ANALYTICAL CHEMISTRY OF THORIUM. PART III. SEPARATION FROM CERITE EARTHS WITH o-TOLUIC ACID AND ACETYLSALICYLIC AClD

From solutions just neutral to Congo red, \(o\)-tolaic acid precipitates thorium quantitatively and also affords a method of separating the cerite-earths, if the amount of the latter is not higher than ten-fold. The \(p\)H of the liquid, which is not critical, falls between 3 and 4. Acetylsalicylic acid exhibits a similar behaviour, but the presence of ammonium acetate is necessary. When the ThO2: R2O3 ratio is not greater than 5, double precipitation is necessary. The pm of the liquid in this case Its between 4 and 4.4. Both the reagents have been employed for the estimation of thorium in monazite