升温速率对粘土矿物热效应特征的影响——以四川三台钙基膨润土为例  

STUDY ON THE THERMAL EFFECT OF CLAY MINERALS UNDER DIFFERENT HEATING RATE——TAKING THE BENTONITE FROM SANTAI,SICHUAN,AS AN EXAMPLE

作　　者：张湘辉[1,2] 汪灵[1,2] 邓苗[1] 冯谦 

机构地区：[1]成都理工大学材料与化学化工学院,四川成都610059 [2]成都理工大学金刚石薄膜实验室,四川成都610059 [3]耐驰科学仪器商贸有限公司成都分公司,四川成都610017

出　　处：《矿物岩石》2010年第2期1-6,共6页Mineralogy and Petrology

基　　金：国家自然科学基金(50974025;40572030);四川省应用基础研究基金(07JY029-029)

摘　　要：以四川三台钙基膨润土为例,采用热重（TG/DTG）、差示扫描量热（DSC/DDSC）同步热分析技术系统研究升温速率对粘土矿物加热过程中热效应特征的影响。根据实验结果,可将三台钙基膨润土的热分解过程可分为表面吸附水（114.1℃左右）和层间水（约181.9℃）失去,羟基的脱出（约651℃）,蒙脱石晶体结构破坏（876.8℃）等3个阶段。证明升温速率对TG,DTG,DSC,DDSC等曲线热效应特征均有显著影响：（1）热失重（TG）是一种相对热失重,其结果与升温速率成反比,升温速率越慢,热失重越逼近绝对值,升温速率越快,热失重率越小。（2）加热温度≤400℃时,DTG,DSC曲线的分辨率与升温速率成反比,低升温速率有利于粘土矿物脱水反应类型的辨别;在400℃~900℃时,DTG,DSC的分辨率与升温速率成正比,提高升温速率有利于粘土矿物脱羟基反应的分辩。（3）加热温度≤400℃时,与TG,DTG,DSC等曲线相比,DDSC曲线中对粘土矿物脱水反应的分辨率最高;在400℃~1 100℃时,升温速率对粘土矿物脱羟、相变反应中DDSC曲线热效应特征的影响较为复杂。Ca-bentonite from Santai,Shichuan Province was used to study the thermal effect of clay minerals under different heating rates by thermogravimetry analysis（TG/DTG） and differential scanning calorimetry（DSC/DDSC）.Curves from TG,DTG and DSC analyses showed that the sample decomposition consists of four stages,and represents the evolution stage of adsorbed（about 114.1 ℃） and cation-coordinated water（about 181.9 ℃）,dehydroxylation stage（about 651 ℃）,destroyed stage of crystal structure in montmorillonite（about 876.8 ℃）,respectively.It demonstrated that the heating rate had a strong influence on the thermal effect of clay mineral as following：（1）Thermogravimetry analysis showed a relative mass change and the result was inversely proportional with the heating rate.With increase of the heating rate,the mass losses were more close to the absolute value,while the mass loss rate was the smaller.（2）When heating temperature is beyond 400 ℃,the resolution of the sample DTG,DSC curves was inversely proportional with the heating rate.The low heating rate was in favor of analysis of dehydration reaction of clay mineral.Between 400 ℃ and 900 ℃,the resolution of the sample DTG,DSC curves was proportional to the heating rate,and improving the heating rate was benefit to distinguish the dehydroxylation reaction.（3）Beyond 400 ℃,the resolution of dehydration reaction of clay mineral was the highest.At the temperature range of 400 ℃～1 100 ℃,the effect of the heating rates to the dehydroxylation and phase reaction of clay mineral sample was very complex.

关 键 词：热效应特征 矿物热分析 粘土矿物 钙基膨润土 升温速率 

分 类 号：P619.255[天文地球—矿床学]