Non-ferrous extractive metallurgy

Electrowinning of copper

Non-ferrous extractive metallurgy is one of the two branches of extractive metallurgy which pertains to the processes of reducing valuable, non-iron metals from ores or raw material.[1][2][3] Metals like zinc, copper, lead, aluminium as well as rare and noble metals are of particular interest in this field,[1] while the more common metal, iron, is considered a major impurity.[4][5] Like ferrous extraction, non-ferrous extraction primarily focuses on the economic optimization of extraction processes in separating qualitatively and quantitatively marketable metals from its impurities (gangue).[6]

Any extraction process will include a sequence of steps or unit processes for separating highly pure metals from undesirables in an economically efficient system. Unit processes are usually broken down into three categories: pyrometallurgy, hydrometallurgy, and electrometallurgy. In pyrometallurgy, the metal ore is first oxidized through roasting or smelting. The target metal is further refined at high temperatures and reduced to its pure form. In hydrometallurgy, the object metal is first dissociated from other materials using a chemical reaction, which is then extracted in pure form using electrolysis or precipitation. Finally, electrometallurgy generally involves electrolytic or electrothermal processing. The metal ore is either distilled in an electrolyte or acid solution, then magnetically deposited onto a cathode plate (electrowinning); or smelted then melted using an electric arc or plasma arc furnace (electrothermic reactor).[7]

Another major difference in non-ferrous extraction is the greater emphasis on minimizing metal losses in slag. This is widely due to the exceptional scarcity and economic value of certain non-ferrous metals which are, inevitably, discarded during the extraction process to some extent.[6] Thus, material resource scarcity and shortages are of great concern to the non-ferrous industry. Recent developments in non-ferrous extractive metallurgy now emphasize the reprocessing and recycling of rare and non-ferrous metals from secondary raw materials (scrap) found in landfills.[8][9]

  1. ^ a b Gosh, A., and H.S. Ray. Principles of Extractive Metallurgy. 2nd Ed. New Delhi: New Age International Ltd, 1991. pp 1-10.
  2. ^ Reardon, Arthur C. Metallurgy for the Non-Metallurgist. 2nd Ed. U.S.: ASM International, 2011. Pp. 11.
  3. ^ Habashi, F. (2005). "Mining, Metallurgy, and the Industrial Revolution Part 3". CIM Bulletin. 98 (1091): 81–82.
  4. ^ Potts, D. T. (2012). A Companion to the Archaeology of the Ancient Near East. John Wiley & Sons. pp. 300–302. ISBN 978-1-4051-8988-0.
  5. ^ Nakamura, Takashi (2007). "Present Status and Issues of Non-Ferrous Extractive Metallurgy". Journal of MMIJ. 123 (12): 570–574. doi:10.2473/journalofmmij.123.570. ProQuest 33106898.
  6. ^ a b Waseda, Yoshio.The Structure and Properties of Oxide Melts: Application of Basic Science to Metallurgical Processing. Singapore: World Scientific Publishing, 1998. Pp. 174.
  7. ^ Mathur, V.N.S.. "Waste Management in Mineral Industries-Some Considerations." Proceedings of the International Conference on Environmental Management in Metallurgical Industries: EMMI 2000. Ed. R.C. Gupta. New Delhi: Allied Publisher Ltd., 2000. 87. Web. 21 Apr. 2013.
  8. ^ Gordon, R. B.; Bertram, M.; Graedel, T. E. (31 January 2006). "Metal stocks and sustainability". Proceedings of the National Academy of Sciences of the United States of America. 103 (5): 1209–1214. doi:10.1073/pnas.0509498103. PMC 1360560. PMID 16432205.
  9. ^ Djokic, Sasa; Djokic, Biljana (February 2005). Metallic secondary raw materials recycling strategy in Serbia. EPD Congress 2005 as held at the 2005 TMS Annual Meeting. San Francisco. ProQuest 28530773.