Résumé: Purpose. The purpose of our study involved the improvement of the Zn-recovery and its content in the concentrate while floating the sphalerite from raw ore, by controlling the behavior of sphalerite surface and its floatability in the cases of presence and absence of copper sulfate as activator reagent. Methodology. Experimental flotation tests were carried out to assess the impact of two variable parameters: the dosage of copper sulfate and the dosage of ethyl xanthate. The mineralogical composition was obtained by Xray Diffraction (XRD). The Complexometric titration method was used to measure the zinc grade and determine the Zinc recovery. The adsorption mechanism of EX on non-activated and activated sphalerite surfaces was analyzed, using the infrared (FTIR) analysis. Findings. The results indicated that the ethyl xanthate does not respond well in the absence of the activator with sphalerite surface. Thus, the copper ions (Cu2+ ) significantly enhance the hydrophobicity of sphalerite. The optimal conditions were found at pH 11, with a CuSO4 dosage of 1.3 ⋅ 10-3 mol/L achieving a zinc recovery of 87.19 % with zinc grade of 38.17 %. Infrared analysis confirmed that EX reacts with Cu2+ ions, facilitating better adsorption on activated surfaces compared to non-activated surface. Originality. The originality of the present request can be summarized first of all, in the new insights explaining the copper sulfate manner to improve the sphalerite flotation, then in the exploration of copper and collector ions chemical interaction on the mineral surface, leading to understand their role to enhance the flotation process. Practical value. Practical importance can be concluded in the enhancing of technological process of flotation in Chaabet El Hamra factory, by giving more accurate reagents concentrations for instance ethyl-xanthate as a collector and copper sulfate as surface activator. Keywords: sphalerite, ethyl xanthate, copper sulfate, flotation, adsorption

Résumé: Phosphate is one of the most important natural resources because it is so crucial to the production of fertilizers and phosphoric acid. However, many undesirable elements are present in raw phosphate ores, which need to be refined in some way to boost their market value is the objective of this work. The most efficient technique for upgrading phosphate ores by the selective removal of gangue minerals is reverse flotation. This study aims to determine the physicochemical properties and the flotation behavior of sedimentary phosphate ore from the Kef Essenoun deposit (Tebessa, Algeria), with the intention of developing an effective beneficiation process. To develop the processing parameters for the medium grade phosphate ore, a thorough investigation was conducted to ascertain its mineralogical composition, particle size distribution, and degree of impurity elimination. Particle size distribution measurements, XRF, XRD, SEM/EDS analysis, and petrographical evaluation were used to describe these phosphates. 69.64% of the total mass of the phosphate raw ore sample fell between the –0.5 and +0.1 mm range, which also showed a reasonably acceptable particle size distribution. In addition to the related impurities of MgO and SiO2, chemical analysis revealed that the phosphates had P2O5 values ranging from 24% to 26%. According to mineralogical analysis, dolomite, calcite, and quartz were the related gangue minerals, whereas hydroxyapatite and fluorapatite were the predominant phosphate minerals. The traditional coprolitic and bioclastic characteristics of sedimentary phosphates were observed when examining the details on a smaller scale. Reverse flotation studies revealed that the produced concentrate reached 30% P2O5, confirm the effectiveness of this method for the perspective of valorization of sedimentary ore from the Kef Essnoun at Djebel Onk deposit and that this technique can increase the value of the ore. These findings support the idea that Algerian phosphate ore processing could benefit economically and environmentally from reverse flotation.

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Résumé: The treatment of barite ore of vein 10 and 4 poses certain difficulties because of its mineralogical structure. Mineralogical analysis has shown that the barite particles are encrusted with those of silica, which makes their separation difficult by jigging at the Ain Mimoun plant. A broad granulo-chemical and mineralogical characterization of the representative samples taken from the two veins 4 and 10, by means of sieving analysis, X-ray Diffraction (DRX), microscopic observation of different particle size slices under a binocular microscope, X-ray fluorescence (FRX) and scanning electron microscopy (SEM-EDX), to identify veins 4 and 10, and be able to choose a reliable enrichment process for these two veins. The results of the microscopic observation showed that the best release of barite particles from that of the gangue is in the classes -500+250, -250+125 and -125+63 μm with significant weighted yields. The X-ray diffraction of the samples studied shows that the main minerals constituting our sample are: BaSO4 barite, SiO2 quartz, CaMg(CO3)2 dolomite and CaCO3 calcite. The XRF analysis confirms the presence of the various components of barite, for instance BaSO4, SiO2, CaO, Fe2O3, Al2O3, P2O5, K2O, Na2O, TiO2, MnO, and other oxides such as ZnO, CuO, the predominance of BaSO4, SiO2, CaO is proven. These results were confirmed by those of scanning electron microscopy (SEM-EDX).

