Photometric determination of Zirconium in Magnesium and Aluminium alloys

Abstract

Photometric method for the determination of zirconium in magnesium and aluminium alloys by the use of sodium alizarin sulfonate have been worked out. Using hydrochloric acid only or others, a rapid and reliable method was developed which can be applied to separate acid soluble zirconium from acid-insoluble one in many types of magnesium and aluminium alloys.Results summarized are as follows:(1) To 0.2 to 0.4N hydrochloric acid solution of zirconium, hydroxylamine hydrochloride was added, and then 5ml. of 0.20% sodium alizarin sulfonate, at 10 to 30°C, to make colored complex.Absorbancies measured at 520mμ. represent constant values for 0.5 to 3 hours after coloring. Thus, zirconium was determined quantitatively in the presence of magnesium, aluminium and many others. Working range were up to 1.7mg. of zirconium per 100ml. of solution using 10-mm cell.(2) The dissolution with dilute (1 to 1) or (1 to 2) hydrochloric acid, to separate acid-soluble from acid-insoluble zirconium in both magnesium and aluminium alloys were very satisfactory and reliable; the insoluble fraction was changed to a soluble form by fusion with potassium hydrogen sulfate.These methods were applied to the determination of zirconium in many types of magnesium and aluminium alloys with successful results.