α→γ→β-phase transformation of spodumene with hybrid microwave and conventional furnaces

Spodumene: The Lithium Market, Resources and Processes

“…The third phase is less known and has several different names. It is referred to as virgilite, γ-spodumene or spodumene-III [37,38]. It has a hexagonal structure and a density of 2.399 g•cm −3 .…”

“…The crystal lattice expands massively (27%) during the phase transition [44]. The γ-spodumene is known to appear before the β-spodumene [37] but is metastable and transitions to β-spodumene at higher temperatures.…”

Influence of interlayer species on the thermal characteristics of montmorillonite

“…S1c). This was quite different from the case of Ca-Mt, probably because Li + located in Mt layers could directly interact with β-quartz solid solution, transforming to the stable β-spodumene at 1100°C (Mandal et al, 2004;Peltosaari et al, 2015). As such, the migration of Li + into Mt layers could not only lower the phase-transition temperature of Mt (e.g., the presence of cristobalite at 900°C instead of at 1100°C), but also greatly affect the final products (e.g., the presence of β-spodumene and absence of mullite).…”

Microwave enhanced roasting for pyrite ore samples with dielectric properties strongly dependent on temperature

“…The effect is a reduced difficulty for grinding minerals by traditional means (e.g. a mill) and an increased capacity for absorbing leaching reagents, hence improving the recovery rate of the mineral [10], [20], [21]. Amaya et al have previously obtained experimental results regarding microwave processing of Gold ores [22].…”

“…They showed that within the microwave furnace, phase transformation of spodumene began after 110 s of heating, and samples were converted almost completely to β-spodumene after 170 s. They observed that the grain size did not affect significantly the conversion rate, and stated that heating in microwave furnace for 170 s corresponded with the heating of approximately 480-600 s at temperature of 1100 °C in the conventional furnace. Also, Peltosaari and coworkers validated the conversion of spodumene samples with X-ray diffraction (XRD) and with field emission scanning electron microscope (FESEM) [10].…”