Calcination kinetics of cement raw meals under various CO2 concentrations

Abstract

The manuscript is focused on the investigation of the calcination kinetics of fine particles (<50 µm) of limestones, natural marls and raw meals in a drop tube reactor, under conditions very similar to those expected in suspension calciners of CaL systems. Experiments have been carried out with very short gas-solid contact times (t<2 s), at temperatures up to 1000 ºC and varied concentrations of CO2 (up to 90 vol.%). High calcination conversions have been measured in these conditions with all the materials tested regardless of their origin and composition. The experimental results can be reasonably well described by means of a standard calcination model, in which the reaction rate depends directly on the specific BET surface area of the solid and the activation energy takes a value of 195 kJ/mol