Post-Doc position at the University of Lorraine (France)
GeoRessources Laboratory

Title: Fundamentals of the quartz/feldspars separation and recovery as by-products of Li processing from LCT pegmatite and rare metal granite deposits.

General requirements:

Candidates should have an outstanding research record in the field of Minerals processing with extensive knowledge in physical chemistry, process mineralogy, minerals and/or chemical engineering. The selected candidate will join the “Georessources” research Laboratory, a major international research center with about 60 academics for a total staff about 180 persons developing research programs in all fields of applied geosciences including, mineral processing, minerals engineering, ore genesis, 3D modeling and economic geology.

The research activity will be in the “Minerals Engineering” team on fragmentation techniques and processing of ores by flotation. Innovative research on the beneficiation of non-conventional and lowgrade resources can be developed.

The candidate will integrate a research group with three senior researchers and 2-3 PhD students and will be involved in experimental research and academic tuition depending on candidate’s curricula.

Scope of the proposal

As part of its green energy transition and decarbonisation efforts, the European Union (EU) is aiming to have at least 30 million electric vehicles (EVs) by 2030. EU is heavily reliant on lithium imports from few dominated countries which forces supply security issues. To combat the supply risk of lithium, 15 European partners gathered and advanced a new mining paradigm i.e. zero-waste, multimetal/ mineral mining called EXCEED which stands for “Cost-effective, sustainable and responsible extraction routes for recovering distinct critical metals and industrial minerals as by-products from key European hard-rock lithium projects“.

Particularly, this project is in close partnership between Imerys, Keliber and GeoRessourcces (University of Lorraine) and aims to utilize all possible beneficiation routes for recovering critical raw materials and industrial materials, as by-products from Li-bearing hard-rock ores.

Quartz and feldspars are commonly by-products of Li-bearing pegmatite and rare metal granite deposits. These minerals are widely applied in the production of glass, ceramics, and as fillers and extenders. Traditionally, there are two main flotation processes to separate quartz and feldspar. The first one is fluorine-flotation, which uses hydrofluoric acid (HF) or sodium fluoride (NaF) as pH regulator and feldspar activator. Then, feldspars are floated from quartz using amine collectors under highly acidic conditions. This process provides excellent selectivity with high-grade feldspar and highquality quartz. However, the toxicity and harmful environmental impacts of fluoride ions limit the use of HF at industrial scale application. In addition, this process will also increase cost production due to the treatment of flotation fluoride-containing tailwater. The second method is fluorine-free flotation, which could be addressed the problem caused by HF flotation. Several studies comprising mixing of cationic and anionic collectors in strong acidic conditions using H2SO4 and HCl as pH regulator have been proposed. However, when compared to conventional HF flotation, the effectiveness of the separation is still unsatisfactory. Thus, there is a strong need for more fundamental approach on the selective separation of quartz and feldspar without the harmful effects of HF treatment.

Description and objectives of the proposal

This project aims to develop a safe and environment friendly (fluorine-free) flotation method and at the same time improve feldspar flotation selectivity. The project focuses on the most fundamental aspects of flotation which are mineral surface chemistry and reagents performance. The study will begin with mineralogical study in which the sample feed will be analysed through its chemical and mineral composition. Then the floatability of feldspar and quartz, both pure minerals and mineral mixtures, will be comparatively studied with and without HF treatment and collect the experimental data on the understanding of separation mechanisms. The detailed mechanisms will be experimentally examined using various techniques such as zeta-potential, contact angle measurement, infrared and insitu Raman spectroscopies, adsorption tests, etc to identify interesting surfactants (collectors, activators and pH modifiers). The flotation separation using the combination of the surfactant of different molecular structure will constitute the main scientific approach to develop environmentally friendly reagents regime at neutral or slightly alkaline medium.

The most fundamental aspects of the work will focus on the understanding of the self-assembled hydrophobic monolayer formation on the feldspar minerals surface to control the process selectivity and coarse particles flotation. Then, the project will study the effectivity of determined surfactants and its optimised usage on the separation characteristics of feldspar and quartz through flotation from the rare metals granites and pegmatite ores. Finally, there is also a possibility to utilize further the physical properties of quartz and feldspar to explore other beneficiation route to compare it to flotation approach. In the other hand, to approach zero-waste concept, the research topic related with the recovery by flotation of the other minor but critical elements (Be,...) will be examined. Thus the flotation of Be phosphate minerals may be explored.

Funding: This postdoc position will be supported by the Horizon Europe EXCEED Project
Duration: 24 months (possible extension by 12 months)

Provided documents:

  • list of publications,
  • experience in field, analytical, experimental or modeling approaches
  • project in two-three pages summarizing the main trends in research that the candidate would like to develop based on the above mentionned work program ( or on the selected points of proposed program)

Applicants should send via email a Curriculum Vitae, Provided documents and the names and email addresses of two references to: Pr Lev FILIPPOV,

Calendar for applying:

  • March 5th 2023: Deadline for submitting your application
  • March 15: Preliminary review, the candidates will be contacting after being preselected.
  • For definitive selection, an audition of the candidate will be arranged either in Nancy or by video-conference

Starting expected from 13 March, 2023 but is depending on the instruction of the application by the administration of the university.

Level of salary: minimum 3500 Euros brut/month depending on the post-doc experience and according to the University’s “working experience/salary” scale after PhD thesis

posted: 09 February 2021     Please mention EARTHWORKS when responding to this advertisement.