This paper reviews the application of carbonation technology to the environmental industry as a way of reducing carbon dioxide (CO₂), a green house gas, including the presentation of related projects of our research group. An alternative technology to very slow natural carbonation is the co-called ‘accelerated carbonation’, which completes its fast reaction within few hours by using pure CO₂. Carbonation technology is widely applied to solidify or stabilize solid combustion residues from municipal solid wastes, paper mill wastes, etc. and contaminated soils, and to manufacture precipitated calcium carbonate (PCC). Carbonated products can be utilized as aggregates in the concrete industry and as alkaline fillers in the paper (or recycled paper) making industry. The quantity of captured CO₂ in carbonated products can be evaluated by measuring mass loss of heated samples by thermo-gravimetric (TG) analysis. The industrial carbonation technology could contribute to both reduction of CO₂ emissions and environmental remediation.

Mine tailings from an abandoned metal mine in Korea contained high concentrations of arsenic (As) and heavy metals [e.g., As: 67,336, Fe: 137,180, Cu: 764, Pb: 3,572, and Zn: 12,420 (mg/kg)]. US EPA method 6010 was an effective method for analyzing total arsenic and heavy metals concentrations. Arsenic in the mine tailings showed a high residual fraction of 89% by a sequential extraction. In Toxicity Characteristic Leaching Procedure (TCLP) and Korean Standard Leaching Test (KSLT), leaching concentrations of arsenic and heavy metals were very low [e.g., As (mg/L): 0.4 for TCLP and 0.2 for KSLT; cf. As criteria (mg/L): 5.0 for TCLP and 1.5 for KSLT].

Wt% of aragonite, a CaCO₃ polymorph, increased with higher hydraulic activity (°C) of limestone in precipitated calcium carbonate (PCC) from the lime-soda process (Ca(OH)₂-NaOH-Na₂CO₃). Only calcite, the most stable polymorph, was crystallized at hydraulic activity under 10 °C, whereas aragonite also started to crystallize over 10 °C. The crystallization of PCC is more dependent on the hydraulic activity of limestone than CaO content, a factor commonly used to classify limestone ores according to quality. The results could be effectively applied to the determination of polymorphs in synthetic PCC for eco-friendly paper manufacture.

In recent years, heat treatment has attracted attention as a means to improve the color sorting technology with the aim of improving the quality of low-grade limestone. The crucial stage in this technique is to evaluate the breakage characteristics of the sample materials after color sorting. In this study, the breakage characteristics of samples showing color differences after heat treatment and of the original raw material were investigated using a laboratory ball mill. The grinding was characterized using the population balance model. Specific rates of breakage and the primary breakage distribution were experimentally determined by first-order kinetic plots and the BII method. The breakage parameters were also back-calculated by employing a simplex method. Grinding of the three materials indicated first-order kinetics, and the experimental results were well described by the model with parameters obtained by back-calculating.

Adsorption of particles at fluid–fluid interfaces is of great scientific and industrial importance, encompassing a variety of applications, from the stabilization of bubbles and emulsions to the fabrication of sophisticated materials with micro‐ and nanostructures. The enormous adsorption energy of a particle is believed to be the origin of adsorption, but it cannot fully explain many systems that do not adsorb, even with large adsorption energy. Here, it is systematically shown that the dynamic process of particle adsorption plays a critical role in determining whether particles are adsorbed at interfaces. Using a model system composed of a droplet and solid particle monolayer, the adsorption dynamics of cellulose nanofibrils are studied, focusing on the drainage time of a liquid thin film between the droplet and solid surface. Both the experimental and theoretical results indicate that the drainage time is regulated by the dimensionless capillary number. Controllable particle adsorption in conventional emulsions is further examined, confirming that results from this model system can be extended to large capillary numbers. This study provides important insight that it is not the adsorption energy, but the drainage process that governs particle adsorption, which can be quantitatively controlled by viscosity, interfacial tension, and particle approaching velocity.