The atomic-absorption spectrophotometric determination of total aluminium in steel after its dissolution in a pressure bomb

Abstract

A method is described for the determination of 0·001 to 0·14 per cent. of total aluminium in irons and steels, which does not involve fusion of an oxide residue. The iron or steel is completely dissolved by first subjecting it to conventional treatment with acid in an open beaker and then to attack by acid in a PTFE-lined bomb at 200 °C. The oxide residue is completely dissolved by attack in the bomb with hydrochloric acid alone or with a mixture of hydrochloric and hydrofluoric acids, the latter solvent being preferred. Iron(III) is extracted from the solution of steel, 6 M in hydrochloric acid, with isobutyl methyl ketone and aluminium is then extracted from the aqueous phase buffered at pH 4·7 with acetylacetone. The concentration of aluminium in the organic phase is determined by atomic-absorption spectrophotometry with a nitrous oxide-acetylene flame. Good results were obtained for the determination of aluminium in eleven standard irons and steels.