Leaching of Germanium from the Slag of the GECAMINES Factories in Lubumbashi by Oxalic and Sulfuric Acids
The objective of this study is to contribute to the study of the purification of germanium in the slag of the pyrometallurgy of the GCM factories of Lubumbashi. To do this, a pre-treatment of the slag was done by drying at 105°C for 24 hours and a grindability study using a sieve whose mesh was 75mm maximum for 90 minutes. The moisture content was 0.52%, the grinding time 90 minutes to obtain 89% of passers-by. Initially, the slag assayed 0.02% Ge; 0.008% Ga; 5.4% Cu; 0.21% Co; 10.40% Zn; 10.30% Fe and 10.30% Si.
Our concern to recover the germanium from the slag with the other accompanying metals was to carry out the tests for dissolving the slag with oxalic and sulfuric acids after having characterized it. This slag was shown to be acidic and without a defined crystalline structure. The various dissolution tests were carried out by varying the quantity of oxalic acid for the preparation of the oxalic acid solution (100 to 150g/L), the leaching time (1h to 4h). The ratio between the amount of slag and the acid solvent was 1÷10 respectively. At this stage of our study, the optimal conditions for the dissolution of germanium were 4 hours of leaching at 40°C with one liter of acid solution of 125g/L for 100g of slag to obtain a yield of 98% of the Ge and a low yield of 42% Cu, 41% Co and 11% Zn. The low leaching yield observed for the other metals is explained by the high silica content of 10.30%. Indeed, the silica leads to a gel trapping the metals and preventing them from going into solution.
This is how we considered the elimination of silica by choosing the procedure using citric acid by varying the concentration in g/L of acid and the leaching time.
The optimal conditions were the use of one liter of aqueous citric acid solution consisting of 75g/L for 30 minutes of agitation in contact with 100g of slag to eliminate up to 99% of the silica. This process was followed by sulfuric acid leaching tests. The optimal conditions set was the preparation of one liter of acid solution of 122g of sulfuric acid to leach, in 2 hours, 150g of slag, i.e. a solid-liquid ratio of 15÷100. Leach results were 94% Ge, 91% Cu, 85% Co and 91% Zn.
Bodas G. (1996). Hydrometallurgical treatment of zinc silicate ore from Thailand. Hydrometallurgy, 40(1-2), 37-49. doi.org/10.1016/0304-386X (94)00076-F.
Boldrini, V., Carturan, S. M., Maggioni, G., Napolitani, E., Napoli, D. R., Camattari, R., & De Salvador, D. (2017). Optimal process parameters for phosphorus spin-on-doping of germanium. Applied Surface Science, 392, 1173-1180.
Christman, P., Angel, J.M., Bailly, L., Barthélémy, F., Benhamou, G., Billa, M., Gentilhomme, P., et al. (2010). Compagnie Européenne d'Intelligence Stratégique (CEIS) (2010) - Panorama mondial 2010 du germanium BRGM/RP-60584-FR, 54 p., 14 fig., 6 tabl.
Depuydt, B., Theuwis, A., & Romandic, I. (2006). Germanium: From the first application of Czochralskicrystal growth to large diameter dislocation-free wafers. Materials Science in Semiconductor Processing, 9, 437-443.
Elamari, K. (1993). Traitement hydro métallurgique en milieux acide des boue anodiques d'electroaffinage du cuivre. Thèse de l'Université de Lorraine p 11- 46.
Fujiwara, M., Hirao, T., Kawada, M., Shibai, H., Matsuura, S., Kaneda, H., Patrashin, M., & Nakagawa, T. (2003). Development of a gallium-doped germanium farinfrared photoconductor direct hybrid two-dimensional array. Applied Optics, 42(12), 2166-2173.
Harbuck, D. (1993). Increasing germanium extraction from hydrometallurgical zinc residues. Mineral and Metallurgical Processing, 10. doi.org/10.1007/BF03402990.
He, S., Wang, J., & Yan, J. (2010). Pressure leaching of high silica Pb–Zn oxide ore in sulfuric acid medium. Hydrometallurgy, 104(2), 235-240.
Heberlein, W., Rahway, N.J. & Udin, H. (1950). Process for Purifying Indium-Containing Material. U.S. Patent US2, 526, 354, 17 October 1950.
Hu, Z., Qi, H., Zhou, F., Su, C., Bi, W., Peng, T. & Zhong, H. (2009). Geological and geochemical constraints on the origin of the giant Lincang coal seam-hosted germanium deposit, Yunnan, SW China: A review. Ore Geology Reviews, 36, 221–34. doi:10.1016/j. oregeorev.2009.02.007.
Hua. Y., Lin, Z. & Yan, Z. (2002). Application of microwave irradiation to quick leaching of zinc silicate ore. Minerals Engineering, 15(6), 451-456. doi.org/10.1016/S0892-6875(02)00050-X
Llewellyn, T. O. (1989). Germanium. Sec. in Bu Mines Mineral Commodity Summaries 1989, pp. 62-63.
Matthew, G. & Elsner, D. (1977). The hydrometallurgical treatment of zinc silicate ores. Metallurgical Transactions B, Process Metallurgy, 8(1), 73-83. doi:10.1007/BF02656354
Meshram, P., Prakash, U., Bhagat, L., Abhilash, Zhao, H., & van Hullebusch, E. D. (2020). Processing of waste copper converter slag using organic acids for extraction of copper, nickel, and cobalt. Minerals, 10(3), 290. doi:10.3390/min10030290
Petkof, B. (1985) Gallium. Ch. in Mineral Facts and Problems, 1985 Edition. Bu Mines B 675, 1985, pp. 291-296.
Rouessac, et al. (2004). Analyse chimique méthodes et techniques instrumentales modernes. Dunond, p. 245.
Schimmel, R.C., Faber, A.J., De, W.H., Beerkens, R.G.C., & Khoe, G.D. (2001). Development of germanium gallium sulphide glass fibres for the 1.31 µm praseodymium-doped fibre amplifier. Journal of Non-Crystalline Solids, 284(1), 188-192.
Tshibanda, K.D. (2012). Contribution à la recherche d'un modèle de gestion d'un passif environnemental issu d'un traitement métallurgique des minerais sulfures cuivre-winc en rdc. Bruxelles : Thèse, p 73.
Xu, H., Wei, C., Li, C., Fan, G., Deng, Z., Li, M., & Li, X. (2010). Sulfuric acid leaching of zinc silicate ore under pressure. Hydrometallurgy, 105(1-2), 186-190. doi.org/10.1016/j.hydromet.2010.07.014.
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