Concentration of isotopes of potassium by the counter-current electromigration method

Abstract

A new electromigration method for the separation of isotopes is described. This method ba ed on the pririciple of setting up a flow of electrol yte tlu'ough a packed colu mn in a direction counttlJ"current to the flow of the i otopic ions being separated and at a rate intermediate between the velocities of these ions. Under these conditions, the faster moving ions will make headway against t he electrolyte str eam, while t he slower moving ion s will be carried back. The separation coefficient .-1 in the case, for ' example, of cations, is given as equal to FVoCln S/ 1000 l +t, where F is the Far'aday constant, Vo i cathode volume in cubic centimeters, C is normality of the electrol yte , S is separation factor, 1+ is positive ion current, and t is time in seconds. Free sFace and temperature distribution in the packing, balance bet\\'een ion transport and stream counter flow, and other factors which determine column efficiency are described. In a series of experiments for the concentration of 30K in the cathode compartment of the electromigration celi, t he abundance ratio N = 30K/4IK was increased from its normal value of 14.2 to a maximum of 24 in about 500 hours of operation and a maximum separation coefficient of 0.385 X 10-3 was obtained. Attempts to concentrate .I K in the anode compartment resu lted in a lowering of the isotope abundance ratio to a minimum of 9.1. A stud y of t he distribution of 30K in the r;acking in experiments carried out for the concentration of 30K in the cathode compartment, showed that the abundance ratio decreases rapid ly from the cathode to anode direction. A desclipt,ion is given of the mass spectrometer used in measming t he abundance ratio 30K/Il K, also, of the automatic control used in regulating the counter flow in some of the electromigration cells.