Use of Taguchi approach for synthesis of calcite particles from calcium carbide slag for CO2 fixation by accelerated mineral carbonation

Abstract

This study is focused on the conversion of harmful materials (calcium carbide slag [CCS] and flue gas) into CaCO3 particles through an accelerated mineral carbonation process. The influences of reaction temperature, amount of Na-oleate, solid-to-liquid ratio, and stirring speed on the properties of CaCO3 particles were determined using XRF, XRD, SEM, FTIR, TG, and contact angle measurements. Experiments were designed based on an orthogonal array L9 (34) of the Taguchi approach. The gas mixture of CO2/N2 (16.3% of CO2 cons.) gas was used to represent the flue gas for each experiment. The formation of CaCO3 particles from CCS depending on time was monitored via SEM. Experiments showed that the presence of Na-oleate in the slurry played a curial role in the carbonation process, and the conversion ratio of CO2 into a solid carbonate phase was higher than that in the experiments conducted without Na-oleate. The crystallite size of CaCO3 particles varied between 11.55 and 38.11 nm depending on the production conditions. Each obtained CaCO3 particles were identified as calcite (cubic-like rhombohedral), which is in high demand in many industrial applications.