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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