Mineralizing CO₂ as MgCO₃·3H₂O Using Abandoned MgCl₂ Based on a Coupled Reaction–Extraction–Alcohol Precipitation Process

Abstract

A novel coupled reaction–extraction–alcohol precipitation process was proposed to mineralize CO2 as MgCO3·3H2O directly by abandoned MgCl2. Rod-like crystal MgCO3·3H2O was obtained, and the conversion rate of MgCl2 increased sharply by using this novel coupled reaction–extraction–alcohol precipitation process. The effect of an added C1–C3 alcohol precipitation agent on the conversion rate of MgCl2 was in the following order: ethanol > isopropanol > n-propanol > methanol. Moreover, the optimal conditions for the highest conversion rate of MgCl2 by single-factor experiments were obtained as follows: initial concentration of MgCl2 solution is 2 mol·L–1, volume ratio of ethanol and aqueous phase is 2, mole ratio of N235 and aqueous phase is 2, volume ratio of diluent and N235 is 0.5, with a stirring rate of 300 r·min–1 at 298.15 K and at atmospheric pressure.