| abstract |
PROCESS FOR PURIFYING SILICON FOR APPLICATIONS REQUIRING HIGH PURITY; METAL SILICON IS PURIFIED BY 1 DENSITY SEPARATION OF CRUSHED SILICON USING A HEAVY LIQUID SUCH AS ACETYLENE TETRABROMIDE, METHYLENE BROMIDE, BROMOFORM, ETC. AS A SEPARATION FLUID SUCH AS A THINNER, 2 PRODUCT PURIFIED IN STAGE 1 IN PARTICULAR WITH HYDROCHLORIC ACID AT HIGH TEMPERATURE AND 3 MELTING OF SAID SILICON (PURIFIED IN STAGES 1 AND 2) BY CONTACT OF MOLTEN SILICON WITH A GAS OXIDIZING IMPURITIES SUCH AS A MIXTURE OF FREON-12 AND OXYGEN AND B A SILICA-BASED MILK SUCH AS A MIXTURE OF SIOCAOCAF TO ECONOMICALLY PRODUCE A VERY PURE SILICON SUITABLE FOR USE IN THE SEMICONDUCTOR, ELECTRONICS, CAMERA INDUSTRY OR IN METALLURGY. |