Frederick Otto Simon 1962 <p>Rhenium is determined by spectrophotometry of the tellurium sol formed by the reduction of tellurate by stannous chloride under the catalytic influence of rhenium. A detailed investigation of the conditions for high sensitivity and stability at lowest concentration levels of rhenium is presented as well as the behavior of twenty-six ions. The method is applied to the determination of some tenths of a part per million or more of rhenium in a milligram aliquot of mineralized rocks, mixtures of molybdenite and rocks, and molybdenite concentrates. The practical quantity limit of detection is 2 x 10^-10 gram of rhenium. Samples are decomposed with a mixture of calcium oxide, calcium chloride, and magnesium oxide. On leaching, the constituents of the sample are precipitated either as calcium salts or as hydroxides except for rhenium and a small amount of molybdenum which pass into the filtrate. Residual molybdenum is removed extraction with 8-quinolinol in chloroform. Better than ninety-five percent recoveries are obtained with two fusions with flux.</p> application/pdf 10.3133/ofr62126 en U.S. Geological Survey Spectrophotometric catalytic determination of small amounts of rhenium in mineralized rocks and molybdenite reports