High lithium content silicates: A comparative study between four routes of synthesis

Development of sodium/lithium/fly ash sorbents for high temperature post-combustion CO 2 capture

“…This method was used because compared to other synthesis methods (e.g. spray drying and reflux) produces a single and highly crystalline orthosilicate phase, minimising the metasilicate phase (Li 2 SiO 3 ) [24]. The nucleation of lithium orthosilicate occurs at temperature between 425°C and 465°C [24].…”

“…spray drying and reflux) produces a single and highly crystalline orthosilicate phase, minimising the metasilicate phase (Li 2 SiO 3 ) [24]. The nucleation of lithium orthosilicate occurs at temperature between 425°C and 465°C [24]. After calcination, the materials were homogenised using a Mortar Grinder (Pulverisette 2, Fritsch) for 1 min to eliminate any potential agglomeration.…”

“…The isolated SiO 4 tetrahedra presents a strong absorption band around 900 cm À1 caused by the Si-O asymmetric stretching vibration, while the absorption band near 800 cm À1 is due to the Si-O holo-symmetric one [31]. The vibration due to the SiO 4 structure is a triply degenerative splitting in three vibrations in the case of [24]. Bands at 1080, 740 and 847 cm À1 are attributed to the SiO bond stretching in the silica tetrahedra, while the bands at 600 and 580 cm À1 are related to the bending vibrations [24,32].…”

“…The crystalline lithium ortho-silicate is built up of an isolated SiO 4 tetrahedron connected to LiO-polyhedra. The band in the range of 1400-1500 cm À1 is linked to Li 2 CO 3 and Na 2 CO 3 present in the material [24]. The isolated SiO 4 tetrahedra presents a strong absorption band around 900 cm À1 caused by the Si-O asymmetric stretching vibration, while the absorption band near 800 cm À1 is due to the Si-O holo-symmetric one [31].…”

“…Global production of lithium containing minerals was about 37,000 tonnes of contained lithium metal in 2012 [23]. Lithium silicate as such is not mined and is typically synthetised following the reactions presented below [24]:…”