中文摘要：

采用水热碱法制得纯相六方钾霞石（KAlSiO_4）,在H_2SO_4-H_2O溶液中破坏其晶体结构,K_2O溶出率达99.8%,固相产物Si/Al摩尔比≈1,用作合成高岭石（Al_2[Si_2O_5]（OH）_4）的前驱体。采用OLIAnalyzer 9.2软件对Al_2O_3·2SiO_2·nH_2O-HCl-H_2O体系进行化学平衡计算,预测了水热法合成高岭石的初始HCl浓度、水/固质量比和晶化温度范围,以及平衡固相中高岭石的含量（〉98%）。在此基础上通过单因素实验,确定了水热合成高岭石的优化条件和晶化历程。典型合成产物接近纯相纳米高岭石（~91.8%）,结构高度有序,1Tc多型;晶体形态呈似六方片状,片径400-500 nm,厚度约20 nm。高岭石的晶化反应历程确定为：铝硅前驱体→板状勃姆石→板状勃姆石＋片状高岭石→似六方片状高岭石。

英文摘要：

Nearly pure kalsilite （KA1SiO4） was synthesized via hydrothermally treatment of K-feldspar powder with alkaline solution, and an aluminosilicate precursor with a Si/Al molar ratio close to 1.0 for synthesizing kaolinite （AI2[Si2Os]（OH）4） was obtained by destroying the structure of kalsilite in HESO4-H20 solution with a K20 solubility of 99.8%. The chemical equilibrium in the system of Al_2O_3·2SiO_2·nH_2O-HCl-H_2Owas simulated by OLI Analyzer 9.2 thermodynamical software, predicting the ranges of initial concentration of HC1, water to solid matter ratio and crystallization temperature, in which the equilibrated solid phase is kaolinite with a proportion of 〉 98%. The optimal conditions and crystallization process of hydrothermally synthesis of kaolinite were determined via the single factor experiments at the predicted parameters. The typical as-synthesized product is nearly single phase nano-sized kaolinite with a purity of 91.8%, highly ordered structure, 1Tc polymorph, and sub-hexagonal flake-shape with the diameter of 400-500 nm and the thickness of 20 nm. The crystallization process of kaolinite from the aluminosilicate precursor is aluminosilicate precursor --〉 platy-shaped boehmite--〉 platy-shaped boehmite ＋ flake-shaped kaolinite --~ sub-hexagonal flake-shaped kaolinite.