• Resources Recycling
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• v.29 no.1
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• pp.3-16
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• 2020

This work provides an overview of the steel production process, pretreatment and tramp elements of scraps and recycling technology of dust generated from steelmaking process. Steel is the most common metal used by mankind, with the world production of crude steel in 2018 exceeding 1.8 billion tonnes. Recycling of ferrous scraps reduces CO₂ emissions by about 42 % and saves about 60 % of energy, compared to production steel from iron ore. Steel scraps are usually recycled to both an electric arc furnace (EAF), scrap-based steelmaking and the basic oxygen furnace (BOF), in ore-based steelmaking. EAF steelmaking, which uses iron scrap as a main raw material, is changing to an energy-saving type with a device for preheating scrap. Dust generated from the steelmaking process is recycled in various ways in the steel mill to recover iron and zinc.

• Journal of Biosystems Engineering
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• v.29 no.6 s.107
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• pp.544-552
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• 2004

This study was conducted to suggest the efficient gathering and recycling method of disused agricultural machinery in rural environment. In order to suggest this methods, the keeping means, maintenance, disused period and kinds of agricultural machinery were investigated. The results obtained in this study were as follows : The disused agricultural machinery have been leaved on the vacant lot of a farmhouse and an around field for $2\~5\;years$. The leaving reason of the disused agricultural machinery was low interesting and gathering price for the disused agricultural machinery. The present situation for recycling method was using as a scrap iron, however to increase recycling percent the disassembling process has to divide as using and parts concretely. And the design of agricultural machinery was considered the easiness of a disassemble and assemble the agricultural machinery. To manage and supply efficiently for the second-hand parts of agricultural machinery need to the establishment of circulation information center and internet site for the parts.

• Journal of Powder Materials
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• v.25 no.3
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• pp.240-245
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• 2018

This study focuses on the fabrication of a WC/Co composite powder from the oxide of WC/Co hardmetal scrap using solid carbon in a hydrogen gas atmosphere for the recycling of WC/Co hardmetal. Mixed powders are manufactured by mechanically milling the oxide powder of WC-13 wt% Co hardmetal scrap and carbon black with varying powder/ball weight ratios. The oxide powder of WC-13 wt% Co hardmetal scrap consists of $WO_3$ and $CoWO_4$. The mixed powder mechanically milled at a lower powder/ball weight ratio (high mechanical milling energy) has a more rapid carbothermal reduction reaction in the formation of WC and Co phases compared with that mechanically milled at a higher powder/ball weight ratio (lower mechanical milling energy). The WC/Co composite powder is fabricated at $900^{\circ}C$ for 6 h from the oxide of WC/Co hardmetal scrap using solid carbon in a hydrogen gas atmosphere. The fabricated WC/Co composite powder has a particle size of approximately $0.25-0.5{\mu}m$.

• Resources Recycling
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• v.14 no.2
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• pp.43-55
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• 2005

As world population increases and the world economy expalds, so does the demand for natural resources especially strategic metals such as cobalt. An accurate assesment of the nation's minerals must include not only the resources available in the ground but also those that become available through recycling. In this paper, data on domestic and international supply of cobalt and its applications by end-user were analyzed for stable security of cobalt resources and effective recycling of cobalt scraps. Also, an initial evaluation of the flow of cobalt-containing materials in the United States was prepared. In 2003, 8,000 metric tons of cobalt were consumed in the United States and an estimated 28% of U.S. cobalt supply was derived from scrap. The superalloy industry and catalyst industries have well-established recycling or cobalt recovery practices. Recycling rates of cobalt scraps from magnet alloy and cemented carbide were relatively low.

• Resources Recycling
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• v.26 no.4
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• pp.9-18
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• 2017

Recently, the amount of electronic scrap is rapidly increasing due to the rapid growth of the electronics industry. Among the components of electronic scrap, the printed circuit board(PCB) is an important recycling target which includes common metals, precious metals, and rare metals such as gold, silver, copper, tin, nickel and so on. In Korea, however, PCB recycling technologies are mainly commercialized by some major companies, and other process quantities are not accurately counted. According to present situation, several urban mining companies, research institutes, and universities are conducting research on recovery of valuable metals from PCBs and/or reusing them as raw materials that is different from existing commercialization process developed by major companies. In this study, we analyzed not only current status of collection/disposal process and recycling of waste PCBs in Korea but also the trend of recycling technologies in order to help resource circulation from waste PCBs become more active.

• Resources Recycling
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• v.20 no.6
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• pp.3-18
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• 2011

In order to review the recycling status of urban mine resources in Korea, metal consumption, metal stock reserves and metal scraps and wastes such as iron scrap, end of life vehicles(ELV), E-waste were surveyed. In making up the list of the metal consumption, the statistical data from the Korea Non-Ferrous Association, the Korea Iron and Steel Association, the HS code of Korea Custom Service, the symposium and the related companies were collected. Finally, "Principle uses and recycling potential of metals in the periodic table" by T.E.Graedel was introduced. This paper suggested the key point for development of urban mine resources.

• Resources Recycling
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• v.16 no.4
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• pp.33-39
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• 2007

Titanium scrap was re-melted and refined by using a DC-ESR (Direct Current Electro Slag Remelting) apparatus. A graphite rod was used as an anode. The used slag was $CaF_2-TiO_2-CaO$ slag system. The effect of slag composition on the shape and oxygen content of re-melted ingot was studied. The titanium ingot was produced very well from the $CaF_2-TiO_2$ slag system, and the oxygen content of the ingot was less than that of titanium scrap. The addition of CaO into $CaF_2-TiO_2$ slag system made the bad shape of titanium ingot. The oxygen content of the ingot was also higher than that of titanium scrap.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2002.05a
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• pp.99-100
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• 2002

• Resources Recycling
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• v.3 no.1
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• pp.38-43
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• 1994

The separation of valuable metals from IC chip scrap generated by domestic electronic company was carried out using the mechanical beneficiation such as shredding, crushing, screening and magnetic separation. The distribution of metals in various sizes of crushed IC chip scrap was investigated and metals present in crushed products was separated with the magnetic separator. The particle size distribution of crushed IC chip scrap was 7.5% for +3mm, 17.0% for 3~1mm and 75.5% for -1mm. The weight loss of crushed IC chip scrap was 18% when roasted at $700^{\circ}C$. The content of metals was 96% for +3~1mm, 13% for 1~0.595mm, 3.7% for 0.95~0.5. Au of 99% was present in -1mm crushed IC chip scrap. Ni, Fe, Cu, Sn and Pb were separated from crushed IC chip scrap by the magnetic separator under 700 and 2, 500 Gauss.

• Resources Recycling
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• v.23 no.3
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• pp.61-70
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• 2014

Tin has been widely used to solder, tin plated steel, bronze alloy, sputtering target for transparent electrode and chemical additives. It has been widely reported to the recycling technologies for tin scraps because of the scarcity and economic efficiency of the reserve. This study was analyzed by using open/registered patents KR, US, CN, JP and EP related to recycling technologies for processing scrap, sludges, waste fluid for plating process and spent alloy containing tin in between 1970 and 2013. Patents were collected using key-words searching and filtered by filtering criteria. The trends of the patents were analyzed by year, country, appliant and technology.