Project Details
Projekt
Switchable selective collectors for flotation of engineered artificial minerals
Applicant
Professor Dr. Andreas Schmidt
Subject Area
Mechanical Process Engineering
Chemical and Thermal Process Engineering
Chemical and Thermal Process Engineering
Term
since 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 470324113
In the first funding period of the priority program, the natural product punicine from Punica granatum and a selection of its derivatives prepared according to a LEGO kit chemistry were successfully investigated as switchable collectors for flotation. We initially focused on the engineered artificial mineral (EnAM) lithium aluminate from Li recycling and its gangue material gehlenite. Through our work, together with our project partners, we gained valuable insights into the mode of action of our punicines in flotation and the mechanisms of surface hydrophobization. The properties of the punicines can be adjusted by selecting the pH value and the influence of light (UV light, daylight, darkness), as this allows punicines to be converted optionally and reversibly into cations, neutral betaines, anions, dianions or radical species, the properties of which can be utilized for flotation. Punicines are therefore switchable collectors that can achieve almost quantitative yields after adjusting the influence of light and pH value. Conversely, by varying these parameters, it is possible to assign punicines the role of a suppressor in the flotation of lithium aluminate, for example. Initial tests with the minerals spodumene (Li-containing) and galaxite (Mn-containing) as well as various slags from our project partners (Li/Ta-containing) were also so promising that the investigations are to be intensified in the second funding period. Inspired by investigations into the mode of action, punicine derivatives with stronger electron donor properties will first be synthesized in order to provoke an even more effective reaction with the partially hydrated surface of the EnAM particles of the lithium aluminate. The findings will then be transferred to spodumene, which is an important natural source of lithium. Surface treatments of the particles in preparation for effective flotations with punicines will then be investigated on the basis of promising preliminary experiments; we will alter the surface chemistry with water by plasma and the modification of the lithium aluminate by thermal treatment. Our work will require the synthesis of customized new punicines: For this purpose, the punicines will be functionalized with groups that already play important roles in flotations (without being switchable). Through the links with the punicine backbone, the properties of these groups can also be adjusted by light and the pH value, so that effective flotations are possible after fine-tuning of the properties. This experience gained from model reactions will be applied in parallel to authentic slags from our project partners, such as fayalite slags, which can then be effectively processed by flotation with switchable punicines by varying the influence of light and the pH value.
DFG Programme
Priority Programmes
