Production research progress report, February 16--29, 1948

Abstract

The equipment for the Bismuth-II process has been installed at Unit IV., and two runs have been made. The results on the potential of bismuth in bismuth chloride solutions have been summarized and calculations made on the concentration of silver in solution which must be present if silver is to be reduced to the metal by Metallic bismuth. The results have been compared with earlier experiments in which the deposition of silver on bismuth was investigated by the use of gamma active silver as a tracer. From the results it becomes quite evident that the scrubbing of silver on bismuth, under the present conditions employed in the production process, cannot be attributed to the reduction of silver to the metal, but must result from the adsorption of silver ions on the surface of the bismuth powder. From these same calculations it is also evident that when silver is employed as a scrubbing medium, bismuth will be deposited on the silver surface until the silver concentration in the bismuth chloride solution reaches a concentration of 20--200 ppM of silver in the bismuth, depending on the chloride concentration of the solution.