The solubilities of sodium p-toluenesulfonate (NaPTS), sodium sulfite (Na2SO3), and sodium p-methylphenoxide (NaCRS) in aqueous NaOH solutions and Na2SO3 in aqueous ethanol solutions were investigated using a dynamic method over the temperature range from 277 to 341 K at atmospheric pressure. The experimental results showed that the solubilities of NaPTS, Na2SO3, and NaCRS in aqueous NaOH solutions and Na2SO3 in aqueous ethanol solutions decreased distinctly with the solute free mass fraction of NaOH (w(4)(0)) and ethanol (w(5)(0)). Further, there were obvious transition points in the solubility temperature curves of NaPTS and Na2SO3 in aqueous NaOH solutions, and the transition points shifted to lower temperature as w(4)(0) rose. The forming of transition point was due to the different equilibrium solid phase, which was revealed by characterization of the equilibrium solid phase. But the transition points in the solubility-temperature curves of Na2SO3 in aqueous ethanol solutions remained constant at different w(5)(0) values. As the temperature rose, the solubilities of NaPTS and NaCRS in aqueous NaOH solutions increased, while the solubilities of Na2SO3 increased at first and then decreased after the transition points in both aqueous NaOH and ethanol solutions. The experimental data were correlated with the electrolyte nonrandom two-liquid (E-NRTL) model, and model parameters were determined simultaneously. On the basis of the solubility difference between Na2SO3 and NaCRS, a new process for reusing the NaOH in the alkali fusion reaction residue was proposed theoretically.