Antimony recovery from SbCl₅ acid solution by hydrolysis and aging

This study aimed to find an efficient way to recover Sb from the SbCl₅ acid solution obtained by the chloride leaching process of the tin-depleted residue. Sb was recovered in the form of hydrated antimony pentoxide through the hydrolysis process. The effects of hydrolysis ratio and aging time on the Sb recovery process were studied, and the corresponding trends were established. The experimental results show that the amount of the antimony free ions increases with the hydrolysis ratio and aging time. This decreases the concentration quotient of the hydrolysis reaction and thus facilitates the reaction. Product crystallinity is affected by the solution supersaturation, which varies at different stages with aging time. As a result, the optimal conditions of recovering Sb correspond to the hydrolysis ratio of 1.5 and aging time of 7 days with the recovery rate of 97 %.