水热法合成云母氧化铁结晶条件

云母氧化铁为鳞片状细微晶体，有金属光泽，其主要化学成分为α-Fe2O3．由于是片状结构，它具有优良的耐介质性、耐大气老化和封闭性能，作为底漆和面漆应用十分广泛．近年来，随着磁性材料、涂料工业等的发展，对云母氧化铁的纯度、粒度及形貌提出了更高的要求．目前云母氧化铁大多

CONDITIONS OF CRYSTALLIZATION OF MICACEOUS IRON OXIDE BY HYDROTHERMAL REACTION

The conditions of crystallization of micaceous iron oxide (MIO) were studied through the synthesis of MIO from precursor Fe(OH)₃ formed during oxidization of FeSO₄•7H₂O with H₂O₂. The experimental results showed that the concentration of NaOH as a hydrothermal medium had a strong effect on the formation, morphology, color and luster of crystal. The red iron oxide, yellow iron oxide and MIO with various types of crystal could be produced in the range of 0.019—14 mol•L^-1 of NaOH concentration with the reaction temperature equating to 433 K or above. The color of MIO crystal produced varied from reddish brown, brown to steel grey with increasing NaOH concentration.The reaction temperature also affected the formation, morphology, color and luster of crystal. There was a great difference in conversion time from precursor Fe(OH)₃ to MIO because of the changes of both NaOH concentration and reaction temperature. It was an effective method to age the crystal for a certain length of time to get more thinner MIO. The preferred technology parameters for the crystallization of MIO were as follows:a reaction temperature of 443—453 K,a NaOH concentration 12—14 mol•L^-1 and a reaction time of 250min.