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2. 2) F. Espiell, A. Roca, M. Cruells and C. Nunez: Hydrometallurgy 19 (1988) 321-333.
3. 3) C.A. Fleming and G. Cromberge: Journal of The South African Institute of Mining and Metallurgy 84 (5) (1984) 125-137.
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5. 5) R.J. Lewis: Hazardous Chemicals Desk Reference, (4th Edition), (International Thomson Publishing Company, NY, 1997).