The study of weathering alteration of phyllosilicate minerals is of great significance for understanding the chemical cycle of the earth surface, soil formation and environmental changes. A phlogopite from Xinjiang, China was used as a raw material to control the oxidation environment, pH value, ion species and concentration of sulfuric acid solution in the process of phlogopite vermiculization. The phase, composition release law, spectroscopic properties and thermal properties were characterized by X-ray diffraction, inductive coupled plasma emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetry-differential scanning calorimetry, respectively. The results show that the degree of vermiculite increases with the increase of Mg²⁺ ions concentration in the solution, but the less conversion effect exists at a certain H₂O₂ content in the solution. The conversion effect can be enhanced after the use of sulfuric acid to adjust the solution pH value, because the acidic environment can improve the oxidation capacity of hydrogen peroxide and the increase of SO₄^2– ions concentration. The more jarosite substances are formed, thus accelerating the process of vermiculization.

A series of expanded vermiculites with a high expansion ratio were prepared with a vermiculite from Xinjiang, China as raw material by an intercalation microwave method and an intercalation calcination method, respectively. The phase composition and morphology of the products were characterized by X-ray diffraction and scanning electron microscopy, and the cation exchange capacity and methylene blue (MB) adsorption capacity of the expanded vermiculite prepared by the two different methods were analyzed. The results show that there is a significant difference in the expansion ratios of expanded vermiculite prepared by the two methods, and the expansion ratio of calcined expanded vermiculite (BCV) is 0.4 times greater than that of microwave expanded vermiculite (WCV). For adsorption in a methylene blue solution with a concentration of 300 mg/L, the calcined expanded vermiculite has a poor adsorption capacity for MB, while the microwave expanded vermiculite has a good adsorption performance for MB due to its higher cation exchange capacity with an adsorption capacity of 391.26 mg/g.