Structural Investigation of Some Important Chinese Diatomites

摘要

The structure of some important diatomites has been investigated systematically. It has been revealed that the Zhejiang white soil contains bound, isolated, and neighboring hydroxyl groups and that other diatomites involve hydroxyl groups of two types, i.e., isolated and neighboring hydroxyl groups. The IR spectra exhibit bands associated with the Si-O and Al-0 bonds. The acid treatment and calcination lead to a change in the size, size distribution, and structure of pores. The calcination results in a change in the diatomite structure, the removal of free water, and a decrease in the content of bound water. Upon calcination at a temperature of 1150°C, amorphous silica constituting the diatomite crystallizes into α-cristobalite. The Jilin diatomite has primary pores, the Yunnan diatomite has tertiary pores, and the other diatomites have secondary pores.