Spectrophotometric Determination Of Niobium Research Articles

Determination of Niobium in Parts per Million Range in Rocks

A modified niobium thiocyanate spectrophotometric procedure relatively insensitive to titanium interference is presented. Elements such as tungsten, molybdenum, vanadium, and rhenium, which seriously interfere in the spectrophotometric determination of niobium, are separated by simple scdium hydroxide fusion and leach; iron and magnesium are used as carriers for the niobium. Tolerance limits are given for 28 elements in the spectrophotometric method. Specific application is made to the determination of niobium in the parts per million range in rocks. The granite G-1 contains 0.0022% niobium and the diabase W-1 0.00096% niobium. (auth)

Spectrophotometric Determination of Niobium in Tantalum

Spectrophotometric Determination of Niobium in Tantalum

Spectrophotometric Determination of Niobium in Niobium-Bearing Steels

Spectrophotometric Determination of Niobium in Niobium-Bearing Steels

Spectrophotometric Determination of Niobium and Tantalum in Alloy Steel

As a method of analysis of niobium and tantalum in alloy steels, the spectrophotometric determination by use of pyrogallol has been investigated. Containing tungsten in sample, the precipitates was ignited to convert it into oxide and treated with dilute alkali to remove tungstic acid. Since the separation of titanium is difficult, a method of determination in the presence of niobium, tantalum and titanium has been used. Although the maximum absorption of Nb-pyrogallol complex showed at 380 mμ and that of Ta-pyrogallol complex at 400 mμ, the result of investigation revealed that using of the absorption at 430 mμ for Nb-pyrogallol complex was convenient as the maximum absorption remained constant with pH 6.57.5, while it decreased with an increase of acidity. The absorption of Ta-pyrogallol complex was the highest with pH 2. 1 and the value were less with the increase or decrease of the pH. The light absorbency of Ta-pyrogallol complex was influenced by the change of temperature and its correction was made by use of a factor ± 0.0015 /°C/mg Ta. Determination of niobium and tantalum in alloy steel by this method gave a satisfactory result.