GB794490A - Improved process for separating uranium - Google Patents

Abstract

794,490. Electrolysis. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. Oct. 3, 1945 [Sept. 14, 1944], No. 25764/56. Class 41. A process for separating uranium from a uranium-containing solution, e.g. an oxalic acid solution, containing a dissolved metallic impurity, e.g. Fe, Cu, Ni, or Cr, comprises admitting the solution to the anode chamber 30 of a mercury cathode electrolytic cell which is separated by an ion-permeable barrier 28, e.g. a ceramic, e.g. alundum, from a cathode chamber 31 containing an acidic solution, e.g. hydrochloric acid, the barrier 28 preventing passage of liquid between the chambers 30; 31 and electrolysing the oxalic acid whereby uranium ions pass to the acidic solution, for subsequent removal and the metal of the impurity is deposited in the cathode mercury 62. The cell comprises two insulating casings 11, 12 bolted together at 22 along co-operating peripheral flanges 16, 20, the floor 17 of the casing 12 having lateral slots 17a to receive cathode discs 46, e.g. of nickel, mounted on a shaft 41 which is rotated by a motor through a shaft 52 and bevel gearing 51, 47. The lower portions of the discs 46 dip in the mercury 62 and the upper portions are immersed in the HCl solution in the chambers 31. Anodes 38, e.g. of graphite, platinum or platinum-iridium alloy connected to bus-bars 32 dip in each chamber 30. The anode and cathode chambers 30, 31 are arranged in groups which are connected in parallel for liquid flow, the liquid passing in series through each group, the chambers of each group being interconnected externally of the casing 12 by U-tubes 103, 106. The oxalic acid solution is delivered by pipes 101 to the chambers 30 and leaves at 102, e.g. at a rate of 150 c.c. per minute, and the HCl solution is delivered by pipes 104, e.g. at 15 c.c. per minute, leaving at 105 enriched in uranium ions. A mixture of nitrogen and chlorine, or chlorine alone, is passed continuously through the apparatus, entering through pipes 110 and 111, Fig. 3, which run inside the walls 18 of the casing 12, each pipe 110, 111 communicating by ducts in the walls 18 with the anode chambers 30. The gas agitates the oxalic acid solution and the chlorine reduces it to CO 2 and HCI, a process which is assisted by anodic oxidation, the CO 2 , most of the nitrogen and some of the chlorine leaving the cell by an outlet in the top of a casing (not shown) surrounding the cell. Mercury is passed continuously through the casing 11 from a pipe 116 to a pipe 117. In one operation of the apparatus, in which the anode and cathode solutions flowed at 50 and at 5 c.c. per minute respectively, a voltage of 4 gave a current density of 0.2 amp. per sq. cm. of cathode and the temperature of the electrolyte rose to 70-75‹ C. The positive terminal 36 is secured to a strap 34 which bridges the ends of the busbars 32 and a plate 63 forms the cathode terminal.