Abstract: An improved process for economically and effectively granulating solid, finely-divided, particulate feedstock comprising phosphogypsum, limestone, or mixtures comprising sulfogypsum, natural or mineral gypsum, or mixtures thereof and limestone and having from about 80 to 95 percent by weight of such sulfogypsum/mineral gypsum to effect products which exhibit excellent physical and chemical properties relative to dustiness, storage, handling, and perhaps most importantly, aqueous media-induced rapidity of reversion to a mesh-size distribution of particles substantially similar to the initial size distribution of said feedstock, which improved process involves introducing such relatively finely-divided feedstock, together with material comprising recycle thereof into a suitable agglomeration device, such as a rotary drum, and therein effecting agglomeration/granulation of such feedstock in the presence of aqueous media, the improvement comprising the utilization, in combination with said aqueous media, of relat