Preparation of Powdery Metallic Oxides and their Reactivity

粉末状金属氧化物在工业上用作磁性材料、传感器、催化剂、磨料、颜料和陶瓷生产的原料。氧化物的反应性和性质强烈地依赖于它们的制备条件这一事实已经是已知的，但原因仍然不清楚，因为控制氧化物的反应性和性质的许多因素的复杂相互作用。本课题研究了制备条件与-Fe_2O_3，V_2O_5，MnO_2反应活性的关系。以-Fe_2O_3为催化剂，研究了它对KCl_（10）_4粉末的催化热分解反应，与ZnO和MgO的铁氧体生成反应，以及外来金属离子对Fe（Ⅲ）-氢氧化物生成-Fe_2O_3的影响。与V_2O_5反应，研究了它与-Fe_2O_3和SO_2的粉状反应活性。在MnO_2存在下，表面羟基在水溶液中的解离行为发生了变化。 ...更多信息 研究了研究了金属Al表面氢氧化物膜和不锈钢表面Zr（IV）-Cr（III）、Ti（IV）-Cr（III）复合氧化物膜的形成，发现随着-Fe_2O_3粉末制备温度的升高，ZnFe_2O_4和MgFe_2O_4铁氧体的生成速率和催化活性降低。结果表明，对于这些反应，反应物颗粒之间的接触影响的反应性和ZnO，具有相对较高的挥发性显示出较高的初始反应性。在加热过程中，Cu^（2+）、Ni^（2+）、Al^（3+）等金属离子的加入阻碍了Fe（III）-OH向-Fe_2O_3的晶化。添加过程（共沉淀、凝胶混合和砂浆混合）影响阻碍作用的程度。用酸碱滴定法测定了MnO_2在水溶液中表面羟基的离解常数。发现FTIR-RAS方法有助于分析铝阳极氧化形成的氢氧化铝膜的结构。少

The powdery metallic oxides are used in the industries as magnetic material, sensor, catalyst, abrasive, pigment and raw material for the ceramic production. The fact that the reactivity and the properties of the oxides are strongly dependent on the preparation conditions of them has been known, but the reasons are still not clear because of the complex interaction of many factors controlling the reactivity and the properties of the oxides. In this project, the relation between the preparation conditions and the reactivity for -Fe_2O_3, V_2O_5 and MnO_2 was investigated. With -Fe_2O_3, its reactivity was studied for the catalytic thermal decomposition of KC10_4 powder, the ferrite formation reactions with ZnO and MgO, and the effect of foreign metallic inos on -Fe_2O_3 formation from Fe(III)-hydroxides. with V_2O_5, its reactivity was studied for the powdery reaction with -Fe_2O_3 and SO_2. With MnO_2, the dissociation behavior of the surface hydroxyl group in the aqueous solutions was … More studied. The formation of hydroxide film on Al-metal and Zr(IV)-Cr(III) and Ti(IV)-Cr(III) composite oxide films on stainless steel were also investigated.The increase in preparation temperature of -Fe_2O_3 powders resulted in the decrease in the catalytic activity and the formation rate of ZnFe_2O_4 and MgFe_2O_4 ferrites. It was found that for these reactions, the contact between the reactant particles affects the reactivity and ZnO which has relatively high volatility shows the high initial reactivity. The crystallization of amorphous Fe(III)-hydroxide to -Fe_2O_3 in the course of heating process was observed to be hindered by an addition of foreign metallic ions, such as Cu^<2+>, Ni^<2+>, Al^<3+>. The addition procedure (co-precipitation, gel-mixing and mortar-mixing) affected the degree of the hindering effect. With MnO_2, the dissociation constant of hydroxyl groups formed on the surface in aqueous solutions were determined by the acid-base titration of the suspensions containing MnO_2. It was found that FTIR-RAS method was helpful to analyse the structure of Al-hydroxide film formed on Al-metal by the anodizing. Less