| 摘要 |
<p>799,195. Extracting and distilling metals; alkali metals; alkaline earth metals; zinc; bismuth. KNAPSACK-GRIESHEIM AKT.- GES. June 22, 1956 [June 23, 1955; Sept. 6, 1955], No. 19483/56. Class 82(1) [Also in Group XII] Metals having a boiling point between 400‹C. and 200‹C. at a pressure of 10 m.m. Hg. (e.g. K, Na, Li, Ca, Ba, Sr, Mg, Zn and Bi) are continuously produced by heat radiation on to the surface of reaction material spread out in a thin layer (preferably 1-20 m.m.), the reduced metal is distilled off, the evolved metal vapour is condensed,' and the non-volatle reacted hot residue retained after the reaction is sunk in the reaction chamber and then serves as a support for freshly introduced reaction material. The reaction may be carried out under reduced pressure in an inert atmosphere, and the source of radiant heat may be an electric arc or resistance, or gaseous, either of which may be assisted by direct gas heating. Between the reaction mass and the walls of the furnace there may be disposed a thin sliding layer (preferably 2-20 cm.) of material which is constantly renewed at about the level of the reaction zone, which partially or wholly follows the descending product, which is chemically inert or does not sinter or melt at the reaction temperature, and which may be introduced through the top or side walls of the furnace either continuously or at intervals. In the form shown, the reaction mixture is introduced into the furnace 7 as a powder, a granulate, or as a briquette or other shaped body, by means of containers 1, 3, a valve 2, a distributer 4, and a rotary mixing plate 5 with a periodically variable rotary speed, and is spread over the previously reacted material 6. The sliding layer 29 is introduced by a pipe system 28 and passes over a dam 30. The furnace is heated by graphite electrodes 10 and has a grate 17 which is cooled and continuously or intermittently rotated or otherwise moved. The residue bursts into a powder or otherwise breaks up on the grate and is discharged from the lower part 18 by valves 19, 21 and a container 20. The metal vapour flows through part 32 into a cyclone or other dust chamber 11 and thence'into a condenser 12 with a barometric column 13 and an overflow 16. Any vapour which does not condense in condenser 12 passes into condensers 24, 25. Conduits 22, 23, 26 and 27 lead to a vacuum pump, and a conduit 33 supplies gas for auxiliary direct heating. In an example an alloy containing Al 30 per cent, Fe 30 per cent and Si 40 per cent is used as a reducing agent for dolomite.</p> |
