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cobalt, gallium, and tin, it has an advantage over the carrier distillation procedure, because certain elements forming highly refractive oxides, such as the rare earths, can be determined with a high degree of sensitivity.The simplicity of the ion exchange procedure makes it ideal for spectrographic purposes because the elemental contamination can be held to very low levels. The manipulations can be easily carried out in a glove box. The number of additives is held to a minimum.The visual comparison procedures used in the preceding work have already provided valuable information and were adequate for the present application. The desirability of extending the usefulness of the method through the increased accuracy of densitometric procedures is also recognized. These procedures have been applied and are being prepared for publication.It appears entirely possible to develop a method for plutonium using nitric acid exclusively except for the initial dissolution.However, hydrochloric acid prepared as described above had smaller amounts of the common impurities, such as calcium, magnesium, sodium, aluminum, and boron, than the nitric acid used. Consequently, hydrochloric acid was preferred for the determination of these elements. Furthermore, the division of the sample into hydrochloric and nitric acid fractions reduces the possibility of matrix effects in the excitation of an impure sample.In specific instances the ion exchange technique used in conjunction with conventional spectrographic methods may provide the means of extending the concentrational limits of detection another order of magnitude. ACKNOWLEDGMENTThe authors wish to express their appreciation to D. C. Stewart and . H. Studier for helpful discussions during the course of this work. They are also grateful to J. A. Goleb for the carrier distillation results of Table I. This paper is based on work performed under the auspices of the U. S. Atomic Energy Commission.

The value of g was chosen so that glo equaled the calculated intensity one quarter of the distance into the suspension. Kinetic constants and the extinction coefficient, e, for Beer's law were taken from the literature (72). The lines in Figure 5 show that Equation 5 is sufficient for estimating order-of-magnitude effects of rotor speed ; the value f = ' 1 2 seems to be somewhat better than the value f = ' / 4 ; in more dense suspensions than used here, perhaps the latter value woiild be more appropriate.A flowsheet is presented which includes cesium loading, sodium removal with oxalic acid, water wash, and acid removal with N H 4 0 H , all a t low temperatures, and elution with 2M (NHJzC03 a t elevated temperature. The clinoptilolite column can b e re-used with bed make-up of about 2% per cycle. A relatively pure ( C S )~C O~ solution is obtained b y volatilization of the (NH&C03 from the eluate. Data on the effects of varied flow rate, temperature, waste dilution, exchanger particle size, and cesium concentration are given.The flowsheet is adaptable to removal of small amounts of cesium from various solutions high in salts or acid.IJJTONITIM and fission products are produced by the irradia-P tion of uranium in nuclear reactors. These materials are chemically separated from each other by the Purex process, with the gross fission product portion becoming the socalled high-level radioactive wastes. These wastes can be treated directly for long-term confinement or first treated to separate certain long-lived fission products such as cesium-1 37 and strontium-90.Research on the use of minerals and other inorganic ion exchangers for treatment of low-level wastes has been in progress a t General Electric, Hanford Laboratories, and other sites for several years l(7, 5, 6 ) . Recently this work has been extended toward separation, purification, and packaging of specific radionuclides from high-level wastes. Mineral and inorganic ion exchangers show considerable promise in this type of application because of their ionic selectivity. thermal stability, and radiation stability. Work by Hanford Laboratories personnel has shown that the natural zeolite, clinoptilolite, has unique properties that make it especially attractive for use in separation of cesium from many types of wastes. The objective of the investigation reported in this paper was a chemical flowsheet for the separation of cesium from acid Purex formaldehyde-treated waste (FTW) as a step in a highlevel radioactive waste treatment program.The flowsheet presented in Figure 1 was conceived as a part of an over-all process to separate and concentrate cesium from high salt wastes on an exchanger of high cesium selectivity. followed by elution and reloading on an exchanger of high capacity. The cesium on the high capacity exchanger could be used as such, stored, shipped, or removed at any time for additional processing.Zeolites of highest cesium selectivity generally do not also VOL. 3 NO. 2 A P R I L 1 9 6 4 143 Downloaded by KTH ROYAL INST OF TECHNOLOGY on August 26...

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