高岭石-多水高岭石演化系列的热谱特征

高岭石-多水高岭石演化系列共包括四种矿物:结晶良好的高岭石、结晶差的或b轴无序的高岭石、7Å多水高岭石和10Å多水高岭石。我们将结晶良好的高岭石和10Å多水高岭石分别视为这一演化系列的两个端元矿物,其余两种矿物则是演化系列的中间矿物。该系列中的矿物同属于1:1型含水的层状铝硅酸盐矿物,因而它们的化学成分基本相同,主要差别是在晶体结构上由于单位结构层沿c轴彼此堆叠的方式而引起从有序向无序变化,同时层间键力的减弱引起水分子进入,促使层间水的含量逐渐增大。基于以上特征,这一系列中的四种类型矿物受热以后的热效应很灵敏,详细研究它们在加热脱水过程中的变化规律,可以加深对矿物特性的认识和鉴别。

ON THE THERMAL SPECTRA FEATURES OF THE KAOLINITE-HALLOYSITE EVOLUTION SERIES

The kaolinite-halloysite evolution series consists of four minerals: well-crystallizing kaolinite, poorly crystallizing kaolinite or disordering kaolinite, 7Å halloysite and 10Å halloysite. They are characterized by similar chemical composition and crystal structures, but the differences between them are the presence and content of the interlayer water. Thus, thermal reaction is highly sensitive on these four minerals, and the features of their thermal spectra are discussed in the paper.The well-crystallizing kaolinite and 10Å halloysite are considered to be the minerals of both ends in this evolution series. From the well-crystallizing kaolinite to 10Å halloysite, the crystal structures evolve from order to disorder, with the change of contents of interlayer water, the DTA curves and TGA curves of this series minerals show some regular change.The thermal reaction of these four minerals are mainly influenced by the mineral content, crystallinity, grain size, heating speed etc. In this paper, the various factors effecting the thermal reaction are discussed with some examples.Usually, kaolin consistes of kaolinite, 7Å halloysite and 10Å halloysite, associated with montmorillonite, alumstone and gibbsite, etc. Various standard thermal analysis curves of nature and artifical mixture of the kaolinite-halloysite and the kaolinite-mon-tmorillonite, from results of experiments are obtained. At the same time, the content of kaoline minerals and impurities are calculated attemptably from thermal analysis data.