The present disclosure relates to a process for preparing a MgCl2-alcohol adduct which comprises (a) forming a mixture of an MgCl2-alcohol adduct in molten form and a liquid which is immiscible with the adduct, (b) subjecting the mixture to a shear stress to obtain an emulsion, and (c) rapidly cooling the emulsion to solidify the disperse phase and collecting the solid adduct particles, the process being characterized by the fact that step (b) is carried out in a device comprising a first outer and second inner cylindrical members that define an annulus between them, wherein at least one of the cylindrical members rotate with respect to the other.