DJELEL Kherifi

عمارة فؤاد

دراسة تأثير اضافات سيليكات الصوديوم على خصائص الهيدروكسي أباتبت الطبيعي

لكحل رحيمة , بوراس سمية

Calcul De L' énergie Solaire Incidente et Produite Par Le PVsyst Dans quelques Zones Algeriènne

Hydroxyapatite (HA) is a biocompatible and bioactive material used as bone-substitute materials in both orthopedics and dentistry. This work is devoted to studying the synthesis of hydroxyapatite (HA) by sol–gel route using triethyl phosphate (TEP) and calcium nitrate tetrahydrate as calcium and phosphor precursors. In order to optimize the hydrolysis of TEP, each prepared solution was aged in a closed Teflon ® container. Several factors were tested in order to improve the synthesis conditions of well-crystallized HA. The effect of aging time (4 h, 16 h, and 24 h), aging temperature (25 °C, 50 °C, 70 °C, and 90 °C) of the prepared solutions, and the type of solvents (ethanol and/or distilled water) were tested. All dried gels were calcined at 700 °C for 1 h. The obtained results showed that the crystallinity degree of hydroxyapatite increases with aging time and temperature, which must not exceed 70 °C. When the prepared solutions were aged at 90 °C, the tri-calcium phosphate (TCP) was formed as a major phase and HA was present as a very minor phase. It was remarked that the aging of sols in a closed Teflon container ® leads to an important decrease of the aging time and temperature. It was found that 24 h and 70 °C are the optimal conditions for the synthesis of well-crystallized HA. Also, it was deduced that a sufficient amount of water was needed to hydrolyze the triethyl phosphate and consequently, to obtain a well-crystallized HA.

Citation

Fatima Zohra MEZAHI , malika MERZOUGUI , Achour Dakhouche , Foudil SAHNOUNE , DJELEL Kherifi , , (2022), Improvement of the reactivity of triethyl phosphate and structural behavior of hydroxyapatite versus the synthesis conditions by sol-gel route, Chemical Papers, Vol:76, Issue:2, pages:1045-1061, springer

Industrial-scale cement production has a negative impact on the environment due to the release of CO2. The cement industry continues to search for less environmentally harmful such as Calcium Sulfoaluminate cements are an alternative to Portland cement. The aim of this work is the preparation and characterizations of Calcium Sulfoaluminate cement from natural materials. On the other hand, different experimental techniques, including density, porosity, shrinkage, Vickers hardness, XRD and DSC were used to analyse the transformation of various phases at different temperatures. Keywords: Calcium Sulfoaluminate cement, Portland cement, Natural materials, Characterisations.

Citation

ZEYNEB Hammou , Hocine BELHOUCHET , DJELEL Kherifi , ,(2022), Calcium Sulfoaluminate Cement Synthesis by Natural Materials,The first national Seminar on Green Chemistry and Natural Products (GCNP’22),University of Echahid Hamma Lakhdar, El-Oued

Calcium sulfoaluminate, also called Yeelimite cement, is attracting a lot of interest due to its inherently low emissions during production and its very high mechanical properties compared to Portland cement. The objective of this work is to use local natural materials obtained from Algeria to produce Yeelimite-based cement with good physical and mechanical properties. On the other hand, we have developed many compounds based on natural phosphates, bauxite and gypsum and have produced many mixtures with different sphalorite contents. Various experimental techniques including: density, porosity, XRD, vickers hardness HV and FTIR were used to analyze the physical and mechanical properties. KEYWORDS: Calcium sulfoaluminate, Yeelimite, Portland cement, Low emissions.

Citation

ZEYNEB Hammou , Hocine BELHOUCHET , DJELEL Kherifi , ,(2022), THE EFFECT OF ADDITION SPHALERITE (ZnS) ON YEELIMITE PREPARATION,1 ST NATIONAL CONFERENCE ON MATERIALS, ENERGY& ENVIRONEMENTAL November 9 TH and 10 TH, 2022.,University of Biskra

In recent years, reducing greenhouse gas emissions and saving energy have become a priority for global environmental protection. Calcium sulfoaluminate (C4A3S), also called Yeelimite cements, have been promoted as an alternative binder to Portland cement due to their much lower CO2 emissions. The aim of this work is the production of Yeelimite-based cement from local natural materials (natural phosphate from Djebel el-Onk). On the other hand, we have developed many compounds based on natural phosphate, bauxite and gypsum and have produced two mixtures with and without sand. Different experimental techniques: XRD, TG-DSC and MEB were used to analyze the formation of different phases at different temperatures. Through these results, we have demonstrated the possibility of making the Yeelimite from natural materials. Keywords: Calcium sulfoaluminate; Yeelimite; Portland cement; Natural phosphate.

Citation

ZEYNEB Hammou , Hocine BELHOUCHET , DJELEL Kherifi , ,(2022), The Influence of Addition Sand (SiO2) On Yeelimite-Based Cement Prepared by Natural Materials,Materials Sciences And Technology, (MatScience-2022),University of khenchela

In this work, the sintering behaviour of fluorapatite (FAp)–silicate composites prepared by mixing variable amounts of natural quartz (2.5 wt% to 20 wt%) and FAp was studied. The composites were pressureless sintered in air at temperatures from 1000 °C to 1350 °C. The effects of temperatures on the densification, phase formation, chemical bonding and Vickers hardness of the composites were evaluated. All the samples exhibited mixed phase, comprising FAp and francolite as the major constituents along with some minor phases of cristobalite, wollastonite, dicalcium silicate and/or whitlockite dependent on the quartz content and sintering temperature. The composite containing 2.5 wt% quartz exhibited the best sintering properties. The highest bulk density of 3 g/cm3 and a Vickers hardness of >4.2 GPa were obtained for the 2.5 wt% quartz–FAp composite when sintered at 1100 °C. The addition of quartz was found to alter the microstructure of the composites, where it exhibited a rod-like morphology when sintered at 1000 °C and a regular rounded grain structure when sintered at 1350 °C. A wetted grain surface was observed for composites containing high quartz content and was believed to be associated with a transient liquid phase sintering.

