| 摘要 |
PURPOSE: A purification method of ferric oxide is provided to remove impurity ions from ferric oxide produced by thermal decomposition by treating them with ferric nitrate solution and ammonium hydroxide solution, in two times. The resultant ferric oxide is applied to ferrites and pigments requiring high purity. CONSTITUTION: The purification method of ferric oxide is as follows: removing impurity cations(Na+, Ca2+, Mg2+, Zn2+ and Al3+) in ferric oxide(alpha-Fe2O3) by putting less than 300g of ferric oxide into 1L of aqueous ferric nitrate solution(Fe(NO3)3·9H2O) of pH3-5 with air poring; washing with water and filtering; removing impurity anions(Cl-) by putting cations-removed ferric oxide into ammonium hydroxide solution of pH9-10, which is expressed by the formula, NH4OH + H+ + Cl --->NH4Cl + H2O; washing with water to be less than pH7.8; and filtering. |
