Research on NaCaHSiO4 decomposition in sodium hydroxide solution

The decomposition of NaCaHSiO4 is an important step in the hydro-chemical process to recover sodium when treating red mud. In this study, the phase transformation during the NaCaHSiO4 decomposition and the key influential factors, including sodium concentration, reaction temperature, CaO addition and particle size were investigated. In addition, the sodium content in the residue, where NaCaHSiO4 had completely exhausted, was also studied. Finally, the kinetic data were fitted by the Avrami–Erofeev equation and the activation energy of the reaction was calculated.

Research highlights
► Researched the phases produced during NaCaHSiO4 decomposition in different conditions;
► analyzed the factors such as sodium concentration, reaction time, CaO dosage and particle size which influenced NaCaHSiO4 decomposition;
► investigated the sodium content in the final residues of decomposed NaCaHSiO4 in different conditions;
► studied the kinetics of NaCaHSiO4 decomposition.