Hydrometallurgy extraction

R. Audinos, Liquid waste concentration by electrodialysis, Separation and Purification Technology, ed N.N. Li and J.M. Calo, Marcel Dekker, Inc. New York, 1992 T. Sata, Application of ion exchange membrane to hydrometallurgy, Extraction Metallurgy 89, The Institute of Mining and Metallurgy, 1989, p. 977. 

In some respects, hydrometallurgy can be described as wet analytical chemistry carried out on a large scale. Many different dow sheets can be designed with various types of unit operations and most metals can be extracted from a complex ore and recovered at the desired level of purity. A viable hydrometaHurgical process, however, must achieve that goal at an economically acceptable cost. 

White, D.A., Fathurrachman, Extraction of uranium (VI) and uranium (IV) from hydrochloric acid using tri-n-octylamine in a benzene diluent, Hydrometallurgy, v.36, pp. 161-168, 1994. 

The liquid-liquid extraction (solvent extraction) process was developed about 50 years ago and has found wide application in the hydrometallurgy of rare refractory and rare earth metals. Liquid-liquid extraction is used successfully for the separation of problematic pairs of metals such as niobium and tantalum, zirconium and hafnium, cobalt and nickel etc. Moreover, liquid-liquid extraction is the only method available for the separation of rare earth group elements to obtain individual metals. 

Solvent extraction is intrinsically dependent on the mass transfer across the interface and the chemical inversion at the interfacial region. Researchers in the field of solvent extraction, especially in the field of analytical chemistry and hydrometallurgy, observed effects of interfacial phenomena in the solvent extraction systems. This gave them a strong motivation to measure what happened at the interface. 

The second example is the extraction of Ni(II) with 2-hydroxy oxime. 2-Hydroxy oxime including 5-nonylsalicylaldoxime (P50) [15], 2-hydroxy-5-nonylacetophenone oxime (SME529) [16], and 2-hydroxy-5-nonylbenzophenone oxime (LIX65N) [17], are widely used as commercial extractants of Ni(II), Cu(II), and Co(II) in hydrometallurgy. These extractants are adsorbed at the interface even in their neutral forms following the Langmuir isotherm,... 

The separation of solids from liquids forms an important part of almost all front-end and back-end operations in hydrometallurgy. This is due to several reasons, including removal of the gangue or unleached fraction from the leached liquor the need for clarified liquors for ion exchange, solvent extraction, precipitation or other appropriate processing and the post-precipitation or post-crystallization recovery of valuable solids. Solid-liquid separation is influenced by many factors such as the concentration of the suspended solids the particle size distribution the composition the strength and clarity of the leach liquor and the methods of precipitation used. Some important points of the common methods of solid-liquid separation have been dealt with in Chapter 2. 

D. S. Flett, Solvent Extraction in Hydrometallurgy, in Hydrometallurgy Research Development and Plant Practice, Symposium, Atlanta, p. 39, AIME, New York, 1983. 

F. Habashi, Principles of Extractive Metallurgy, Vol. 1, General Principles, Vol. 2, Hydrometallurgy, Gordon and Breach, New York, 1970. 

F. Habashi, A Textbook of Hydrometallurgy, Metallurgie Extractive, Quebec, Enr., Canada, 1993. 

The Alcoa (Aluminum Company of America) process involves the electrolysis of aluminum chloride which is carried out in a molten bath of the composition 50% sodium chloride, 45% lithium chloride and 5% aluminum chloride, maintained at 700 °C. The Bayer process, which involves the production of pure alumina by the dissolution of bauxite with caustic soda and which has been described in the chapter on hydrometallurgy, must be taken into account while presenting a complete picture of the aluminum extraction flowsheet. It... 

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