Analyse thermofiabiliste de matériaux poreux céramiques à haut taux de densification

National audienceSee http://hal.archives-ouvertes.fr/docs/00/59/27/90/ANNEX/r_IF8J8H1Q.pd

Effects of Grain Size and Shape of alumina aggregates on the Sinterability and Thermal Shock Resistance of Refractory Materials

The Concerted European Action on Sustainable Application of REFractories ( is a consortium created to drive sustainable refractory materials and processes in steel production. This project which runs from 2022 2025 seeks to improve the microstructure for increased sustainability and thermo mechanical performances of refractory castables. In this work, different formulations of alumina spinel refractory castables are considered The main objective is to propose a new design for the microstructure of refractory materials with improved thermo mechanical properties by considering • The nature of aggregates ( crystallinity, physical properties • The arrangement of the calcium aluminate phases network (formation temperatures, unique formation mechanisms, location and morphology

Insights on numerical models to predict potential recyclability of spent refractories from steel making industry

The present study is part of the CESAREF (Concerted European action on Sustainable Applications of REFractories) doctoral network, started in late 2022. The aim of the consortium is the contribution to scientific breakthroughs inherent to refractories for steel making sector thanks to transversal competences deriving from academic and industrial realities. European green deal and circular economy targets set by EU for 2025 are also related to the massive consumption of refractory materials in the steel industry. Operative lifetimes of refractories range from hours to several months depending on their role. As a result of increasingly tightened policies and disposal costs, and due to recent supply chain shortages, end-of-life refractories recovery and recycling practices are receiving great attention. Some of the core requirements for sustainability and circularity are the reduction of open-loop and down scaling strategies, to maintain refractory materials value as long as possible, of the end-of-life materials. Over the years application of numerical models has proved to be a useful strategy for researchers facing in-use issues related to refractory materials. In this study, different finite element models (FEM) applied to end-use refractories are discussed to understand their suitability for potential recyclability prediction. Thermomechanical characterization of prior- and post-use materials allow to identify the critical issues related to numerical models' development. The comparison between empirical results and the appropriate numerical model allow us to identify suitable pathways to improve refractories sustainability

Reuse and recyclability of refractories from steel industry

Part of the CESAREF consortium, the study presented here is dedicated to the characterization of refractory material properties after usage for potential reuse and recyclability determination. The aim of this doctoral study is to provide an insight on the variation of specific materials’ key properties (such as thermal conductivity, thermal expansion, Young’s module, modulus of rupture) after operations. Mesoscale aging studies may allow to define appropriate Finite Element Models ( to foreseen operative conditions of the refractory. Furthermore, application of an adapted FMECA (Failure Modes, Effects, and Criticality Analysis) fatigue integrated approach can be a further reliable tool to better predict refractories’ lifetime. Also, MCDA (Multi Criteria Decision Approach) implementation could help in detecting the necessary strategies to define the most convenient recycling routes

Thermal conductivity of porous materials

Incorporation of porosity into a monolithic material decreases the effective thermal conductivity. Porous ceramics were prepared by different methods to achieve pore volume fractions from 4 to 95%. A toolbox of analytical relations is proposed to describe the effective thermal conductivity as a function of solid phase thermal conductivity, pore thermal conductivity, and pore volume fraction (νp). For νp 0.65, the thermal conductivity of kaolin-based foams and calcium aluminate foams was well described by the Hashin Shtrikman upper bound and Russell's relation. Finally, numerical simulation on artificially generated microstructures yields accurate predictions of thermal conductivity when fine detail of the spatial distribution of the phases needs to be accounted for, as demonstrated with a bio-aggregate materia

Development of a Chitosan-Based Biofoam: Application to the Processing of a Porous Ceramic Material

Developing biofoams constitutes a challenging issue for several applications. The present study focuses on the development of a chitosan-based biofoam. Solutions of chitosan in acetic acid were dried under vacuum to generate foams with high-order structures. Chitosan concentration influenced significantly the morphology of developed porosity and the organization of pores in the material. Physico-chemical characterizations were performed to investigate the effects of chitosan concentration on density and thermal conductivity of foams. Even if chitosan-based biofoams exhibit interesting insulating properties (typically around 0.06 W·m−1·K−1), it has been shown that their durabilities are limited when submitted to a wet media. So, a way of application consists to elaborate a ceramic material with open porosity from a slurry prepared with an organic solvent infiltrating the porous network of the foam

Etude expérimentale et numérique du comportement thermomécanique de matériaux réfractaires modèles

LIMOGES-BU Sciences (870852109) / SudocLIMOGES-ENSCI (870852305) / SudocSudocFranceF

Homogeneization of glass/alumina two-phase materials using a cohesive zone model

International audienc