Mixer-decanter for liquid-liquid extraction - with transfer pump and channel inducing min. turbulence, allowing pre-coalescence, giving economical construction

摘要

The mixer is a vessel fed separately with the two liquids and having an agitator on a vertical shaft. Above the agitator is a pump with a conical stator, widened at the top, and a rotor with trapezoidal blades. The rotor is fixed on to the same shaft as the agitator. The predetermined mixt. leaving the pump flows through a long wide, shallow horizontal channel. It extends to the end of the decanter remote from the mixer, so that the liq. circulates in the decanter towards the mixer. A distributor, formed by horizontal parallel blades extends over the height and width between the place where the channel discharges and the rest of the decanter. There may be a battery of mixer-decanter units, in series, with the two liquids circulating counter-currently. The battery may be used e.g. to purify an aq. soln. of a metal ion by an organic phase e.g. kerosene in which is dissolved an ion-exchanger specific to the ion being extracted, with a re-extraction battery fed with aq. NaCl soln. and the organic phase from the extraction battery. The plant occupies less space than existing plants of the same type, and requires considerably less piping and auxiliaries.