Search

The Oued Zemmour deposit is associated to Neogene volcanism in the Kert basin, Nador area (Morocco), and thus one of the numerous bentonite occurrences in the Gourougou volcano's region. To assess their potential use, this article examines the Oued Zemmour bentonite deposit, helping with mineralogical, physicochemical, morphological, geotechnical analyses and ceramic performances. Mineralogical associations are essentially made of montmorillonite, K-feldspars and plagioclase, associated with lower quantities of calcite, dolomite and quartz. The main chemical composition in oxides is SiO2 and Al2O3. Geotechnical results show that the swelling index and Atterberg limits widely vary within the deposit, but all studied samples display high plastic and swelling qualities. The 10 representative bentonite samples of the area (Oz 1–Oz 10) were subjected to a ceramic technological assessment, and all samples have displayed good quality after dry pressing method and sintering at 1000 °C without any defect or cracks (except for Oz 4, Oz 5, and Oz 8 samples). Therefore, two mixtures (Oz M and Oz M1) have been developed from the samples studied, using the same manufacturing protocol. The obtained ceramics were evaluated by studying their morphological structure and macroscopic aspect, as well as their bulk density, porosity, water absorption, shrinkage and tensile strength properties. Resumen: El depósito de Oued Zemmour está asociado al vulcanismo neógeno de la cuenca de Kert, en la zona de Nador (Marruecos), y es por tanto uno de los numerosos yacimientos de bentonita de la región del volcán Gourougou. Para evaluar su potencial de uso, este artículo examina el yacimiento de bentonita de Oued Zemmour, ayudándose de análisis mineralógicos, fisicoquímicos, morfológicos, geotécnicos y rendimientos cerámicos. Las asociaciones mineralógicas están constituidas esencialmente por montmorillonita, feldespatos-K y plagioclasa, asociados a cantidades menores de calcita, dolomita y cuarzo. La composición química principal en óxidos es SiO2 y Al2O3. Los resultados geotécnicos muestran que el índice de hinchamiento y los límites de Atterberg varían ampliamente dentro del yacimiento, pero todas las muestras estudiadas presentan altas cualidades plásticas y de hinchamiento. Las 10 muestras de bentonita representativas de la zona (Oz 1 - Oz 10) fueron sometidas a una evaluación tecnológica cerámica, y todas las muestras han mostrado una buena calidad tras el método de prensado en seco y la sinterización a 1000 °C sin ningún defecto o grieta (excepto las muestras Oz 4, Oz 5 y Oz 8). Por lo tanto, se han desarrollado dos mezclas (Oz M y Oz M1) a partir de las muestras estudiadas, mediante el mismo protocolo de fabricación. Las cerámicas obtenidas se evaluaron mediante el estudio de su estructura morfológica y de su aspecto macroscópico, así como de sus propiedades de densidad aparente, porosidad, absorción de agua, contracción y resistencia a la tracción.

This work focuses on the characterization of lizardite and studying the technological and dielectric features of ceramics based on this geomaterial by experimental measurements. Note that, the physical evaluation (dielectric properties) of magnesian clay has never been studied. Natural lizardite was extracted from the Beni Boussera massif (Rif, Morocco), and was characterized in terms of chemical, physical, mineralogical and thermal aspects. A purification process was carried out to identify the mineral phases present in this material. The results showed that the studied material is mainly composed of silica (47.16 wt%) and magnesia (31.21 wt%), it is also richer in clay minerals such as lizardite and chlorite. The ceramic specimens were prepared by the uniaxial pressing method, followed by sintering to different temperatures (i.e., 900, 1000, 1100, and 1200 °C). The influence of the sintering temperature on porosity, density, shrinkage, water absorption, mechanical and microstructural properties of ceramics was evaluated, as well as chemical resistance and dielectric properties were studied. The evaluation of the optimized ceramic materials shows that good dielectric properties are obtained when sintered at a temperature of 1100 °C with a dielectric constant of 1.33, a dielectric loss of around 0.08, and a conductivity of 4.86 E−8 S/cm, at high frequency. Furthermore, the obtained ceramic specimen has a porosity of 17%, a density of 2.02 g/cm3, a water absorption of 9.86%, and a mechanical strength of 19.3 MPa. As a consequence, the results obtained have provided ceramics based on a natural resource with favorable technological and mechanical properties, and very interesting dielectric properties.

