Ana Rita Damasceno Costa, Luanne Bastos de Britto Barbosa, Ana Paula Kirchheim, Jardel Pereira Gonçalves
Abstract: The development of sustainable production has motivated using alternative raw materials in Portland cement manufacture. Co-processing industrial by-products containing impurities can change the stability of the clinker phases. Several studies have explored the effect of minor elements in the clinkering process. However, the effect of lanthanides remains unclear. This class of elements has been scarcely investigated due to its limited content in conventional alternative materials. Nevertheless, the increasing co-processing of by-products from the oil industry containing lanthanides demands further investigations on the effects of these elements. Furthermore, using alternative raw materials demands extensive experimental programs and investing time and financial resources. In this context, this study uses thermodynamic modelling to evaluate the effect of lanthanides on Portland clinker production. Systems containing La, Ce, Eu, Gd, Pr, and Nd as oxides in up to 10 wt.% of clinker raw meal processed at 1200 and 1400 °C were simulated. Thermodynamic calculations were based on the Gibbs energy minimisation method and performed in the FactSage software. La, Pr, Eu, Nd, and Gd improved the clinker C3S content. This effect was more significant for up to 3 wt.% of added dopant. These elements stabilised C2(A,F) rather than C3(A,F), suggesting a possible application in manufacturing high-ferrite and sulphate-resistant cements. Ce2O3 promoted notably different behaviour on phase assemblage, decreased the C3S development, and depleted C2(A,F). The cubic perovskite was the main solid phase incorporating the lanthanides, forming LaAlO3, NdAlO3, PrAlO3, EuAlO3, or GdAlO3. According to thermodynamic modelling, the co-processing of raw materials containing lanthanides can be environmentally safe since the emission of polluting gases containing impurities was negligible even when co-processing 10 wt.% of lanthanide oxide in the clinker raw meal.
Keywords: Clinker, Cement, Thermodynamic modelling, Dopants, Lanthanides.
Date Published: October 10, 2023 DOI: 10.11159/ijmmme.2023.003
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