• Resources Recycling
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• v.24 no.5
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• pp.72-79
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• 2015

Since there are many kinds of non-ferrous metal, it is difficult to investigate the current status on the recycling of all the non-ferrous metals. Therefore, the survey is confined to some commercially important non-ferrous metals such as copper, aluminum, zinc, lead, nickel and magnesium in this article. Domestic demand and production of these non-ferrous metals in recent years (2010-2014) and recycling ratio of the scraps are estimated briefly here.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.3
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• pp.493-501
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• 2012

A rotational force generator for molten metal is developed using a linear motor design technology. Also, the developed device is applied to reproduce aluminum scraps and easy to control the rotate, stop, and forward and reverse rotation of molten metal. In addition, the developed device improves the melting speed and reproduction rate about 250 (%) and 96-99 (%), respectively, compared to the conventional handmade methods. Because it generates almost no dusts, it can improve working environments in a factory. Also, it has no losses in energy because it directly melts scraps. The device generates small amounts of the loss in refractory materials and aluminum caused by its oxidation because the molten metal is continuously rotated in which the loss and oxidized aluminum are the problems in the conventional melting and holding furnaces. Thus, it is possible to extend the life of furnaces and to produce high quality aluminum products.

• Resources Recycling
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• v.18 no.1
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• pp.52-57
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• 2009

Since there are many kinds of non-ferrous metal, it is difficult to investigate the current status on the recycling of non-ferrous metals. Therefore, the survey is confined to some commercially important non-ferrous metals such as copper, lead, zinc, aluminum, nickel and magnesium in this article. Domestic demand and production in recent years and current status on the recycling of the scraps of these non-ferrous metals are introduced briefly here.

• Resources Recycling
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• v.22 no.6
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• pp.81-86
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• 2013

Since there are many kinds of non-ferrous metal, it is difficult to investigate the current status on the recycling of all the non-ferrous metals. Therefore, the survey is confined to some commercially important non-ferrous metals such as copper, aluminum, zinc, lead, nickel and magnesium in this article. Domestic demand and production of these non-ferrous metals in recent years(2010-2012) and recycling ratio of the scraps are estimated briefly here.

• Applied Chemistry for Engineering
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• v.25 no.4
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• pp.414-417
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• 2014

LED scraps consisting of highly crystalline GaN and their leaching behavior are comprehensively investigated for hydro-metallurgical recovery of rare metals. Highly stable GaN renders the leaching of the LED scraps extremely difficult in ordinary acidic and basic media. More favorable state can be obtained by way of high temperature solid-gas reaction of GaN-$Na_2CO_3$ powder mixture, ball-milled thoroughly at room temperature and subsequently oxidized under ambient air environment at $1000-1200^{\circ}C$ in a horizontal tube furnace, where GaN was effectively oxidized into gallium oxides. Stoichiometry analysis reveals that GaN is completely transformed into gallium oxides with Ga contents of ~73 wt%. Accordingly, the oxidized powder can be suitably leached to ~96% efficiency in a boiling 4 M HCl solution, experimentally confirming the feasibility of Ga recycling system development.

• 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.

• The Research Journal of the Costume Culture
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• v.28 no.6
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• pp.890-911
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• 2020

This study proposed a base framework for creating sustainable designs with textile production waste and unused neckties with the "design thinking" approach, which is an iterative process. It aimed to set an example of how fashion designers can plan and manage their clothing design processes in a more sustainable way by recycling textile production scraps and unused neckties into unique clothing pieces with the upcycling method. Unused neckties and upholstery scraps were turned into skirts, blouses, and dresses by using creative techniques in line with current fashion trends. In addition, the five-stage iterative design process followed was explained, and the way in which the waste textile materials gained value by being converted into unique garments was discussed in terms of the user and the designer. Through the study, it was observed that the smallest amount of textile waste can be transformed into upcycled clothing via the iterative process, and original, value-added products enjoyed by consumers can be created. In addition, it was observed that the design thinking approach improves the understanding of the context of the problem, creativity in the generation of insights and solutions, skills to materialize those solutions through iterative prototyping, and the ability to combine these factors. Promising ideas to help designers develop recycling strategies were also provided.

• Archives of Metallurgy and Materials
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• v.66 no.3
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• pp.729-733
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• 2021

Ferrotitanium can be produced as a method of recycling Ti scraps. The eutectic composition of ferrotitanium, Fe_29.5Ti_70.5, can be obtained as a nanocrystalline phase due to relatively low melting point. Fe_29.5Ti_70.5 in which FeTi and β-Ti form a lamellar structure have high strength but low strain. To improve this, impurities were removed through hydrogen plasma arc melting (HPAM) and annealed. HPAM can remove substitutional/interstitial solid solutions. As a result, from 6733 ppm to 4573 ppm of initial impurities were removed by HPAM process. In addition, the strain was improved by spheroidizing and coarsening the lamellar structure through annealing. The effect of impurities removed through HPAM on the Young's modulus, yield strength, and strain was observed.

• Resources Recycling
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• v.18 no.4
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• pp.14-23
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• 2009

In terms of resources recycling and resolving waste disposal problems, it is very important to recover precious metals like Au, Ag and Pd and valuable metals like Cu, Sn and Ni from the scraps of waste electrical and electronic equipment(WEEE) that consists of detective electrical and electronic parts discarded during manufacturing electrical and electronic equipments and waste electrical and electronic parts generated during disassembling them. In general, the scraps of WEEE are composed of various metals and alloys as well as refractory oxides and plastic components. Precious and valuable metals from the scraps of WEEE can be recovered by gas-phase-volatilization, hydrometallurgical, or pyrometallurgical processes. However, the gas-phase-volatilization and hydrometallurgical processes have been suggested but not yet commercialized. At the present time, most of the commercial plants for recovering precious and valuable metals from the scraps of WEEE adopt pyrometallurgical processes. Therefore, in this paper, the technical and environmental aspects on the important pyrometallurgical processes through literature survey are reviewed, and the scale-up result of a new pyrometallurgical process for recovering the precious and valuable metals contained in the scraps of WEEE using waste copper slag is presented.

• Resources Recycling
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• v.30 no.1
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• pp.60-65
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• 2021

The recycling of titanium turning scraps requires the removal of cutting oil and other contaminants remaining on the surface. In this study, an experiment was conducted in which titanium scraps were cleaned by a combination of ultrasonic immersion-steam cleaning and subsequent drying at high temperature. To determine the removal mechanism of cutting oil, the contact angle between titanium surface and cutting oil was measured. The result confirmed the optimum condition of the immersion solution of the titanium turning scraps. In the case of immersion cleaning of Na4P2O7 aqueous solution, the degree of carbon removed in the cutting oil was the highest at 50℃, and it was confirmed that the carbon content obtained from the combination of steam cleaning and ultrasonic immersion-steam cleaning was lower than that from steam cleaning after ultrasonic immersion. The oxidation and decomposition behaviors of cutting oil were investigated using Thermogravimetric analysis (TGA) and the result was applied in the high temperature drying process. From the results of the high temperature drying tests, it was concluded that 200℃ is the optimal drying temperature.