| 摘要 |
A stable, solid, substantially dry alkali metal borate-hypochlorite bleach is prepared by chlorinating an alkali metal hydroxide solution before or after mixing with it a previously prepared mixture of a mineral acid and an alkali metal tetraborate and/or metaborate or before or after mixing it with an alkali metal tetraborate and/or metaborate and before mixing the slurry so produced with a mineral acid, and rapidly drying the resulting slurry, the ingredients being used in proportions such that the final product contains 0.029-0.36 moles of (OCl) per mole of B2O3 and the relative proportion of the mineral acid being so chosen that the titratable alkalinity of the product reckoned as X2O (X being the alkali metal) is 0.2-0.9 moles per mole of B2O3. The alkali metal tetraborates and metaborates may be sodium tetraborate pentahydrate or decahydrate, anhydrous sodium tetraborate, lithium tetraborate pentahydrate, potassium tetraborate or sodium, potassium or lithium metaborate and the mineral acid may be sulphuric, hydrochloric, nitric or phosphoric acid. The compositions may also contain soluble crystalline salts such as alkali metal chlorides and chlorates and the alkali metal salts of the mineral acids used. The slurry may be dried by spray drying, drum drying, vacuum oven drying or forced air drying. |
