| 摘要 |
Pure silicon metal is produced from a silicon metal which contains 1-10% Ca and which is cast into molds with relatively slow rate of cooling. The cast metal is pre-crushed and thereupon subjected to a purification process consisting of two leaching steps where in the first leaching step there is employed an aqueous solution of FeCl3 or FeCl3+HCl which causes a disintegration of the metal. The fines are washed away in place thereof, and the metal is further leached in the second leaching step with an aqueous HF+HNO3 solution. The necessary amount of calcium is supplied in the smelting furnace in the form of CaO or other suitable Ca compound.
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