Relationship between Chemical Structure and Adsorption Preference to Metal Ions of Chelating Resins and Their Applications in Removal of Iron from Copper Leach Solutions

除铁是生产纯有色金属的一个必不可少的过程。铜浸出液在电积回收铜之前必须净化以除去铁。我们最近发现一种具有优良洗脱性能的羟基肟树脂Z-Fe对Fe的选择性吸附优于Cu。研究结果已发表在《湿法冶金》（Zhang et al.，2016年），并提交给2016年国际矿物加工大会。 然而，这种羟基肟树脂Z-Fe的作用机理尚不清楚。文献综述表明，螯合树脂的化学结构与其对金属离子的吸附偏好之间的关系，这是选择和设计合适的树脂用于湿法冶金中金属离子吸附的关键，尚未完全理解和系统研究。理解这种关系是这项发现补助金提案的重点。 螯合树脂具有官能团，并且可以对特定的金属离子具有高的吸附偏好。它们在从水溶液中回收（或去除）和分离金属方面具有广泛的应用前景。通过研究螯合树脂的化学结构与其对金属离子的吸附性能之间的关系，为金属离子的分离和回收提供树脂的选择和设计依据，是一项基础性的、长期的系统工作。这将使选择和设计适合金属离子吸附的树脂成为一个科学的程序，而不是目前的筛选测试程序。 对于短期目标（即，该程序），首先，螯合树脂的化学结构与它们对金属离子的吸附偏好之间的关系（即，本研究中的铁或铜离子）将通过将它们对铁/铜离子的吸附性能与它们的电子/化学结构相关联来确定。选择或设计对铁或铜离子具有吸附偏好的树脂的基本规则将被开发。其次，为了使使用螯合树脂的铁去除工艺商业化可行，将研究通过电沉积回收铁和回收洗脱剂（如草酸）。螯合树脂法从铜浸出液中除铁是一种创新工艺。有了这些初步工作，选择或设计具有理想除铁性能的树脂是可行的。 本项目的研究成果及后续研究将为湿法冶金中螯合树脂分离金属离子提供理论指导，并具有广阔的应用前景。这些结果也可能应用于从海洋中回收金属和从污染的河流和湖泊中去除重金属以改善环境健康，这将为未来的研究任务奠定基础。

The removal of iron is a necessary process with common concern in the production of pure nonferrous metals. Copper leach liquors must be purified to remove iron before copper recovery by electrowinning. We recently found that a hydroxy-oxime resin with excellent elution property, named Z-Fe, has selective adsorption for Fe over Cu. The research results have been published in Hydrometallurgy (Zhang et al., 2016), and presented to the International Mineral Processing Congress 2016. However, the functioning mechanism of this hydroxy-oxime resin Z-Fe is not clear. Literature review indicates that the relationship between the chemical structure of chelating resins and their adsorption preference to metal ions, which is critical for the selection and design of suitable resins for metal ion adsorption in hydrometallurgy, has not been fully understood and systematically studied. Understanding this relationship is the focus of this Discovery Grant proposal. Chelating resins have functional groups and can be of high adsorption preference to specific metal ions. They have broad prospective applications in recovery (or removal) and separation of metals from aqueous solutions. Through study on the relationship between the chemical structures of chelating resins and their adsorption performances for metal ions, which is a fundamental and long term systematic work, we will develop rules for the selection or design of resins used in the separation or recovery of metal ions. This will make the selection and design of suitable resins for metal ion adsorption a scientific procedure, rather than the current screening test procedure. For short term objectives (i.e., this program), firstly, the relationship between the chemical structure of chelating resins and their adsorption preference to metal ions (i.e., iron or copper ions in this study) will be determined by correlating their adsorption performances to iron/copper ions with their electronic/chemical structures. The fundamental rules for the selection or design of resins with adsorption preference to iron or copper ions will be developed. Secondly, to make the iron removal processes using chelating resins viable for commercialization, recovery of iron and recycling of elution agents (such as oxalic acid) by electrodeposition will be investigated. Removal of iron from copper leach solution using chelating resins is an innovative process. With this preliminary work, selection or design of resins with ideal iron removal properties is feasible. Our research results from this program and follow-up studies will provide theoretical guidance and have broad applications for the separation of metal ions using chelating resins in hydrometallurgy. These results may also have applications in the recovery of metals from oceans and removing heavy metals from contaminated rivers and lakes to improve environmental health, which will build up future study tasks.