铵伊利石矿物热稳定性研究

Study on the Thermal Stability of Ammonium Illite

通过室内对含铵伊利石粘土岩样品加热处理，利用DTA、XRD、FTIR、氮元素分析等方法研究了铵伊利石的热稳定性，发现铵伊利石矿物中的氮含量随温度的升高而逐渐降低。铵伊利石矿物晶格结构在500℃之前，具有稳定性，层间的N表现为缓慢释放的特征。在500—600℃温度区间，层间N的释放速率加剧。600℃开始向半晶质化方向发展，700℃以上晶格结构破坏，层间NH4^＋消失。加热到700～800℃高温相中，仍残留有0．3％-0．5％的氮，这表明矿物中的N在高温下通过与Si、Al和O原子化学结合，仍具有比较高的相对稳定性。本研究对于认识地球系统幔源物质演化、运移、分异、脾气作用和氮循环等具有重要理论意义。

The thermal stability of ammonium illite was investigated by heating treatment of NH4-bearing illite samples based on the DTA, XRD, FTIR and N element analysis. The research showed that the contents of N in the samples decreased steadily with the rise of temperature. The structure of ammonium illite kept stable with the gradual slow release of N from the interlayer of NH4-illite under the temperature of 500℃. But the release rate of N increased sharply when the samples were heated up to 500 - 600℃ and the minerals began to be transformed to become semi-crystalline at 600℃. The ions of NH4^＋ in the interlayer of illite disappeared above 700℃, but 0. 3 -0. 5% nitrogen still remained in the high temperature phases （ 700 -800℃ ）, which suggested that N still possesses a relative stability under high temperature by being chemically bonded with other elements, such as Si, Al and O. This study is of great significance in recognizing the mantle material evolution, transport, separation, degassing and nitrogen cycle in the Earth system.