| abstract |
FIELD: etching processes. SUBSTANCE: invention concerns etching solutions containing nitric and hydrofluoric acid salts and can be used in technology of metal-containing precipitates' isolation. Zirconium fluoride compounds are isolated by concentrating nitric acid to 750-900 g/l at fluorine to zirconium molar ratio (6- 7):1 followed by ageing for 10-15 hr, separation of crystals, adjusting remaining solution to its initial composition, and returning it into etching stage. Concentration process is accomplished by adding concentrated nitric acid or by evaporation. EFFECT: increased isolation of zirconium and simplified regeneration of etching solutions. 2 cl, 1 tbl, 8 ex |