• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.17-25
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• 2014

Wide spread application and non-biodegradability of the poly(ethylene terephthalate) generate a huge amount of waste and disposal, posing serious environmental problems. Disposal of the PET wastes also can be thought as an economic loss of valuable chemical resources. We present various ways of feedstock recycling of PET waste to deal with environmental and economic problems. Feedstock recycling is one of promising technologies. It is based on the concept of depolymerizing the condensation polymer such as PET through solvolytic chain cleavage into low molecular products which can be purified and reused as raw materials for the production of high quality chemical products.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.178-196
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• 2005

• Resources Recycling
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• v.5 no.4
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• pp.3-10
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• 1996

• Journal of Environmental Science International
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• v.5 no.1
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• pp.83-91
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• 1996

A recycling soap was prepared from non-cooking oils. The effects of physlcal and chemical properties of the recycling soap on biodegradation are expected to be different due to the thermal histories of the non-cooking oils. Therefore, the biodegradation rate of the recycling soap was studied by using Klebssella Pneumoniae(K. pneumoniae), and the growth rate of K. pnewoniae in soap solution was observed. The biodegradation rate of the recycling soap appeared to be slower as the thermal histories of the non-cooking oils became larger. This might be resulted from hydrolysis, in which the ester bonds in the oils are broken to produce hydroxyl group. It was also observed that the growth rate of the microorganism decreased with the increase in the thermal histories of the oils. As a result, it is desired that recycling soap should be produced from the non-cooking oils with the prober ranges of thermal histories to reduce water contamination. The non-cooking oils with larger thermal histories are considered to be recycling through the cracking process before used. Key Words : non-cooking oils, recycling soap, thermal history, biodegradation, microorganism growth.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 1993.03a
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• pp.24.1-24
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• 1993

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 1993.03a
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• pp.16-16
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• 1993

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.563-568
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• 2003

Recently, the recycled amount of electric, mechanical parts, and appliances in artifacts has increased. These products use valuable rare metals such as platinum group metals and gold, which are included occasionally as additives. Rare metals are maldistributed in the world and most of them are produced in small quantities. A small amount of rare metals used in the appliances causes a large loss of rare metal resources because of the lack of an economically recycling method. The present recycling technologies including physical and chemical separation methods that are considered for recycling of electric, mechanical parts and appliances.

• Resources Recycling
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• v.19 no.4
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• pp.13-18
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• 2010

Effort of reducing wastes and their recycling is increasing in worldwide. Especially, extreme care for alkali recycling is required because of its environmental pollution and its corrosive characteristics. In order to manage alkali wastes effectively, it is necessary to make quality standards for recycling products from the alkali wastes because there are no quality specifications yet. In this study, we selected several recycling candidates from the alkali wastes based on the analysis of the most recent data of the various industrial sites. As a result, the recycling candidates from the alkali wastes are sodium hydroxide, aluminum sulfate, poly aluminum chloride. It is believed that the proper management system for waste products is required in governmental point of view and it propagates positively for resolving various environmental issues.

• Resources Recycling
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• v.10 no.1
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• pp.56-65
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• 2001

Chemical decontamination techniques have been employed to reuse the high cost check valves contaminated with radioactivity and to reduce the radiation exposure during the inspection and maintenance work of safety injection system containing check valves. After chemical decontamination, an ultrasonic treatment was conducted to remove the fine solid particles retained in the crevices of check valves. The decontamination process conditions and the amount of chemical reagents were determined from the results of a pre-test, using the (list arm holder. The decontamination factors (DF), estimated from the activity in the solution, ranged from 14.5 to 18.5 corresponding to the activity removal of 93-95ft. The corrosion test data indicated that the general corrosion rate during a chemical decontamination-ultrasonic treatment process are low for type 304 S tainless steel, Inconel -600 and Stellite-6 materials $ (2.1\times10^{-2}$ $6.0\times10^{-2}$ and$ 1.7\times10^{-2}$ mil, respectively).

• Resources Recycling
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• v.28 no.1
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• pp.3-14
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• 2019

Copper is used in many electronic components and construction parts due to its excellent electrical conductivity and heat transfer characteristics, and also used for pre-plating for double layer coating such as nickel, so that copper is an essential material in modern industry. Despite the expected increase of usage and importance on wiring, sensors and data equipment in the next generation industries, it is hard for securing stable copper supply and resource management resulting from the copper prices are fluctuating owing to the economic crisis in Europe, the low economic growth trend in China, and President Trump's commitment to public industrial facilities investment in U.S.. Since most of the domestic copper consumption is used by electrolytic copper cathode, we studied not only copper recycling technology which is being commercialized but also current research trend under the research stage. This study aims to examine the characteristics of each process and the areas where future recycling technology development is required.