Jo Apr 9, 2026
Fluorapatite Ca10(PO4)6F2 containing the most phosphorus is widely found in igneous and sedimentary rocks. More than 60% of the phosphate currently marketed worldwide is concentrated via flotation processes. To date, there has been a growing body of research on the factors affecting apatite flotation.
According to previous literature, first-principles simulation of such mineral processing has not been fully performed. The only attempt they have made is to build a crystallographic model of a particular mineral to study its material properties and determine the relationship between its composition and properties or to compare what material is more effective as a collector for that ore.
Kim Wi Ryok, a researcher at the Faculty of Chemical Engineering, proposed a new analytical method for determining the optimum value of sodium oleate, considering the effect of the combination of pH modifier NaOH and sodium carbonate on the flotation efficiency with collectors when the optimum value of sodium oleate is used as a collector in the process of apatite flotation. He evaluated the flotation efficiency by calculating adsorption energy by first-principles calculations, calculating ion concentration variations and measuring experimental zeta potential.
The results show that flotation efficiency varies with the amount of the pH modifier even with the same collector, and the optimum value is 1:3 OH-/CO32- mass ratio. It is also shown that the simulated results estimated by the first-principles method are in good agreement with the experimental values and there is enough evidence to apply this method to other ore beneficiation processes.
You can find the details in his paper “Ab Initio Study of the Effect of OH-/CO32- Molar Ratio on Joint Characteristics between Ore & Sodium Oleate Collector in Apatite Flotation” in “Proceedings of KUTIC-2025”.
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Jo Apr 8, 2026
For building demolition and tunneling, many shock tubes must be simultaneously initiated by a detonator. Bunches of shock tubes can be initiated by bunch blocks. The initiation reliability of shock tubes depends primarily upon bunch block design.
Understanding the structural explosion shock mechanisms of bunch blocks is very important in designing bunch blocks without consumption of many shock tubes in experiments.
Choe Yong Chol, a researcher at the Faculty of Mining Engineering, investigated the structural influence of frontal bunch blocks on the initiation reliabilities of bunches of shock tubes by a detonator experimentally and numerically.
The thicker and stronger bunch block bodies and the smaller the standoff distance between detonators and bunches of shock tubes were, the more the experimentally obtained initiation rates increased. And the pressure peaks of explosion shock obtained from numerical simulations increased with increase in the thickness of bunch block bodies and decrease in the standoff distance. The numerically obtained pressure peaks were in good relation with the initiation rate obtained from the experiments.
The results can be employed for evaluating initiation reliability and designing bunch blocks when simultaneous bunch-series initiation of many shock tubes by bunch blocks is needed.
For more information, please refer to his paper “Structural Influence of Frontal Bunch Blocks on the Initiation Reliability of Bunches of Shock Tubes” in “Proceedings of KUTIC-2025”.
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Jo Apr 7, 2026
Metal hydrides have been widely used in H2 storage application because of their superior property. Among them, perovskite-type metal hydrides are considered as promising candidates of hydrogen storage due to their diversity in crystalline structure and distinctive physicochemical properties.
This attracted many researchers to the investigation into them. However, only a few papers have focused on the structure, thermal analysis and dehydrogenation kinetic properties of KxNa1-xMgH3 hydride, and yet they failed to provide full theoretical insights into the material properties of double perovskite-type hydride NaKMg2H6.
Jo Son Il, a section head at the Faculty of Material Science and Technology, elucidated the hydrogen storage property of metal hydride NaKMg2H6 by the first-principles.
Based on electronic properties, geometric factors, elastic constants and self-consistent phonon calculations, he found that NaKMg2H6 is dynamically and mechanically stable in cubic phase at elevated temperatures.
He illustrated that gravimetric and volumetric H2 storage capacities are 5.19% and 72.548g/L, respectively, and H2 desorption temperature is 470.4K.
You can find the details in his paper “Elucidating the Hydrogen Storage Property of Perovskite-Type Metal Hydride NaKMg2H6 from First-Principles” in “Proceedings of KUTIC-2025”.
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Jo Apr 6, 2026
The rapid development of modern industry requires products with good mechanical properties and light weight and thus, the application of Al and its alloys attracts a great deal of attention. Inclusions and gas in molten aluminum decrease its fluidity and make its structure rough to decrease the castability and serve as the source of crack. Also, they decrease the workability and surface finish, and especially it is unfavorable to the toughness and fatigue strength. Therefore, there have been many researches to remove these inclusions and gas.
