| 摘要 |
<p><PICT:1025716/C1/1> An aqueous insoluble material is stripped from an organic solvent by countercurrent flow in a vertical column (Fig. 3), loaded solvent being sprayed at 60 into the lower end of the column and overflowing at 42 from a floating layer of stripped solvent while an aqueous stripping solution is supplied to the upper end at 64 and is withdrawn at 54 together with precipitated solid material. A rake 70 directs solids to outlet 54 and heating/cooling coils 56 are supplied. In an alternative embodiment (Fig. 2, not shown) the aqueous solution is sprayed into the floating layer of solvent, and the column has a heating/cooling jacket. The process is applicable to extraction of vanadium, uranium, scandium, tungsten. In Fig. 1 (not shown) metal salts are extracted (at A) from an aqueous feed liquor by an organic solvent which is then supplied through a heat exchanger 16 to the stripping column (B) (Fig. 2, not shown, and Fig. 3). The stripping solution and precipitate are separated in a filter or centrifuge (C). Various valves 18, 22 are controlled to ensure that the respective influx and eflux of both solvent and aqueous solution to and from the column (B) are equalized. Heat exchanger 24 and an aqueous solution make-up line are shown. In a particular example vanadium held as a solvent soluble complex with an agent such as tertiary amines, quaternary ammonium chloride (e.g. tricaprylyl methyl ammonium chloride) is extracted by an aqueous stripping solution. The solvent also contains 4% isodecanol. The aqueous stripping solution contains 200 gms./l. of ammonium chloride and sufficient free ammonia to produce a pH of 8.3 ... 8.5. The temperature in the column (B) is held at 150 ... 160 DEG F.</p> |
