Skip to content
1887
Volume 40, Issue 2
  • ISSN: 0032-1400

Abstract

Since the introduction of palladium-gold catchment gauzes for the recovery of the platinum lost from the catalyst gauzes used in the manufacture of nitric acid, the mechanism by which these high palladium content alloys catch and recover the platinum has been of interest to both researchers and manufacturers, alike. Using analyses of the surface chemical species which form on palladium, both in flowing oxygen and during the ammonia oxidation reaction, this paper describes how the surface of the palladium, at temperatures above 800°C, is a multilayer structure with the bright palladium metal surface being covered by a thin layer of palladium metal vapour and then by a layer of palladium oxide vapour. The mechanism of the platinum recovery is related to the surface state of the palladium, and the high recovery rate by the palladium alloy catchment gauze is attributed to this unique multilayer structure and to the ability of palladium to reduce platinum oxide. Damage to either the surface multilayer structure or the oxidation characteristics of palladium decreases the platinum recovery rate. Thus, catchment gauzes made from palladium alloys containing high concentrations of base metal solutes, such as nickel, cannot be expected to have such a high platinum recovery rate.

Loading

Article metrics loading...

/content/journals/10.1595/003214096X4028087
1996-01-01
2024-06-18
Loading full text...

Full text loading...

/deliver/fulltext/pmr/40/2/pmr0040-0080.html?itemId=/content/journals/10.1595/003214096X4028087&mimeType=html&fmt=ahah

References

  1. Holzmann H. Platinum Metals Rev., 1969, 13, (1), 2 [Google Scholar]
  2. Heywood A. E. Platinum Metals Rev., 1973, 17, (3), 118 [Google Scholar]
  3. Heywood A. E. Platinum Metals Rev., 1982, 26, (1), 28 [Google Scholar]
  4. Hatfield R. W., Beshty B. S., Lee H. C, Heck R. M., and Hsing T. S. European Patent77, 121; 1982 [Google Scholar]
  5. Fierro J. L. G., Palacios J. M., and Tomás F. Platinum Metals Rev., 1990, 34, (2), 62 [Google Scholar]
  6. Fierro J. L. G., Palacios J. M., and Tomás F. Surf. Interface Anal., 1989, 14, 529 [Google Scholar]
  7. Ning Y., Wen R, Zhao H., and Deng D. Rare Metals, 1994, 13, (2), 143 [Google Scholar]
  8. Slavinskyi M. P. Physico-chemical Properties of Elements, Metallurgizdat, Moscow, 1952, (in Russian) [Google Scholar]
  9. Hultgren R., Desai P. G., and Hawkins D. T. Selected Values of the Thermodynamic Properties of Elements”, American Society for Metals, Metals Park, Ohio, 1973 [Google Scholar]
  10. Kim K. S., Gossmann A. R, and Winograd N. Anal. Chem., 1974, 46, (1), 197 [Google Scholar]
  11. John RM. Handbook of X-ray Photoelectron Spectroscopy, Perkin-Elmer Corporation, Physical Electronic Division, U.S.A., 1992 [Google Scholar]
  12. Chaston J. C Platinum Metals Rev., 1965, 9, (4), 126 [Google Scholar]
  13. Ning Y., Yang Z., and Zhao H. Platinum Metals Rev., 1995, 39, (1), 19 [Google Scholar]
  14. Yang Z., Ning Y., and Zhao H. J. Alloys Compd., 1995, 218, 51 [Google Scholar]
/content/journals/10.1595/003214096X4028087
Loading
/content/journals/10.1595/003214096X4028087
Loading

Data & Media loading...

  • Article Type: Research Article
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error