Lab-scale chromium electrowinning in a diaphragm-type cell: effect of anode material and the head between the catholyte and anolyte levels (Δh)

Author(s)

Abstract
Turkey has a 6% share in the world of chromite mining and ferrochromium is the most important product in exports. The electrowinning of chromium metal follows the dissolution of chromium from chromite or high-carbon ferrochrome after its separation from gangue and metallic impurities. Although ferrochrome was found to be the most expensive starting material, the use of chromite ore is not practical because of the number of processing steps involved. Production of electrolytic chromium for Turkey becomes important because of having large reserves of chromite ores and producing an important amount of ferrochromium in the world. It is also one of the most important strategic and critical materials for nations. In the frame of electrolytic chromium production from domestic resources, laboratory-scale chromium electrolysis was conducted using a diaphragm-type cell. A synthetically prepared chrome-alum solution and different anode materials, such as pure lead, Pb-Ca-Sn alloy, carbon plate, pressed & sintered graphite, and IrO2-coated titanium anode were used. The fixed experimental conditions were: temperature of 52°C, solution pH:2.1, 750 A/m2 current density, and electrolyte concentrations of 40 g/L Cr and 90 g/L NH4+. Moreover, the head between the catholyte and anolyte levels (Δh) was also changed to examine its effect on the cathode morphology, which was characterized by the SEM analyses. The dimensionally stable IrO2-coated titanium anode was found to be the supreme electrode among those tested, in terms of both giving the lowest cell potential and yielding the least amount of Cr6+ in the anolyte.

Keywords
Chromium, electrowinning, anode material, Cr(VI) concentration

Cite this paper
Cüneyt Arslan, Sebahattin Gürmen, Fatma Arslan, Ayşe Gamze Onuk Elçin, Lab-scale chromium electrowinning in a diaphragm-type cell: effect of anode material and the head between the catholyte and anolyte levels (Δh) , SCIREA Journal of Metallurgical Engineering. Volume 5, Issue 1, February 2022 | PP. 1-14. 10.54647/metallurgical45024

References

[ 1 ]	URL: https://geology.com/usgs/uses-of-chromium/
[ 2 ]	J.F. Papp, Chromium-A National Mineral Commodity Perspective, Open-File Report 2007–1167, U.S. Department of the Interior, U.S. Geological Survey.
[ 3 ]	The Republic of Turkey –Ministry of Trade, 2019, https://www.trade.gov.tr/data/5b8fd5bf13b8761f041fee9b/Mining.pdf
[ 4 ]	URL: https://www.hsgmetal.com/good-quality-pure-chromium
[ 5 ]	F. Gu and B.A. Wills, Chromite- mineralogy and processing, Miner. Eng., 1988, 1, 235–240.
[ 6 ]	J.K. Dennis and T.E. Such, Nickel and Chromium Plating; A volume in Woodhead Publishing Series in Metals and Surface Engineering Book, 1993, Third Edition.
[ 7 ]	C. Arslan and G. Orhan, Investigation of chrome(VI) oxide production from chromite concentrate by alkali fusion, Int. J. Miner. Process., 1997, 50, 87–96.
[ 8 ]	National Academies of Sciences, Engineering, and Medicine. High-Purity Chromium Metal: Supply Issues for Gas-Turbine Superalloys. Washington, DC: The National Academies Press, 1995, https://doi.org/10.17226/9248.
[ 9 ]	M. Hansen and K. Anderko, Constitution of Binary Alloys, 1958, McGraw-Hill, New York.
[ 10 ]	A.H. Sully and E. Brandes, Chromium, 1967, Plenum Pub., New York.
[ 11 ]	N.E. Nechaeva, D.P. Zosimovich, and E.E. Kupich, Study of polarization of a chromium cathode in solutions of chromous and chromic chlorides, Ukrainskii Khimicheskii Zhurnal, 1972, 38 (4), 318-321.
[ 12 ]	N.E. Nechaeva and S.S. Afonskii, Anodic dissolution of technical ferrochrome in chloride electrolytes, In Electrode Processes in Electrodeposition and Dissolution of Metals [in Russian], 1975, Naukova Dumka, Kyiv, 114-118.
[ 13 ]	N.E. Nechaeva, Effect of SO42 anion on the cathodic process in the electrolysis of chromic chloride, Ukrainskii Khimicheskii Zhurnal, 1976, 42 (1), 25-29.
[ 14 ]	NMAB-480, “High-Purity Chromium Metal: Supply Issues for Gas-Turbine Superalloys”, Committee on High-Purity Electrolytic Chromium Metal, National Materials Advisory Board, Commission on Engineering and Technical Systems, National Research Council, 1995, pp. 29-38, National Academy Press, Washington D.C.
[ 15 ]	B. DeBecker, F. Peeters, and P.F. Duby, Recovery of chromium from chromate waste by electrowinning from Cr(III) solutions, In “Extraction and Processing for the Treatment and Minimization of Wastes”, 1993, J. Hager, W. Imrie, J. Pusateri, and V. Ramachandran (Editors), Warrendale, Pennsylvania: The Minerals, Metals, and Materials Society.
[ 16 ]	C. Arslan and P.F. Duby, The Anodic Oxidation of Cr(III) to Cr(VI) in a Laboratory-scale Chromium Electrowinning Cell, Hydrometallurgy, 1997, 46, 337-348.
[ 17 ]	N.P. Lyakishev and M.I. Gasik, Metallurgy of Chromium, 1998, Allerton Press Inc., New York.
[ 18 ]	C. Arslan, Modeling the Performance of Aqueous Chromium Electrowinning Cells, Ph.D. Thesis, 1991, Columbia University, New York.
[ 19 ]	R.J. Vora, S.R. Taylor, and G.E. Stoner, Factors affecting the performance of PbO2 anodes in the generation of hexavalent chromium, in F. Hine et al. (Eds.), Proceedings of the Symposium on Performance of Electrodes for Industrial Electrochemical Processes, 1989, The Electrochemical Society, pp. 279-289.
[ 20 ]	D.Y. Kim, S.U. Park, M. Kim, S.C. Kwan, J.W. Choi, and Y. Choi, Effect of Electrolysis Conditions on Hard Chromium Deposition from Trivalent Chromium Bath, J. Kor. Inst. Surf. Eng., 2003, Vol 36, No 2, pp 155-160.
[ 21 ]	Patent: EP 2 944 709 A1, 2015, A method for electrowinning of metallic chromium from acidic waste electrolytes, Bulletin 2015/47, Printed by Jouve, 75001 Paris (France).
[ 22 ]	V.S. Protsenko, L.S. Bobrova, D.E. Golubtsov, S.A. Korniy, and F.I. Danilov, Electrolytic Deposition of Hard Chromium Coatings from Electrolyte Based on Deep Eutectic Solvent, Russian Journal of Applied Chemistry, 2018, Vol. 91, No. 7, pp. 1106−1111.
[ 23 ]	S.L. Lee, D. Windover, and K.E. Mello, Grain orientations in electrolytic high concentration and low contraction chromium deposition, Technical report ARCCB-TR-98004, US Army Armament Research, Development, and Engineering Center-Close Combat Armaments Center-Benet Laboratories, 1998, Watervliet, N.Y. 12189-4050.