Mixing of two liquid phases can be advantageously conducted when the two phases are supplied at steady flow rates. Variations in the rates of supply of the phases are compensated for by pumping each liquid at a constant flow rate higher than the maximum flow rate provided by the supply, and permitting recirculation of disengaged phase in the amount necessary to meet the demand of the system.
A liquid-liquid contacting apparatus is provided having the capacity to control and contain a fire occurring within a separator vessel. Mixing of two liquid phases such as an organic and an aqueous solution may be advantageously conducted when the two phases are supplied at steady flow rates. Variations in the rates of supply of the phases are compensated for by pumping each liquid at a constant flow rate higher than the maximum flow rate provided by the supply, and permitting recirculation of a disengaged phase in the amount necessary to meet the demand of the system. The organic solution having a lower density than the aqueous solution rises within a separator vessel and may be ignited upon its upper surface. By flooding the vessel with a third nonflammable liquid such as water, the liquid level within the vessel is raised until the organic solution is removed by flowing over a channel weir within the vessel and is drained away through a fluid trap. The trap prevents the surface fire from propagating beyond the vessel and weir.
The invention relates to a method for settling the dispersion formed in the mixing unit of liquid-liquid extraction, for controlling solution flows and for creating pure solutions in the separation part. According to the method, the flow speed of the organic solution phase is adjusted to be clearly higher than the flow speed of the aqueous solution phase, in which case in order to prevent border flow turbulence caused by the speed difference of the solution phases, the water drop dispersion layer left in between the separating solutions is adjusted to extend as far as the discharge end of the separation part. In order to settle the solution phases, at the front end of the separation part there are arranged at least three spots where the dispersion and the already settled solutions are made to flow through a picket fence forming a restricted transversal surface, in which case the first restricted transversal surface turns the flow fed into the separation part to follow the longitudinal direction of the separation part, and the second picket fence in the flow direction forming a restricted transversal surface allows the settled aqueous solution phase to flow freely in the bottom part of the separation part. The invention also relates to an extraction apparatus according to the method.
The invention relates to a method for recirculating the heavier solution from the separation part of liquid--liquid extraction to the mixing unit of the same extraction step, so that part of the recirculated solution is returned to the mixing unit from the overflow of the discharge end of the separation part. An essential feature of the invention is that the major part of the heavier solution recirculated into the mixing unit is obtained from the separation part proper, along the whole width thereof. The invention also relates to an apparatus based on said method, in which apparatus, in the bottom part of the settler (6) there is located a heavier solution collecting channel (13) extending over the whole width of the settler and being provided with suction pipes (15) which are oriented in an inclined fashion towards the solution to be collected from the channel.
A process and apparatus for effecting liquid-liquid contact in a plurality of stages between heavy and light liquid streams is provided wherein said streams are capable of undergoing mass transfer with one another or constituents in either stream are capable of reaction therebetween and where either of said streams can be intercirculated or intracirculated through each stage.
A method of solvent extraction for extracting a required component, such as a metal value, dissolved or dispersed in a support medium, constituting a first phase, e.g. an aqueous phase, by mixing the first phase with an extractant, constituting a second phase, e.g. an organic phase, insoluble or immiscible with the first phase. The second phase has a greater affinity for the required component in order to extract the component from the first phase into the second phase. After the mixing step, the phases are subjected to a settling phase in which the phases are caused to flow in counter-current fashion with respect to each other in order to separate the phases. Apparatus for carrying out the method is also provided.
