Metakaolin as cementitious material: History, scours, production and composition – A comprehensive overview

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.

Common calcination temperatures versus research numbers at different heating periods. Paper sludge calcinations temperature versus research number at 2 h heating period.Figure optionsDownload as PowerPoint slideHighlights
► 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 1–12 h.
► Most authors calcined kaolin at 700 °C for 12 h to obtain MK.
► Most of authors calcined paper sludge at 700 °C for 2 h to obtain MK.