A process is described for the comminution of a solid material in the presence of a saturated solution of the solid in a liquid in which the solid has a solubility greater than 1 %, and also in the presence of an additive dissolved in the saturated solution which can at least partially inhibit re-growth at crystal surfaces of the solid material. The process is of particular interest for the comminution of water-soluble salts in the presence of their saturated aqueous solutions and may be employed to make, inter alia, improved slurry explosives and fluid fertiliser compositions.