Micaceous iron oxide (MIO) with a hexagonal flaky shape was prepared by hydrothermal method. The ferric hydroxide used as precursor was obtained by an acidic leaching solution of pyrite cinders reacting with ammonia...Micaceous iron oxide (MIO) with a hexagonal flaky shape was prepared by hydrothermal method. The ferric hydroxide used as precursor was obtained by an acidic leaching solution of pyrite cinders reacting with ammonia solution. The optimal experimental conditions for preparing micaceous iron oxide were investigated by orthogonal experiments. Micaceous iron oxide can be successfully prepared when optimal parameters of total iron concentration of 2.0 mol/L, pH value of 8, n(Fe2+)/n(Fe3+) of 0.1, mass of seed crystal of 1 g, reaction temperature of 260 ℃ and reaction time of 30 min are applied. X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected area electron diffractometry (SAEM) were adopted to characterize the hydrothermal products prepared under optimal conditions. The results indicate that highly crystallized α-Fe2O3 hexagonal flakes, about 1.0-1.5 μm in diameter and 0.1 μm in thickness, are prepared. Furthermore, the quality of micaceous iron oxide prepared can meet the required characteristics of micaceous iron oxide pigments for paints (ISO 10601--2007).展开更多
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 sho...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 250 min.展开更多
基金Project(2008A090300016) supported by Major Science & Technology Special Program of Guangdong Province,China
文摘Micaceous iron oxide (MIO) with a hexagonal flaky shape was prepared by hydrothermal method. The ferric hydroxide used as precursor was obtained by an acidic leaching solution of pyrite cinders reacting with ammonia solution. The optimal experimental conditions for preparing micaceous iron oxide were investigated by orthogonal experiments. Micaceous iron oxide can be successfully prepared when optimal parameters of total iron concentration of 2.0 mol/L, pH value of 8, n(Fe2+)/n(Fe3+) of 0.1, mass of seed crystal of 1 g, reaction temperature of 260 ℃ and reaction time of 30 min are applied. X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected area electron diffractometry (SAEM) were adopted to characterize the hydrothermal products prepared under optimal conditions. The results indicate that highly crystallized α-Fe2O3 hexagonal flakes, about 1.0-1.5 μm in diameter and 0.1 μm in thickness, are prepared. Furthermore, the quality of micaceous iron oxide prepared can meet the required characteristics of micaceous iron oxide pigments for paints (ISO 10601--2007).
文摘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 250 min.