Refractory materials for high-temperature applications often face thermal shock challenges. Incorporating aluminum titanate (Al2TiO5, AT) into an alumina matrix allows to tailor a relevant microcracked network via thermal expansion mismatch, enhancing thermal shock resistance. This study examines thermomechanical behavior of Al2O3/AT composites (0-10 wt% AT) using various specific experimental high-temperature techniques. Increasing AT content amplifies microcrack density, reducing Young's modulus from 360 GPa (pure alumina) to 40 GPa (10 wt% AT). Comparison of experimental results of Young's modulus variation versus temperature with Hashin-Shtrikman model allow to well quantify damage evolution. Composites with 10 wt% AT exhibit a strong nonlinear stress-strain behavior in tension and an exceptional strain to rupture (1.6 %), while miniaturized wedge splitting test confirms reduced brittleness and elevated fracture energy. These findings underline the role of tailored microcracking in optimizing thermomechanical performance, offering insights for designing refractory materials with improved durability under extreme thermal cycling.

Advanced statistical image analysis workflows were developed to segment and quantitatively evaluate 2D electron-backscatter diffraction (EBSD) maps and 3D synchrotron X-ray computed tomography (SXCT) volumes of a polycrystalline Al2TiO5 refractory composite that contains microcracks and pores. Several size, shape, and further geometric descriptors were determined for both the solid phase (Al2OTi5 grains) and the pore space. The resulting pore-size distribution is distinctly bimodal: coarse pores (tens to hundreds of micrometers), traced to incomplete powder compaction, coexist with fine pores generated during sintering. The two pore populations appear to be correlated with grain growth and crystallographic orientation in different ways. Finally, the descriptors obtained from the 2D EBSD and 3D SXCT data sets are internally consistent but complementary, highlighting the value of characterizations based on EBSD and SXCT in the microstructural study of refractory ceramics.

Aluminum titanate is widely used in various industries due to its superior intrinsic properties for thermal shock applications. At the microstructural scale, this material is characterized by its original grain crystallinity, leading to anisotropic thermal expansion behavior at the crystallographic grain level. Consequently, aluminum titanate undergoes spontaneous microcracking at high temperatures during operational conditions due to mismatches in the Coefficient of Thermal Expansion (CTE) between grains. These microcracks within the refractory microstructure result in quasi-brittle, non-linear mechanical behavior under tensile loading. Experimental findings suggest that the non-linear macroscopic response signifies material toughening, enhancing fracture toughness and, consequently, improving its thermal shock resistance. To better understand these phenomena, this study presents a simplified polycrystalline microstructure model using the Discrete Element Method (DEM), with aluminum titanate as the reference material. The research focuses on predicting the role of grain-level thermal anisotropy in microcrack nucleation and propagation, critical for thermal shock sustainability. A novel DEM approach, based on the bonded particle element method, is proposed. This approach quantitatively accounts for anisotropic CTE, thermomechanical coupling, crack nucleation, propagation and closure under Periodic Boundary Conditions (PBC), enabling multiscale analysis. The results obtained align quantitatively with experimental macroscopic observations, including the evolution of CTE and Young’s modulus with temperature.

Robust ceramic membranes, characterized by low fabrication costs and excellent separation performance, are particularly suitable for treating dyes in wastewater. This research focuses on the development of low-cost nanofiltration (NF) membrane using spin-coating technique, where purified clay is deposited onto a clay support. The study examines how the content of purified clay influences the properties of the membrane. The optimized membranes demonstrated promising characteristics with an average pore size of 5.4 nm and a permeability of 26.1 L/h & sdot;m2 & sdot;bar. Filtration performance was evaluated through tangential filtration experiments, utilizing Methyl Orange (MO) as an anionic dye and Rhodamine B (RhB) as a cationic dye, at a pressure of 4 bar. Systematic investigations were conducted to assess the effects of pH, filtration time, and initial feed concentration on the flux and dye rejection rates. The membranes achieved high rejection rates, with 84.5 % for MO and 85.7 % for RhB. Additionally, Density Functional Theory (DFT) was employed to explore the interactions between the membrane layer and the dyes, providing deeper insights into the removal mechanisms. The results confirm that these membranes are cost-effective and possess advantageous properties for effective wastewater treatment.

This study investigates the anisotropic grain growth of Fe-doped aluminum titanate ceramics using Electron Backscatter Diffraction (EBSD). Three grades of materials exhibiting various grain size distributions were prepared on the basis of different sintering conditions. The crystal structure of the raw powder was first refined using X-ray diffraction. Then the microstructure variation of sintered polycrystalline aluminum titanate associated to anisotropic grain coarsening was accurately studied. Due to the orthorhombic structure of β-Al2TiO5, the crystal shape is prismatic and elongated along the [100] direction. This specific grain shape is analyzed in relation with crystallographic axes in the frame work of the Wulff approach. The obtained results provide valuable information regarding the microstructure of such flexible ceramics made off anisotropic grains.

