Liu B.-T.,Qiqihar North Machinary Corporation Ltd |
Wang D.-S.,Qiqihar North Machinary Corporation Ltd |
Shi D.-H.,Qiqihar North Machinary Corporation Ltd |
Yu Y.,Qiqihar North Machinary Corporation Ltd
Yejin Fenxi/Metallurgical Analysis | Year: 2013
After the sample was dissolved with sodium hydroxide and hydrogen peroxide, hydrochloric acid was added. Under anoxic conditions, the high-valence tin was reduced to divalent by sodium hypophosphite with mercuric chloride as catalyst. Then the content of tin in aluminum-copper intermediate alloy was determined by potassium iodate titration after the sample solution was cooled to below 10°C. The experiment showed that, the interference of copper could be eliminated by adding 5 mL of 250 g/L ammonium thiocyanate to form cuprous thiocyanate precipitate with copper (I) before titration. Meanwhile, the other coexisting impurities had no interference with the determination. The proposed method was applied to determination of tin several times in certified reference material of casting aluminum alloy, which had the same matrix with aluminum-copper intermediate alloy. The results were consistent with the certified values. The relative standard deviations (RSD, n=8) were between 1.5% and 3.6%, and the relative error was between 0.0% and 1.6%.