Ceramics-Silikáty 37, (4) 199 - 204 (1993)

The conditions have been presented for the chelatometric determination of yttrium, magnesium and calcium in the spray-coating materials based on the oxide zirconium compounds after their decomposition by fusion with alkali fluorides and removal of the latter with sulphuric acid evaporated to fumes. Yttrium and calcium are determined chelotometrically after separating them as oxalates at pH = 2.2 ± 0.2 and pH = 4-10, respectively. Both oxalates are decomposed to oxides by fusion with sodium or potassium carbonates in a Pt crucible. The determination of magnesium necessitates masking the traces of zirconium by an α-hydroxyacid and hydrogen peroxide in a NH₄OH-NH₄Cl buffer solution, with eriochrome black T as indicator. The procedures have relative errors of 3.2, 1.4, and 1.2 % for yttrium, calcium, and magnesium, respectively, provided that the oxide contents of about 10 % are involved.