Novel duplex vapor-electrochemical method for silicon solar cells. Quarterly progress report No. 9, February 1--April 30, 1978
Economic studies of the SRI process for the production of silicon are described. These studies cover the recovery of SiF/sub 4/ gas from fluosilicic acid (H/sub 2/SiF/sub 6/), sodium reduction of SiF/sub 4/ gas, separation of silicon from the reaction products by leaching the sodium fluorides, conversion of residual fluorides to cryolite, and the environmental treatment of the waste effluents. Since the sodium reduction of SiF/sub 4/ gas is highly exothermic, an attempt was made to understand the problems of heat transfer in the system and possibly predict their effect on the annual rate of silicon production. The details of the process economics are discussed, and the heat transfer studies are described. Economic analyses of the SRI process for the production of silicon show that silicon can be produced at a cost of $6.20/kg with a total fixed capital of $9,006,985 (1975 dollars) for a 1000 MT/yr operation. The cost per kilogram of silicon varies with the annual tonnage produced. On increasing the annual production to 3000 MT/yr, the cost was calculated to be $5.30/kg, while for a 5000 MT/yr operation, the cost of silicon production dropped to $5.00/kg. The yield of acceptable product silicon from the silicon produced was assumed to be 80%. By-product credit was obtained by converting the fluorides of sodium and hydrofluoric acid to marketable cryolite (Na/sub 3/AlF/sub 6/). These calculations also include the cost of environmental treatment and disposal for the waste effluents.
- Research Organization:
- SRI International, Menlo Park, CA (United States)
- DOE Contract Number:
- NAS-7-100-954471
- OSTI ID:
- 6617970
- Report Number(s):
- DOE/JPL/954471-2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
SILICON
PRODUCTION
ALUMINIUM FLUORIDES
BY-PRODUCTS
CAPITAL
CHEMICAL REACTIONS
COST
ECONOMIC ANALYSIS
ECONOMICS
ENERGY BALANCE
FLOWSHEETS
HEAT TRANSFER
INDUSTRIAL PLANTS
MANPOWER
MATERIAL BALANCE
REDUCTION
SILICON FLUORIDES
SILICON SOLAR CELLS
SODIUM
SODIUM FLUORIDES
WASTES
ALKALI METAL COMPOUNDS
ALKALI METALS
ALUMINIUM COMPOUNDS
DIAGRAMS
DIRECT ENERGY CONVERTERS
ELEMENTS
ENERGY TRANSFER
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
METALS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
SEMIMETALS
SILICON COMPOUNDS
SODIUM COMPOUNDS
SOLAR CELLS
140501* - Solar Energy Conversion- Photovoltaic Conversion
360601 - Other Materials- Preparation & Manufacture