Determination of Lead in Leaded Free Cutting Steels by the Chelatometric Titration Method

A simple chelatometric titration method for the determination of Lead in Leaded free cutting steel has been developed. The samples are dissolved in HCl, HNO3 and HClO4 and Iron (III) is extracted into Methyl Isobutyl Ketone from 6 N HCl solution. Chromium (VI), Molybdenum (VI), Vanadium (V), are also extracted. In the aqueous solution, Aluminum, Copper, Nickel, Cobalt and Manganese ions are masked with Triethanolamine and Potassium Cyanide. Lead is titrated at pH 10 to pH 11 using Thymolphthalein complexone as an indicator. The proposed has the advantage of speed, yet has the same accuracy as the classical gravimetric method.