GB781224A - Combined mixing and settling apparatus for liquids - Google Patents

Abstract

An apparatus which may be used for handling an aqueous solution of a solvent-extractible metal nitrate, such as cerium nitrate, containing a salting-out agent such as nitric acid (this solution being the heavier liquid) and a substantially- <PICT:0781224/III/1> <PICT:0781224/III/2> <PICT:0781224/III/3> <PICT:0781224/III/4> water-immiscible organic solvent such as tributyl phosphate (this being the lighter liquid) which extracts and dissolves the cerium nitrate comprises a multi-stage arrangement of feeder-mixer-settler units and includes means for individual control of the interface in each unit. In Fig. 1 each unit comprises a feeding chamber 11, a mixing chamber 10 and a settling chamber 13. The units are arranged in two staggered rows, Fig. 2, and are numbered consecutively by the figures in parentheses. The heavier liquid, e.g. an aqueous solution, rises from the bottom of, e.g. settling chamber 13(5), Fig. 1, up a duct 14(5) to a feeding chamber 11(5) and down through a vertically-adjustable weir tube 12(5) into a mixing chamber 10(5). The mixture is impelled by a rotating impeller 26(5) through an outlet 16(4)(5) which forms at the same time the inlet of the settling chamber 13(4) in the rear row. After settlement therein the heavier liquid proceeds up a duct 14(4) and after further mixing in 10(4) reaches settling chamber 13(3) in the front row through aperture 16(3)(4), thus proceeding generally from right to left. The lighter liquid, e.g. an organic solvent, meanwhile rises in, e.g. settling chamber 13(3) and passes by an overflow 15(3) to the same feeding chamber 11(5) and down the weir tube 12(5) to mixing chamber 10(5). It also is impelled therefrom into settling chamber 13(4) in the rear row and rises therein to overflow at 15(4) into feeding chamber 11(6). After mixing in mixing chamber 10(6) it passes through aperture 16(5)(6) into settling chamber 13(5) in the front row-thus proceeding generally from left to right. The interface 21(5) in settling chamber 13(5) is adjusted to be at the level of the aperture 16(5)(6) by screwing the weir tube 12(5) up or down (see Fig. 3). In Fig. 5 the units are placed side-by-side and the ducts 14 (4) &c. are replaced by vertical channels 38(3) &c. open at the bottom. Heavier liquid from settling chamber 34(2) passes up channel 38(2), through an aperture 39(2)(3) near the bottom of feeding chamber 31(3), into the mixing chamber below it and through aperture 35(3) to settling chamber 34(3) whence it passes up channel 38(3) and so on to the right. Lighter liquid from settling chamber 34(4) passes over overflow 40(3)(4) into the same feeding and mixing chambers and through the same aperture to settling chamber 34(3) and so on to the left.