Effects of Oxalic Acid Addition on the Hydrothermal Synthesis of Kaolinite

来源期刊：中南大学学报(英文版)2000年第1期

论文作者：LIU Su-qin HUANG Ke-long

文章页码：34 - 36

Key words：kaolinite; hydrothermal synthesis; oxalic acid

Abstract: Kaolinite was hydrothermally synthesized from alumina gel and silicate by dissolving alumina gel in oxalic acid before it was mixedwith silicate, effects of the amount of addition on the species of synthetic productswere discussed. The reaction product was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that analcite is the only phase of the reaction solutionwithout oxalic acid, the proportion of kaolinite in product increaseswith the amount of addition, and kaolinite is the main specieswhen the molar ratio of oxalic acid to alumina reaches 0.6∶1.0. This is because oxalic acid addition is beneficial to the formation of kaolinite through changing the coordination number of aluminium from four to six, while the mixture of alumina gel, before it was dissolved in oxalic acid with silicate interfered with the crystallization of kaolinite.