Calcined gypsum hydration enhancing additives

摘要

An additive for accelerating the setting reaction of gypsum products is disclosed. It comprises a gypsum accelerator combined with a bisulfate salt. The gypsum accelerator is calcium sulfate dihydrate. The accelerator may optionally be ground with a sugar, a starch and/or boric acid. A process utilizing this additive combination is also disclosed. The bisulfate salt is most advantageously prewet with a portion of the calcium sulfate hemihydrate feed before being combined with the gypsum accelerator, water and the remaining portion of the calcium sulfate hemihydrate feed in the main mixer.