Zircon is a critical mineral for the extraction of zirconium, uranium and hafnium. Physical separation techniques like gravity and electrical separation have been widely used to obtain a commercial-grade zircon. Flotation, as a supplementary approach, can be used to separate fine zircon from heavy minerals (i.e. rutile, cassiterite). However, it is challenging to selectively recover iron/aluminosilicate contaminated zircon, due to its low floatability. In this study, two zircon samples containing high and low amounts of impurities were selected in order to determine the influence of surface composition on flotation. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), speciation diagrams, and zeta-potentials demonstrated that pretreatment methods can improve the surface purity of zircon via the removal of coated impurities (iron-oxides and aluminosilicates) as well as increasing the exposure of the ZrO₂ and ZrSiO₄ phases. SEM, XPS, zeta-potential and flotation studies performed with sodium oleate (NaOL) as an environmentally benign collector show that the pretreated zircon samples display better flotation performance than the untreated zircon. First-principle calculations revealed that the chemical bond between NaOL and zircon is ionic in nature; NaOL can be both chemically and physically adsorbed onto zircon surfaces. Adsorption is mainly affected by electrostatic attractions reflected by changes in the zeta-potential. Surface pretreatment can thus substantially improve the flotation performance of zircon.

锆石是提取锆、铀和铪的关键矿物。重力和电分离等物理分离技术已被广泛用于获得商业级锆石。浮选作为一种补充方法，可用于从重矿物中分离细锆石（即金红石、锡石）。然而，由于其低可浮性，选择性回收受铁/铝硅酸盐污染的锆石具有挑战性。在这项研究中，为了确定表面成分对浮选的影响，选择了两个含有高和低杂质的锆石样品。扫描电子显微镜 (SEM) 和能量色散 X 射线光谱 (EDS)、X 射线光电子能谱 (XPS)、形态图和 zeta 电位表明，预处理方法可以通过去除涂层来提高锆石的表面纯度杂质（氧化铁和硅铝酸盐）以及增加 ZrO ₂和 ZrSiO _4的暴露阶段。使用油酸钠 (NaOL) 作为环境友好型捕收剂进行的 SEM、XPS、zeta 电位和浮选研究表明，经过预处理的锆石样品比未经处理的锆石具有更好的浮选性能。第一性原理计算表明，NaOL和锆石之间的化学键本质上是离子键；NaOL 可以化学和物理方式吸附在锆石表面上。吸附主要受 zeta 电位变化所反映的静电吸引力的影响。因此，表面预处理可以显着提高锆石的浮选性能。