Switchable selective collectors for flotation of engineered artificial minerals

人们越来越担心能否可靠、畅通地获取关键原材料，如铂、钯、钽、稀土元素，以及铜和锂等在现代技术中发挥重要作用的其他元素。在项目支柱A和B中，优先方案SPP 2315处理形成矿渣以将稀释元素浓缩为工程人工矿物（EnAMs）。申请人的提案位于项目支柱C中，因为其目标是通过新的和可切换的收集器开发选择性成分依赖分离，这些收集器与来自石榴的天然产物石榴碱有关。嘌呤衍生物的电荷可以通过ph值从正电荷调整到两倍负电荷。此外，暴露在日光（> 5000勒克斯；3300-5300 K）下，在水中可逆地产生具有氧化还原活性的持久自由基。库仑相互作用、氢键形成、供体、受体和供体能力对表面络合和吸附很重要，它们可以通过外部参数（如pH或光）可逆地调节，甚至可以“打开”和“关闭”。在模型反应中发现了对金属的显著可调选择性。在第一次浮选实验中，通过将光照条件从“日光”改为“黑暗”（< 40 lux），在pH值6-7时，重要的工程人工矿物（EnAM）铝酸锂的回收率提高了60%。在这些有希望的初步结果的基础上，本提案的目标是开发用于浮选EnAMs的可切换捕收剂，同时研究浮选后捕收剂中颗粒的有效和经常存在问题的释放。我们将在石榴核上安装已知的浮选活性官能团，使其可切换，即根据pH值和光照选择性地选择目标enam，以便与不需要的enam或脉石材料有效分离。目标EnAM颗粒含有锂、铜、钽、稀土元素和铂族元素。

There is growing concern about reliable and unhindered access to critical raw materials such as platinum, palladium, tantalum, rare-earth elements, but also other elements such as copper and lithium, which play important roles in modern technology. In the project pillars A and B, the priority programme SPP 2315 addresses slag formation to concentrate diluted elements as engineered artificial minerals (EnAMs). The applicant´s proposal is located in project pillar C as its goal is to develop selective composition-dependent separations by means of new and switchable collectors which are related to the natural product Punicine from Punica granatum. The charges of Punicine derivatives can be adjusted from positive to twofold negative by the pH. In addition, exposure to daylight (> 5000 lux; 3300–5300 K) reversibly gives persistent radicals in water which are redox active. Coulombic interactions, hydrogen bond formations, pi-donor, pi-acceptor and sigma-donor capabilities, important for complexation and adsorption on surfaces, can either be reversibly tuned by external parameters such as pH or light, or even switched “on” and “off”. Remarkable adjustable selectivities toward metals have been identified in model reactions. In first flotation experiments, the recovery rate of lithium aluminate, an important engineered artificial mineral (EnAM), increase at pH 6-7 by 60% simply by changing the light scenario from “daylight” to “darkness” (< 40 lux). On the basis of these promising preliminary results, the objective of this proposal is the development of switchable collectors for the flotation of EnAMs which goes in parallel with studies of effective and often problematic releases of the particles from the collectors after the flotation. We will install known flotation-active functional groups onto the Punicine core to make them switchable, i.e. selective toward target EnAMs depending on pH and light in order to allow effective separations from undesired EnAMs or gangue materials. Target EnAM particles contain lithium, copper, tantalum, rare-earth elements and those of the platinum group.