Gypsum is a crystalline form of hydrated calcium sulfate (CaSO4 center dot 2H(2)O) generally used in cements and plasters in the construction industry, though also in paints, fertilizers, medicines, papers, and textiles. For use in these materials, gypsum must be ground finely (<100 mu m), if not ultra-finely (<10 mu m), for which ball mills are most effective. Despite gypsum's widespread use and the regular need to grind it, studies concerning the grinding of gypsum ore remain scarce. In response, in this study, we have systematically investigated how certain grinding parameters (i.e., mill speed, ball filling ratio, ball size distribution, powder filling ratio, grinding aid ratio, and grinding time) of conventional dry ball mills affect the grindability of gypsum ore. We determined the properties of the micronized gypsum products obtained in optimal grinding conditions, and the results showed that the dry ball mill grinding process can effectively produce ultra-fine gypsum products. (C) 2015 Elsevier B.V. All rights reserved.