抄録
For the determination of residual Ce, La and Ca in cast iron, the following methods were employed. Namely, colorimetry by oxine-chloroform for Ce, flame-metry for La and colorimetry by plasmocorinth for Ca. They were extended for the analysis of cast iron and accurate results was obtained.
1) Ce: Anhydrous Na2 SO4 was added to the extracted oxinate chloroform solution. After 30 min., stable color was obtained. Ca, Mg and Th did not interfere, but Mn effected when it's content exceeded 0.75%. The accuracy in analysis was within +0.001%∼−0.002%.
2) La: Addition of ethyl alcohol to the La containing solution enables more accurate results for it, by the excitation of flame emission. Mn, Ca, Ce, Th, Mg did not interfere. The error was within ±00.001%.
3. Ca: The method that does not collect Ca in precipitation but keeps in solution was examined. Above method assured ±0.001% accuracy. Mn, Cr, Ni, Mg, Ce, Th did not interfere.