The influence of the removal of carbonates on the ceramic properties made of Moroccan red clay as a main material and tea waste as pore-forming agent, has been investigated. ATD-TG, dilatometry, dimensional changes, weight loss, water absorption, open porosity, bulk density, flexural and indirect tensile strengths were assessed at different firing temperatures within the range of 900-1150 degrees C. SEM was used to evaluate the microstructures of the fired samples, while XRD was used to study the phase evolution. At varying firing temperatures, the materials which contains the carbonate (CC) exhibit greater weight loss, water absorption, and porosity compared to the materials without carbonate (NCC). On the other hand, NCC materials has greater mechanical strength than that CC materials. The microstructural analysis conducted through SEM revealed distinct changes in the fired samples when comparing observations at 1100 degrees C to those at 900 and 1000 degrees C. At 1100 degrees C, there was a noticeable increase in particle contacts and layered structures, which can be attributed to the presence of dehydroxylated clay minerals (illite and chlorite), quartz particles, and pores formed during firing. Subsequently, at 1150 degrees C/ 2 h, further alterations in the microstructures were observed due to a higher degree of vitrification in the fired samples. This resulted in material consolidation, interparticle and neck contacts, leading to the formation of vitrified bridges. Firing has resulted in the formation of closed and open pores of varying sizes, in the vitrified structures associated with anorthite, hematite, and quartz, a thin crystal precipitation of small particles was observed. This alteration in microstructure made it possible to conclude that the flexural and indirect tensile strength increased during firing, reaching its pinnacle at 1150 degrees C. As a result of the firing process, the ceramic supports underwent heightened sintering, leading to a gradual decline in open porosity. The present inquiry proved to be intriguing as it led to a deeper understanding of the utilization of Moroccan red clay as a ceramic's raw material.

This study presents a cost-effective method for synthesizing refractory cordierite using a combination of two natural raw materials: biokaolin (65 wt%) and the stevensite-rich ghassoul (35 wt%). We mill the mixtures and then compact them uniaxially at 96 MPa. Subsequently, they are sintered at 1250 degrees C, 1300 degrees C, 1350 degrees C, and 1380 degrees C for 1 hour. The samples underwent various tests, including X-ray diffraction (XRD), differential thermal/ thermogravimetric analysis (DTA/TGA), scanning electron microscopy (SEM), dilatometry, three-point bending, and indirect tensile tests. The DTA results indicated cordierite crystallization at 1240 degrees C. The Rietveld quantitative phase analysis shows a continuous increase in the proportion of cordierite phase from 94.4 wt.% at 1250 degrees C to 99.8 wt.% at 1380 degrees C. The mechanical properties improved with increasing sintering temperature, and cordierite sintered at 1380 degrees C exhibited optimal performance: flexural strength of 44.4 +/- 4.6 MPa, tensile strength of 20.2 +/- 2.5 MPa, and Young's modulus of 34.6 +/- 2.4 GPa. The coefficient of thermal expansion (CTE) for cordierite sintered at 1380 degrees C was 2.96 +/- 10-6 degrees C.

In this study, the exploration of utilizing oil shale as a pore-forming agent in the fabrication of porous ceramic supports was undertaken. The ceramics were prepared through a uniaxial pressing process, incorporating a mixture of red clay and 20 wt% oil shale. Subsequently, they underwent firing at different temperatures (900, 1000, 1100, and 1150 °C). The research involved characterizing the raw materials and resulting ceramic supports using various analytical techniques, including X-ray diffraction, Scanning Electron Microscopy (SEM), bulk density, open porosity, and indirect tensile strength measurements. The results of this investigation have the potential to lay the groundwork for advancing ceramic supports with improved mechanical properties, consequently broadening their utility in diverse industrial processes, particularly in membrane fabrication.

The increasing generation of food waste worldwide necessitates innovative solutions to limit environmental impact and optimize resource use. This research explores the potential of using food waste as a pore-forming agent into the main material, which is red clay to produce porous ceramic membranes as a sustainable approach. This membrane was investigated to see how effective it was at eliminating methylene blue (MB), a typical organic cationic dye, from industrial wastewater. The ceramic membranes were analyzed using various techniques, XRD, FT-IR, TGA, AFM, and a universal testing machine. The morphologies of the membranes were observed using SEM and elemental mapping. The optimized membrane containing 10 wt% of FW has a surface roughness of 162.5 nm, water permeability of 160 L h(-1) m(-2) bar(-1), and could reject 79 % for MB. The membrane had a negative surface charge at the pH >5.37, while the pH of MB was 6.17, implying adsorption as the removal mechanism for the cationic dye, this has been confirmed by DFT calculations. The dye removal for 20 mg L-1 feed concentration was 79 % which increased to 86.1 % at pH = 10 and decreased to 74.26 % at the pH = 2. The total fabrication cost of this membranes is approximately 52.38 USD/m(2), which is cheaper than the conventional membranes. The affordability of these ceramic membranes is attributed to the use of economical materials that don't need high sintering temperatures. The results of this research demonstrate that these membranes are both cost-effective and have favorable characteristics that make them suitable for water treatment purposes.

