ABSTRACT

The rhenium contents of about 200 molybdenites have been determined by the neutron-activation or the catalytic spectrophotometric analyses. The present authors developed these methodes for the determination of the rhenium content of a very wide range, taking only a small amount of each sample. The data obtained show that 1) the rhenium content of molybdenite covers the range from 10^-8 to 7 × 10^-3 in atomic ratio of Re/Mo, 2) the rhenium contents generally decrease with the following order of occurrence of the molybdenites: volcanic sublimate, porphyry copper deposits, contact-metasomatic deposits, disseminated deposits and quartz veins, 3) as far as plutonic type of molybdenites are concerned, rhenium increases generally with decrease in estimated temperature of molybdenite deposition, 4) the rhenium contents of the molybdenites from Daito area, Shimane Prefecture.as a whole are contrary to the above rule and are higher than those from similar deposits in other areas, 5) low rhenium contents are found in cavity molybdenites, 6) rhenium in an euhedral crystal of molybdenite shows a regular distribution which obeys the Doerner-Hoskins' law, indicating that rhenium forms a solid solution with molybdenum.