Process for making a solid compound by precipitation, using a high intensity mixing reactor and comprising the steps of (A) introducing a first fluid material containing a first reactant and a second fluid material containing a second reactant into said reactor, in order to obtain a mixed fluid, in order to cause the first reactant to react with the second reactant to form a solid compound by precipitation in the mixed fluid; (B) withdrawing the mixed fluid containing the precipitated solid obtained in step (A) from the reactor, and; (C) optionally separating the precipitated solid compound from at least one fraction of the mixed fluid.