The kinetics of dissolution of colemanite in H3PO4 solutions

The dissolution kinetics of colemanite in phosphoric acid solutions was stu died. The effects of particle size, temperature, acid concentration, solid- to-liquid ratio, and stirring speed on the dissolution rate were determined . It was observed that the dissolution rate increased with decreasing parti cle size and solid-to-liquid ratio and with increasing temperature, but sti rring speed had no effect on it. The dissolution rate increased up to an ac id concentration of 19.52% (by wt) and then decreased with increasing acid concentration. The dissolution kinetics of colemanite were examined accordi ng to the heterogeneous and homogeneous reaction models for the acid concen tration range of 1.43-19.52% (by wt) of acid concentration, and it was foun d that the dissolution rate was controlled by surface chemical reaction. Th e activation energy of this process was determined to be 53.91 kJ mol(-1).