The characteristics of the Ningyo-toge ore. Especially comparison with the representative ores abroad

The authors have studied about the mineralogical characteristics of the Ningyo-toge ore with reference to uranium processing, comparing with the ores from some representative mines in foreign countries. The uranium contents of the Ningyo-toge ore are about 0.06 to 0.1% U₃O₈ and comparatively lower than those of foreign ores ranging generally over 0.1% U₃O₈. In spite of such low uranium contents, the Ningyo-toge ore has good qualities as raw material of uranium, as will be mentioned below. (1) The ore is very loose and uranium has a tendency to be more concentrated in the fine part, so that washing and screening are sufficiently effective. (2) The structure of the ore is so porous that the leaching solution can penetrate very easily, and the uranium minerals of the ore are readily dissolved in acid. (3) The ore has the simple mineral association, and it includes scarcely unfavorable materials for extraction and recovery processes of uranium. (4) It is also an important advantage that there is no trouble caused by some impurities having high cross section for neutron absorption. (author)