Method of, and apparatus for, effecting liquid-liquid contact

A method of effecting liquid-liquid contact between an aqueous liquid medium and an organic hydrophobic liquid medium capable of undergoing mass transfer with the aqueous medium, comprising:

• providing a chamber containing a body of each of the aqueous and organic liquid media;
• agitating the liquid media within a mixing zone in the chamber so as to form a dispersion band which contains a dispersion of droplets of one of the media dispersed within the other, the droplets of dispersed medium being of a size such that upon standing under gravity the dispersion will substantially completely disengage into two separate liquid layers, the volume ratio of the media in the dispersion band corresponding substantially to a selected value, and the mixing zone being disposed within the chamber with a free space that is devoid of baffles above and/or below the mixing zone so that there are formed above and below the dispersion band respectively an upper layer of lighter medium and a lower layer of heavier medium, at least one of which layers extends at least partially into the corresponding free space and so that dispersion can freely re-enter the mixing zone;
• supplying at least one of the aqueous and organic liquid media to the mixing zone at a respective preselected feed rate;
• allowing dispersion freely to re-enter the mixing zone;
• allowing disengaged lighter and heavier media to pass from the dispersion band to the upper and lower layers respectively;
• and
• recovering disengaged lighter and/or heavier medium from the upper and/or lower layer respectively at a rate in each case substantially equal to the rate of supply of that medium to the mixing zone, thereby to maintain the volume ratio of the media in the dispersion band substantially at the selected value.