다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

An introduction to heat transfer

Drying shrinkage in alkali-activated binders – A critical review

Dynamic spillovers between commodity and currency markets

Supply and demand of some critical metals and present status of their recycling in WEEE.

Experimental investigation of diffusion behavior between molten Mg and Nd–Fe–B magnets

Material flow analysis (MFA) requires the use of reliable data. In intermediate or the end industries that lack field survey data or actual statistical data, the integrated material flow analysis methodology uses bottom–up flow analysis for primary and secondary resources, and top–down flow analysis for the distribution structure. By combining the advantages of the top–down and bottom–up methods, the Integrated Material flow Analysis Methodology (IMFAM) can overcome the limitations of each methodology. Using the IMFAM, this study surveyed the material flow of palladium, and a platinoid element used in Korea. Palladium is produced as a byproduct in the copper refining process in Korea, and about 80% of used palladium as a three-way catalyst (TWC), i.e., an exhaust gas purifying system for automobiles. As automobile production in Korea is expected to continually increase, the usage of palladium is also expected to increase. Moreover, the increase in the use of printed circuit board (PCB) plating solutions is expected to further increase the use of palladium. This MFA results well represent the flow of palladium in Korea and give a strategy to secure palladium steadily.

Material flow and industrial demand for palladium in Korea

Korean automobile industry was the fifth largest in the world in 2014, and there was a steady demand for batteries that are essential for automobile production. The battery used in automobile production is a lead acid battery, and since 2010, Korea has been conducting material flow analysis for major industrial-related materials such as lead. Lead material flow had focused on the production of raw and base materials and the battery production, which is one of the intermediate products. Many of these products were exported. Most of the primary leads used in the production of the basic materials were smelted with imported lead ores. Compared to the production capacity of secondary lead companies in Korea, a number of used batteries collected in Korea were insufficient, and the shortages were dependent on imports. 94.7% of the base materials were used for battery production through first processed products as metal, and 5.3% was used as an oxide. In addition, lead is a globally important environmental regulatory substance, and Korea has also managed the recycling of lead acid batteries. 98.2% of the leads collected through recycling process were reintroduced into the base material as the secondary lead.

Lead acid battery recycling and material flow analysis of lead in Korea

The spinel structure of the nanosize powder (Ni0.3Zn0.3Cu0.4Fe2O4) substituted by Ni, Zn, and Cu was fabricated by the sol-gel process. Changes in weight, crystal formation, and magnetic properties were observed by XRD, TG-DTA, VSM in the annealing process of the sol and gel. The saturation magnetization of the sol showed 54.8–58.6 emu/g at 500–800°C, and the gel showed 52.3–56.8 emu/g at 600–800°C. The coercive force of the sol decreased in the range −136 Oe to −11.4 Oe at 500–800°C, and the gel decreased in the range −95 Oe to −44 Oe at 600–800°C. Therefore, the deviation of the annealing temperature of the nanopowder fabricated in the sol process and the gel process was about 100°C.

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Jeong-Gon Kim

Papers

Experimental investigation of diffusion behavior between molten Mg and Nd–Fe–B magnets

Material flow and industrial demand for palladium in Korea

Lead acid battery recycling and material flow analysis of lead in Korea

Study on Crystallization and Magnetic Property Deviation of Ni-Zn-Cu Ferrite Depending on the State of the Starting Material in the Annealing Process

Separation of Heavy Rare Earth Elements with Extraction Chromatography