| 摘要 |
A solid composition suitable for use as a bleach comprises a borate and hypochlorite of an alkali metal, in which the molar ratio (OCl-): X2O : B2O3 (where X represents an alkali metal atom, and only titratable alkalinity is taken into account in determining X2O) corresponds with proportions of from 0,029 to 0,36 moles of OCl-per mole of B2O3 and from 0,30 to 0,65 moles of X2O per mole of B2O3. The composition may be either in crystalline or amorphous form and may also contain soluble crystalline salts such as alkali metal chlorides and chlorates. The composition may be prepared by the addition of an alkali metal borate to an alkali metal hypochlorite, the alkali metal hypochlorite first being produced by chlorinating an aqueous solution of one or more alkali metal hydroxides, and one or more alkali metal borates and/or boric acid then being slurried into this solution and the slurry then dried. Alternatively the composition may be prepared by chlorinating a solution of one or more alkali metal borates, with or without boric acid, and with or without one or more alkali metal hydroxides, or by chlorinating a solution of boric acid with one or more alkali metal hydroxides, followed by drying, suitable starting materials which may be submitted to chlorination being borax and caustic soda, sodium metaborate, potassium metaborate, borax and boric acid, lithium borate and borax, potassium borate and caustic soda, sodium metaborate and boric acid, and boric acid and sodium or potassium hydroxides. The composition may also be prepared by admixing borax and caustic soda in a dry state and chlorinating the dry mixture with chlorine gas. |
