Decolorization method for sodium aluminate solution

A decolorization method of sodium aluminate solution relates to a manufacturing method of non-electrolytic diverse aluminium hydroxide by an alkaline process. The invention is characterized in that the method comprises the following steps: milk of lime is added to refined aluminium oxide liquid for decolorization reaction to seed out iron and silicon in the refined liquid in the form of compounds of calcium hydrating garnet and iron hydrating garnet; calcium salt crystals are formed by vanadium acid radicals, chromium acid radicals, fluorinion and organic matters; the milk of lime absorbs black particles in the refined liquid; liquid solid separation is carried out on serosity after reaction by a leaf filter to obtain the refined liquid with qualified extinction value. In the method, the milk of lime is added to the refined liquid for decolorization reaction to seed out iron and silicon in the solution in the form of compounds of calcium hydrating garnet and iron hydrating garnet, calcium salt crystals are fo