Kiln atmosphere during clay calcination – effects on emissions and product properties
Calcined clays as the main cement constituent are an essential part of the cement industry's decarbonisation strategy. Many clay deposits have iron-rich impurities that form hematite during calcination, which colors the product, the cement and ultimately the concrete red. A reducing atmosphere during calcination and/or cooling can prevent the formation of hematite. Systematic findings on the influence of secondary constituents in clays on their reactivity, emissions and cement-technical properties have hardly been available to date and are to be systematically investigated in the project.