ABSTRACT

Scheelite and calcite are usually intergrown calcium minerals that are separated via froth flotation. However, their selective separation remains difficult because of their similar surface properties. 2-phosphonobutane −1, 2, 4-tricarboxylic acid (PBTCA or H₅L) is widely used in water treatment due to its low phosphorus content and efficient anti-scaling performance. With its excellent calcium-chelating ability, PBTCA was used as a novel depressant to selectively separate scheelite from calcite in this study. The flotation results of single mineral, binary mixed minerals, and real ore showed that PBTCA could selectively depress calcite at pH 9.0 using sodium oleate as collector. The results of zeta potential measurements, solution chemistry calculation, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and density functional theory calculation indicated that the dominant form of PBTCA was L^5-. This anion had a stronger adsorption on negatively charged calcite surfaces through electrostatic interaction. Higher Ca density and stronger Ca activity on calcite promote the adsorption of L^5-. Moreover, the active O atoms in L^5- could better match with two Ca sites on calcite in the interatom distance. Thus, PBTCA provides a new option for calcite depressants and has great industrial application potential.

摘要

白钨矿和方解石通常是通过泡沫浮选分离的共生钙矿物。然而，由于它们相似的表面性质，它们的选择性分离仍然很困难。2-膦酸丁烷 -1, 2, 4-三羧酸（PBTCA 或 H ₅l) 因其磷含量低、阻垢性能好而被广泛用于水处理。在本研究中，PBTCA 具有优异的钙螯合能力，被用作一种新型抑制剂，可选择性地将白钨矿与方解石分离。单矿物、二元混合矿物和真矿的浮选结果表明，PBTCA 可以在油酸钠作为捕收剂的条件下，在 pH 9.0 时选择性地抑制方解石。zeta电位测量、溶液化学计算、傅里叶变换红外光谱、X射线光电子能谱和密度泛函理论计算结果表明，PBTCA的主要形式为L ^5-. 这种阴离子通过静电相互作用在带负电荷的方解石表面上具有更强的吸附作用。较高的Ca密度和较强的Ca在方解石上的活性促进了L ^5-的吸附。此外，L ^5-中的活性O原子可以更好地与原子间距中方解石上的两个Ca位点匹配。因此，PBTCA为方解石抑制剂提供了新的选择，具有巨大的工业应用潜力。