Ultrafast Chemical Separations (1993) / Chapter Skim
Currently Skimming:
6. Continuous Liquid-Phase Chemical Separations
6. Continuous Liquid-Phase Chemical Separations
Pages 59-69
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 59... ...
6.! High-Speed Centrifuge for Phase Separation One of the most common techniques used for radiochemical separations, as discussed in Sec.
|
From page 60... ...
There are two collection chambers, one above and one below the separation volume; the light phase is discharged from the upper collection chamber, whereas the heavy phase is discharged from the lower chamber. Different types of pump wheels are used for discharge.
|
From page 61... ...
Aronsson and coworkers utilized the rapid phase-separation power of the H-centrifuge to develop new, rapid, continuous radiochemical separations and caned the technique "SISAK," i.e., short-lived isotopes studied by the AKUFVE technique [Aro74al. The general characteristics of the technique and a two-detector, dynamic-flow method for the determination of half-life are discussed in their paper.
|
From page 62... ...
The gas carrying the fission products was thoroughly mixed with IM HNO3, degassed before contact with organic solvent. Examples of these separation procedures are given in Sec.
|
From page 63... ...
6, early attempts at on-line chemistry involved transferring radioactive products carried by the gas jet to aqueous phase by simply bubbling me gas through an aqueous solution. It is known that nuclear-reaction products are being carried by clusters present in the gas jet (see Sec.
|
From page 64... ...
The bromine procedure was utilized by Skarnemark and coworkers [Ska86al in their study of the beta decay of 88Br. Table gives a list of known continuous aqueous chemical separation procedures arranged alphabetically according to the element; the table also gives the separation time, the extraction reagent, and the procedure number.
|
From page 65... ...
Porous plastic membranes impregnated with ion-exchange resin or organic solvent and thin, preformed precipitate are used to obtain a sample of radionuclides of Interest; thin samples prepared in this way are very useful for beta, x-ray, and low-energy gamma-ray spectroscopy. Persson and coworkers [PerS9]
|
From page 66... ...
A gas mixture containing nitrogen and hydrogen chloride in the ratio of 20:1 was used to stop the recoiling fission fragments and to carry them to the chemistry system. Volatile chlorides of arsenic and germanium, along with bromine, iodine, krypton, and xenon, were carried out by Me gas stream; nonvolatile fission products were deposited on the waBs of the target chamber and capillary tube.
|
From page 67... ...
Flow sheet for the continuous separation of arsenic from fission products. Dg = degassing unit; CI, C2 = mixer-centrifugal separator units; D = detector positions.
|
From page 68... ...
The activity in die aqueous phase leaving unit 2 was mostly due to lanthanum since the fission yields of praseodymium, neodymium, etc., are very low. In the third unit, the fission products were stripped from the organic solvent and He solvent was recycled to unit I
|
From page 69... ...
Chemical separation system for the isolation of i43La. CI, C2, C3 = mixer-centrifugal separation units; DIl, DI2 = delay lines; GJ = gas jet (N2 + C2H41; M static mixer for gas and liquid; DG = degassing unit; NG = noble gases; FP = fission products; C = counting cell (Dowex-50W X4, 5~100 mesh)
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.