Abstract:Twelve kinds of compound salts were selected to purify GH4169 returned alloy. Effects of compound salt purifiers on composition and microstructure of returned alloy were studied. Composition, oxygen and nitrogen level; morphology and size of inclusions of purified returned alloy were tested and characterized by different methods. The results indicate that the best compound salts purifiers, 80?O3 20%Na2B4O7 and 50?F2 45%AlF3 5?O trace amounts of (Al2O3 MgO), can obviously drop oxygen and nitrogen level of returned alloy, while content of main elements remains more or less constant. The oxygen level drops by 82.10% and 96.21% respectively, and nitrogen content drops by 69.10% and 14.55% respectively. Absorption and removal of Al2O3 and TiN in returned alloy by compound salts is the main reason to reduce oxygen and nitrogen level.