In barium carbonate manufacture from barium sulfate (heavy spar) (see Fig. 3.1-3), the heavy spar is first crushed and pulverized then reduced with coke to barium sulfide at 1000 to 1200°C in a rotary tube furnace.

The barium sulfide is then leached from the ground melt with hot water and the solution either reacted with carbon dioxide or sodium carbonate, whereupon barium carbonate precipitates out:

Synthetic (precipitated) barium sulfate is manufactured by reaction of a barium sulfide solution with sodium sulfate. Synthetic barium carbonate is utilized as a filler and white pigment in the manufacture of paper (blanc fixe) and in the paint, rubber and plastics industries. In medicine it is used as a contrast agent.