This study combines flotation experiments and simulations to improve the anionic flotation of fluorapatite from Florida waste clay (FWC) by investigating the depressing effects of sodium silicate and citric acid, in presence of sodium oleate (NaOl), on dolomite, quartz, and fluorapatite. First, we show that the order of natural floatability with NaOl of the three pure minerals is fluorapatite > dolomite > quartz, in agreement with the first-principles calculations. Second, sodium silicate has a strong calculated affinity with fluorapatite surface, which explains the dramatical drop observed experimentally in the floatability of this mineral. From simulations, citric acid exhibits a poor affinity for fluorapatite surface but a strong affinity for dolomite and quartz surfaces, even stronger than NaOl, related to strong differences in the adsorption mechanisms. This trend in terms of affinities is consistent with the trend in terms of floatabilities, observed on pure minerals. Consistently, during FWC flotation, citric acid allows an efficient and satisfactory depression of gangue minerals (quartz and dolomite) and enhances P recovery and grade by 14 % and 2 %, respectively. Using citric acid in FWC flotation makes possible the efficient beneficiation of this material with a cleaner product compared to the classical processes.

中文翻译：

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使用多尺度方法优化佛罗里达废粘土中氟磷灰石的浮选分离

本研究将浮选实验和模拟相结合，通过研究硅酸钠和柠檬酸在油酸钠 (NaOl) 存在下对白云石、石英和氟磷灰石的抑制作用，改进佛罗里达废粘土 (FWC) 中氟磷灰石的阴离子浮选。首先，我们发现三种纯矿物的NaOl自然可浮性顺序为氟磷灰石>白云石>石英，与第一性原理计算一致。其次，硅酸钠与氟磷灰石表面具有很强的计算亲和力，这解释了实验观察到的这种矿物可浮性的急剧下降。从模拟结果来看，柠檬酸对氟磷灰石表面的亲和力很差，但对白云石和石英表面的亲和力很强，甚至比NaOl还要强，这与吸附机制的巨大差异有关。这种亲和力的趋势与在纯矿物上观察到的可浮性的趋势一致。一致地，在 FWC 浮选过程中，柠檬酸可以有效且令人满意地抑制脉石矿物（石英和白云石），并将 P 回收率和品位分别提高 14% 和 2%。与传统工艺相比，在 FWC 浮选中使用柠檬酸可以通过更清洁的产品对该材料进行有效选矿。