Method for dispersing two phases in extraction and apparatus for realizing the method
AssigneeOutokumpu Oy
InventorsBror G. Nyman, Stig-Erik Hultholm, Launo L. Lilja, Valto J. Makitalo
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Abstract
The invention is related to a method for dispersing two phases in an extraction process so that each extraction step includes several mixing stages, and at each mixing stage the mixing is carried out by means of a vertical circulation and advantageously at least one mixing stage is provided with an intensified vertical circulation. According to the invention, the dispersing apparatus of one extraction step in an extraction process is formed of several mixers provided with circulation cylinders (11). Advantageously at least one of the mixers is provided with a dispersing pump (16).
Claims15
An apparatus for dispersing two phases in one step of an extraction process and for controlling the desired type of dispersion, comprising a presettler and a settler and a circulation cylinder installed in the bottom part of a mixing chamber and a turbine placed above the circulation cylinder, and including at least two mixers for carrying out an extraction step, at least one of the mixers being provided with a dispersion pump and with return conduits for the phases from a settler of said extraction step, said conduits being connected to said circulation cylinder;
- and wherein in order to control the type of dispersion and in order to create a double-loop circulation, to a top of the circulation cylinder there are connected both a heavy phase return conduit and a light phase conduit coming from the settler of the same extraction step, that above a pump of the turbine there is installed a dispersion pump coaxially with the turbine, a suction inlet of a suction cylinder of the said dispersion pump being located above the middle of the turbine, that in the suction cylinder which is closed at the top, there are seated at least two rising pipes which form an upwards widening cone, that around the rising pipes there are fitted cone plates which at the bottom extend to below a liquid surface in said mixing chamber and at the top at least to the same level with said liquid surface, that the rising pipes end up to a connecting circular pipe wherefrom the dispersion flow is directed into a next stage through a collecting trough placed above the liquid surface.
A method for dispersing together a heavy liquid phase and a light liquid phase in two mixing stages of one extraction step by causing both said phases to flow in the same direction through said two mixing stages and including creating an intensified liquid circulation in at least one of said mixing stages and causing the dispersion to rise to a vertically higher level than a liquid surface level in a mixing chamber in which said mixing is carried out, said method further including directing mainly upwards a dispersion jet discharged from a mixing member located no lower than a middle part of said mixing chamber;
- causing the dispersion to flow downwards at outer edges of said mixing chamber;
- causing said downwards flow of dispersion to turn at a bottom part of said mixing chamber and thence causing the dispersion to flow upwards through a separate part of said mixing chamber;
- selecting a phase for said return flow from the settler and causing said return flow of said selected phase to return to the mixing chamber;
- and discharging the dispersion from said mixing chamber as at least two rotating sub-flows rise to a level higher than the liquid level in said mixing chamber;
- then turning the dispersion to a direction tangential to the direction of rotation of said sub-flows, whereby centrifugal force causes partial classification of said phases;
- and conducting the dispersion away as a thin layer.
Dependencies are inferred from the claim text.