COMPLEXOMETRIC METHOD OF DETERMINING THORIUM AND ZIRCONIUM IN MAGNESIUM ALLOYS

Journal Article · Fri Jan 01 00:00:00 EST 1960 · Zavodskaya Lab.

OSTI ID:4008916

Volodarskaya, R S

Arsenazo was found to be best for the complexometric determination of thorium. Thorium and arsenazo form a colored complex which is stable also in acid solutions, and which does not form complexes with Mg, Zn, Cd, Mn, Ca, and rare earths. One molecule of Trilon B forms a complex with one molecule of Th. Magnesium alloys, containing up to 4% of Th and 1% of Zr, were analyzed with this indicator. Larger quantities of Mg, Zn, Al, Mn, Cd, Ce/sup 3+/, Nd, Pr, and La do not affect the thorium titration. The color transition is not affected by a content of up to 0.02% of Cu, 0.5% of Ni, and 0.1% of Pb. Before the titration Ce/sup 4+/ must be reduced by ascorbic acid. Zr interferes and cannot be masked by additions of citric and tartaric acids, since at the same time thorium also forms a complex. The precipitation of Zr by the five-fold amount of phenylarsonic acid was successful. The analyses of alloys with and without zircorium are described. The back-titration of the Trilon excess at a pH of 2.0-- 2.5 by an iron chloride solution in the presence of sulfosalicylic acid, was used for the determination of zirconium in magnesium alloys. Mg, Ag, Cd, Zn, Al, Mn, Nd, La, and Pr do not interfere, while titration is found to be impossible in the presence of Th. At a pH of 2.0--2.5 Trilon B and thorium form a complex which is destroyed by iron. An addition of iron chloride makes the pink color of the iron sulfosalicylate disappear quickly even without Trilon excess. This is also the case in the titration of thorium alone. Therefore, it is necessary that zirconium be precipitated by a 10% phenylarsonic acid solution in the presence of thorium in the alloy, the precipitation be dissolved after fusion, and the zirconium be determined by complexometric titration. Trilon must be added to a strongly acid, hot zirconium solution containing approximately 20% of HCl. For the complex formation, the solution then must be boiled for some minutes. Soluions which are warm, but not necessarily hot, can be titrated. For one molecule of Trilon B one zirconium atom is used. The analysis is described in detail. (OTS)

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-15-026004
• OSTI ID: 4008916
• Journal Information: Zavodskaya Lab., Vol. Vol: 26; Other Information: Orig. Receipt Date: 31-DEC-61
• Country of Publication: Country unknown/Code not available
• Language: Russian

Related Subjects

CHEMISTRY
ACIDS
ALUMINUM
ARSENAZO
ARSONIC ACID
ASCORBIC ACID
BOILING
CADMIUM
CALCIUM
CERIUM
CITRIC ACID
COLOR
COMPLEXES
COPPER
EDTA
HYDROCHLORIC ACID
IRON CHLORIDES
LANTHANUM
LEAD
MAGNESIUM
MAGNESIUM ALLOYS
MANGANESE
NEODYMIUM
NICKEL
ORGANIC ACIDS
ORGANIC SULFUR COMPOUNDS
PHENYL RADICALS
PRASEODYMIUM
PRECIPITATION
QUANTITATIVE ANALYSIS
RARE EARTHS
REDUCTION
SALICYLIC ACID
SOLUTIONS
STABILITY
TARTARIC ACID
THORIUM
VITAMINS
ZINC
ZIRCONIUM