Investigation of States of Water in Hydrous Minerals

为了弄清含水矿物中水的状态，研制了平衡水蒸气压测量(TDEP)、绝热气体吸附量热计(AGA)和绝热微量热计(AMC)三种仪器。TDEP配备了MKS Baratron 127A高进动数字压力计，对Mizota等人最初开发的仪器进行了改进。(1989年)。AGA和AMC均由微型计算机控制，用于测量和数据处理。所采用的热敏温度计的温度精度为0.0001K。高精度。能够以相对较少的样品量(0.11g)准确地测定水化能。测定了几种天然沸石和合成沸石的水化能。例如，在45ﾟ℃左右，分子筛5A沸石的构型熵为50JK^~(-1)~(-1)~(Gt)，与绝热热容计测得的绝对零凯尔文数据相当。用AGA法得到的沸石的水化热为-55kJ/mol(H20)，这与水的蒸发热(约44kJ/mol)和AMC的水化热之和是一致的。这表明，通过这三种方法得到的热值是相互核对的。剩下的一个问题将是改进更准确地确定三种仪器中每一种的脱水水量的方法。TDEP是一种适合于定量研究水分子状态的方法，因为水的微分吸附热和构型熵都可以在水化物质的水化水平和温度下测量。

To clarify states of water in hydrous minerals, three instruments have been made and developed during this work, suchas equipment for temperature dependence of equilibrium water vapor pressure measurement (TDEP), adiabatic gas adsorption calorimeter (AGA) and adiabatic micro-calorimeter (AMC). TDEP was equipped with high precession digital manometer (MKS Baratron 127A) by improving the instrument initially developed by Mizota et al. (1989). Both AGA and AMC are controlled by a microcomputer for measurements and for data processing. The thermister-thermometer adopted for them has the temperature precision of 0.0001K. The high precision. enables accurate determination of hydration energy with relatively small amount of sample (0.11g). Hydration energies were measured for several natural zeolites and synthetic zeolites. Configurational entropy of molecular sieve 5A zeolite was obtained, for example, to be 50JK^<-1>mol^<-1> at around 45ﾟC, the value of which is comparable with those obtained by adiabatic heat capacity calorimeter from absolute zero-kelvine. Hydration enthalpy of these zeolites obtained from AGA method were -55kJ/mol(H20) which is consistently explained as a total of the heat of evaporation of water (about 44kJ/mol) and the hydration heat obtained from AMC. This indicates that enthalpy values derived through these three methods were cross-checked with each other. A remaining problem will be to improve the method of determining more accurately the dehydration amount of water for each of three instruments. TDEP is a suitable method for investigating, states of water molecules quantitatively, because both of the differential heat of adsorption of water and the configurational entropy can be measured at a temperature and at a hydration level of a hydrated material.