Diagnosis of sources of current inefficiency in industrial molten salt electrolysis cells by Raman spectroscopy: A topical report on chlorides: Topical report, June 1982-June 1987
Molten salt electrolysis, a very energy-intensive process, is used in the extraction of light metals. Aluminum production by the Hall process and magnesium production in the Dow and I.G. Farbenindustrie cells constitute the major commercial applications of metal electrowinning from molten-salt media at present. The energy input into the electrolysis cell is in the form of direct current, and the energy efficiencies in the magnesium or aluminum processes are only in the 30 to 40% range. Major energy reductions are achieved by reducing the cell voltage or by increasing the current efficiency. Goal of the research is to identify the sources of the current losses occurring in molten salt electrolysis. This research worked on the systems of I.G. Farben magnesium chloride and Alcoa smelting aluminum chloride processes. Raman spectra were measured and analyzed for each component or their mixtures of the electrolyte for magnesium and aluminum reduction in chloride melts. Raman measurements were also conducted on the melts of industrial composition for aluminum and magnesium electrolysis. In laboratory-scale cells which imitated industrial practice, Raman spectra were measured in situ during electrolysis in attempts to identify the streamers, coloration of electrolyte, and any subvalent species. They were known to occur only during electrolysis, and they have been reported to be possible current losses. Cyclic voltammetry was conducted to obtain information about the generation of subvalent species which were not detected by Raman measurement. These were thought to be kinetic entities present only during electrolysis. Results of Raman spectroscopy and electrochemistry of magnesium and aluminum reduction from molten chloride bath are presented. The results would be useful to establish the basis for the study of electrolysis of aluminum from molten fluoride media. 119 refs., 66 figs.
- Research Organization:
- Massachusetts Inst. of Tech., Cambridge (USA)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FG07-82CE40545
- OSTI ID:
- 5533461
- Report Number(s):
- DOE/CE/40545-20; ON: DE88005025
- Country of Publication:
- United States
- Language:
- English
Similar Records
Diagnosis of sources of current inefficiency in industrial molten salt electrolysis cells by Raman spectroscopy
Survey of potential processes for the manufacture of aluminium
Related Subjects
320303* -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes-- Equipment & Processes
36 MATERIALS SCIENCE
360101 -- Metals & Alloys-- Preparation & Fabrication
ALKALINE EARTH METAL COMPOUNDS
ALKALINE EARTH METALS
ALUMINIUM
CALCIUM CHLORIDES
CALCIUM COMPOUNDS
CALCIUM HALIDES
CHLORIDES
CHLORINE COMPOUNDS
ELECTROLYSIS
ELECTROLYTES
ELEMENTS
ENERGY CONSERVATION
HALIDES
HALOGEN COMPOUNDS
INDUSTRY
LASER SPECTROSCOPY
LYSIS
MAGNESIUM
MAGNESIUM CHLORIDES
MAGNESIUM COMPOUNDS
METAL INDUSTRY
METALS
MOLTEN SALTS
RAMAN SPECTROSCOPY
SALTS
SPECTROSCOPY
VOLTAMETRY