Photometric Determination of Tungsten in Iron and Steel. (Studies on Extraction and Determination of Metal Salts with Methyl Isobutyl Ketone, VII)

Abstract

Studies were carried out on the photometric determination of microamount of W in iron and steel. W and Mo were separated from the main component of Fe and other elements by α-benzoinoxime-chloroform extraction. When larger amount of Mo was present than that of W in the sample, most of Mo in HCl solution was separated from W by methyl isobutyl ketone extraction. After reducing W⁶⁺ to pentavalent W with SnCl₂ in HCl solution, thiocyanate complex of W was formed by addition of NH₄SCN. The complex was extracted with methyl isobutyl ketone and the amount of W was determined by measuring its light absorbancy. When V was not contained in the sample, W was separated from Fe and other elements by precipitating their hydroxides with NaOH in the place of α-benzoinoxime-chloroform extraction method.