Alkaline Autoclave Leaching of Refractory Uranium-Thorium Minerals

A. Milani, S; Sam, A

Alkaline Autoclave Leaching of Refractory Uranium-Thorium Minerals

Document Type : Research Paper

Authors

S A. Milani

A Sam

Abstract

This paper deals a with the study of an innovative method for processing the Oman placer ores by alkaline leaching in ball mill autoclaves, where grinding and leaching of the refractory minerals take place simultaneously. This was followed by the selective separation of thorium and uranium from lanthanides by autoclave leaching of the hydroxide cake with ammonium carbonate-bicarbonate solutions. The introduced method is based on the fact that thorium and uranium form soluble carbonate complexes with ammonium carbonate, while lanthanides form sparingly soluble double carbonates. It was found that a complete alkaline leaching of Oman placer ores (98.0%) was attained at 150 and 175^°C within 2.5 and 2h, respectively. Oman placer ores leaching was intensified and accelerated in a ball mill autoclaves as a result of the grinding action of steel balls, removal of the hydroxide layer covering ores grains and the continuous contact of fresh ore grains with alkaline solution. The study of selective carbonate processing of hydroxide cake with ammonium carbonate-bicarbonate solutions on autoclave under pressure revealed that the complete thorium recovery (97.5%) with uranium recovery (90.8%) and their separation from the lanthanides were attained at 70-80^°C during 1-2h. The extraction of lanthanides in carbonate solution was low and did not exceed 4.6%.

Highlights

1. Habashi, Fathi, “A textbook of hydrometallurgy, extractive metallurgy, Quebec, Enr, 65-95, 243-249 (1993).

2. G.P. Demopouls, “Acid pressure leaching of sulfuric uranium ore with emphasis on radium extraction,”

3. Aly M. Abdel-Rehim, “An innovative method for processing Ejyptian monazite,” Hydrometalurgy 67, 9-17 (2002).

4. Sreenivas, T and Rao, K Anand and Rao, M Manmadha and Rajan, K. C and Serajuddin, Md. and Karthikayini, P and Padmanabhan, NPH(2010), Autoclave leaching of refractory uranium minerals, Proceedings of the XI International Seminar on Mineral Processing Technology (MPT-2010), 673-680.

5. A.K Suri, Innovative process flowsheet for the recovery of Uranium from Tummalapalle Ore, BARC, ISSue No. 317. Nov. Dec (2010).

6. RJ Verster, and HJH Pieterse, “The use of autoclaves in uranium leach flowsheets,” ALTA 2008 Nickel-Cobalt, Copper & Uranium Conference, June 2008, Perth-Australia.

7. Abdel-Rehim, A.M., 2005, “A new technique for extracting zirconium from Egyptian zircon concentrate,” Int. J. of mineral Processing. 76, 234-243 (2005).

8. Gafari M.; Eskandari M., Determination of optimum process of ball mill variables, Bachelor^,s Degree Thesis, Bahonar Uni., Zarand Faculty, 42-50 (2008).

9. M. Eskandari Nasab, S.A. Milani, A. Sam, Thorium-Uranium processing with Gravity, Magnetic and Electrical Separation in Zarigan Ore Deposit, Nuclear Science and Technology, AEOI, No. 40 (2010).

10. Liptay, G.(Ed.), Atlas of Thermoanalytical Curves v.,Hung. Acad Sci. Budapest, 106-107 (1975).

11. Mirson, G.A. et al., “Alkaline leaching of monazite,” At. Energy. (Moscow) 3(9), 259-264 (1957).

Zelikman, A.N. “Metallurgy of rare earths, Thorium and Uranium, Mettalurgy, Moscow (1963).

Sinyaver, B.V., “Autoclave process in non ferrous metallurgy, metallurgy of nonferrous metals and gold. Nonfe. Metal Inf. (Moscow), 171-158 (1966).

Kaplan, G.E., al., Thorium, its ore Resources, Chemistry and Technology. Atom Publish., Moscow (1960).

Tshernayev, I.I., al., Ammonium thorium pentacarbonate. J. Inorg. Chem. Izd-va Akad. Nauk. SSr (Moscow) 6(2), 394 (1961).

Keywords

Alkaline Autoclave Leaching

Uranium-Thorium Refractory Minerals

Ball Mill Autoclave

Oman Placer

1. 1. Habashi, Fathi, “A textbook of hydrometallurgy, extractive metallurgy, Quebec, Enr, 65-95, 243-249 (1993).
1. 2. G.P. Demopouls, “Acid pressure leaching of sulfuric uranium ore with emphasis on radium extraction,”
1. 3. Aly M. Abdel-Rehim, “An innovative method for processing Ejyptian monazite,” Hydrometalurgy 67, 9-17 (2002).
1. 4. Sreenivas, T and Rao, K Anand and Rao, M Manmadha and Rajan, K. C and Serajuddin, Md. and Karthikayini, P and Padmanabhan, NPH(2010), Autoclave leaching of refractory uranium minerals, Proceedings of the XI International Seminar on Mineral Processing Technology (MPT-2010), 673-680.
1. 5. A.K Suri, Innovative process flowsheet for the recovery of Uranium from Tummalapalle Ore, BARC, ISSue No. 317. Nov. Dec (2010).
1. 6. RJ Verster, and HJH Pieterse, “The use of autoclaves in uranium leach flowsheets,” ALTA 2008 Nickel-Cobalt, Copper & Uranium Conference, June 2008, Perth-Australia.
1. 7. Abdel-Rehim, A.M., 2005, “A new technique for extracting zirconium from Egyptian zircon concentrate,” Int. J. of mineral Processing. 76, 234-243 (2005).
1. 8. Gafari M.; Eskandari M., Determination of optimum process of ball mill variables, Bachelor^,s Degree Thesis, Bahonar Uni., Zarand Faculty, 42-50 (2008).
1. 9. M. Eskandari Nasab, S.A. Milani, A. Sam, Thorium-Uranium processing with Gravity, Magnetic and Electrical Separation in Zarigan Ore Deposit, Nuclear Science and Technology, AEOI, No. 40 (2010).
10. Liptay, G.(Ed.), Atlas of Thermoanalytical Curves v.,Hung. Acad Sci. Budapest, 106-107 (1975).

11. Mirson, G.A. et al., “Alkaline leaching of monazite,” At. Energy. (Moscow) 3(9), 259-264 (1957).
1. Zelikman, A.N. “Metallurgy of rare earths, Thorium and Uranium, Mettalurgy, Moscow (1963).
1. Sinyaver, B.V., “Autoclave process in non ferrous metallurgy, metallurgy of nonferrous metals and gold. Nonfe. Metal Inf. (Moscow), 171-158 (1966).
1. Kaplan, G.E., al., Thorium, its ore Resources, Chemistry and Technology. Atom Publish., Moscow (1960).
Tshernayev, I.I., al., Ammonium thorium pentacarbonate. J. Inorg. Chem. Izd-va Akad. Nauk. SSr (Moscow) 6(2), 394 (1961).