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US 2003/0150293 A1Published application
Apparatus for enhanced purification of high-purity metals
AssigneeDowa Mining Co., Ltd.
InventorsKishio Tayama, Toshiaki Hodozuka
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AssigneeDowa Mining Co., Ltd.
InventorsKishio Tayama, Toshiaki Hodozuka
Estimating the term…
A 99.99% pure indium feed is charged into crucible 8 and heated to 1250° C. by upper heater 6 in a vacuum atmosphere at 1×10−4 Torr, whereupon indium evaporates, condenses on the inner surfaces of inner tube 3 and drips to be recovered into liquid reservoir 9 in the lower part of tubular member 11 whereas impurity elements having lower vapor pressure than indium stay within crucible 8. The recovered indium mass in liquid reservoir 9 is heated to 1100° C. by lower heater 7 and the resulting vapors of impurity elements having higher vapor pressure than indium pass through diffuser plates 12 in the upper part of tubular member 11 to be discharged from the system whereas the indium vapor recondenses upon contact with diffuser plates 12 and returns to liquid reservoir 9, yielding 99.9999% pure indium while preventing the loss of indium.
A method of enhanced purification of high-purity metals which comprises purifying a metal feed by distillation in a vacuum atmosphere to yield the desired metal with high purity, said method further comprising a first thermal purification step in which said metal feed in a feed crucible positioned in the upper interior of an inner tube maintaining said vacuum atmosphere is heated and the generated vapor of said desired metal is brought into contact with the inner surface of said inner tube so that it is condensed and recovered in a separate form from impurity elements that have lower vapor pressure than said desired metal and which are allowed to stay within said feed crucible, and a second thermal purification step in which said desired metal as recovered is admitted into and heated in a liquid reservoir in the lower part of a tubular member positioned in the lower interior of said inner tube and the generated vapor is passed through a diffuser positioned in the upper part of said tubular member and guided by suction so that the vapors of impurity elements having higher vapor pressure than said desired metal are solidified in a separate form in a cooling trap positioned below said tubular member and the vapor of said desired metal is brought into contact with said diffuser so that it is condensed and returned to said liquid reservoir.
An apparatus for enhanced purification of high-purity metals, which comprises an inner tube in which a vacuum atmosphere is to be formed, a first heating chamber provided in the upper interior of said inner tube, a second heating chamber provided in the lower interior of said inner tube, said first heating chamber accommodating a feed crucible with an open top into which a metal feed is charged and the desired metal in said metal feed is evaporated for recovery while impurity elements having lower vapor pressure than said desired metal are separated by being allowed to stay within said feed crucible, said second heating chamber accommodating a tubular member having in the top an inlet for receiving said desired metal as recovered and an outlet through which impurity elements that have higher vapor pressure than said desired metal and which are evaporated in separate form upon heating are discharged, as well as a liquid reservoir for heating said desired metal which is formed in the lower part of said tubular member, and a diffuser for condensing said desired metal as evaporated which is installed across the upper part of said tubular member.
Dependencies are inferred from the claim text.