Thermodynamic modelling of cements clinkering process as a tool for optimising the proportioning of raw meals containing alternative materials

Ana R D Costa; Mateus V Coppe; Wagner V Bielefeldt; Susan A Bernal; Leon Black; Ana Paula Kirchheim; Jardel P Gonçalves

doi:10.1038/s41598-023-44078-7

Thermodynamic modelling of cements clinkering process as a tool for optimising the proportioning of raw meals containing alternative materials

Sci Rep. 2023 Oct 16;13(1):17589. doi: 10.1038/s41598-023-44078-7.

Authors

Ana R D Costa^{1

2}, Mateus V Coppe³, Wagner V Bielefeldt³, Susan A Bernal⁴, Leon Black⁴, Ana Paula Kirchheim⁵, Jardel P Gonçalves^{6

7}

Affiliations

¹ Polytechnic School, Post-Graduate Program in Civil Engineering (PPEC), Federal University of Bahia (UFBA), Salvador, 40210-630, Brazil. cnardc@leeds.ac.uk.
² School of Civil Engineering, University of Leeds, Leeds, LS2 9JT, UK. cnardc@leeds.ac.uk.
³ Iron and Steelmaking Laboratory (LASID), Department of Metallurgy, Post-Graduate Program in Mining, Metallurgical, and Materials Engineering (PPGE3M), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, 91501-970, Brazil.
⁴ School of Civil Engineering, University of Leeds, Leeds, LS2 9JT, UK.
⁵ Building Innovation Research Unit (NORIE), Department of Civil Engineering, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, 90035-190, Brazil.
⁶ Polytechnic School, Post-Graduate Program in Civil Engineering (PPEC), Federal University of Bahia (UFBA), Salvador, 40210-630, Brazil.
⁷ Interdisciplinary Centre of Energy and Environment (CIENAM), Federal University of Bahia (UFBA), Salvador, 40170-115, Brazil.

Abstract

The valorisation of waste or by-products in Portland clinker production is a promising alternative for developing sustainable cements. The complexity of the chemical reactions during clinkering demands an adequate dosing method that considers the effect of feedstock impurities to maximise the potential substitution of natural resources by waste or by-products, while guaranteeing the clinker reactivity requirements. This study proposes a raw meal proportioning methodology for optimising co-processing of natural feedstocks with alternative raw materials in clinker production, intending to reduce the content of natural raw materials needed, while promoting an optimal clinker reactivity. A thermodynamic modelling sequence was developed considering the variability of raw materials composition and heating temperatures. The model was then validated by comparing simulation outcomes with results reported in previous studies. An experimental case study was conducted for validation of the proposed method using a spent fluid catalytic cracking catalyst (SFCC), a by-product from the oil industry as an alternative alumina source during clinkering. The modelling simulations indicated that substitution of natural feedstocks by 15 wt% SFCC promotes the formation of reactive clinkers with more than 54% tricalcium silicate (C₃S). Mixes with the potential to form the highest C₃S were then produced, and heating microscopy fusibility testing was applied for evaluating the clinkers' stability. The main factors governing the reactivity and stability of the clinker phases were the melt phase content, alumina modulus, and formation of C₃S and dicalcium silicate (C₂S). The self-pulverisation of clinker during cooling was observed in selected mixes, and it is potentially associated with high viscosity and low Fe content in the melt phase. The proposed framework enables optimisation of the dosing of raw meals containing alternative alumina-rich feedstocks for clinker production and allows a deeper interpretation of limited sets of empirical data.