| Aluminium isopropoxide [Al(OC3H7)3] is the precursor of many important materials, which has been applied to the preparation of high-purity alumina nanometer powders and phosphors, and has shown its merits. However, the trace iron in the Al(OC3H7)3 dramatically affects properties of products made from Al(OC3H7)3. In this thesis, a complexation-crystallization purification technique was used to remove the trace iron in Al(OC3H7)3, because it has a lot of advantages such as low energy cost, high separation ability, low temperature and so on. The details of this complexation-crystallization technique was studied in this thesis.Several aspects of study were investigated in this thesis: (1) A sensitive and simple analysis method concerning the trace iron in aluminium isopropoxide [Al(OC3H7)3] based on the 1,10-phenanthroline spectrophotometry was proposed. This method had been applied to the determination of the trace iron in [Al (OC3H7)3] with satisfactory results. (2) The optimum conditions for the complexation-crystallization such as the crystallization means, crystallization time and the solution concentration were determined. (3) Through experiments, several complexes with a good iron-removal effect were selected, the optimum solution concentration and molar ratio to the iron were determined. These selected complexes were also added in the process of preparing alumina nanometer powders to remove the iron. (4) A purification method of marinating alumina powder with HCl/HNO3 to remove the iron was proposed.The results show: the complexation-crystallization can enhance the efficiency of normal crystallization purification. At the higher solution concentration, more iron can be removed. Hox, AA and complex L3, L4 which had better iron-removal effect in the complexation-crystallization was chosen in the process of preparing alumina nanometer powder, however the iron-removal effect was not so good as the one in the complexation-crystallization. |
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