Rare Metal Extraction and Processing: Solvent Extraction for Rare Metals
Sponsored by: TMS Extraction and Processing Division, TMS: Hydrometallurgy and Electrometallurgy Committee
Program Organizers: Takanari Ouchi, University of Tokyo; Gisele Azimi, University of Toronto; Kerstin Forsberg, KTH Royal Institute of Technology; Hojong Kim, Pennsylvania State University; Shafiq Alam, University of Saskatchewan; Neale Neelameggham, IND LLC; Alafara Baba, University of Ilorin; Hong (Marco) Peng, University of Queensland

Monday 2:00 PM
February 28, 2022
Room: 213B
Location: Anaheim Convention Center

Session Chair: Takanari Ouchi, University of Tokyo; Hojong Kim, Pennsylvania State University; Kerstin Forsberg, KTH Royal Institute of Technology

2:00 PM Introductory Comments

2:10 PM  Keynote
Physicochemistry in Service of Process Design: Case of Uranium Recovery by Liquid-liquid Extraction: Alexandre Chagnes1; 1Universite De Lorraine-Georess
    Although solvent extraction seems to be easy to operate, its implementation at industrial scale can be difficult and costly. In order to reduce capital and operation expenditures, process optimization is mandatory. It consists in using appropriate equipment, flowsheet and parameters optimization in order to reduce energy and reactive consumption, effluent generation, etc. For this goal, it is relevant to understand the physicochemistry involved in the processes to get them more flexible. For the sake of illustration, this conference will address two cases: (i) the comprehension of the physicochemical phenomena responsible for the chemical degradation of the extraction solvent during liquid-liquid extraction of uranium from acidic sulfate media in order to keep high uranium extraction efficiency; (ii) the development of a new extractant for the recovery of uranium from wet phosphoric acid by means of a rational approach combining modelling of uranium extraction and investigation of uranium speciation in extraction solvent.

2:50 PM  
Effect of Antisolvent Type and Concentration on Morphology and Crystal Size of (NH4)3ScF6 Obtained by Antisolvent Crystallization: Edward Peters1; Michael Svärd1; Kerstin Forsberg1; 1KTH Royal Institute of Technology
    Scandium is a metal of value with increasing demand but limited supply. During the valorization of bauxite residue, scandium becomes concentrated in an NH4F strip liquor, from which it can be recovered as (NH4)3ScF6 by antisolvent crystallization. This study investigates the use of different antisolvents and their concentrations on the morphology and crystal size of the (NH4)3ScF6 crystals produced. The antisolvents include alcohols, ketones and a sulfoxide. These were added all at once, either pure or diluted, to the aqueous solution to attain final concentration of 2, 4 or 8 mol/L total solution in separate experiments. Changes in the functional group and concentration of the antisolvents were observed to induce morphological and crystal size modifications of (NH4)3ScF6. The differences are likely due to the specific interactions of the antisolvent molecules with the atoms at the different faces of the crystals and/or differences in initial supersaturation.

3:10 PM  
Tellurium Recovery – Development of a Novel Hydrometallurgical Process: Shijie Wang1; 1Coeur Mining, Inc
    Since the cadmium telluride (CdTe) PV modules have become among the lowest-cost products of solar electricity, tellurium recovery is a hot special metals topic in today’s bull market. This paper summarizes the recovery of tellurium and its processing technology from electrolytic copper refinery slimes, which almost invariably contain tellurium, selenium, copper, silver, gold, and traces of platinum group metals. A novel hydrometallurgical process (Wang’s Process) that was developed in bench scale experiments and pilot tests and led to commercial applications is presented. The process chemistry is also publicly discussed for the first time in this paper.

3:30 PM Break

3:50 PM  
Purification of a Low-grade Molybdenite Ore for Industrial Steel Production: Alafara Baba1; Christianah Adeyemi2; Mamata Mohapatra3; Mustapha Raji1; Fausat Akanji4; Abdul Alabi5; 1University of Ilorin; 2University of Ilorin & The Federal Polytechnic, Offa; 3CSIR-Institute of Minerals and Materials Technology; 4University of Ilorin & Sheda, Kwali, Abuja; 5Kwara State University, Malete
    Continuous demands for industrial molybdenum compounds such as MoO3 for steel coating applications cannot be overemphasized, as its highly characterized with improved pitting corrosion and heat resistance properties. In this study, molybdenum purification from a Nigerian low-grade molybdenite ore was investigated by sulphuric acid solution. The raw ore and selected products at optimal conditions were accordingly characterized. At optimal leaching conditions: temperature = 75 °C, [H2SO4] = 2.5 M, particle size < 50 µm, S/L ratio = 1:10 at 300 rpm, 64.7% molybdenum dissolution was achieved within 120 minutes. Calculated activation energy of 35.46 kJ/mol and a reaction order 1.02 established suggests a first order diffusion-controlled reaction mechanism. The residual products analyzed by X-ray diffraction containing co-mixtures of siliceous materials including quartz (SiO2 : 96-900-5020) and haleniusite (La1.84Ce1.80Nd0.28Pr0.08O4.48F3.52 : 96-901-0570) could be further re-processed as precursor for stainless steel production.

4:10 PM  
Comprehensive Processing of Mica Concentrate from Yaroslavsky GRK for Lithium Carbonate, Potassium Sulfate, Aluminum Sulfate, Rubidium and Cesium: Andrey Panov1; Aleksandr Suss1; Nataliya Kuznetsova1; Sergey Ostashin2; Evgeniy Isakov3; 1RUSAL Engineering and Technology Center; 2JSC RUSAL Management; 3Yaroslavsky GRK
    UC RUSAL’s Yaroslavsky Mining Company (Yaroslavsky GRK) operated two world’s largest fluorite deposits in East Cost of Russia. The fluorite extraction process leaved rare alkali metals (Li, Rb, Cs, and K) in the tailings and becomes a potential raw material source for these elements. In 2015-2018 Irgiredmet (Irkutsk, Russia) jointly with Central South University (Changsha, China) developed and pilot tested the technology of beneficiation of the tailings from Yaroslavsky GRK to extract fluorite and produce mica concentrate with rare alkali metals content ΣLi2O+Rb2O+Cs2O = 1.5÷1.7 mass. %. To process mica concentrate the energy-efficient technology of sulfuric acid – fluoride low-temperature atmospheric leaching was developed enabling to exclude the preliminary roasting commonly used for processing such ores. The technology was proven in pilot scale resulting in range of products meeting customer requirements: battery grade lithium carbonate (Li2CO3 ≥ 99.9 %), first grade potassium sulfate, rubidium and cesium formiats, and aluminum sulfate.