Anodic Dissolution of Used Nickel-Base Superalloy U-500 in Sulfate Media for Recycling of Ni, Co and Cr

Document Type : Original Articles

Authors

Seyyed Reza Bagherzadeh Ghazi

Mehdi Ojaghi-Ilkhchi

Ahad Samadi

Faculty of Materials Engineering, Sahand University of Technology, Sahand New Town, Tabriz

10.22067/jmme.2022.77146.1056

Abstract

U-500 is a nickel-based superalloy which has significant amounts of some precious elements such as cobalt and chromium. Due to the economic and strategic value of these metals, their recovery from the used superalloys is of great importance. Hydrometallurgy is an economical and effective method for recovering these valuable metals from the superalloy scraps. So in this investigation, the dissolution behavior of nickel, cobalt and chromium elements from the used U-500 superalloy in the electro leaching process as well as the effect of different process parameters (such as: sulfuric acid concentration, applied voltage, process temperature, stirring and cathode-anode distance) on the dissolution of these elements are studied in details. The results show clearly that by increasing the concentration of sulfuric acid in the electrolyte, the applied voltage, and temperature, as well as decreasing the cathode-anode distance, the anodic dissolution of the superalloy U-500 is improved. Electrolyte stirring has no significant effect on increasing the anodic dissolution of the superalloy. The optimum conditions for the anodic dissolution of superalloy U-500 in sulfuric acid electrolyte was determined as acid concentration of 125 g/L, applied voltage of 4 V, stirring speed of 300 rpm, and cathode-anode distance of 3 cm without temperature control (starting with ambient temperature as the initial temperature(. Under these conditions, about 75% nickel, 84% cobalt and 67% chromium were durnig 25 minutes.

Keywords

Recycling

U-500 superalloy

Hydrometallurgy

Anodic dissolution

Nickel

Cobalt

Chromium

Subjects

• Extractive Metallurgy

---

References

1. Asgari, S., "A comprehensive study on the superalloys production in the country", Iranian Mines & Mining Industries Development & Renovation Organization (IMIDRO), Research Report No. 7004, Tehran, Iran, (2015). In Persian
2. Hall, J. D., "Method of preparation of metal salts", U.S. Patent No. 2716588, (1955).
3. Brooks, P. T., Potter, G. M. and Martin, D. A., "Processing of superalloy scrap", JOM, 22, No. 11, pp. 25-29, (1970).
4. Redden, L. D., Groves, R. D. and Seidel, C. C., "Hydrometallurgical recovery of critical metals from hard face alloy grinding wastes: A laboratory study", US Bureau of Mines, Report of Investigations 9210, Salt Lake City, Utah, (1988).
5. Shen, Y. F., Xue, W. Y. and Niu, W. Y., "Recovery of Co (II) and Ni (II) from hydrochloric acid solution of alloy scrap", Transactions of Nonferrous Metals Society of China, Vol. 18, No. 5, pp. 1262-1268, (2008).
6. Naghashian, S. and Halali, M., "Investigation on effecting parameters on the electrochemical dissolution of Inconel 617 superallloy for Ni recovery", Proceedings of the 8^th Students Congress of Materials Engineering & Metallurgy of Iran, Amir Kabir University of Technology, Tehran, Iran, (2008). )In Persian(
7. Naghashian, S. and Halali, M., "Nickel recovery from Inconel alloy 617 scrap via anodic dissolution", Proceedings of the 2nd joint conference of Iranian Metallurgical Engineers Society and Iranian Foundrymen’s Society, Karaj, Iran, (2008). )In Persian(
8. Ghandchi, A., "Study on the effect of various factors on the recovery of cobalt from FSX-414 superalloys with reverse pulse method", M.Sc. Thesis, Amir Kabir University of Technology, Tehran, Iran, (2007). )In Persian(
9. Palant‚ A. A., Levchuk‚ O. M., Bryukvin‚ V. A., Levin‚ A. M. and Paretskii, V. M., "Complex electrochemical processing of the metallic wastes from a rhenium - containing nickel superalloy in sulfuric acid electrolytes", Russian Metallurgy, 2011, No. 4, pp. 589-593, (2011).
10. Palant‚ A. A., Levin‚ A. M., Levchuk‚ O. M. and Bryukvin‚ V. A., "Electrochemical processing of the metallic wastes of Zh-32 nickel superalloys", Russian Metallurgy‚ 2013, No. 7, pp. 497-500, (2013).
11. Jackson, E., "Hydrometallurgical Extraction and Reclamation", Ellis Horwood Limited, Chichester, (1986).
12. Sharan, R. and Narain, S., "An Introduction to Electrometallurgy", Standard Publishers Distributors, NewDelhi, (1991).
13. Sims, C. T., Stoloff, N. S. and Hagel, W. C., "Superalloy II", John Wiley & Sons, USA, pp. 97-134, (1987).