水热法合成FeS2粉晶及其生长热动力学的研究

采用溶胶_凝胶水热法合成了单相黄铁矿结构的FeS2₂粉晶. 用x射线衍射、傅 氏变换红外光谱等分析手段对FeS2₂粉晶进行了表征，以简化的数学模型及相 变理论讨论了晶体 生长过程. 结果表明：FeS2₂晶粒的生长过程属于相变与扩散的混合机制，符 合经时间 指数修正的二次方动力学方程，是一个生长速率随时间变化的过程；水热晶化温度高于453 K、反应时间超过18 h且有适量的硫参与反应时，可得到单相的黄铁矿型的FeS2₂关键词： 溶胶_凝胶水热法 2粉晶')" href="#">FeS2₂粉晶 晶粒生长 热动力学

Hydrothermal synthesis of iron pyrite (FeS22) crystalpowder and the rmal-kinetic study on crystal growth

Single-phase iron pyrite (FeS 2 ) crystalpowder was prepared by sol-gel hydrothermal method, which was characterized via x-ray diffraction, Fourier transform infrared and scanning electron microscope. A simplified mathematic model was established to analyze the crystal growth process. Results indicate that phase transformation and diffusion mechanism control the process, which fits the second-order kinetic equation with an exponent 3.215 for time t. This is a decelerated process that can be divided into three steps: during the first period, marcasite and pyrite phases are produced, and then with inducting of sulfur into the reaction, the process is dominated by the merging of marcasite into pyrite. Ultimately, with the fuse of small grains and the growing of larger ones, single-phase iron pyrite crystals grow up through diffusion mechanism.