| 摘要 |
1399473 Solid/liquid contact; ion-exchange NATIONAL INSTITUTE FOR METALLURGY 11 May 1972 [14 May 1971] 22078/ 72 Headings B1F and B1J A process similar to that disclosed in 1070251 modified to ensure the trays remain flooded with solids comprises contacting solids and liquids in general counter-current in a series of stages between which liquids and solids can flow in both directions, the solids being introduced into a first stage and flowing from the first stage to a last stage and out of the last stage, the liquid flowing generally from the last stage to the first stage and out of the first stage, and the rate of liquid flow being cyclically varied so that during a first part of each cycle the solids are allowed to settle in the liquid phase, in a second part are caused to pass with the liquid from one stage to the next in the direction towards the last stage, while in a third part of the cycle liquid is caused to flow from the last stage towards the first stage while fluidising the solids in its path, the arrangment being such that the volume of solids that is caused to pass out of the last stage is less than the volume of solids that can flow between any pair of stages during the second part of a cycle. Thus in the embodiment of Fig 1, domes 8 of the last tray 6 of an ion exchange column are larger than the domes of the proceeding trays so that the amount of solids that passes through chimneys 7 in the last tray is less than can pass through the chimneys 7 of the proceeding trays. |
