Transformation of NaCaHSiO4 to sodalite and katoite in sodium aluminate solution

• We studied the decomposition of NaCaHSiO4 in sodium aluminate solution.
• NaCaHSiO4 transformed to sodalite and katoite.
• The morphology of reaction products changed with Na2O concentration.
• Temperature significantly affected the NaCaHSiO4 decomposition.
• Al2O3 concentration significantly affected the NaCaHSiO4 decomposition.

The decomposition of NaCaHSiO4 in sodium aluminate solution was investigated. NaCaHSiO4 transformed to sodalite and katoite during decomposition. Parameters, such as Na2O concentration, reaction time, temperature and Al2O3 concentration, had a significant influence on the NaCaHSiO4 decomposition. The optimal Na2O concentration and reaction time for the NaCaHSiO4 decomposition were 150 g/L and 105 min, respectively. The extent of NaCaHSiO4 decomposition largely depended on Al2O3 concentration in sodium aluminate solution. Reaction products were composed of thin flakes with a loose structure at 50 g/L of Na2O concentration, and were agglomerates with a compact surface composed of tabular and rod crystals at 150 g/L of Na2O concentration.