Using a hydroferite desilication reagent, calcium hydroferrocarbonate (CHFC), the desilication reaction in concentrated caustic aluminate solution was studied. The results indicated that process parameters, such as temperature, Na2O concentration, molar ratio of Na2O to Al2O3, and initial mass ratio of alumina to silica (mass ratio of alumina to silica), significantly affected the reaction efficiency. The reaction kinetics were found to exhibit a reaction order of 1.3 ± 0.15 for desilication; the empirical rate constant k was 64.4 ± 2.4 and the apparent activation energy Ea was 25.8 ± 3.2 kJ/Mol, which was much lower than the values obtained by adding Ca(OH)2, C3AH6(calcium Hydroaluminate, 3CaO·A12O3·CaCl2·6H2O), and Friedel's salt (3CaO·A12O3·CaCl2·10H2O). In the desilication process, silica reacts with CHFC on the surface to form hydroandradite and calcium aluminum iron hydroxide. Subsequently, with an increase in Na2O concentration and temperature, hydroandradite and calcium aluminum iron hydroxide dehydrated to form calcium aluminum iron silicate and Fe(OH)3