| 摘要 |
<p>PROBLEM TO BE SOLVED: To recover valuable metals at a high yield by supplying a prescribed amt. of a reducing gas as a carrier gas for the metal vapor generated from powder and granular materials to a treating chamber. SOLUTION: The treating chamber 23 is evacuated to vacuum and a heater 33 is operated to maintain the treating chamber 23 at a prescribed temp. A valve 43a is opened to drop the powder and granular materials from a hopper 15 to a plate 111 of the uppermost stage and a valve 53a is opened to supply the reducing gas from plural nozzles 53b. The dropped powder and granular materials are extruded to fall onto the plate 112 of the lower stage while the powder and granular materials are agitated on the plate 111 and are simultaneously spread thin. Henceforce, the powder and granular materials are successively dropped to the lower stages in the same manner and are finally dropped to a discharge chute 23a. When the reducing gas is supplied as the carrier gas to the surfaces of the powder and granular materials in such a state, the temp. boundary layers of the metal vapor formed around the powder and granular materials are made sufficiently thinner or are substantially destroyed. The zinc, lead, etc., in the powder and granular materials are efficiently and rapidly evaporated and are recovered into a condenser 73.</p> |
