Material for retarding the setting of cement, and process for the manufacture thereof

摘要

Material for retarding the setting of cement and a process for the manufacture thereof by producing pellets which consist of a mixture of a calcium sulphate dihydrate and anhydrite and, if appropriate, further materials, or pellets of a shell-type structure, the core consisting of anhydrite or dihydrate and/or further additives and the shells consisting of dihydrate and/or anhydrite and/or further additives.