Lyotropic ion effects in interfacial phenomena in mineral processing

矿物加工的物理化学方法，如泡沫浮选，依赖于矿物-溶液界面上发生的几种相关的界面现象。聚合物和表面活性剂的吸附、表面电荷、颗粒-气泡附着以及颗粒的聚集/分散都是pH和离子强度的函数。虽然离子强度一词传统上用来表示处理水中的总电解液浓度，但它没有考虑离子大小不同所产生的某些特殊效应，通常被称为溶致效应。根据它们对周围水结构的影响，所有离子大致可分为两类：kosmotrope(水结构形成离子)和chaotrope(水结构破坏离子)。直到最近，离子尺寸效应对界面水结构和相关界面现象的潜在影响才得到充分认识，但它们在选矿应用中的意义从未被系统地研究过。拟议研究的主要长期目标是确定溶致效应在基本界面现象中的作用，并演示如何控制或操纵这种效应以改善泡沫浮选过程的性能。实验计划将包括广泛的技术和方法，从对真实矿石的简单批量浮选测试到对矿物表面物理化学性质的高级光谱和热量研究。拟议的研究应加强该行业通过从复杂化学过程水中浮选处理矿物资源的能力，并应为高盐度废水的循环利用提供指导方针。泡沫浮选是最重要的细粒浮选方法。考虑到采矿业正逐步转向开采非常规矿物资源(例如海底矿藏)，这项工作的成果将成为关于这种具有技术挑战性的系统行为的宝贵数据来源。

The physicochemical methods of mineral processing, such as froth flotation, rely on several related interfacial phenomena occurring at the mineral-solution interface. Polymer and surfactant adsorption, surface charging, particle-air bubble attachment, and aggregation/dispersion of particles are known to be a function of pH and ionic strength. While the term ionic strength has traditionally been used to denote the total electrolyte concentration in processing water, it does not take into account some specific effects, commonly referred to as lyotropic effects, that result from differences in ionic sizes.In terms of their effect on the surrounding water structure, all ions can broadly be divided into two groups: kosmotropes (water-structure making ions) and chaotropes (water-structure breaking ions). Only recently, has the potential impact of ionic size effects on the interfacial water structure and the associated interfacial phenomena been fully recognized but their significance in mineral processing applications has never been systematically studied. The main long-term objective of the proposed research is to determine the role of lyotropic effects in the fundamental interfacial phenomena, and to demonstrate how such effects can be controlled or manipulated to improve the performance of the froth flotation process.The experimental program will include a wide range of techniques and methods, from simple batch flotation tests on real ores to advanced spectroscopic and calorimetric studies of the physicochemical properties of mineral surfaces. The proposed research should enhance the industry's ability to treat mineral resources by flotation from process waters of complex chemistries and should also provide guidelines for recycling of high-salinity waste waters. Froth flotation is the most important fine particle processing method. Considering the fact that the mining industry is gradually moving towards recovering unconventional mineral resources (e.g., seafloor deposits), the results of this work will become a valuable source of data about the behavior of such technologically-challenging systems.