An aluminium titanate based (AT) material doped with silica was investigated as refractory model material in order to highlight its thermomechanical properties through various techniques of characterization operating at high temperature such as ultrasonic pulse echography technique operating in long bar mode, acoustic emission, dilatometry and tensile test measurements up to 1400 & DEG;C. Young's modulus (MoE) as a function of temperature evolves in the form of a large hysteresis loop with a maximum value of about 170 GPa due to the healing of diffuse microcracks during heating. A sharp decrease in MoE occurs on cooling at about 780 & DEG;C, corresponding to the re-opening of the microcracked network due to a high level of stress around AT grains. In addition, during cooling, the dilatometric analysis shows a quasi-linear shrinkage followed by a sudden non-linear expansion from 750 & DEG;C. The thermal expansion coefficient value determined between 1100 & DEG;C and 750 & DEG;C is about 8.8 10-6 & DEG;C-1. By recording the evolution of the cumulative number of hits as a function of temperature, the results of the acoustic emission clearly confirm the resurgence of microstructural defects at 780 & DEG;C. The incremental tensile loading test performed at 1400 & DEG;C shows a greater degree of nonlinearity suggesting a higher flexibility of the studied AT due to both the microcracks network and the low viscosity of intergranular glassy phase. Symmetric alternating loading tests have highlighted that the viscous contribution in the viscoelastic behaviour of such materials is increasing from 850 H & DEG;C to 1400 H & DEG;C as the viscosity of the silica-riched amorphous phase is decreasing. These results are very useful to understand the more sensitive parameters involved in the high thermal shock resistance of aluminium titanate.

In wastewater treatment, the application of ceramic membranes has gained significant attention due to their potential for highly effective filtration. These membranes are typically produced using methods such as spin coating, dip-coating, and spray coating. However, these techniques have limitations when applied to large-scale industrial applications due to their high cost, time consuming process, and difficulty of control. Moreover, obtaining a complete and uniform coating typically requires several attempts. This research demonstrates the highly effective treatment of tannery wastewater using cost-effective porous ceramic membranes, by incorporating bio-based materials, such as tea waste, as porosifying additives into the main material, which is Moroccan red clay. Various analytical techniques, including X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Thermogravimetric Analysis (TDA-TG), Scanning Electron Microscopy (SEM), and the Archimedes principle test, were used to investigate the properties of these ceramic membranes. The impact of the pore-forming agents on the membranes physical and mechanical properties, such as open porosity, bulk density, average pore diameter, flexural and indirect tensile strength, was evaluated. Filtration tests demonstrated effective removal of turbidity, suspended matter and chemical oxygen demand from the wastewater. The optimized membrane exhibited a permeability of 1249 L/h.m2.bar and turbidity removal efficiencies of 99.76% for seawater and 99.16% for tannery wastewater.

The stress-strain behavior of ceramics, such as aluminum titanate, has certain features that are unusual for brittle materials-in particular, a substantial nonlinearity under uniaxial tension, and load-unload hysteresis caused by the sharp increase of the incremental stiffness at the beginning of unloading. These features are observed experimentally and are attributed to microcracking. Here we compare different degrees of stress-strain nonlinearity of aluminum titanate materials and quantitatively model them. We use advanced mechanical testing to observe the mechanical response at room and high temperature; electron microscopy, and X-ray refraction radiography to observe the microstructural changes. Experiments show that two types of microcracks can be distinguished: (i) microcracks induced by cooling from the sintering temperature (due to heterogeneity and anisotropy of thermal expansion), with typical sizes of the order of grain size, and (ii) much larger microcracks generated by the mechanical loading. The two microcrack types produce different effects on the stress-strain curves. Such microcracks and the features of the stress-strain behavior depend on the density of the cooling-induced microcracks and on the distribution of grain sizes. They are modeled analytically and numerically.

