• Resources Recycling
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• v.28 no.2
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• pp.40-45
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• 2019

During steelmaking in EAF, recycled scraps is used as a main material, melted by arc, and electricity use as a main energy. Slag foaming is an important technology for reducing electrical energy. CO gas generated by the reaction between injection carbon and (FeO), [C] and injection {$O_2$}. CO gas generated by this reaction is collected in slag, resulted in slag foaming. In general, the carbon materials used in the EAF process is anthracite and coke. This study investigated the effects of the carbon materials used on slag foaming in the steelmaking process. As a result of this study, the slag foaming height is increased by cokes rather than anthracite, and with an increase in the amount of particles samller than $500{\mu}m$. Based on these results, the application to the operation resulted in increase of slag forming height, reduction of injection carbon, and reduction of electrical energy.

• Resources Recycling
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• v.27 no.6
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• pp.76-83
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• 2018

This article aims to summarize the scrap recycling status of gold, silver, platinum and palladium from foreign countries by courntires and industries in order to utilize the data for securing the raw materials of the domestic urbanmining industry. The amount of gold from scrap has shown a tendency to decrease in countries other than China, which is attributed to the large imports of scrap containing gold in China. The industry demand for gold is the highest in electronic products, but demand is decreasing. The amount of scrap recycling in silver has declined in other regions compared to those in Europe, indicating that the world's overall scrap recycling volume has declined. Production and demand from scrap of platinum and palladium are mostly for catalysts and have been steadily increasing until now. However, it is expected that the amount of waste catalysts in automobiles will decrease with the increase of electric vehicle use.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.8
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• pp.950-958
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• 2019

Digital Social Innovation, social innovation utilizing digital technology, is gaining attenntion as an innovative new way of solving pressing social problems such as ageing, traffic, unemployment etc. while some raise concerns as to the negative impact of digital technology on society associated with Share-the-Scraps-economy and On-demand-economy. The paper aims to address these concerns by examining the nature and source of business values generated in digital social innovation. Donation, cooperation/solidarity and sharing are identified as sources of business value from social innovation. Digitization, Platform may present infrastructure upon which efficiency of economic transaction can be elevated. The participation of consumers/users in the value chain and value network enabled by digital technology is identified and discussed as the critical source of business value in digital social innovation. The business model of Docksan-dong Happy Parking Street living lab project is analysed to illuminate the realization of business vaules in real life setting. Policy recommendations and future research directions are suggested.

• Journal of the Korea Fashion and Costume Design Association
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• v.23 no.2
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• pp.165-176
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• 2021

To solve environmental problems, research and efforts are required to reduce leather waste that is generated in large quantities during the leather manufacturing process. Leatherboard is a plate-like material that is made by crushing leather waste, such as trimming or shaving scraps and mixing fibers, pulp, rubber, and adhesives. The aim of this study is to provide basic data on the localization of leatherboard manufacturing technology for outsoles, which are increasingly in demand due to their excellent performance and price competitiveness. Interviews with experts and related organizations were conducted to investigate the related global technology trends. Also, the performance of three products that can be used as reference materials were evaluated and compared. As part of the research and efforts to reduce the amount of leather waste generated, high-performance materials using leather waste were developed and commercialized by major western companies. In Korea, various efforts have been made since 2000, and some companies have produced leatherboard for interior uses. However, the amount of waste recycled relative to that generated is not large due to the limited demand. Natural leather soles perform better than leatherboard soles in all evaluation aspects. In the case of leatherboard, performance varied by manufacturer. German products showed flexibility resistance and dimensional stability, thereby meeting performance requirements. However, abrasion resistance and cleavage resistance were slightly below the required performance standards, and research and development is needed to improve performance in those areas. Currently, it is impossible to evaluate the performance of domestic products due to underdevelopment. However, if the development of process technology continues based on the performance evaluation results of the best leatherboard in the shoe industry, materials for outsoles will be able to be produced domestically with prices competitiveness while realizing natural leather materials performance to some extent.

• Elastomers and Composites
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• v.58 no.1
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• pp.32-43
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• 2023

The worldwide use of polyurethane foam products generates large amounts of waste, which in turn has detrimental effects on the surroundings. Hence, finding an economical and environmentally friendly way to dispose of or recycle foam waste is an utmost priority for researchers to overcome this problem. In that sense, the glycolysis of waste flexible polyurethane foam (WFPF) from automotive seat cushions using different industrial-grade glycols and potassium hydroxide as a catalyst to produce recovered polyol was investigated. The effect of different molecular weight polyols, catalyst concentration, and material ratio (PU foam: Glycols) on the reaction conversion and viscosity of the recovered polyols was determined. The obtained recovered polyols are obtained as single or split-phase reaction products. Besides, the foaming characteristics and physical properties such as cell morphology, thermal stability, and compressive stress-strain nature of the regenerated flexible foams based on the recovered polyols were discussed. It was observed that the regenerated flexible foams displayed good seating comfort properties as a function of hardness, sag factor, and hysteresis loss compared to the reference virgin foam. With the growing demand for a sustainable and circular economy, a global valorization of glycolysis products from polyurethane scraps can be realized by transforming them into profitable substances.