Potential use of raw clayey deposits from El Jadida, Morocco, in the manufacture of traditional ceramic products has been evaluated through a careful sampling and an in-depth characterization of the outcropping features around Ouled Sidi Ali Ben Youssef area (El Jadida city). We collected six representative clay-rich materials (C1–C6) for subsequent analyses by several spectroscopic and mineralogical techniques including physico-chemical, mineralogical, and thermal analyses. Our results revealed high amounts of oxides, mainly SiO2, Al2O3, Fe2O3, CaO and MgO. Those ferruginous clays were found suitable for dark ceramic bodies. Further mineralogical examination confirmed low to medium contents of clay minerals, but subordinated by quartz, calcite, dolomite and plagioclase as the main nonclay minerals. Ternary diagram plots indicated that the studied clays were suitable for structural clay products and clay roofing tiles. C5 sample exhibited the best physico-chemical and mineralogical properties due to its illitic nature (64%), low quartz content (28%), high plasticity index (32) and lower loss on ignition (10.84%). Therefore, C5 clayey sample was selected as a potential candidate to be mixed with expanded perlite (EP) for the production of insulating ceramics. Specimen were prepared from the new mixture (i.e., C5 and EP) by pressing and firing at 1100 °C. The obtained ceramic bodies were ascertained by addressing their bulk density, water absorption, shrinkage, bending strength, thermal conductivity, structural and mineralogical properties. Resumen: El uso potencial de depósitos de arcilla en bruto de El Jadida, Marruecos, en la fabricación de productos cerámicos tradicionales se ha evaluado mediante un muestreo cuidadoso y una caracterización en profundidad de las características de afloramiento alrededor del área de Ouled Sidi Ali Ben Youssef (ciudad de El Jadida). Recolectamos seis materiales representativos ricos en arcilla (C1 a C6) para análisis posteriores mediante varias técnicas espectroscópicas y mineralógicas, incluidos análisis fisicoquímicos, mineralógicos y térmicos. Nuestros resultados revelaron altas cantidades de óxidos, principalmente SiO2, Al2O3, Fe2O3, CaO y MgO. Esas arcillas ferruginosas se encontraron adecuadas para cuerpos de cerámica oscura. Un examen mineralógico adicional confirmó contenidos bajos a medios de minerales arcillosos, pero subordinados por cuarzo, calcita, dolomita y plagioclasa como los principales minerales no arcillosos. Los diagramas de diagrama ternario indicaron que las arcillas estudiadas eran adecuadas para productos de arcilla estructural y tejas de arcilla. La muestra C5 exhibió las mejores propiedades fisicoquímicas y mineralógicas debido a su naturaleza ilítica (64%), bajo contenido de cuarzo (28%), alto índice de plasticidad (32) y menor pérdida por ignición (10.84%). Por lo tanto, la muestra arcillosa C5 se seleccionó como un candidato potencial para ser mezclado con perlita expandida (EP) para la producción de cerámica aislante. Las muestras se prepararon a partir de la nueva mezcla (es decir, C5 y EP) presionando y disparando a 1100 ̊ C. Los cuerpos cerámicos obtenidos se determinaron abordando su densidad aparente, absorción de agua, contracción, resistencia a la flexión, conductividad térmica, propiedades estructurales y mineralógicas.

The present paper focuses on the elaboration and characterization of akermanite-rich bioceramics from abundantly available local dolomite and perlite. Different mixtures have been prepared for low-cost ceramic manufacturing by uniaxial pressing method and firing at 1250 °C for 2 h. The obtained results showed that akermanite is the predominant crystalline phase through the addition of natural perlite for a maximum of 30% in weight, accompanied by some small traces of diopside and periclase. The experimental results indicated that the sample M2-B (25 wt% of perlite) is the optimized body from all the tested specimens. The optimized ceramic was subjected to an SBF test to evaluate the bioactivity of the sample, and experimentally the combination between the microstructural and the mineralogical composition of the obtained material after soaking in SBF solution has confirmed the quality of the developed bioceramic by the formation of apatite layer.

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 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

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/cm3); 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.