Effects of Grinding on Hydrothermal Alternation of Tosudite Clay Mineral

Abstract

Li-bearing tosudite has a regularly interstratified structure consisting of chlorite and smectite layers. Hydrothermal treatment of unground and ground Li-tosudite was carried out under 150°C to 250°C in a distilled water and various concentrations of NaOH solutions, and the reacted products were examined by XRD, ethylene gricol treatment and methylene blue absorption capacity.
The final reacted products obtained from the both of unground and ground Li-tosudite were mainly analcime, and swelled Li-tosudite was also formed as a by-product. The formation temperature of analcime using ground Li-tosudite was low compared with that using unground Li-tosudite, and its temperature was also related to concentration of NaOH solution. The analcime formation temperature become low with increasing NaOH concentration in the both cases of unground and ground Li-tosudite.
Heterogeneous substitution of interlayer cation (Na⁺) was considered to be occurred on the basis of different features of XRD profile after ethylene gricol treatment and under various relative humidity states.
The interlayer structure of Li-tosudite was altered into complex interlayer structure of swelled Li-tosudite, and analcime was readily obtained as a final product from the unground Li-tosudite compared with the ground Li-tosudite. These facts suggest that the reacted products of hydrothermal treatment reflect an original crystal structure of the starting material.