Citation

DJELEL Kherifi , Hocine BELHOUCHET , ADMIN Admin , RAMESH SINGH (ramesh79@um.edu.my), K.Y. Sara Lee, Abdelghani Kenzour, Samira Djoualah, M.K.G. Abbas, Y.H. Wong, , (2021), Sintering behaviour of fluorapatite–silicate composites produced from natural fluorapatite and quartz, Ceramics International, Vol:47, Issue:12, pages:16483-16490, Elsevier

In this investigation, we studied the reaction-sintering between fluorapatite and alumina using natural phosphate and boehmite. The addition of alumina, resulting from the boehmite transitions, to the fluorapatite (FAp) has been carried out to obtain various composites based on FAp, yeelemite, mayenite, grossite (CA2), hibonite (CA6) and β-TCP. Several samples were prepared by varying the boehmite (AlOOH) amount to obtain six compositions which contain after sintering: 5, 10, 15, 20, 25 and 30 wt% of Al2O3. After ball-milling for 5 h, all compositions were sintered in the air for 2 h at different temperatures ranging from 1000 to 1500 °C. The reactions and phase transformations between fluorapatite and boehmite were studied and characterized by DTA/TG, XRD, FT-IR, apparent density and open porosity measurements, micro-hardness and SEM analysis. The micro-hardness and densification of the sintered body showed a marked improvement by increasing the alumina content and sintering temperature. Especially, sample containing 25% alumina exhibited the highest densification at 1400 °C (2.95 g/cm3) and excellent micro-hardness of about 6.5 ± 0.25 GPa. So the preparation of low cost composites based on fluorapatite, yeelimite and grossite from natural phosphate and alumina are feasible.

Citation

Hocine BELHOUCHET , DJELEL Kherifi , Samira Djouallah, Abdelghani Kenzour, , (2021), Sintering behavior of fluorapatite-based composites produced from natural phosphate and alumina, Ceramics International, Vol:47, Issue:3, pages:3553-3564, Elsevier

Hydroxyapatite (HAp) presents a very important bioceramics and has been widely applied as bone substitutes because of its excellent bioactive properties. But has poor mechanical properties such as: toughness and flexural strength; therefore, it is usually reinforced with particles, fibres or whiskers to improve its properties. Among particles added to Hydroxyapatite are alumina particles which improve its mechanical properties. The aim of the present work is to explore the utilization of Algerian Hydroxyapatite and boehmoite (AlOOH) to synthesise Hydroxyapatite/alumina composites through reaction sintering and investigate phase transformation and sintering behaviour of the composites. The sintering behaviour was investigated using X-ray diffraction and electron microscopy. Several calcium aluminate phases were produced by the solid-state reaction between Hydroxyapatite and Al2O3. The mixture of hydroxyapatite and boehmite shows the partial decomposition of hydroxyapatite at high temperature. The increase in alumina ratio (20%wt) promoted the enhancement of mechanical properties of Hydroxyapatite.

Citation

Hocine BELHOUCHET , DJELEL Kherifi , Samira DJOUALLAH, Andelghani Kenzour, ,(2019), Phase transformation and sintering behavior of flurapatite-alumina composite materials,Third International conference of mechanics and materials ICMM 2019,Setif, Algeria

In this work, several composite materials were prepared using natural phosphate (Fluoroapatite) and Alumina. The mixtures were milled by attrition milling for 1h and then pressed in cylindrical form. Finally, the simples’ compacts were sintered between 1000 and 1600°C for 2 h. Reactions and phase transformations of the powder sintering were studied by X-ray diffraction, density, open porosity, Vickers hardness and SEM analysis. From the X-ray patterns, we put in evidence the formation of some composites such as: fluoroapatite-alumina in the low temperature and α-TCP-hibonite in the high temperature. The open porosity is decreased while the bulk density increases relatively with the increase of the sintering temperature. The correlation between morphological and mechanical properties is confirmed by Vickers hardness values, SEM imaging, and qualitative analysis using XRD.

Citation

DJELEL Kherifi , Hocine BELHOUCHET , Samira Djouallah, Andelghani Kenzour, ,(2019), The reaction between alumina and algerian natural phosphate,Third International conference of mechanics and materials ICMM 2019,Setif, Algeria

In this work, several composite materials were prepared using natural phosphate (Fluoroapatite), kaolin and Alumina. Reactions and phase transformations of the powder sintering were studied by X-ray diffraction, density, open porosity, shrinkage, hardness and SEM analysis. From the X-ray patterns, we put in evidence the formation of some composites such as: Fluoroapatite-Yeelmite in the low concentrations and Fluoroapatite-anorthite in the high concentrations. The open porosity is decreased while the bulk density increases relatively with the increase of the sintering temperature. The correlation between morphological and mechanical properties is confirmed by Vickers hardness values, SEM imaging, and qualitative analysis using XRD.

Citation

DJELEL Kherifi , Hocine BELHOUCHET , Andelghani Kenzour, ,(2019), The effect of additions (kaolin DD3 + alumina) on the sintering of natural fluoroapatite.,4th INTERNATIONAL SYMPOSIUM ON MATERIALS AND SUSTAINABLE DEVELOPMENT (ISMSD2019),Boumerdes, Algeria