Factors influencing reactivity of quicklime from zero-emission electrified calcination processes

Quicklime is a noninterchangeable multi-purpose industrial product produced by heating and calcining limestone in high-temperature kilns. Quicklime slaking reactivity (reaction rate and heat development when mixed with water) is a key quality parameter of quicklime, and it is influenced by characteristics of the limestone used as well as by the calcination conditions. In this paper results are presented from a systematic experimental study focused on how the slaking reactivity of quicklime calcined in CO 2 atmosphere depends on calcination parameters (time and temperature). Limestone samples were calcined at a range of temperatures (1000–1200°C) and times (10–60 min.). CO 2 atmosphere was chosen to simulate the conditions of electrified industrial quicklime production, which is of relevance for emerging technologies aiming at efficient CO 2 separation and sequestration. The calcination parameters and specific surface area of the quicklimes produced were correlated with slaking reactivity. The results show that the calcination temperature has greater effect on the slaking reactivity than calcination time within the conditions tested. It was also found that the slaking reactivity was not easily explained by the measured specific surface area. The findings show that, from a reactivity point of view, there is potential for an electric calciner to, combined with carbon capture and storage (CCS), provide a solution for zero-emission production of quicklime of controlled medium to high reactivity.