The worldwide consumption of wollastonite has been increasing from day
to day. It is a calcium metasilicate with the chemical formula CaSiO3.
Wollastonite is the only naturally occurring, nonmetallic, white mineral
that is needle-shaped in a crystal habit. Due to its high chemical and
thermal resistance and nontoxic properties, wollastonite replaces
asbestos. Apart from this, the acicular property of wollastonite allow
it to compete with other acicular materials where improvements in
dimensional stability, flexural modulus and heat deflection are sought.
Due to its unique properties such as: its high brightness and whiteness,
low moisture and oil absorption, low volatile content, and acicular
properties, it is used also as a filling material for ceramics, plastics
and paints, thermal and electrical insulator, wetting agent and smelter
for glaze. Three methods are used for the beneficiation of wollastonite:
mechanical sorting, dry or wet magnetic separation and flotation.
Magnetic separation and flotation can be applied together in some cases.
In this study, flotation has been investigated for the selective
separation of calcite-rich wollastonite ores from the Buzlukdağ deposit,
in the Kırşehir-Akpınar region, in the middle of Anatolia. The
mineralogical analysis of the sample used in the study shows that the
ore sample contains 60–62% wollastonite (CaSiO3), 4–5% augite
(Ca,Na)(Mg,Fe,Al)(Si,Al)2O6, 30–32% calcite (CaCO3) and minor amount of
other minerals. As a result of this study, the wollastonite concentrate
which contains 0.44% Fe2O3, 52.71% SiO2, 87.85% wollastonite with 0.60%
loss on ignition (using 1500 g/t potassium oleate) was obtained. The
ultimate grade concentrates of calcite that can also be obtained as
by-products are with 99.80% calcite content and 85.4% recovery.