The preparation of calcium carbonate and hydrogen chloride from calcium chloride and carbon dioxide by the reactive extraction-crystallization coupled process is an effective way for the utilization of alkaline waste liquid. In this paper

Box-Behnken Design (BBD) in response surface methodology was used to design the experiments to investigate the effects of concentration of calcium chloride (CaCl2)

volume fraction of extractant

phase ratio

and temperature on the conversion of CaCl2

concentration of hydrogen chloride (HCl) in organic phase

and the average particle size of calcium carbonate (CaCO3) in the reactive extraction-crystallization coupled process

respectively. Three quadratic models were developed to correlate the variables to the response values and were proved to be significant. The optimal values were found as follows: conversion of CaCl2 95.08% and 92.35%

concentration of HCl in organic phase 1.126 mol·L-1 and 1.123 mol·L-1

and average particle size of CaCO3 48.71 μm and 49.14 μm. The small errors between the predicted and experimental values showed that the established models were accurate and reliable for the analysis and prediction of the reactive extractioncrystallization process.