Abstract
Common calcination temperatures versus research numbers at different heating periods. Paper sludge calcinations temperature versus research number at 2h heating period. [Display omitted]
► Kaolin and paper sludge are the main sources of metakaolin (MK). ► The optimal calcination temperature and period are still undetermined. ► The optimum temperature for heating kaolin may be in the range 600–850°C for 1–12h. ► Most authors calcined kaolin at 700°C for 12h to obtain MK. ► Most of authors calcined paper sludge at 700°C for 2h to obtain MK.
Kaolin can satisfy the world demand for filler, paper and ceramic industries. Kaolin converts to a pozzolan material named metakaolin (MK) after suitable thermal treatment. MK can be used in mortar and concrete to improve their properties. In addition, MK can be used as a source of cementing materials in alkali activation or geopolymer. This part presents a comprehensive overview of the previous works carried out on kaolin history, MK sources, production and composition.