130 kg of zinc oxide is dispersed in a rotor-stator shear machine with 16 liters of 25% aqueous ammonia in 480 liters of cold water with simultaneous introduction of gaseous carbon dioxide. Simultaneously, 900 kg of molten stearic acid is emulsified at 80° C. in 180 liters of water and to the emulsion there is added 36 liters of 25% aqueous ammonia. Both dispersions are fed at 80° C. through correspondingly adjusted dosing pumps to a rotor-stator shear machine likewise heated to 80° C., so that stoichiometric amounts are reacted per unit of time. From the 130 kg of zinc oxide and 900 kg of stearic acid (saponification number=204) there is formed 1000 kg of zinc stearate. The pasty zinc stearate drawn off from the rotor-stator shear machine has a water content of about 45%. It is fed directly to a flowing air dryer in which it is dried to a water content of 0.2%. The end product is a finely granular, extremely pure, electrolyte-free zinc stearate.