This study evaluates the possibilities to produce new materials, starting from Moroccan oil shales, for different applications. More specifically, the authors aimed to demonstrate that the organic fraction of the oil shales could be used as a precursor of carbon foams and graphitizable carbons, after appropriate chemical treatments resulting in the "maturation" of this organic phase. First, the researchers studied the optimization of experimental conditions and the identification of various parameters influencing the yield and composition of oils obtained by the supercritical extraction of Moroccan oil shale. The effect of various experimental parameters, such as mineral matter, thermal treatment temperature (T), treatment duration (t) and solvent type, was studied. The experimental results obtained show clearly that the organic matter contained in the Moroccan Tarfaya oil shale (sub-layer R3 ) can be recovered by phenol under the following optimal conditions: T = 390 degrees C, t = 2.5 hours using phenol as a solvent with an amount of 15 g for each 10 g of sub-layer R3 carbonate-free oil shale (RH). The results reveal that the yield and composition of the oil obtained by extraction with phenol is markedly different from those obtained by extraction with toluene, quinoline or without solvent. Furthermore, the phenol has a very significant role in increasing the recovery yield and the degree of maturation of the obtained oil. It was shown that phenol was a suitable extraction solvent to produce graphitizable carbon at a relatively low temperature, below 1800 degrees C.

This study focuses on investigating the effect of various solvents on the supercritical extraction of organic matter from Moroccan oil shales, with the goal of determining the optimal operating conditions that result in a high yield of high-quality oil rich in aromatic compounds. The results of this study demonstrate that the extraction yield and quality of the extracted oil heavily depend on the chosen operating conditions for supercritical or subcritical extraction of organic matter from oil shale. Additionally, the study found that phenol can effectively degrade oil shale and enable extraction of nearly all the organic matter, even under mild conditions (T = 390°C, P = 1.2 MPa, Time = 2.5 h. Furthermore, the oils obtained through this extraction process are of high quality, with a rich content of maltenes, and a higher concentration of aromatic compounds and lower levels of sulfur than those obtained using other solvents.

Chiastolite-type andalusite, whose genesis occurred in the currently unexploited deposit of Sidi Bou Othman (Morocco), has been extensively characterized. The phase composition, microstructure, thermal behavior, sinterability, and evolution of the crystallographic structure associated with the transformation of andalusite to mullite were accurately analyzed. Parallelepiped-shaped crystal grains exhibited off-white X crosses, typical of the chiastolite group. The chemical composition is closely dependent on the crystal size and proportion of alumina. The crystal structure was successfully refined using XRD, and chemical analysis was performed for different crystal sizes up to 30 mm. Powder compacts were prepared from these chiastolites for further characterization after various thermal treatments. According to the Rietveld refinement analysis, the mullization ranges from 1200 to about 1500 °C, and crystallographic parameters have been compared with other andalusites reported in literature. In agreement with this phase transformation, variations related to different material properties such as thermal expansion, pore volume fraction, and mechanical strength were evaluated. These results highlight the potential for further exploitation of the Sidi Bou Othman deposit to produce refractory materials.

The phosphate mining industry produces large amounts of waste rocks during the open-pit mining operation. In the present paper, phosphate waste rocks, abundant in different regions of Morocco, are investigated as a candidate material for partial/entire replacement of conventionally used industrial minerals. Several recipes for the production of tiles are tested, based on raw materials from five representative phosphate waste rocks mine sites and a raw clay from Safi's region in Morocco. The phosphate waste rocks are shown to be mainly composed of phyllosilicates (smectite, sepiolite, and palygorskite), carbonates (dolomite and calcite), and silica frameworks (quartz, tridymite, and cristobalite) as major phases. The raw samples and calcined mixtures were characterized by using X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), thermogravimetric analysis (TGA), and Fourier transformed infrared spectroscopy (FTIR). Properties analyses revealed that the produced ceramic tiles can be classified as porous bodies. The tiles based on 100% of phosphate waste rocks have shown excellent mechanical properties (similar to 55 MPa) in terms of compression and they can be used in the traditional wall tiles called "Zellige" in Morocco.

. In the present work, Moroccon Tarfaya oil shale was treated by acids and different solvents under supercritical conditions, successively. Experimental results showed clearly that residual mineral matter had a significant effect on the yield and composition of the resulting organic fraction. Indeed, the oil yields obtained from some samples, 43% and 56%, respectively, were much higher than that from the sub-layer, 18%. In addition, the yield of recuperation and quality of extracted oils were largely dependent on the nature of solvents (toluene, water, shale oil). Thus, phenol was shown to be a very efficient modifier for the supercritical extraction of organic matter from Tarfaya oil shale with toluene, affording a good yield of recovery and a suitable maturation of organic matter. The pitches prepared by mixing phenol and toluene contained more aromatics and had a high char yield (46%) at 950 °C compared to those obtained by extraction with supercritical toluene alone.

In the present work, the effect of phenol on the supercritical extraction of the organic matter from Tarfaya's oil shale with toluene was evaluated. The experimental results showed clearly that phenol had a significant effect on the yield and the composition of the oils obtained. Moreover, it was shown that phenol was a very efficient modifier for oil shale, giving a good yield of recovery and a suitable maturation of the organic matter. The pitches prepared by mixing phenol and toluene contain more aromatics and have a high char yield at 950 °C compared to those obtained by extraction with supercritical toluene alone.