A spectrophotometric method for the determination of traces of silicon in copper and aluminium alloys

Abstract

A rapid and accurate spectrophotometric method has been developed for the determination of silicon in the range 0.02-1 ppm in copper and aluminium alloys based on the formation of reduced silicomolybdate in the presence of bismuth as catalyst. The possibility of extraction of the silicomolybdate complex formed, with an organic solvent like isoamyl alcohol has been explored. It is found that the method is more sensitive compared to existing methods and it gives a molar absorptivity of 30,000 at 800 nm. The standard deviation calculated at the 0.45 µg Si/ml level is found to be 0.008 ppm for a set of four weighings. Interference studies for some of the important ions which arc relevant to silicon determination have also been carried out.