Based on the mass balance principle, mineral contents of the bentonites from Yangxian of Shaanxi province, Queshan of Henan province, and Chifeng of the Inner Mongolia Autonomous Region were estimated by resolving the Phase Mixing Equation constructed from the data of X-ray diffraction, microprobe analysis of montmorillonite grains, and chemical anaysis of the bentonites. The crystal formulas of montmorillonite in the bentonites were calculated based on the anion hydrogen equivalent method. The cell lattice constants of the principal minerals in the bentonites were calculated with a FORTRAN90 program CELLSR. When compared with both methods of the methylene blue absorption and XRD Rietveld quantitative phase analysis, the Phase Mixing Equation was confirmed to be the most effective modal analysis method for determing content of montmorillonite in bentonites with several minerals coexisted.

The morphology and particle size of boehmite play a decisive role on the application of alumina that derived from it. In this paper, we employed pseudoboehmite that produced from Al2 (SO4)3•18H2O and NH3•H2O at 70 °C, pH 7.5 as precursor to synthesize boehmite, and utilized different seeding when preparing pseudoboehmite and boehmite. To identify the influence of seeding on the microstructure of pseudoboehmite and boehmite, the products were characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and BET. The results indicate that the pseudoboehmite seeding has a significant influence on the morphology and particle size of pseudoboehmite to which we should pay high attention. However, the boehmite seeding does not play the role of crystal nucleus as expected. The further intrinsic mechanism study is ongoing.