Abstract: This disclosure concerns the production of ZnO (zinc oxide) coated particles for use in rubber as a substitute for bulk ZnO particles. Compared to bulk oxide, oxide coated particles offer the advantage of a higher specific surface per mass unit of ZnO. This implies both ecological and economical benefits. An enhanced process is presented for the synthesis of aggregate particles, comprising a core of CaCO3, which is at least partially coated with ZnO, comprising the steps of: heating a metallic Zn bath, thereby evaporating Zn and forming a Zn-vapor atmosphere; injecting CaCO3 particles as core compound in the Zn-vapor atmosphere; injecting air in the Zn-vapor atmosphere in an amount in excess of the stoechiometric need for the oxidation of the Zn vapor to ZnO. This process is clean and sustainable, producing no unnecessary phases.