Laboratory vs. pilot scale calcination of illitic and smectitic clays

Abstract

One strategy to reduce the carbon footprint of concrete is the partial substitution of cement clinker with supplementary cementitious materials (SCMs). In particular, clays have a potential to fulfil this role, as they are globally abundant and can be activated using simple methods. In regions with temperate climates, such as in Germany, the clays are mainly of illitic or smectitic nature. Therefore, the present study focuses on the calcination of such locally available clays under both pilot scale (rotary kiln) and laboratory scale (chamber furnace) conditions. In the laboratory, calcination temperature and residence time were varied to determine the potential of the 2:1 clays. The properties of these metaclays were characterised among others by X‐ray diffraction (XRD), the rapid reliable relevant (R ³ ) test, and compressive strength. The investigations aim to facilitate the transfer of calcination processes for smectitic and illitic clays from laboratory to pilot scale, and ultimately toward industrial application.