Research Article
Synthesis of Analcime Crystals and Simultaneous Potassium Extraction from Natrolite Syenite
Table 2
The phase composition of as-prepared product and the extraction rates of potassium under different concentrations of NaOH solution.
| | Samples | Experiment conditions | Results | | (mol/L) | T
(°C) | t
(h) | Solid product phase composition | Si/Al ratio | ηK2O
(%) |
| | SM-0 | Soda roasting at 830°C for 2 h | Sodium silicate | Na2SiO3 | 2.4 | — | Sodium alumina silicate
Al2Si2O9 |
| | SM-1 | 0.0 | 175 | 4 | Phillipsite-Na | Na4KAl5Si11O32·10H2O | 2.1 | 54.6 | | SM-2 | 0.5 | 175 | 4 | Analcime | NaAlSi2O6·H2O | 2.0 | 92.6 | | SM-3 | 1.0 | 175 | 4 | Sodalite | Na8Al6Si6O24(OH)2·2H2O | 1.0 | 86.5 | | SM-4 | 1.5 | 175 | 4 | Sodalite | Na8Al6Si6O24(OH)2·2H2O | 1.0 | 86.4 | | SM-5 | 2.0 | 175 | 4 | Sodalite | Na8Al6Si6O24(OH)2·2H2O | 1.0 | 86.0 | | SM-6 | 2.5 | 175 | 4 | Sodalite | Na8Al6Si6O24(OH)2·2H2O | 1.0 | 85.9 |
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