Experimental and modeling study of flash calcination of kaolinite rich clay particles in a gas suspension calciner

• Flash calcination of kaolinite in a pilot-scale calciner is experimentally studied.
• The raw feed and the calcined samples are all characterized experimentally.
• A generic 1D mathematical model for single clay particle calcination is developed.
• The model is validated by various experimental results under different conditions.
• Model-based sensitivity study is done to better understand the calcination process.

Calcination of kaolinite particles under appropriate conditions to produce materials that can replace part of the CO2 intensive clinker is gaining an increasing interest in cement industry worldwide. This paper presents a study of flash calcination of kaolinite rich clay particles in a pilot scale gas suspension calciner, with the aim to derive useful guidelines on smart calcination for obtaining products of the best pozzolanic properties. Calcination tests are performed in the calciner under six different operation conditions. The raw feed and the calcined clay samples are all characterized experimentally and a mathematical model is also developed to predict the conversion of the clay particles. The model properly accounts for the particle–ambient flow interaction and numerically solves all the processes occurring within the clay particles. The model predictions are compared against the experimental results. A good agreement is achieved. Finally, a model-based sensitivity analysis is conducted.