Colorimetric determination of rhenium in ores

• Main Author: Rogers, Clair Winston
• Format: Others
• Published: BYU ScholarsArchive 1955
• Subjects: Rhenium; Chemistry
• Online Access: https://scholarsarchive.byu.edu/etd/8343; https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=9343&context=etd

The problem of colorimetrically determining rhenium in the presence of molybdenum, copper, iron, sulphur, and rare earth elements with the use of dimethylglyoxime as the complexing compound was accomplished by the method reported here-in. The interfering elements were eliminated either as gaseous oxides and sulfides or were precipitated from a highly basic solution by means of a strong alkaline fusion of equal weights of sodium hydroxide and sodium peroxide, and the ore sample containing rhenium. The fusion product was dissolved in water, the solution boiled with a slight excess of sodium peroxide, and the hydroxide of all the interfering ions precipitated. The filtrate was neutralized with sulphuric acid after the precipitate had been removed and thoroughly washed. Aliquot portions of this solution were then diluted to specified concentrations in fifty ml. flasks. Stannous chloride was used for the reduction of rhenium to an oxidation state wherein it forms a colored complex with dimethylglyoxime. The optical density of the rhenium color complex was measured with a Colman Spetrophotometer and compared with the optical density of the same concentration of standard solution. The optical densities of the fusion rhenium solutions were exactly equal to those of the standard solutions of equal rhenium concentration up to about twenty-five parts per million. This method appears to give very accurate results for the determination of rhenium up to this concentration.