ORALS

SESSION: RecyclingSatAM-R4	Kozlov International Symposium on Sustainable Materials Recycling Processes and Products (7th Intl. Symp. on Sustainable Materials Recycling Processes and Products)
Sat Oct, 26 2019 / Room: Adonis
Session Chairs: Florian Kongoli; Dominik Hofer; Session Monitor: TBA

12:10: [RecyclingSatAM03]
Optimization of a Leaching Process for Pulverized Metal-Containing Residues
Eva Gerold¹ ; Stefan Luidold² ; ¹Montanuniversitaet Leoben, Chair of Nonferrous Metallurgy, Leoben, Austria; ²Montanuniversitaet Leoben, Leoben, Austria;
Paper Id: 234 [Abstract]

The selective recovery of valuable metals from metal-containing residues not only conserves the primary resources, but also improves the availability of raw materials. First and foremost, the focus must be kept on previously unrecycled wastes as these have been removed from the circular resource flow. The recycling of used batteries effects not only the treatment of hazardous waste, but also the recovery of valuable elements used in this field. On the commonly used pyrometallurgical route, mostly only the main metals are recovered. The application of hydrometallurgy remedies this problem and is mentioned in various research papers [1]. This process route gives the possibility of recycling for materials such as rare earths, cobalt and nickel which are often slagged in the pyrometallurgical process [2]. The recycling of metal-containing residues from the battery sector by hydrometallurgical means offers a wide range of possibilities. It is assumed that many different residues, as well as nickel-cadmium or nickel-metal hydride batteries and lithium-ion batteries can be recycled. Recycling processes for these metal-containing residues are divided in chemical processes (leaching, selective precipitation, solvent extraction) and mechanical and/or thermal processes [2,3]. The optimization of leaching parameters in the field of recycling of metal-containing residues represents a complex topic in the literature. In addition to the selection of an appropriate leaching medium, the variation of different leaching parameters such as temperature, time, solid-liquid ratio and concentration of the leaching medium have to be investigated in order to obtain the best possible result. Efficient leaching can only occur if there is an optimized process window with upper and lower limits for the respective parameters [4]. For experimental design and evaluation, a statistical software for design of experiments based on a fully factorial model serves for the interpretation of the process area [5].

References:
[1] Ordonez, J., Gago, E. J., Girard, A. (2016). Processes and technologies for the recycling and recovery of spent lithium-ion batteries. Renewable and Sustainable Energy Reviews 60, 195-205.\n[2] Kaindl, M., Luidold, S., Poscher, A. (2012). Recycling von Seltene Erden aus Nickel-Metallhydrid-Akkumulatoren unter besonderer Beruecksichtigung von Saeurerueckgewinnung. Berg Huettenmaenn Monatsh 157/1, 20-26.\n[3] Xu, J., Thomas, H. R., Francis, R. W., Lum, K. R., Wang, J., Liang, B. (2008). A review of processes and technologies for the recycling of lithium-ion secondary batteries. Journal of Power Sources 177/2, 512-527.\n[4] Takacova, Z., Dzuro, V., Havlik, T. (2017). Cobalt precipitation from Leachate Originated from Leaching of Spent Li-ion Batteries Active Mass-Characterization of Inputs, Intermediates and Outputs. World of Metallurgy - ERZMETALL 70/6, 336-343.\n[5] Mantuano, D. P., Dorella, G., Elias, R. C. A., Mansur, M. B. (2006). Analysis of a hydrometallurgical route to recover base metals from spent rechargeable batteries by liquida-liquid extraction with Cyanex 272. Journal of Power Sources 159/2, 1510-1518.

SESSION: RecyclingSatPM1-R4	Kozlov International Symposium on Sustainable Materials Recycling Processes and Products (7th Intl. Symp. on Sustainable Materials Recycling Processes and Products)
Sat Oct, 26 2019 / Room: Adonis
Session Chairs: Tsuyoshi Hoshino; Alexandra-Georgiana Vatui; Session Monitor: TBA

14:00: [RecyclingSatPM105]
Slag Basicity Variation at Block Smelting for the Recycling of Tantalum
Dominik Hofer¹ ; Stefan Luidold¹ ; Tobias Beckmann² ; ¹Montanuniversitaet Leoben, Leoben, Austria; ²H.C.Starck Tantalum & Niobium GmbH, Laufenburg, Germany;
Paper Id: 228 [Abstract]

Tantalum rich ores containing oxidic minerals like tantalite or columbite are primarily mined by artisanal and small scale practices. [1] Major sources located in countries around the African Great Lakes like Congo and Rwanda control global output with a 60 % share. [2] Direct treatment of concentrates with a Ta₂O₅ content higher than 25 % takes place via leaching followed by liquid-liquid extraction. Recycling, chlorination and processing of low grade residues, slags, sludges or dusts represent aspiring alternatives accounting for approximately 30 % of the tantalum world production. [3] The pyrometallurgical manufacturing of synthetic tantalum concentrate (syncon) in a multi-stage process constitutes an established procedure for various input materials. [4] Within this study, the first step (smelting and reduction) is recreated in a small scale induction furnace as well as a DC-EAF. Huge amounts of high melting slag comprising mostly Al₂O₃, CaO, MgO, SiO₂, TiO₂ and ZrO₂ arise whilst Nb and Ta concentrate in the metal phase. Previous flow behaviour investigations [5] and viscosity calculations reveal low viscous slag to be crucial for good metal/slag separation at elevated CaO content. Therefore, a variation of slag basicity is tested for further process optimization and to attain technical standard regarding treatment time, tapping procedure and slag composition of < 0.2 % Ta₂O₅. Accumulation of value components was successfully realized and validated by SEM/EDX. Thus, yield, energy saving potential and other process adjustments for the syncon production can be investigated at the laboratory scale before upscaling to industrial quantity.

References:
[1] Killiches F. et al.: Sorgfaltspflichten in den Lieferketten von Zinn, Tantal, Wolfram und Gold. DERA Deutsche Rohstoffagentur Commodity TopNews 46, 2014.
[2] Reichl C., M. Schatz and G. Zsak: World Mining Data. Minerals Production, 2017.
[3] Andersson K., K. Reichert and R. Wolf: Tantalum and Tantalum Compounds: Ullmann's Encyclopedia of Industrial Chemistry (2000), 1-15.
[4] Schulenburg F., H. Rossel and U. Bartmann: Tantalrecycling: Thiel, Thome-Kozmiensky et al. (Hg) 2017 - Recycling und Rohstoffe, 137-154.
[5] Hofer D. et al.: Influence of CaO/SiO₂/Al₂O₃ Ratio on the Melting Behaviour of SynCon Slags. In: Minerals, Metals and Materials Society, TMS Annual Meeting & Exhibition (Hg.): TMS 2019 148th Annual Meeting & Exhibition supplemental proceedings. Cham: Springer, 1139-1148.