A non-thermal process for producing barium carbonate from barite by means of mechano-chemical treatment has been developed. This process is composed of three steps : The first step is to produce barium hydroxide and potassium sulfate powders by milling of the barite and dry potassium hydroxide powder mixture in a mill. Milling for a short time enables the reaction to be initiated. The second step is to transform the barium hydroxide obtained into barium carbonate by exposing the milled mixture to an air or CO2 gas environment. The final step is to purify the barium carbonate by removing potassium sulfate from the exposed mixture by rinsing with carbonate solution. In the present experiment, about 83% barium of barite could be recovered from a 15-minute milled mixture as barium carbonate by the proposed method when 0.2 mol/dm(3) K2CO3 solution was used in the third step.