Geochemical Studies on the Radioactive Sediments. I-V V. Sulfur and Uranium in the Sedimentary Uranium Deposits

Abstract

To clarify the geochemical nature of the uramium deposits in the Misasa- group sedimentary beds in western Japan, total sulfur contents of the samples taken mainly from Ningyo-Pass Mine were determined by the tin(II)-phosphoric acid reduction method. From the result, it was found that the total sulfur contents had positive correlations with the contents of both arsenic and uranium in the samples from unoxidized zones of this area. Cn the contrary, in oxidized zones the total sulfur contents were small and independent of the contents of arseric and uranium. The effects of hydrogen sulfide on the solutions contairing uranyl ions were tested in the laboratory. The reactions in the presence of carbonate, phosphate, and calcium ions were also examined, and the results were compared with the reactions in the solutions without hydrogen sulfide. It was found from these experiments that hydrogen sulfide was able to reduce uranyl ion in hot solution and to precipitate uranous compound. From tols fact, the function of the sulfide in the case of the deposition of uranium in the sedimentary beds was suggested. In conclusion, the problems of the origin of the uranium deposits in this area were considered in general. (auth)