| 摘要 |
PURPOSE:To enable effective decolorization of a colored alkaline solution to a reutilizable state at a low cost, by adding a magnesium compound to a colored alkaline solution left after the filtration and separation of synthesized zeolite, stirring the mixture and separating the additive by filtration. CONSTITUTION:A solution of sodium aluminate is made to react with a water- glass composition and produced synthetic zeolite is separated by filtration. A colored alkaline solution obtained as a filtrate is added with a magnesium compound and optionally a calcium compound, the mixture is stirred and the additives are separated by filtration. The magnesium compound is e.g. oxide, hydroxide, salt, silane water mud, etc., and is especially preferably a material having large surface area such as calcined magnesia. The calcium compound used as a filter aid is preferably Ca(OH)2 having particle diameter of several - ten odd mu. The amounts of the magnesium compound and the calcium compound are preferably about 0.2-5g/l and about 0.2-2g/l based on the filtrate, respectively.
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