Volatilisation of elements during clinker formation in a carbon dioxide atmosphere

In the future, cement clinker formation is likely to take place in high temperatures and high carbon dioxide atmospheres in carbon-neutral production processes as part of, for example, electrified processes. The aim of this study was thus to compare the volatilisation of minor and trace elements during cement clinker formation in a high carbon dioxide atmosphere and a conventional combustion atmosphere. Raw meal samples were exposed, at high temperature, to the two different atmospheres, with elemental analysis performed before and after. For both atmospheres, the minor elements potassium and sulfur, and the trace elements rubidium, lead, thallium, caesium, cadmium and mercury were highly volatile. For most of the analysed elements, no difference was observed between the two atmospheres. However, volatilisation of potassium, sodium and sulfur was lower in the high carbon dioxide atmosphere. It is suggested that this should be further studied in relation to the molar ratio of sulfur to alkalis in the clinker and the effect on clinker quality.