Emulsion precipitation of submicron zinc oxide powder

Ultrafine zinc oxide powder was successfully synthesized through the emulsion precipitation process. The aqueous solution containing zinc cations was well emulsified in n-heptane solution, and then precipitated by adding ammonia. After calcination of the precipitates, submicron zinc oxide powder with a near spherical morphology was obtained. On comparison with the conventional precipitation method, this developed process was confirmed to be superior in preparing uniform ZnO powder and reducing its particle size. The emulsion stability was significantly affected by the ratio of the volume of the oil phase to that of the aqueous phase, and this ratio also influenced the mean particle size of ZnO powder. (C) 1997 Elsevier Science B.V.