Seong-Young Nam

Accelerated carbonation of municipal solid waste incineration bottom ash for CO2 sequestration

Municipal solid waste is being produced in large quantities, in keeping with a dramatic population increase and the growth of industrialization. Most of this waste is sent to landfills in South Korea. However, current treatment methods including incineration and recycling is limited owing to insufficient landfill space and the generation of leachates and soil contamination. Generally, 250–300 kg of bottom ash and 30–50 kg of fly ash are generated from one ton of incinerated municipal solid waste. This study seeks to determine the degree of influence of several main factors, such as the optimum temperature, solid-to-water ratio and CO2 concentration, on the process of accelerated carbonation of the bottom ash. The results show that the carbonation rate was at its highest at a temperature of 20°C, a solid-to-liquid ratio of 0.2 and with 20% CO2. This implies that the CO2 gas emitted from incinerators can be used directly as part of an accelerated carbonation process of bottom ash, as the water content of raw bottom ash is 15∼25% and the CO2 concentration emitted from incinerators is 5∼20%. However, the temperature should remain at less than 20°C for more effective carbonation.

Evaluation of Physical Properties of Mine Polymer Liner and Cover Material Containing Re-emulsification Type EVA Resin

The polymer liner and cover material were produced with an admixture of re-emulsification type ethylene vinyl acetate (EVA) powder resin to make the low water permeability mine liner and cover material. The purpose of this study is to improve the basic physical properties and water tightness by filling the space between cement and aggregate with EVA polymer film, which result in the improvement of waterproof performance. It was confirmed that basic properties such as strength and dry shrinkage stability were improved until the re-emulsification type EVA powder resin was mixed up to 4%. However, it was confirmed that the physical properties were not significantly improved when 5% of the re-emulsification type EVA powder resin was used, or decreased compared with the case of using 4% of that. As a result of the measurement of the permeability coefficient, the physical properties were improved from 8.30×10 to 5.50×10.

Calcium Ion Extraction from Blast Furnace Slags for the Synthesis of Pure Calcium Carbonate Polymorphs by Accelerated Carbonation

This study investigates a possibility of synthesizing calcium carbonate following the process of extracting calcium ion (Ca) from air-cooled blast furnace slag by using pure CO2 gas at various pressures and extraction agents. At first, Ca ion Source from air-cooled blast furnace slag was firstly extracted at CO2 pressure and using acids and ammonium solutions. And then, we compared extraction rate CO2 pressure and various solutions. Finally, we performed calcium carbonate synthesis using aqueous CO2 and extracted Ca ion by the CO2 pressure, acetic acid. Following the process, calcium carbonate was effectively synthesized by the reaction between extracted Ca and CO3, a form of dissolved CO2. We expect that this study could demonstrate a possibility of conversing the slag and CO2 from the steel industry into high value added product, Calcium carbonate.