Proceedings of the 1986 International Congress on Renewable Energy Sources. Purification mechanism in the conversion of mg-Si into sg-Si by the VTF technique. International Congress on Renewable Energy Sources [18-23 Mayo 1986, Madrid].

Consejo Superior de Investigaciones Científicas.
Tejedor, P. Olson, J.M.

1987

v. 2
1113
CIENA

84-00-6674-X

The vapor transport filtration process (VTF) for purifying 98. INTRODUCTION. pure metallurgical grade silicon produces 99,9999. EXPERIMENTAL. pure solar grade silicon in a single step. The VTF process in a cold-wall version of an HC1 chemical vapor transport technique using a Si:Cu3Si alloy as the silicon source. The purification achieve is due to four mechanism: a)Gettering of impurities by the Si=2/Cu2O slag formed during the Si:Cu3Si alloy smelting process (Al, Ca, Fe, Mn), b) Chemical selectivity of the HC1 vapor phase transport (Cu, Cr, Mo), c) Trapping of impurities within the bulk of the Si:Cu3Si composite alloy, which acts as a solid-state silicon filter (B, Ba,Ca,Cr, Fe, Mg, Ni) and d) condensation of metal and non-metal chlorides on the reactor baseplate and walls, both during operation and cooling (Al, Mn, Fe, Ti). RESULTS AND DISCUSSIONS. REFERENCES.

Presenta tbls.

GENERAL; ENERGIA FOTOVOLTAICA; CELDAS SOLARES; PURIFICACION; SILICIO;