| 摘要 |
PURPOSE:To readily purify gallium at a low cost and obtain high-purity Ga metal, by forming a seed crystal at one end part of molten gallium, cooling and solidifying the seed crystal with cooling clean air so that the crystal growth speed may be within a specific range. CONSTITUTION:Metallic Ga of about 99.999% purity washed with an acid or alkali, etc., is put in a boat 3 and melted. Warm water at about 30 deg.C is passed through a warm water inlet pipe 9 and discharge pipe 10 to a water tank 8 to keep the metallic Ga at a temperature (about 30 deg.C) near the melting temperature. On the other hand, a cooling gas with <=10,000 cleanness, consisting of clean air and controlled at 0-25 deg.C is ventilated through an air inlet port 5 and vent hole 6 into a clean room 4. Cold pure water at <=5 deg.C is dripped from an operation hole 11 onto one end part of the boat 3 to form a seed crystal and temperature and ventilation seed of the above-mentioned clean air are controlled to give 5-30mm/hr crystal growth rate. A movable lid 7 is slid by operation, as necessary, to grow a Ga metal solidifying part 2 in the boat 3. When 50-90% is solidified, ventilation is stopped to remove the residual molten Ga and afford the aimed high-purity metallic Ga of >=99.9999% purity.
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