WO 2022/194499 A1

A process for the continuous preparation of alpha-calcium sulphate hemihydrate and a particulate gypsum

(22) 22.02.2022

(43) 22.09.2022

(57) The present application describes a process for the continuous production of alpha-calcium sulphate hemihydrate, the process comprising the steps of: providing particulate gypsum; providing water; mixing the particulate gypsum and the water to form a gypsum slurry; and maintaining said gypsum slurry under raised pressure and temperature to convert the particulate gypsum into alpha-calcium sulphate hemihydrate and provide an alpha-calcium sulphate hemihydrate slurry. Additionally, the particulate gypsum comprises a D 10 value greater than or equal to 2 µm, a D90 value smaller than or equal to 90 pm and a D50 value smaller than or equal to 25 µm. Particulate gypsum for use in the process is also provided.

(71) Saint-Gobain Placo, Tour Saint-Gobain, 12 Place de l’Iris, 92400 Courbevoie (FR)


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