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The present study is a contribution to the valorization of halloysite clay from North Eastern Rif (Nador, Morocco) in the field of Silica-alumina refractory. For this purpose, six mixtures (M1–M6) were tested using marl, diatomite and silica sand aggregates in order to enhance halloysite performances, and to develop high temperature ceramic up to 1300 °C (silico-aluminous refractory “S-Al-R”). Among all the mixtures tested, the mixture M6 provides good technical quality: Porosity (P) = 21.75%; density (d) = 1.94 g/cm3; thermal shrinkage (R) = 2.7% and flexural strength (Rf) = 29.05 MPa. Addition to the mixture (M6) of 25% of the recycled alumina “Rec-Al”, obtained from silico-aluminous refractory bricks waste, has substantially strengthened the mechanical performance of the silico-aluminous refractory (Rf = 45.08 MPa). Resumen: El presente estudio es una contribución a la valorización de la halloysita del noreste del Rif (Nador, Marruecos) en el campo de los refractarios de sílice-alúmina. Para este propósito se experimentaron seis mezclas (M1 a M6) usando agregados de arena de marga, diatomita y sílice para mejorar el rendimiento de las instalaciones y desarrollar cerámicas de alta temperatura hasta 1300 °C (refractarios sillico-aluminosos «S-Al-R»). Entre todas las mezclas experimentadas, la mezcla M6 proporciona una buena calidad técnica: porosidad (P) = 21.75%; densidad (d) = 1.94 g/cm3; contracción térmica (R) = 2.7% y resistencia a la flexión (Rf) = 29.05 MPa. La adición a la mezcla (M6) del 25% de la alúmina reciclada «Rec-Al», obtenida a partir de residuos de ladrillos refractarios sillico-aluminosos, ha fortalecido sustancialmente el rendimiento mecánico del producto refractario «M6» (Rf = 45.08 MPa).

This work is based on the valorization and characterization of Moroccan geomaterials (MG) in the ceramic field. The raw materials (Kaolinitic clay of Oulmes: (KC); Red clay of Safi: (SC); Marl of Fez: (FM); Andalusite rich Schists of Oulmes: (AS); Magnesite of Boudkek: (Mag)) have been selected and characterized in terms of chemical, mineralogical composition, and thermal behavior wherein performed. The sintered ceramics (up to 1400 °C) resulted from these natural substances were tested mainly by physical, mechanical, and synthesized phase composition, as well as microstructural analysis, to determine their characteristics. As a result, the ceramic materials based on mullite and periclase have been obtained and confirmed by the X-ray diffraction and the scanning electron microscopy.

This work proposes an effective solution for the recycling of coffee waste by incorporating it (10, 20 and 30 wt.%) as a secondary material with clay (Cretaceous deposit of Moroccan Meseta) to produce porous lightweight ceramics (class BIII) whose quality is similar to that of ceramic materials with insulating character. The applied raw materials were characterized in terms of their composition (XRD, XRF, IR), microstructural analysis (polarized microscope) and thermal behavior (TDA/TGA). The ceramic materials resulted after firing at 1150 °C, were investigated regarding the phases composition, structural characteristics and physical properties of technological interest. In fact, the thermal treatment at 1150 °C gives samples having the following technological characteristics: P = 42.81%, d = 1.46 g/cm3, λ = 0.39 W/m K, WA = 29.25% and F.S = 10.75 MPa. The combination of XRD and polarized microscope, allowed a better analysis of the mineralogical and structural evolution after sintering at 1150 °C. Resumen: Este trabajo propone una solución efectiva para el reciclaje de residuos de café incorporándolo (10, 20 y 30% .wt) como material secundario con arcilla (depósito cretácico de la Meseta marroquí) para producir cerámicas ligeras porosas (clase BIII) cuya calidad es similar a la de los materiales cerámicos con carácter aislante. Las materias primas aplicadas se caracterizaron en términos de su composición (XRD, XRF, IR), análisis microestructural (microscopio polarizado) y comportamiento térmico (TDA / TGA). Los materiales cerámicos obtenidos después de la cocción a 1150 ̊ C, fueron investigados sobre la composición de las fases, las características estructurales y las propiedades físicas de interés tecnológico. De hecho, el tratamiento térmico a 1150 ̊ C da muestras que tienen las siguientes características tecnológicas: P = 42.81%, d = 1.46 g / cm3, λ = 0.39 W / m × K, WA = 29.25% y F.S = 10.75 MPa. La combinación de XRD y microscopio polarizado permitió un mejor análisis de la evolución mineralógica y estructural después de la sinterización a 1150 ̊ C. Keywords: Clay, Coffee waste, Mineralogy, Firing, Ceramic properties, Palabras clave: Arcilla, Residuos de café, Mineralogía, Tratamiento térmico, Propiedades cerámicas

Lizardite rich peridotite has never been used to prepare ceramic specimens, especially in Morocco. For this raison, potential use of naturally abundant lazirditic material from the Rif domain, as a supply for ceramic industry, has been evaluated. The effects of lizardite addition to magnesite and dolomite mixtures on the thermomechanical properties of the calcined ceramics were also detailed. To achieve this target, natural lizardite, magnesite and dolomite samples were collected in ultrabasic Beni Bousra massif. Those raw samples were used for the synthesis of a forsterite-monticellite rich ceramics. Both raw and sintered samples were characterized by x-ray diffraction, scanning electron microscope and fourier transform infrared. The obtained results showed that both magnesite and dolomite were mainly composed of MgCO3 and CaCO3. In contrast, lizardite sample showed high amounts of SiO2, MgO and Fe2O3. An increased amount of lizardite in the initial mixtures enhanced mechanical and dimensional properties of the prepared ceramic specimens, and subsequently, the production of ceramics with the required technological properties. Thus, the preparation of Moroccan lizardite-based ceramics is technically feasible, economically justifiable and socially desirable due to the contribution to the economic growth of the raw materials sector, especially ceramic industry.

