Spectrophotometric Determination of Micro Amount of Alumina in Aluminum Ingot Samples with Aluminon

Based on the different chemical characteristics, in which resultant of AlBr3 from the reaction of metal aluminum with liquid bromine is soluble in absolute methanol and Al2O3 does not react with liquid bromine, the separation of metal aluminum from Al2O3 is realized. And also a method for the determination of micro amount of Al2O3 in aluminum ingot samples by spectrophotometry with aluminon as chromatogenic agent has been developed. Aluminum reacts with aluminon to form a complex with maximum absorption peak at 530 nm in NaAcHCl buffer solution. Beer′s law is obeyed in the range of 0～3.0 mg/L for Al2O3.The method has been applied to the determination of Al2O3 in practical samples with recoveries of 98.9%~99.7% and precision of 3.50%~14.3%RSD (n=5).