Bausano extrusion lines, Single screw and Twin-screw, can process plastic with Wollastonite filler material. Wollastonite is a calcium inosilicate mineral (CaSiO3) that may contain small amounts of iron, magnesium and manganese substituting for calcium. Wollastonite is formed when limestone, or other high-calcium rocks undergo high temperature and pressure changes sometimes in the presence of silica-bearing fluids such as in skarns or contact metamorphic rocks. The structure of the individual wollastonite particles is determined by the respective geological formation and by the processing technology selected. Wollastonite appears as a white powder with high hardness compared to other common fillers. Wollastonite is a naturally occurring calcium silicate that is formed from quartz and calcium carbonate at a temperature of about 450°C.
It is the most common fibrous mineral reinforcement and has replaced asbestos since its demise. Unlike other silicates, wollastonite does not have good resistance to acids and bases. Wollastonite (calcium silicate) is a mineral filler giving properties similar to glass (minus the abrasiveness).
This highly versatile mineral is characterized by its high whiteness, unique needle-like, or ‘acicular’, structure, high brightness, low moisture and oil absorption, and high heat stability.