The Hydrothermal Synthesis of Petalite Mineral Phases and their Morphological Changing by Increasing of Temperature

In this investigation the Petalite minerals were synthesized hydrothermally at different temperatures from a glass with the composition Li 2 CO 3 :Al 2 O 3 : SiO 2 and the relation 1: 1: 8. On that occasion the following mineral phases arised:at low temperatures (410°C) α‐petalite (unit cell å = 11.737 Å/b̊ = 5.17 Å/c̊ = 7.63 Å, space group P 2 /a); At 490 °C α‐petalite was splitted to quartz and an orthorhombic β 1 ‐petalite (unit cell å = 18.24 Å/c̊ = 10.54 Å/c̊ = 10.57 Å, space group P m C n ). β 1 ‐petalite could be observated until 1000 °C. at 560 °C tetragonal β 2 ‐petalite (unit cell å = 7.50 Å/c̊ = 9.07 Å, space group P 4 3 2 1 2) in parallel with β 1 ‐petalite; Behind 750 °C β 2 ‐petalite was not observed. Behind 900 °C a pseudohexagonal mineral phase developed from β 1 ‐petalite. May be it is possible to indicate this phase as hexagonal (unit cell å = 5.217 Å/c̊ = 5.464 Å, space group P 6 2 22 or P 6 4 22). The author suggests to denote this phase as β 3 ‐petalite.