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Letters to Nature

Nature 407, 361-364 (21 September 2000) | doi:10.1038/35030069; Received 31 January 2000; Accepted 31 July 2000

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Direct electrochemical reduction of titanium dioxide to titanium in molten calcium chloride

George Zheng Chen1, Derek J. Fray1 & Tom W. Farthing2

  1. Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, UK
  2. 71 Sir Richards Drive, Harborne, Birmingham B17 8SG, UK

Correspondence to: Derek J. Fray1 Correspondence and requests for materials should be addressed to D. J. F. (e-mail: Email: djf25@hermes.cam.ac.uk).

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Many reactive metals are difficult to prepare in pure form without complicated and expensive procedures1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18. Although titanium has many desirable properties (it is light, strong and corrosion-resistant1), its use has been restricted because of its high processing cost. In the current pyrometallurgical process—the Kroll process4, 5—the titanium minerals rutile and ilmenite are carbo-chlorinated to remove oxygen, iron and other impurities, producing a TiCl4 vapour. This is then reduced to titanium metal by magnesium metal; the by-product MgCl2 is removed by vacuum distillation. The prediction that this process would be replaced by an electrochemical route6, 7, 8, 9, 10 has not been fulfilled; attempts involving the electro-deposition of titanium from ionic solutions have been hampered by difficulties in eliminating the redox cycling of multivalent titanium ions and in handling very reactive dendritic products6, 7, 8, 9, 10. Here we report an electrochemical method for the direct reduction of solid TiO2, in which the oxygen is ionized, dissolved in a molten salt and discharged at the anode, leaving pure titanium at the cathode. The simplicity and rapidity of this process compared to conventional routes should result in reduced production costs and the approach should be applicable to a wide range of metal oxides.

  1. Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, UK
  2. 71 Sir Richards Drive, Harborne, Birmingham B17 8SG, UK

Correspondence to: Derek J. Fray1 Correspondence and requests for materials should be addressed to D. J. F. (e-mail: Email: djf25@hermes.cam.ac.uk).