Potassium (K+) phlogopite was transformed to a vermiculite-like mineral through a topotactic reaction under acidic conditions (pH 2) followed by hydrothermal treatment with Na+, Mg2+, Ca2+, and Al3+ cations. The resulting Na+-, Mg2+-, Ca2+-, and Al3+-altered phlogopites (Phl) denoted as Na-Phl, Mg-Phl, Ca-Phl, and Al-Phl, respectively. Na-Phl, Mg-Phl, and Ca-Phl all exhibited the same high adsorption capacity as natural vermiculite and the absorption of Cs+ and Sr2+ ions on these materials followed the Langmuir model. High-angle annular dark-field scanning transmission electron microscopy showed that Cs+ ions in the Mg-Phl layers were intercalated deep within the crystal structure, along specific interlayer regions. These adsorbed anhydrous Cs+ ions were firmly fixed at the centers of hexagonal rings positioned simultaneously in the upper and lower tetrahedral silicate sheets, whereas Sr2+ ions adsorb into the interlayer in the hydrous state. Al-Phl formed a hydroxyl-interlayered vermiculite and demonstra...

Uptake of Cesium and Strontium Ions by Artificially Altered Phlogopite

The effect of interlayer cations on the expansion of vermiculite

Chemical activation of vermiculite to produce highly efficient material for Pb2 + and Cd2 + removal

Continuous energy efficient exfoliation of vermiculite through microwave heating

The additive injection technology has been effective in alleviating slagging and fouling during coal combustion. In this study, experiments were conducted in a drop-tube furnace to understand the influence of vermiculite injection on ash deposition during the combustion of Zhundong coal. The interaction between coal ash and vermiculite was investigated by inductively coupled plasma optical emission spectrometry (ICP–OES), X-ray diffraction (XRD), scanning electron microscopy–energy-dispersive spectrometry (SEM–EDS). Results show that deposits formed at 1100 °C with vermiculite additive are more friable and polyporous than those without vermiculite additive, and these deposits can be easily removed. The mechanisms behind this phenomenon can be explained as follows: (1) The agglomeration of ash particles is inhibited by the partition of low-viscosity slices formed through vermiculite swelling after heat treatment. (2) Intermetallic reactions occur on the surface of vermiculite particles, resulting in the fo...

I. Rodríguez

Papers

Expansion behaviour of commercial vermiculites at 1000 °C