安徽嘉山坡缕石加热相变的研究

THERMAL PHASE TRANSITIONS OF PALYGORSKITE FROM JIASHAN,ANHUI

研究样品产于安徽嘉山县的第三系沉积型粘土矿层。样品经分离提纯后分别加热,对不同温度的样品进行X射线衍射和红外光谱分析,结合坡缕石的热分析资料的综合研究,证明坡缕石的热相变过程为:200℃前脱失沸石水,对晶体结构没有影响;200—400℃配位水渐次脱失,晶体发生“折叠作用”,为无水坡缕石阶段;400-500℃时大部分羟基脱失,坡缕石结构随羟基脱失逐渐瓦解;700—800℃出现短暂的玻璃相,接着在800—900℃先后重结晶为顽火辉石和方英石。在高温结晶相中未发现硅线石。

The samples under study were eollected from a sedimentary clay layer ofthe Tertiary System, Jiashan, Anhui Province. After separated and refined,the samples were heated at various temperatures. X-ray diffraction and infraredspectral analyses are given. These data, in conjunction with the thermal anal-yses (DTA, TG) of palygorskite, show that the thermal phase transitions ofpalygorskite are: At<200℃, zeolitic water is lost and the crystal structure shows no ch-ange; at 200-400℃, coordinated water is lost gradually and 'folded structure'appears (This is called the anhydropalygorskite stage.); at 400-500℃, mostof the hydroxyls are lost and the structure of palygorskite is disintegratedgradually with decreasing hydroxyl; at 700-800℃, a transient glass-phaseappears; and at 800-900℃, the recrystallized enstatite phase and cristobolite phase appear successively. In the high temperature crystal phases, no sillimanite has been observed.