ECOLOGICALLY LOW-HAZARD FIXING COMPOSITION FOR AUTOMATIC PROCESSING OF X-RAY PHOTOGRAPHIC MATERIALS Russian patent published in 2012 - IPC G03C1/00 

FIELD: physics.

SUBSTANCE: environmentally low-risk fixing composition for automatic treatment of X-ray photographic materials contains a complexing substance Trilon B, solvent silver halide, sodium thiosulphate, a preservative for preventing sulphurisation of the solution selected from sodium and potassium metabisulphite, buffer substances boric acid, citric acid and sodium gluconate, substance for setting the required pH value selected from ammonium, potassium or sodium persulphate and 3-substituted sodium phosphate, and water. The fixing composition further contains an accelerating agent selected from ammonium acetate, nitrate, sulphate, phosphate and citrate, a basic hardener magnesium sulphate and an additional acidic agent sulphosalicylic acid, with the following ratio of components, g/l: Trilon B 0-2.0 g/l; sodium thiosulphate pentahydrate 200-300 g/l; sodium or potassium metabisulphite b/v 6-12 g/l; ammonium salt selected from ammonium acetate, nitrate, sulphate, phosphate and citrate 15-80 g/l; boric acid 1-4 g/l; citric acid 0-2 g/l; sodium gluconate 0.5-2.5 g/l; ammonium, potassium or sodium persulphate 0-20 g/l; sodium orthophosphate dodecahydrate 0-5 g/l; magnesium sulphate heptahydrate 1-15 g/l; sulphosalicylic acid 0-15 g/l; water - up to 1 l.

EFFECT: preparation of a fixing composition for automatic chemico-photographic treatment of X-ray photographic materials, which does not contain ammonium thiosulphate, ammonium halides, sulphuric, acetic or oxalic acid, aluminium compounds, while preserving basic functional properties of the working solution, and the disclosed fixing composition ensures reliable storage of the film in the archive due to the amount of residual thiosulphate.

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