| 摘要 |
Non-crystalline, stable and highly soluble sodium borate containing over 15 per cent by weight of active oxygen is prepared by evaporation to dryness of a solution containing sodium borate and hydrogen peroxide having a molar ratio H2O2 : Na2O of 1.7-2.4 : 1 and at a temperature below 30 DEG C., by passing said solution over a surface (e.g. a series of rollers) at 100-130 DEG C. The solution preferably has a molar ratio B2O3 : Na2O of 1 : 1.1-2, and may be prepared from boric acid, sodium hydroxide and hydrogen peroxide or equivalent reagents, e.g. sodium metaborate or borax, sodium hydroxide and hydrogen peroxide or sodium peroxide, the temperature during preparation preferably not exceeding 30 DEG C. Although the use of stabilizers such as magnesium or sodium silicate is not necessary in general, they may be added during the preparation. Examples are given. |
