首页>
外国专利>
Method for brightening and whitening clays utilizing sodium borohydride
Method for brightening and whitening clays utilizing sodium borohydride
展开▼
机译:利用硼氢化钠对粘土进行增白增白的方法
展开▼
页面导航
摘要
著录项
相似文献
摘要
A method for improving the brightness and whiteness of kaolin clays or the like. An aqueous slurry of the clay is initially treated with a solution of sodium borohydride and sodium hydroxide at a pH of above 7.0 up to about 10.0. Sulphur dioxide is then bubbled through the slurry or otherwise brought into contact with same, the pH being permitted to attain a value of between 6. 0 and 7.0. The pH may thereupon be adjusted to between 2.5 and 4.0 with an acid, at which pH the leach reaction may occur; or the application of gaseous sulphur dioxide may be continued to yield a pH of the indicated 2.5 to 4.0 range.
展开▼