SiC粉体中Fe元素的赋存形态及其提纯工艺

Morphology of Fe element and the purification technology of silicon carbide powders

摘要:

为了探究SiC块体中Fe元素的赋存形态及其粉体纯化机制,分别以冶炼后SiC块体以及经气流磨破碎后的粉体为主要原料,HCl、HNO₃、H₂SO₄和HF作为酸洗剂。通过XRD、SEM和ICP等检测手段对SiC块体和酸洗前后粉体的物相组成、微观结构及Fe元素含量进行表征,重点研究微观状态下SiC中Fe元素的赋存形态及其酸洗提纯工艺。结果表明：Fe元素以Fe_xSi_y固溶体的形式赋存于SiC块体的内部,并且微观状态下呈现出被游离Si所包裹的形态；当控制液固比为5:1时,最佳酸洗的工艺参数为：HF浓度0.15 mol/L,浸出温度70 ℃,浸出时间2 h,在此工艺下Fe元素的去除率可达94.1%。

Abstract:

In order to explore the morphology of Fe element in silicon carbide (SiC) block and the purification technology of SiC powders. The SiC block and powders were used as the main raw materials, respectively. HCl, HNO₃, H₂SO₄ and HF were used as pickling agents, respectively. The phase composition, microstructures and Fe element content of SiC block and powders before and after pickling were characterized by X-ray diffraction, scanning electron microscopy and ICP, respectively. The morphology of Fe element in SiC block under microscopic state and the purification technology of SiC powders were investigated. The results indicated that Fe element existed in the form of Fe_xSi_y solid solution inside the SiC block. It could be seen that Fe element wrapped by free Si in the microscopic state. When the liquid solid ratio about 5:1, the optimum purification technology were considered as follows: The concentration of HF 0.15 mol/L, pickling temperature 70 °C and leaching time 2 h, the removal rate of Fe element could reach 94.1% under this pickling technology.