Spectrophotometric determination of aluminium in alloys and ores. Part 2. Stripping aluminium after chelation of other metals with 2-isopropylquinolin-8-ol in butan-1-ol

Abstract

In Part 1, aluminium was separated after extracting the other metals present, as their 2-isopropylquinolin-8-ol chelates, from aqueous solutions. In this paper a simpler and more efficient method of separation of aluminium is described. Instead of precipitating the interfering metals as their 2-isopropylquinolin-8-ol chelates and then extracting them into chloroform, they are prepared directly in butan-1-ol. Chelation of aluminium with the 2-isopropyl compound does not occur in butan-1-ol medium. The butanolic solution containing unchelated aluminium and the chelates of other metals is mixed with chloroform and then extracted with alkaline tartrate-buffered solution. In this way the uncomplexed aluminium is transferred to the aqueous phase, from which it is extracted as its quinolin-8-ol complex and determined spectrophotometrically. The technique has been applied to the determination of aluminium in complex matrices such as permanent magnet and nimonic 90 alloys.