铵伊利石的高温相变  

Phase Transition of Ammonium Illite at High Temperature

作　　者：吴红丹[1,2] 于吉顺[2] 张锦化[1,2] 雷新荣[1] 

机构地区：[1]中国地质大学(武汉),教育部纳米矿物材料及应用工程研究中心,武汉430074 [2]地质过程与矿产资源国家重点实验室,武汉430074

出　　处：《硅酸盐学报》2011年第4期635-640,共6页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(40972003,90714010)资助项目;中国地质大学(武汉)地质过程与矿产资源国家重点实验室赵来时教授提供的基金资助和支持

摘　　要：对山西阳泉煤层黏土煤矸石中的铵伊利石进行了Fourier变换红外光谱分析、电子探针分析、元素分析、热重-差热分析和高温衍射分析。根据化学成分结果,按O_(10)(OH)_2及四面体阳离子数之和为4计算得其晶体化学式为:[(NH_4)_(0.65)K_(0.02)Na_(0.03)Ca_(0.01)]_(0.71)[Al_(2.04)Mg_(0.01)]_(2.05)[(Si_(3.14)Ti_(0.02)Al_(0.84))_4O_(10)](OH)_2。铵伊利石的晶体结构具有较好的热稳定性,晶体结构随温度的变化分为3个阶段:400℃以前结构保持稳定,层间[NH_4]^+表现为缓慢释放的特征;400～900℃层间[NH_4]^+分解,N快速释放,同时伴随着羟基脱除,表现为层间距缩小直至层状结构垮塌,但TOT结构单元层仍保持一定的完整性,[NH_4]^+分解的精确温度为573℃;900～1300℃为相变阶段,铵伊利石保留的不完整结构向非晶质转变,最后重新结晶生成莫来石和高温方石英。An ammonium illite sample,which was a gangue from Yangquan coal mine in Shanxi province,was investigated by Fourier transform infrared spectroscopy,electronic probe microscopic analyzer,element analyzer,thermogravimetric differential scanning calorimetry and high temperature X-ray diffraction.According to the chemical composition of the sample,the crystallographical formula calculated based on O_（10）（OH）_2 and at the total tetrahedral cations of 4 is[（NH_4）_（0.65）K_（0.02）Na_（0.03）Ca_（0.01）]_（0.71）[Al_（2.04）Mg_（0.01）]_（2.05）[（Si_（3.14）Ti_（0.02）·Al_（0.84））_4O_（10）]（OH）_2.The structure of ammonium illite had a good thermal stability.There are three stages for the evolution of the crystal structure with temperature.In the first stage,the structure is stable,and N from the interlayer of NH_4-illite is released below 400℃. In the second stage,the layer thickness is reduced until the layered structure is collapsed and the TOT silicate framework can be kept in the range of 400 to 900℃mainly due to the fast decomposition of[NH_4]~＋ and de-hydroxylation.In the third stage,the semi-crystalline structure is transformed to amorphous in the range of 900 to 1 300℃,and the sample is re-crystallized to mullite and cristobalite.

关 键 词：铵伊利石 晶体结构 层间铵离子 高温X射线衍射 

分 类 号：P575.5[天文地球—矿物学]