A N A L Y T I C A L EDITION
88
Vol. 1, No. 2 /41
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Per cent Figure.5-Distillation of Benzene-Toluene Mixture in Coated Spiral Column
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Per cent Figure 6-Distillation Data for Materials Recovered from Distillation of BenzeneToluene Mixture i n Coated Spiral Column
Run 1. With a Hempel column filled with glass beads. Run 2. With the same column in which crushed antimony replaced the glass beads. Run 3. With the glass beads coated in the following manner: The beads were wetted with a thin solution of shellac in alcohol and after the shellac had partially dried the beads were shaken with 60-mesh carborundum. After further drying the beads were placed in a round-bottom flask, covered with benzene, and
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The resulting curves of the Engler distillation are plotted in Figure 3.
M. G. Raeder NORGSSTEKNISKE HOISKOL,INSTITUT FOR UORGANISK KEMI, TRONDHJEM, NORWAY
D U R I N G laboratory investigations of methods for leach-
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Received September 8, 1928.
DAY
the whole distilled until all evidence of alcohol in the distillate had disappeared, after which the beads were removed and dried. Run 4. In the coated multiple spiral column, which was the same height as the Hempel column previously used.
Electrically-Heated Thermocirculator for Hot Leaching and Digesting’
ing certain ores, an apparatus was wanted permitting continuous leaching with exceedinglycorrosive, boiling liquids. For this work an all-glass construction as illustrated proved very useful. The apparatus, which is easily made out of a round flask and some glass tubing, consists of a glass bulb connected with a reflux condenser a c t h e top and a circulation tube between the bottom and the upper part. The lower part of the tube is covered, as the illustration indicates, by a layer of asbestos sheet around which a nichrome wire is coiled. This heating coil is insulated and protected on the outside by mica-mantled asbestos fastened with brass caps carrying contact screws and connected with an adjustable resistance. For use the apparatus is filled with preferably preheated leaching liquid to a little below the upper opening of the circulation tube and the current is switched on. Soon a local steam generation drives the liquid into the bulb with considerable force and thus starts a circulation. The material to be leached is then charged through the top opening and the condenser replaced. If the apparatus is of correct di-, mensions, the circulation should not be continuous-as, for instance, in an air lift-but markedly pulsating. In that way not only is the liquid circulated, but-and this is the special feature of the device-the material to be leached is itself brought into vigorous circulation, even when of high specific
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Per cent Figure 7-Distillation Data o n PurMcatlon of Meta-Xylene
directions can be given, different liquids demanding different working conditions. The principle of the apparatus-the leaching matter itself being kept in continuous circula t ion-s h o u l d insure the best possible contact between liquid and solid and thus give a maximum of leaching efficiency. The circulation may be carried on for days without loss of l i q u i d a n d w i t h o u t danger of breakdown, the apparatus being entirely free from moving parts. The apparatus needs no supervision and may be left working during the night
ture.
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