Augmentation du contraste de séparation des minéraux calciques semisolubles à l'aide de combinaisons de réactifs carboxyliques et non-ionique

Abstract : Valorization of calcium minerals is a global problem. Flotation is a technique used for the separation of these minerals since it plays on their surface properties. However, this is an important scientific challenge because the surface properties of calcium minerals are very similar. The difficulties of separation of these minerals are then due to the similarities between their chemical surface properties, but also their electrokinetic and their stability in aqueous solutions. The application of the basic research results will focus on 4 calcites and one apatite of different origins. The main objective is to study the properties and parameters involved in the separation mechanisms of calcium minerals such as the importance of the solubility, the surface speciation of the mineral, the overall loading of the mineral surface and the density of adsorption of surfactants. The electrokinetic properties therefore make it possible to determine the type of collector to be used to selectively float the minerals and to choose the optimum separation pH. Two collectors, sodium oleate and linoleate (different semi-developed formula), were used to study the flotation of calcium minerals. The mixture of these two collectors with different molar ratios was also studied showing a separation contrast at pH 5 with the molar ratio 2: 1 and the ratio 1: 1 at pH 9. In addition, the synergistic effects between ionic collector (oleate or sodium linoleate) and non-ionic (PX alcohol type) in the presence or absence of depressants such as starch and sodium silicate have been studied to improve recovery and selectivity. The adsorption isotherms of sodium oleate and linoleate, in the presence or absence of a non-ionic collector, obtained by the Gregory method demonstrate their co-adsorption on the surface of calcite and apatite. This was also confirmed by the displacements of the symmetric and antisymmetric vibration bands of the CH2-CH3 groups on the infrared spectra in diffuse reflectance. The adsorption of sodium linoleate on one of the calcite minerals (calcite orange) shows different regions which can be explained by multi-layer adsorption resulting from the two-dimensional condensation of the collector on a heterogeneous surface. However, the adsorption of sodium oleate on calcite orange is linear. The apatite from Madagascar and calcite optical have a saturation of the adsorption sites from a concentration of 3.10-5 M in sodium oleate (CMC)
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Submitted on : Wednesday, April 4, 2018 - 9:36:32 AM
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  • HAL Id : tel-01757840, version 1

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Zineb Lafhaj. Augmentation du contraste de séparation des minéraux calciques semisolubles à l'aide de combinaisons de réactifs carboxyliques et non-ionique. Sciences de la Terre. Université de Lorraine, 2017. Français. ⟨NNT : 2017LORR0052⟩. ⟨tel-01757840⟩

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