Rapid routine determination of uncombined lime by an automatic absorptiometric method

Abstract

Calcium forms a 1:1 complex with di-(o-hydroxyphenylimino)ethane, and the formation of the complex provides the basis of an automated method for the determination of uncombined lime in synthetic clinkered calcium silicates. The extraction is based on a modified Schläpfer and Bukowski technique and the colour reaction produced in the Technicon AutoAnalyzer system is measured at 570 nm. Sample-to-sample biasing is prevented by the introduction of EDTA between subsequent samples. The absorptiometric technique is an advance on previously described titrimetric methods.