PURPOSE: To obtain aluminum hydroxide with excellent whiteness by an easy method and at low cost by bringing a caustic solution of aluminum into contact with a specific adsorbent.
CONSTITUTION: The objective aluminum hydroxide is obtained by (a) bringing a caustic solution of aluminum into contact with a adsorbent comprising a compound represented by formula or calcined, and (b) filtering he solution before and/or after said contact, wherein A represents Mg2+, Ni2+, Ca2+, Zn2+; B Al3+, Fe3+, Cu3+; C OH-, Cl-, Br-, NO3-, CH3COO-, C2O42-, CO32-, SO2-, PO43-, Fe(CN)63-, Fe(CN)64-; 1/2≤Z≤2. According to the method for improving whiteness of aluminum hydroxide, divalent, trivalent or higher electronegative or negative ionic colored materials are easily adsorbed. Calcined hydrotalcite, which is an undesirable condition, can also remove monovalent contaminants from a solution.
NANSHII EMU FUITSUTSUJIERARUDO
BENETSUTO ERU MAKOOMITSUKU
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