Flotation is the most essential method for the concentration of phosphate reserves and, hence, the production of apatite concentrate. With the reduction of high-grade reserves and the necessity of exploiting low-grade phosphate ores, many efforts have been made to use different chemical reagents alone and their combinations as collectors for apatite flotation and achieving high-quality concentrates for preparing phosphoric acid and fertilizers. This work focuses on applying direct apatite flotation by employing a novel mixture of fatty acid collectors to optimize the apatite processing plants. Extensive experiments using tall oil fatty acid (TOFA) and oleic acid polyethylene glycol ester 6 mol (OAPEGE6) alone and their mixture in different ratios were conducted in micro-flotation, bench flotation, and plant flotation scales. The micro-flotation experiments showed that using OAPEGE6 and TOFA, the flotation recovery of apatite at a pH of 9.5 is 46% and 86%, respectively. However, by mixing TOFA and OAPEGE6 in a weight ratio of 70% to 30%, the flotation recovery of apatite increases to 95%. At this weight ratio of TOFA and OAPEGE6 using a 600 g/t mixed collector, an apatite concentrate containing 23.2% P2O5 with a recovery of 90.4% is achieved by rougher stage bench flotation in laboratory experiments. Finally, using the mixed collector with the formulation mentioned above on a plant-scale, an apatite concentrate with almost 33% P2O5 and 59% recovery is obtained through rougher and cleaner stages of the flotation process. FTIR analysis and zeta potential measurements show that the simultaneous presence of TOFA and OAPEGE6 with a synergetic effect can strengthen the chemisorption of oleate active species on the apatite surface. As confirmed by contact angle measurements, this improved the formation of an insoluble hydrophobic layer on the apatite surface and resulted in its flotation recovery.

中文翻译：

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一种新的阴离子捕收剂混合物，用于改善磷灰石的可漂浮性


浮选是浓缩磷酸盐储量的最重要方法，因此也是生产磷灰石精矿的最重要方法。随着高品位储量的减少和开采低品位磷矿石的必要性，人们做出了许多努力，单独使用不同的化学试剂及其组合作为磷灰石浮选的捕收剂，并实现用于制备磷酸和肥料的高质量精矿。这项工作的重点是通过采用一种新型脂肪酸收集剂混合物来优化磷灰石加工厂，从而应用直接磷灰石浮选。在微浮选、台式浮选和植物浮选秤中，单独使用妥尔油脂肪酸 （TOFA） 和油酸聚乙二醇酯 6 mol （OAPEGE6） 及其不同比例的混合物进行了广泛的实验。微浮选实验表明，使用 OAPEGE6 和 TOFA，在 pH 值为 9.5 时，磷灰石的浮选回收率分别为 46% 和 86%。然而，通过将 TOFA 和 OAPEGE6 以 70% 至 30% 的重量比混合，磷灰石的浮选回收率提高到 95%。在使用 600 g/t 混合捕收剂的 TOFA 和 OAPEGE6 的重量比下，在实验室实验中通过较粗的阶段台式浮选获得含有 23.2% P2O5 的磷灰石精矿，回收率为 90.4%。最后，在工厂规模上使用具有上述配方的混合捕收剂，通过浮选过程的更粗糙和更清洁的阶段获得具有近 33% P2O5 和 59% 回收率的磷灰石精矿。FTIR 分析和 zeta 电位测量表明，同时存在具有协同效应的 TOFA 和 OAPEGE6 可以加强磷灰石表面油酸盐活性物质的化学吸附。 接触角测量证实，这改善了磷灰石表面不溶性疏水层的形成，并导致其浮选恢复。