The pptn. of barium sulfate from a basic EDTA complex upon addn. of a small vol. of acid in a stirred-tank reactor was used as a model reaction to study the local state of micromixing. Limitations and modifications of this reaction are presented, and its application on an industrial pilot scale is realized. A higher reaction rate is used in order to decrease the reaction time by using different concns. of reactants which modify the stability of the ppt. A study of this stability is presented. [on SciFinder (R)]