Determination of impurities in aluminum metal and aluminum-uranium alloys by atomic absorption spectrophotometry

An atomic absorption spectrophotometric method for the determination of impurities, Ag, Cd, Co, Cu, Fe, Mn, Ni, Pb, and Zn, in aluminum metal and aluminum-uranium alloys has been presented. The impurities except for Fe, Mn, and Zn are extracted into chloroform as diethyldithiocarbamates, and Fe, Mn, and Zn are extracted into the organic phase as 2-methyloxinates from the alkaline aqueous solution containing ammonium citrate, aluminum and uranium.One gramme of sample was decomposed with a mixture of 20 ml of HCl(1+1) and 2 ml of HNO3(1+1). The pH was adjusted to 8.59.0 with ammonia water after the addition of 15 ml of 50% citric acid solution. The solution was transferred into a separatory funnel and 3.0 ml of 2% sodium diethyldithiocarbamate solution was added. The solution was shaken vigorously with two 10 ml portions of chloroform for 5 min. The organic layers were collected in a beaker, and the aqueous solution was transferred into another beaker. The pH of the aqueous solution was adjusted to 11.512.0 with sodium hydroxide solution after the addition of 1 ml of 10% sodium sulfite solution and 3 ml of 2% 2-methyloxine solution. The solution was shaken vigorously with two 10 ml portions of chloroform for 2 min. All the organic layers were combined and evaporated to dryness. The residue was decomposed with HNO3 and HClO4, and the decomposed material was diluted to 25 ml with water. The amount of each element was determined by measuring the absorbance and by referring to the respective calibration curve.