• Resources Recycling
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• v.20 no.3
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• pp.12-27
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• 2011

DOWA group has been working on metal recycling applying the smelting and refining process of KOSAKA Smelter. DOWA has developed it's metal recycling technologies through the treatment of black ore(complex sulfide ores) that contain many kinds of non-ferrous metals. In addition to these special technologies, DOWA has strengthened its hydrometallurgical process of precious metals and ability to deal with low-grade materials such as used electrical appliances or vehicles. On the other hand, JX Nippon Mining & Metals Corporation(JX-NMMC) carries out its metal recycling and industrial waste treatment businesses employing advanced separation, extraction and refining technologies developed through its extensive experience in the smelting of non-ferrous metals. JX-NMMC collects approximately 100,000t/y of copper and precious metal scraps from waste sources such as electronic parts, mobile phones, catalytic converters, print circuit boards and gold plated parts. These items are recycled through the smelting and refining operations of Saganoseki smelter and Hitachi Metal-recycling complex(HMC). In this like, metal recycling industries combined with environmental business service in Japan have been developed through excellent technologies for mineral processing and non-ferrous smelting. Also, both group, Dowa and JX-NMMC, were contributed to establish Japan's recycling-oriented society as the typical leading company of non-ferrous smelting. Now. it is an important issue to set up the collection system for e-waste.

• Resources Recycling
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• v.20 no.5
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• pp.40-45
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• 2011

We carried out to investigate the refining effect of molybdenum by Ar-H$_2$ vacuum arc melting(VAM) process for recycling Mo scrap. The purity of the Mo metals refined by VAM was evaluated using glow discharge mass spectromety(GDMS). From the result of GDMS, most impurities in the Mo metals except for W were removed by Ar-H$_2$ VAM down to a few mass ppm levels. The purity of the refined molybdenum scrap was improved up to 4N5(99.995%) from 3N(99.95%) of the initial Mo scrap. The amount of gaseous impurities such as C, N, and O in Mo scrap were decreased from 1290 ppm to 132 ppm. As a result, it is considered that a possibility of refining and cost-effective method for recycling Mo scrap by Ar-H$_2$ vacuum arc melting process was confirmed in this study.

• Journal of the Korea Organic Resources Recycling Association
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• v.6 no.2
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• pp.7-30
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• 1998

Generation and recycling potential of organic waste in Korea were estimated. Status of organic waste composting and compost utilization also were surveyed to promote the recycling of organic waste. From 1994 to 1997, generation of garbage decreased gradually while recycling rate increased due to positive governmental strategy. During the same period, livestock waste increased 11.2%. Municipal wastewater sludge was generated 3,500 ton/day which was 0.03% of wastewater treated in 1996. The energy Potential of industrial organic waste was estimated to 288 million TOE which was 1.75% of the nationwide first energy consumption in 1996. Recycling of industrial sludge was low to 31%, while recycling of animal waste, plant scraps, and wasted paper were relatively high over 50%. Industrial sludge should be recycled more as it was the most part of industrial organic waste. Conventional composting materials were mainly livestock waste, food processing waste, fishery waste, sawdust, and nightsoil. Garbage and sludge have been composted recently. 420,000 tons of compost in 1996 were produced by 288 makers, the most of which were utilized in agriculture. It was suggested that separated collection, compost standard, and quality management should be provided to promote the composting of organic waste.

• Resources Recycling
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• v.18 no.5
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• pp.26-36
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• 2009

A recovery process of Ruthenium from waste electronic scrap has been investigated by means of nitric acid leaching as a part of development for scrap pretreatment process to obtaining an optimum conditions for removal of removing various impurities such as Pb, Bi, Zn, Al, Bi, Ag Fe, Co, Zr, Si. From the experiments, 90% of Pb leached with 250 g/l pulp density in 10-15% nitric acid. Leaching behavior of Ba was also similar to that of the Pb, but those of other metal impurities, such as Zn, Al, Bi, Ag, Fe, Co, Zr, showed different behavior, in which the dissolution rate increased as the concentration of nitric acid in solution is increased up to the 10% $HNO_3$ in solution and then it was constant above 10% $HNO_3$ concentrations. Meanwhile, the dissolution of Ru in $HNO_3$ solution was less then 100ppm, and that the total content of Ru in undissolved residue scrap was resulted in an increment of 50%.

• Resources Recycling
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• v.27 no.1
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• pp.84-91
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• 2018

In this study, a novel soft information based most probable classification scheme is proposed for sorting recyclable metal alloys with laser induced breakdown spectroscopy (LIBS). Regression analysis with LIBS captured spectrums for estimating concentrations of common elements can be efficient for classifying unknown arbitrary metal alloys, even when that particular alloy is not included for training. Therefore, partial least square regression (PLSR) is employed in the proposed scheme, where spectrums of the certified reference materials (CRMs) are used for training. With the PLSR model, the concentrations of the test spectrum are estimated independently and are compared to those of CRMs for finding out the most probable class. Then, joint soft information can be obtained by assuming multi-variate normal (MVN) distribution, which enables to account the probability measure or a prior information and improves classification performance. For evaluating the proposed schemes, MVN soft information is evaluated based on PLSR of LIBS captured spectrums of 9 metal CRMs, and tested for classifying unknown metal alloys. Furthermore, the likelihood is evaluated with the radar chart to effectively visualize and search the most probable class among the candidates. By the leave-one-out cross validation tests, the proposed scheme is not only showing improved classification accuracies but also helpful for adaptive post-processing to correct the mis-classifications.