High Temperature Solar Electrothermal Processing II. Zinc from Zinc Oxide.
Abstract
The electrolytic decomposition potential of ZnO was studied in a solar furnace in the temperature range 600-1400K and in three electrolytes (Na0H, 0.33ZnF2-0.67NaF, and 0.13AlF3(-) 0.87NaF). From 600 to 1200K, the measured potentials were close to the thermodynamically predicted values for the reaction Zn0(s) yield Zn (stable phase) + 0.5O2(g), if provision is made for reasonable overvoltages. The overvoltages decreased with increasing temperature. In the range 1200-1400K, the direct chemical reaction of ZnO with the graphite cathode resulted in the formation of a gas film in a process analogous to a transition from nucleate to film boiling, which greatly decreased the current. Various materials were tested for use as electrodes and cell casings. Their behavior, experimental problems and methods for dealing with them, as well as the apparatus, are described and discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 03, 1985
- Accession Number
- ADA154747
Entities
People
- D. Kunnerth
- E. A. Fletcher
- F. J. Macdonald
Organizations
- University of Minnesota