Processing of magnesia based ceramic by unidirectional dry pressing from Moroccan magnesite is described. The applied magnesite was characterized in terms of its composition, granulometric analysis, surface specific area, and thermal behavior. After appropriate processing, the prepared specimens were fired at various temperatures up to 1350 °C to study the ceramic properties. The ceramic material resulted after firing was investigated regarding the phases composition, structural characteristics, and physical properties of technological interest. On this way, the production of materials having interesting properties such as shrinkage, porosity, density, flexural strength, toughness, dielectric constant, and thermal conductivity is achieved. An X-ray diffraction (XRD) analysis showed that the ceramic sample is composed of periclase as major phase and monticellite and calcium alumino-ferrite as minor phases. The content of amorphous phase that governs the sample properties varies between 26.5 and 31%. Thermal shock tests realized in water showed that the ceramic sample presents good thermal shock resistance. The results revealed that Moroccan magnesite has qualities necessary for the manufacture of ceramic products.

This work proposes the mixing of two varieties of Moroccan clay (C1 and C2) with silica sand in order to minimize the amount of the feldspar used. The raw materials were previously characterized in terms of their composition and thermal behavior. Two formulations noted M1 and M2 were elaborated according to the experimental protocol and they were evaluated in terms of their mechanical and thermal characteristics. The addition of C2 clay in the formulation allows a reduction in the amounts of feldspar of the order of 5%, while improving the technological characteristics of this new ceramic (M2) compared to that obtained by the conventional formulation. Indeed, the obtained ceramic (M2) shows the following characteristics: porosity (11.65%); density (2.71 g/cm 3 ); shrinkage (4.91%); flexural strength (30.05 N mm −2 ) and thermal conductivity (2.73 W/mK). Results of this study permit a reduction in the amount of the feldspar used, a relatively expensive raw material, and consequently reduces the cost of ceramics.

One of the most important elements of furnaces, boilers and other heating units is the structure (lining), usually made of silica–alumina, basic or special refractories. The basic refractories are materials that are increasingly in demand and whose manufacturing involves necessarily the use of MgO and CaO. In this article, the description and characterization of magnesite (MgCO3) and dolomite (Mg,Ca(CO3)2) and their contribution in industrial ceramics-refractories have been reviewed.

This paper mainly focuses on the preparation of new low-cost ceramic microfiltration membrane made from natural magnesite. Firstly, local Moroccan magnesite was deeply characterized in order to understand its chemical and mineralogical composition, and its thermal behavior. It was confirmed that used natural magnesite exhibits high purity degree in terms of magnesite mineral. Next, flat magnesite membrane was fabricated via uniaxial pressing and sintering methods. The effect of sintering in the range 900−1200 °C on morphology, porosity, pore size, permeability and mechanical strength was investigated. Based on experimental results, the optimized membrane (sintered at 1100 °C) has a porosity of 48.15 %, a pore size of 1.12 μm, a water permeability of 922 L h−1 m-2 bar-1 and a mechanical strength of 6.1 MPa. Finally, the optimized magnesite membrane was subjected to filtration of industrial textile wastewater in order to evaluation its performance as microfiltration membrane. Importantly, experimental results are clearly demonstrated that magnesite membrane effectively clarifies textile wastewater. It was showed that turbidity and chemical oxygen demand removals could achieve 99.9 and 69.7 %, respectively.

Different mixtures of Moroccan silica-alumina geomaterials were used for the preparation of refractory ceramics. A formula of composition (M2) has allowed obtaining a good quality of refractory. Addition of a small quantity of carbon (1%) to the M2 formula has substantially improved the quality of the refractory. The morphological, textural and mineralogical evolution, through SEM and XRD shows that the addition of carbon, which plays a catalytic role, favors the crystallization of andalusite. Then, from 1200°C, the andalusite starts to transform to primary mullite needles. At 1400°C, the mullite becomes the major mineral phase beside cristobalite and vitreous phase.

Investigations were undertaken to assess the chemical and technological characteristics in clay products from the Cretaceous deposit (Moroccan Meseta), in order to use them in refractory products. We have focused mainly on this clay because of its high content of alumina, silica and magnesium oxide, which are very favorable for the synthesis of refractory and ceramic materials. That is why the study has used several techniques of analysis (FX, XRD, SEM and technological tests. The samples were dry pressed on clay bodies and sintered at temperatures ranging from 900 to 1200°C. The relationship between water absorption, shrinkage and flexural strength as a function of the firing temperature was examined in order to enhance the quality of the final products and to optimize the production process. The results revealed that these clays have qualities necessary for the manufacture of ceramic and refractory products.

Refractory materials were elaborated from silica–alumina geomaterials related to granitoids and their direct surrounding rocks (kaolin clay and andalusite rich schist). The use of andalusite rich schist as aggregates (mean grain size: 1000–2000 μm) could improve the mechanical properties of synthesized refractory. The flexural strength increased from 39.10 to 54.16 MPa. The pyroscopic temperature increased from 1400 to 1450 °C. Thermal conductivity of the porous brick produced in this study (1.11 W/m K) showed 39% of reduction compared to initial brick of the same composition (1.83 W/m K). The thermal shock tests showed that the refractory samples have a good thermal shock resistance.