The distiller waste containing mainly calcium chloride (CaCl2) is being discharged in the Solvay process, and it has not been recycled comprehensively. In this study, a novel route for the treatment of the distiller waste was developed, in which CaCl2 solution was transformed into calcium carbonate and hydrogen chloride based on a reactive extraction-crystallization process using N235-isoamyl alcohol as the extraction system. Experimental results showed that the optimum conditions were 240 min as reaction time, 20 degrees C as the best temperature, 1.0 mol L-1 as initial concentration of CaCl2, 50% volume fraction of N235, 2:1 as the best phase ratio, and one-time feeding pattern. The conversion rate of CaCl2 was up to 75% under the optimized conditions; moreover, the concentration of H+ in organic phase was 0.70 mol L-1 and rhomibic calcite of high purity could be obtained. The products were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and thermogravimetry/differential scanning calorimetry. The extraction mechanism involved the ion-pair formation and the extraction complex R3N center dot HCl was determined by saturation method. The enthalpy change of the overall reaction Delta H was -36.47 kJ mol(-1), indicating that it was an exothermic reaction with the possibility of getting hindered at high temperature. (C) 2014 Elsevier B.V. All rights reserved.