| 摘要 |
PURPOSE:To obtain the titled fine bismuth oxide particles which are almost spherical by heating Bi in the lower chamber of a hermetic vessel, mixing air into the Bi vapor which is introduced into the upper chamber, and cooling the formed bismuth oxide under specified conditions. CONSTITUTION:A hermetic vessel 1 is separated with a partition wall 2 into the upper chamber 4 and the lower chamber 5, and the upper chamber 4 is communicated with the lower chamber 5 through a hole 3 provided to the partition wall 2. Bi 10 is charged at the bottom part of the lower chamber 5, heated in an electric furnace 11, and volatilized. An inert gas is blown into the lower chamber 5 through a duct 6 to regulate the vapor density of the Bi to 0.1-0.5g/l. The vapor is sent into the upper chamber 4, and the Bi vapor is oxidized by blowing in a less amt. of air than the inert gas which is blown into the lower chamber 5 through a blowing pipe 7. The temp. is simultaneously lowered preferably to 250-300 deg.C at which the vapor is brought into contact with cooling air at the succeeding stage. The bismuth oxide after passing through the oxidizing zone is sucked by a gas suction pump connected to a suction pipe 8 at 1-5m/sec flow velocity. Meanwhile, cooling air is supplied into the pipe 8 from an air pipe 9 to cool the bismuth oxide.
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