Abstract: A continuous ion exchange system and method for recovering uranium from a pregnant liquor solution wherein the method includes the steps of: (a) treating the pregnant liquor solution (16) with a membrane (28) to produce: i) a leach permeate solution (30) at least partially depleted of uranium and carbonate and ii) a leach concentrate solution (30?) having a relatively higher concentration of uranium and carbonate and which is at least partially depleted of chloride; (b) passing the leach concentrate stream (30?) through an ion exchange bed to load uranium onto a strong base anion exchange resin and produce an untreated barren (18) solution depleted of uranium, (c) passing an eluant solution (20) comprising bicarbonate through the loaded ion exchange bed to strip uranium from the strong base anion exchange resin and produce an eluate (22) comprising uranium and bicarbonate, (d) precipitating uranium (24) from the eluate (22) to produce a residual eluant solution (26) depleted of uranium, and (e) repeating step

Abstract: Disclosed is a process for sealing a hollow fiber membrane separation module into a case. The hollow fiber mambrane separation module is formed from a plurality of hollow fibers arranged in a bundle surrounding a core and having tube sheets surrounding each end of the bundle which bind the hollow fibers together. The disclosed process simultaneous with such sealing creates first and second spaces overlying the ends of the plurality of hollow fibers. Such first and second spaces, in cooperation, permit the introduction and withdrawal of fluids through the lumens of the hollow fibers.

Abstract: An improved hollow fiber membrane device is obtained using an inner wrap extending no farther than 25 percent of the diameter of the hollow fiber bundle from the central, longitudinal axis of said bundle. The fibers within the inner wrap are not necessarily hollow. Optionally, an elastic outer wrap is also employed about the bundle.

Abstract: An improved process for separating gases using a hollow fiber membrane on an intermittent basis is described. It has been found that if the pressure on the feed side of the membrane is maintained essentially constant or is allowed to vary slowly during operation and in the periods between operating cycles the useful lifetime of the separation device is greatly extended. This process is particularly useful for the separation of air into oxygen- and nitrogen-enriched streams using hollow fibers melt spun from poly(4-methylpentene-1).