A researcher prepared KCl-NaCl-NaF-Na2AlF6 system refining agent and estimated the refining efficiency by measuring the density of aluminum to determine the effective composition of KCl-NaCl-NaF-Na2AlF6 system. Some components of KCl-NaCl-NaF-Na2AlF6 generate gas for removing gas, but their main refining action is the absorption of oxide inclusions. In other words, the hydrogen removal effect is not so high. Therefore, it is necessary to select and use an additive to increase the amount of generated gas for improving the hydrogen removal effect.
Ri Hyok, a researcher at the Faculty of Metallic Engineering, selected an additive to improve the refining efficiency of NaCl-KCl-Na2SiF6-NaF system-compound refining agent for gas impurities in molten aluminum for continuous casting, and determined its amount.
Based on the relationship between the partial pressure and the chemical potential of refining gas and those of the hydrogen in molten aluminum, he induced a formula for determining the amount of additives. He conducted a metallic microscope analysis of newly-refined aluminum to confirm the refining efficiency.
He found that the amount of NaNO3 which was selected as an additive is 0.2% of that of refined aluminum and at that time the amount of carbon is 0.1%.
You can find his paper “Improvement of the Refining Effect of NaCl-KCl-Na2AlF6-NaF System-Refining Agent for Gas by Adding NaNO3” in “Proceedings of KUTIC-2025”.
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Jo Apr 3, 2026
Ozone is usually produced by the dielectric barrier discharge (DBD) method. The dielectric barrier discharge can be divided into two categories: volume discharge and surface discharge. In the surface discharge, a ceramic plate is used as a dielectric barrier. As an advanced form of single SDBD, double SDBD was proposed, in which striped electrodes were coated on both sides of the ceramic plate. Double SDBD can simultaneously generate two plasma zones on both sides of the ceramic plate to improve energy efficiency compared to single SDBD. However, it is difficult to realize the cooling of the discharge device.
A previous study proposed a double SDBD reactor in which two silver mesh electrodes were coated on one side of an enameled steel plate. However, an enameled steel plate is easy to deform during the fabrication process and it is difficult to make the discharge device larger. In addition, a silver electrode is not practical because of its low resistance to the oxidation of ozone.
Kim Jong Guk, a researcher at the Institute of Nano Science and Technology, has proposed a cylindrical double SDBD device.
The proposed discharge device can simultaneously produce ozone at both the high voltage electrode and the grounded electrode, thus showing great advantages in getting high ozone concentration.
The optimized reactor ensures ozone generation efficiency of 339g/(kW·h) and ozone concentration of 82g/(N·m3).
You can find the details in his paper “Implementation of Double Surface Dielectric Barrier Discharge with Enamel Ozone Tube” in “Proceedings of KUTIC-2025”.
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Jo Apr 2, 2026
Gliding arc discharge (GAD) generates plasma with relatively high electron density and power, and also provides high operating pressure, low fabrication cost and excellent reaction selectivity. In particular, its power levels higher than other atmospheric pressure non-equilibrium discharges such as dielectric barrier or corona discharges have constantly expanded its applications in combustion support, surface treatment, fuel reforming, chemical synthesis, environmental remediation, etc.
Kim Yong Jun, a researcher at the Faculty of Physical Engineering, has proposed a type of gas discharge defined as a gliding arc-microwave hybrid discharge (also called microwave enhanced gliding arc discharge or gliding arc assisted microwave discharge), and experimentally investigated its coordination effects for generating plasma.
The gliding arc acts as an igniter for generating and maintaining microwave plasma at atmospheric pressure, while the microwave-enhanced gliding arc discharge indicates expansion of the length and bulk of plasma flame, which has a positive effect on the residence time and immersion of reactants in the plasma.
The proposed hybrid discharge can be applied to different fields such as chemical synthesis, surface treatment, fuel reforming and environmental improvement as it can generate efficient and bulk plasma with different temperatures and good reaction selectivity at atmospheric pressure.
You can find the details about it in his paper “Coordination effect in generating plasma by gliding arc-microwave hybrid discharge in atmospheric-pressure air” in “Applied Physics Letters” (NI).
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