Barium carbonate or Witherite, has the molecular formula
BaCO3. The mineral Witherite is named after an English chemist,
William Withering, who recognized Witherite to be distinctive chemically from
barytes in 1784. It is a white crystalline solid which melts at 1740 ˚C and
decomposes at 1300 ˚C. It could be crystallized in the orthorhombic system.
While it is soluble in acidic solutions, it is insoluble in water and alcohol.
It is normally employed in rat poison, bricks, ceramic glazes and cement.
Barium carbonate is made from barium sulphide or black
ash which is dissolved in water. The clear solution is the raw material in
producing barium carbonate.
There are two ways to produce the carbonate anion:
Soda ash method: barium sulphide reacts with the solid form or dissolved sodium
carbonate to produce barium carbonate and sodium sulphide. The resulting barium
carbonate precipitate is filtered, washed and dried.
Straight gassing method: carbon dioxide is passed through barium sulphide to
form barium carbonate and hydrogen sulphide gas. The toxic hydrogen sulphide
gas would then be converted to sulphur compounds or the elemental sulphur,
while the barium carbonate would undergo precipitation, washing, drying and
Due to its physical property of being a white powder
form, it is used as a white pigment and paper coating agent to manufacture
white paper. As a consequence, the optical and tactile characteristics are
improved, in terms of whiteness, gloss and smoothness. The printability of the
paper and print quality of images and texts have been improved with the help of
Barium carbonate is used in ceramic glaze, by acting as a
flux, matting and crystallizing agent, and it is combined with coloring oxides
to produce colors on ceramics.
In glass industry, it is added into glass as a flux for
silica. In brick, tile, earthenware, pottery and clays manufacturing, it is
frequently used. It serves as a brine purification chemical in the chlor-alkali