西藏班戈湖水菱镁的矿热分解特性

Thermal Decomposition Characteristics of Hydromagnesite From Bangor Lake in Tibet

采用热重–差示扫描量热法、热重–质谱分析、原位X射线衍射等手段对西藏班戈湖地区水菱镁矿的热分解过程、气体产物、固体产物进行研究,并对热分解机理进行分析。结果表明:水菱镁矿主要在150~650℃温度区间内发生总吸热量约为889.8 J/g多段分解反应,在350℃前脱去结晶水,生成含碳酸根的非晶态镁化合物,随后脱去结构水,并在350~550℃内脱去碳酸根释放出CO_2生成方镁石;水菱镁矿在不同温度区间产生的H_2O和CO_2逸出峰,可能与晶体结构中存在的复杂氢键系统及不同的碳酸根结构有关。

Thermal decomposition process and properties of the gas and solid products of the hydromagnesite from Bangko Co area in Tibet were investigated by thermogravimetry-differential scanning calorimetry, thermogravimetry-mass spectrometry and in-situ X-ray diffraction, respectively. In addition, the thermal decomposition mechanism of hydromagnesite was discussed. The results indicate that the hydromagnesite occurs multiple endothermic decomposition reactions at 150-650 ℃ with a heat absorption capacity of 889.8 J/g. The crystal water is dehydrated before 350 ℃ with the generation of amorphous carbonic magnesium compounds. The structural water is lost gradually after 350 ℃ and CO2 is decarburized at 350-550 ℃, forming periklase. It is also indicated that the releases of H2O and CO2 at different temperatures should be attributed to the complicated H-bonds and different carbonate structures in the crystal structure of hydromagnesite.