients for glass and cement。.
  1.Ceramic application
  2.Metallurgical industry and refractory application
  3.Rubber and plastic application
  4.Paintings and coatings application
  5.Building material application
  6.Friction material application
  7.Electric insulation material application
  8.Papermaking application Grades and parameters of South wollastonite products