Process for stabilizing pellets of pulverulent mineral materials, for example, iron ores, dolomite, carbonate or phosphate salts for agriculture and the building trade or the like, which are unstable because of redrying, hygroscopicity or reaction with the atmosphere. After they are formed by the well-known buildup granulating process with addition of pelletizing liquid, the pellets are provided with a coating of a mineral material, which is insoluble or only slightly soluble in water. The coating can be applied by dusting the pellets especially with the oxide of a metal of the second main group and subgroup, the oxide being in the form of a dry powder, and hydroxylating by means of water or by spraying an agent in liquid, dissolved or dispersed form, which forms an insoluble or slightly water-soluble compound by reaction with the pellet material.
