Silicon halide-alkali metal flames as a source of solar grade silicon. Final report

Technical Report · Tue Jan 01 04:00:00 EST 1980

DOI:https://doi.org/10.2172/5227974· OSTI ID:5227974

Olson, D B; Miller, W J; Gould, R K

The object of this program was to determine the feasibility of using continuous high-temperature reactions of alkali metals and silicon halides to produce silicon in large quantities and of suitable purity for use in the production of photovoltaic solar cells. Equilibrium calculations showed that a range of conditions were available where silicon was produced as a condensed phase but the byproduct alkali metal salt was a vapor. A process was proposed using the vapor phase reaction of Na with SiCl/sub 4/. Low pressure experiments were performed demonstrating that free silicon was produced and providing experience with the construction of reactant vapor generators. Further experiments at higher reagent flow rates were performed in a low temperature flow tube configuration with co-axial injection of reagents. Relatively pure silicon was produced in these experiments. A high temperature graphite flow tube was built and continuous separation of Si from NaCl was demonstrated. A larger-scaled well-stirred reactor was built. Experiments were performed to investigate the compatibility of graphite-based reactor materials of construction with sodium. At 1100 to 1200 K none of these materials were found to be suitable. At 1700 K the graphites performed well with little damage except to coatings of pyrolytic graphite and silicon carbide which were damaged.

• Research Organization: Aerochem Research Labs., Inc., Princeton, NJ (USA)
• DOE Contract Number: NAS-7-100-954777
• OSTI ID: 5227974
• Report Number(s): DOE/JPL/954777-80/8; AeroChem-TP-395
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
36 MATERIALS SCIENCE
360601 -- Other Materials-- Preparation & Manufacture
ALKALI METALS
CARBIDES
CARBON
CARBON COMPOUNDS
CHEMICAL REACTORS
CHLORIDES
CHLORINE COMPOUNDS
COMPATIBILITY
DIRECT ENERGY CONVERTERS
DISPERSIONS
ELEMENTS
EQUILIBRIUM
EQUIPMENT
FEASIBILITY STUDIES
FLAMES
GRAPHITE
HALIDES
HALOGEN COMPOUNDS
JETS
MATERIALS
METALS
MIXTURES
NONMETALS
NOZZLES
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
PRODUCTION
RESEARCH PROGRAMS
SEMIMETALS
SILICON
SILICON CARBIDES
SILICON CHLORIDES
SILICON COMPOUNDS
SILICON HALIDES
SILICON SOLAR CELLS
SODIUM
SOLAR CELLS
SOLAR EQUIPMENT
THERMODYNAMIC PROPERTIES
VAPOR PRESSURE