| 摘要 |
<p>Ammonium thiosulphate is stabilised with sodium sulphite. Photographic fixers. The ammonium thiosulphate can be stabilised as the solid or as weak or concentrated solutions. The solid is stabilised with fine grain anhydrous sodium sulphite. The solid or solutions generally contain 0.1 - 8% sulphite based on the thiosulphate. The thiosulphate may also contain 0.5-3% dicyano diamide or 0.01-5% complexing agent. 1 kg freshly prepared crystallised ammonium thiosulphate was mixed with 10g anhydrous sodium sulphite having a granule analysis of 15% 0.10-25 mm, 35% 0.10-0.20 mm, 25% 0.05-0.10 mm and 2k% 0.05 mm. The mixture was stable to storage at ambient temperatures for over 10 months, and to further storage at 50-55 degrees C for at least 50 days.</p> |
