Ill give you a brief introduction to silica fume

wollastonite

Appearance: silica fume is a white microstrip gray, red, lamellar, radial or fibrous aggregate, triclinic crystal system, glassy luster, demineralized mask pearl luster.

The chemical formula of silica fume is CaSiO3, theoretical chemical composition: cao 48.25%, SiO251.75%. Pure wollastonite is rare in nature. During its formation, Ca is sometimes partially replaced by Fe, Mn, Ti and Sr plasma, presenting a plasmoid isomer, mixed with a small amount of Al and micro K and Na.

Due to the difference in temperature, pressure and other conditions during the formation of wollastonite, three kinds of homogeneous polymorphisms may appear. 2. ZM type parastolite with single oblique chain structure, commonly known as parastolite; 3. Pseudosiliceous limestone with triclinic ternary ring structure, commonly known as pseudosiliceous limestone. At present, low temperature triclinal silica limestone is widely used as industrial mineral raw materials. Low temperature triclinal limestone is a triclinal crystal system, most of which are acicular, fibrous or lamellar, often clustered in a fan, radiative assembly, some in a small granular form. Microstrip grey, red, white glass luster, cleavage surfaces appear pearly luster, cleavage parallel medium, at 1125 degrees can be converted into false wollastonite, thermal expansion coefficient increase at this moment, and due to the release of the impurities such as Fe, Sr, so the color from white to cream, red or brown.