Preparation of ultrafine calcium carbonate nanoparticles by carbonation in gas–liquid two‐phase impinging stream reactor

In the context of ‘Carbon Peaking and Carbon Neutrality’, carbon dioxide capture, utilization, and storage (CCUS) is an important technology for achieving carbon neutrality. Combining impinging stream and bubble jet, the gas–liquid two‐phase impinging stream reactor was designed and developed. The ultrafine calcium carbonate nanoparticles were prepared by the gas–liquid two‐phase impinging stream reactor using the carbonation method. The effects of dispersant type, dispersant dosage, gas‐phase and liquid‐phase flow rates, synthesis temperature, CO 2 volume fraction and initial Ca(OH) 2 concentration on the average particle size, particle size distribution, and synthesis time were investigated. The results showed that the average particle size and synthesis time of calcium carbonate nanoparticles reached a minimum with the dispersant SDBS. Compared with other surfactants, the average particle size and synthesis time decreased from 188 to 66 nm and from 500 to 226 s, respectively. With the increase of the gas‐phase flow rate and synthesis temperature, the average particle size of calcium carbonate nanoparticles increased and the synthesis time decreased, resulting in a broader particle size distribution. With increasing liquid phase flow rate, the average particle size of calcium carbonate nanoparticles and synthesis time decreased. The particle size distribution was uniform. Based on the reaction mechanism of calcium carbonate nanoparticles prepared by the carbonation method, the crystallization kinetic model of the carbonation reaction process was established, which could accurately predict the crystallization process of calcium carbonate nanoparticles.