Improvement of the sensitivity of molybdenum and tungsten determination in niobium and tantalum

Nonferrous metallurgy. II. Zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten

“…The niobium in niobium-tungstenpalladium alloys was determined by precipitation as the hydroxide by addition of ammonium hydroxide to a solution from which the palladium had been removed by electrolysis (214). The tantalum in tantalum germanides was also determined by precipitation as the hydroxide by the addition of ammonia to a solution from which the germanium had been removed by distillation (298).…”

“…Chrome Azurol S: study of conditions and interferences (272) Cu-Chrome Azurol S + Zephiramine: study of conditions (258) Diantipyrinylmethane: study of conditions (433); steels, ores, alloys (434) Iodide + Brilliant Green or Crystal Violet: study of conditions Comparison of thiocyanate and toluene-3,4-dithiol (182) Thiocyanate: study of photoreduction (466); study of extraction separation (102,140, 332,336,581); study of chromatographic separation (328); Nb (180); perrhenates (570); electric welding aerosols (346); V (27); ores and concentrates (352); soils and rocks (268); soil (317); oil shale (656) Toluene-3,4-dithiol: Nb, Ta (153,298,360); water (22,311); silicate rocks (312); minerals (611) Unithiol: W (104)…”

“…1-Naphthylamine-BrOa: study of conditions (341) Toluene-3,4-dithiol: Nb, Ta (153,298,360); silicate rocks (312); sedimentary rocks (660); ores (611); water (311) Thiocyanate: study of photochemical reduction (467); Mo (450); Pd (214); alkaline earths (219); scheelite (613); sedimentary rocks (660); waste solutions (621); air (654) Phenylfluorone: study of conditions (95); Mo (92); Cu, Bi (94) Pyrocatechol-EDTA: Mo (103) Citrate: V (598) H202: study of conditions (487) Molybdotungstate: Mo (532) Rhodamine B: Mo (100) Zephiramine: study of conditions (429) Malachite Green-Ti(III): study of conditions (471) Basic Blue K-Ti(III): study of conditions (472) H202-Iodide: study of conditions (242) eliminated by the use of standards prepared by spiking portions of the sample (486). Both the metallic disk method and the borax bead method were used for the determination of niobium in zirconium alloys (427).…”

“…Precipitation using -benzoin oxime as the reagent was the concentration method used for the determination of molybdenum in minerals (611). Toluene-3,4-dithiol was also used for the determination of molybdenum in niobium and tantalum (153,298,360). Unithiol was used as the chromogenic reagent for the determination of molybdenum in sodium tungstate (104)-A mixed complex of 4-(2-pyridylazo) resorcinol and hydroxylamine was studied (374) and used for the determination of molybdenum in tungsten compounds (372) and rhenium metal (373).…”