Manganese, the tenth most abundant in the earth’s crust, is commonly present in nature with iron and silica, and it is dissolved into groundwater by various hydro-chemical processes. Appropriate manganese intake is essential for human and animal development and plant growth. However, from a health and sensory point of view, the amount of manganese in drinking water should be limited to a very low value.

The value of manganese intake from drinking water recommended by WHO is 0.4mg/L.

The technique of removing manganese from water is based on the oxidation of soluble manganese forms (Mn²⁺) to insoluble manganese forms (Mn⁴⁺). Various water treatment technologies such as aeration, chlorination, potassium permanganate and ozonization have been proposed. However, these methods are slow in oxidization, require administration of chemical reagents, and are expensive. Therefore, they are complicated to operate in practice and difficult to apply to large-scale water treatment.

Ri Hyang Ran, a researcher at the Faculty of Earth Science and Technology, carried out some experiments to remove manganese from water using brucite marble as filter material and confirmed its applicability.

Magnesium content in the water filtered through the brucite marble filter material layer increased 1.25 times compared to the raw water, and the pH of water increased from 7.4 to over 8. As pH increased, Mn²⁺ concentration in the filtered water decreased from 0.6mg/L to below 0.05mg/L.

The water treatment method using brucite marble as a filter can effectively remove soluble manganese in water and can be applied to large-scale water treatment at low cost.

For more information, please refer to her paper “Experimental Study on Manganese Removal from Water by Brucite Marble” in “Proceedings of KUTIC-2025”.

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^-/CO₃^2- 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^-/CO₃^2- Molar Ratio on Joint Characteristics between Ore & Sodium Oleate Collector in Apatite Flotation” in “Proceedings of KUTIC-2025”.

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”.