Mechanical Activation of Pyrophyllite and Preparation of Porous Silica
Structural alteration of pyrophyllite during mechanical activation in a planetary mill was investigated by X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques.Mechanochemical effect markedly promotes the decrease in reflection intensities with increasing the grinding time. Prolonged grinding causes the pyrophyllite to become the amorphous structure.It can be indicated that pyrophyllite is very susceptible to alteration by grinding. Crystal size (d006) of pyrophyllite appears to be a limit after 2h grinding. R spectroscopy analysis shows a little alteration in the bands of pyrophyllite after mechanical activation. The results indicate that the ordered structure of pyrophyllite is destroyed and lattice deformation occurs.Porous silica was then successfully prepared via leaching the mechanically activated pyrophyllite.Pyrophyllite was first ground for 6 h. Ground samples were subsequently leached with 4 M hydrochloric acid at 80 ℃ for 2 h to produce porous silica with specific surface area of 188.1 m2/g, total pore volume of 0.18 mL/g and average pore size of 3.9 nm from N2 adsorption analysis.Otherwise, the porous silica obtained from direct leaching of the original pyrophyllite only has a specific surface area of 4.3 m2/g and total pore volume of 0.03 mL/g. It is inferred that grinding is favorable for the formation of microstructure pores. It offers a simple and convenient route for the preparation of porous materials from natural minerals.
Mineral materials Pyrophyllite Mechanical activation Porous silica
H. M. Yang C. F. Du
Department of Inorganic Materials, School of Resources Processing and Bioengineering,Central South University, Changsha, China
国际会议
XXIV International Mineral Processing Congress(第24届国际矿物加工大会)
北京
英文
3241-3245
2008-09-24（万方平台首次上网日期，不代表论文的发表时间）