摘要
通过差热-热重分析、X射线粉末衍射(XRD)及磁化率分析等手段,对天然黄铁矿样品在氮气中受热发生的矿物相变过程进行了综合研究。不同温度下黄铁矿煅烧产物的XRD物相分析结果显示,低于500℃时,黄铁矿无显著变化;随着温度的升高(500~600℃),黄铁矿开始转变为单斜磁黄铁矿,进而生成六方磁黄铁矿,磁化率显著升高;700℃~800℃的煅烧产物主要为六方磁黄铁矿,磁化率明显下降,直至900℃进一步形成更稳定的陨硫铁(Fe S),磁化率接近于零。在黄铁矿物相开始转变的温度(500~600℃)区间,黄铁矿生成单斜磁黄铁矿的速率大于单斜磁黄铁矿转化为六方磁黄铁矿的速率;高温(700~900℃)时,黄铁矿转化为单斜磁黄铁矿的速率低于单斜磁黄铁矿转化为六方磁黄铁矿的速率,表现为黄铁矿直接生成六方磁黄铁矿。
The phase transition of pyrite to monoclinic pyrrhotite and monoclinic pyrrhotite to hexagonal pyrrhotite in the nitrogen atmosphere has been investigated. The study was performed using differential thermal analysis and thermo-gravimetric analyzer(DTA-TGA), X-ray powder diffractometer(XRD) and magnetic susceptibility meter. The decomposition of pyrite begins at the temperature of about 400℃. At the temperature below 500℃, there is no phase change. As temperature increases to 500-600℃, pyrite phase begins to transform to monoclinic pyrrhotite and the transformation rate rises as the temperature rises. And the magnetic susceptibility is also higher as a result of the existence of monoclinic pyrrhotite. The rate of pyrite transformation to monoclinic pyrrhotite is higher than the rate of monoclinic pyrrhotite transformation to hexagonal pyrrhotite. With the temperature elevating, the two rates increase as well. When the temperature is higher than 600℃, hexagonal pyrrhotite, even troilite(Fe S), is the primary product. The rate of pyrite transformation to monoclinic pyrrhotite is lower than the rate of monoclinic pyrrhotite transformation to hexagonal pyrrhotite.
出处
《高校地质学报》
CAS
CSCD
北大核心
2015年第4期577-583,共7页
Geological Journal of China Universities
基金
国家自然科学基金(41402029)
关键词
黄铁矿
相变
单斜磁黄铁矿
六方磁黄铁矿
磁化率
pyrite
phase transition
monoclinic pyrrhotite
hexagonal pyrrhotite
magnetic susceptibility