Résumé: Purpose. The main purpose of our research work involves the characterization and environmental management of waste rocks from Djebel Onk phosphate deposit. We propose a valorization of this product as an addition to cement manufacturing technique (the development of a new composite cement based on waste rocks of Djebel Onk phosphate deposit). Methodology. A comparative study was conducted on the physical and mechanical parameters of the composite cement based on phosphate waste rocks with cement without additions (CWA) and other cements based on pozzolan and the blast-furnace slag additives. These additives make, respectively, at mass contents of 5, 10, 15, 20, 25 and 30 % for each addition. Findings. The studies and tests conducted have enabled us to deduce that it is clear that the use of phosphate waste rocks as an additive in the manufacture of cement gives better compressive strengths compared to other additives. Thus, this study has shown that it is possible to incorporate a considerable amount of phosphate waste rock from Djebel Onk deposit in the cement. Originality. It becomes possible to reduce the amount of phosphate waste rocks of Djebel Onk for cost-effectiveness and eliminate their impact from the environmental point of view. Practical value. The reuse of waste as an alternative raw material in building materials is a promising environmental solution. This way of valorization reduces large quantities of tailings and thus their environmental impact, as well as contributes to the preservation of non-renewable natural resources intensively used in construction (clays, limestone, sand, and others). Keywords: phosphate waste rocks, blast-furnace slag, pozzolan, cement, additives, Djebel Onk deposit

Résumé: Purpose. The purpose of our study involved the improvement of the Zn-recovery and its content in the concentrate while floating the sphalerite from raw ore, by controlling the behavior of sphalerite surface and its floatability in the cases of presence and absence of copper sulfate as activator reagent. Methodology. Experimental flotation tests were carried out to assess the impact of two variable parameters: the dosage of copper sulfate and the dosage of ethyl xanthate. The mineralogical composition was obtained by Xray Diffraction (XRD). The Complexometric titration method was used to measure the zinc grade and determine the Zinc recovery. The adsorption mechanism of EX on non-activated and activated sphalerite surfaces was analyzed, using the infrared (FTIR) analysis. Findings. The results indicated that the ethyl xanthate does not respond well in the absence of the activator with sphalerite surface. Thus, the copper ions (Cu2+ ) significantly enhance the hydrophobicity of sphalerite. The optimal conditions were found at pH 11, with a CuSO4 dosage of 1.3 ⋅ 10-3 mol/L achieving a zinc recovery of 87.19 % with zinc grade of 38.17 %. Infrared analysis confirmed that EX reacts with Cu2+ ions, facilitating better adsorption on activated surfaces compared to non-activated surface. Originality. The originality of the present request can be summarized first of all, in the new insights explaining the copper sulfate manner to improve the sphalerite flotation, then in the exploration of copper and collector ions chemical interaction on the mineral surface, leading to understand their role to enhance the flotation process. Practical value. Practical importance can be concluded in the enhancing of technological process of flotation in Chaabet El Hamra factory, by giving more accurate reagents concentrations for instance ethyl-xanthate as a collector and copper sulfate as surface activator

Résumé: Phosphate is one of the most important natural resources because it is so crucial to the production of fertilizers and phosphoric acid. However, many undesirable elements are present in raw phosphate ores, which need to be refined in some way to boost their market value is the objective of this work. The most efficient technique for upgrading phosphate ores by the selective removal of gangue minerals is reverse flotation. This study aims to determine the physicochemical properties and the flotation behavior of sedimentary phosphate ore from the Kef Essenoun deposit (Tebessa, Algeria), with the intention of developing an effective beneficiation process. To develop the processing parameters for the medium grade phosphate ore, a thorough investigation was conducted to ascertain its mineralogical composition, particle size distribution, and degree of impurity elimination. Particle size distribution measurements, XRF, XRD, SEM/EDS analysis, and petrographical evaluation were used to describe these phosphates. 69.64% of the total mass of the phosphate raw ore sample fell between the –0.5 and +0.1 mm range, which also showed a reasonably acceptable particle size distribution. In addition to the related impurities of MgO and SiO2, chemical analysis revealed that the phosphates had P2O5 values ranging from 24% to 26%. According to mineralogical analysis, dolomite, calcite, and quartz were the related gangue minerals, whereas hydroxyapatite and fluorapatite were the predominant phosphate minerals. The traditional coprolitic and bioclastic characteristics of sedimentary phosphates were observed when examining the details on a smaller scale. Reverse flotation studies revealed that the produced concentrate reached 30% P2O5, confirm the effectiveness of this method for the perspective of valorization of sedimentary ore from the Kef Essnoun at Djebel Onk deposit and that this technique can increase the value of the ore. These findings support the idea that Algerian phosphate ore processing could benefit economically and environmentally from reverse flotation.