• Korean Journal of Construction Engineering and Management
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• v.11 no.2
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• pp.45-53
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• 2010

When increasing quantity of construction wastes, how to deal with construction wastes and environmental problems relating to disposal of construction wastes are discussed as social issues, treatment of construction waste and subsidiary issues are raised as important problems. The demolition work produce construction wastes most in construction industry. Various researches on eco-friendly treatment of construction wastes, recycling rates and recycled materials were conducted aspect of sustainability in developed countries, however, domestic remodeling projects were performed demolition work with first-demolition and second-classification method which emphasize productivity focused on efficiency. It caused not only environmental problems, but also economical problems such as increasing disposal cost of construction wastes. Solving these problems, the previous study, suggested the process model of eco-friendly demolition work to recycle materials. This paper applied eco-friendly remodeling process to practical projects and economic feasibility on eco-friendly remodeling process. Moreover these results expect to contribute the revitalization of eco-friendly demolition work in remodeling projects.

• Journal of the Korean Applied Science and Technology
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• v.18 no.2
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• pp.103-110
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• 2001

Resource recovery and recycling of materials and products, including polyurethanes is viewed as a necessity in today's society. Most urethane polymers are made from a polyol and a diisocyanate. these and be chemicals such as water, diamines or diols that react with isocyanate groups and add to the polymer backbone. The problems of recycling polyurethane wastes has major technological, economic and ecological significance because polyurethane itself is relatively expensive and its disposal whether by burning is also costly. In general, the recycling methods for polyurethane could be classified as mechanical, chemical and feedstock. In the chemical recycling method, there are hydrolysis, glycolysis, pyrolysis and aminolysis. This study, the work was carried out glycolysis using sonication ant catalyzed reaction. Different kinds of recycled polyols were produced by current method(glycolysis), catalyzed reaction and sonication as decomposers and the chemical properties were analyzed. The reaction results in the formation of polyester urethane diols, the OH value which is determined by the quantity of diol used for the glycolysis conditions. The glycolysis rates by sonication for the various glycols, increased as fallows: PPG

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.425-432
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• 2021

In this paper, We produced supporting for ginseng cultivation facilities as a material recycling product of CPW(Complex Plastic Wastes, CPW) from households. And we analyzed the characteristics of material recycling products according to the amount of r-LDPE(Recycled low density polyethylene, r-LDPE) used. As a result, as the amount of recycled LDPE used increa sed, the tensile strength a nd elonga tion of ma teria l recycled products using CPW increa sed, but a sh decrea sed. When the recycled r-LDPE usage is 5% or more, the physical properties of the material recycling product using CPW stably satisfy the quality standard (GRM 3093-2021) of supporting for ginseng cultivation facilities.

• Applied Chemistry for Engineering
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• v.23 no.4
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• pp.367-371
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• 2012

Waste printed circuit boards (WPCBs) contain valuable metals such as Cu, Ni, Au, Ag, and Pd. For an effective recycling of WPCBs, it is essential to recover the valuable metals. In recent years, recycling processes have come to be necessary for separating noble metals from WPCBs due to an increasing amount of electronic device wastes. However, it is well known that glass reinforced epoxy resins in the WPCBs are difficult materials to separate into elemental components, namely metals, glass fibers and epoxy resins in the chemical recycling process. $K_3PO_4$ as a catalyst in dimethylformamide (DMF) and N-Methyl-2-pyrrolidone (NMP) was used to depolymerize epoxy resins for recovering metallic and non-metallic components from WPCBs. Reactions of WPCBs were carried out at temperatures $160{\sim}200^{\circ}C$ for 2~12 h. The recycled glass fiber from WPCBs was analyzed by thermogravimetric analyzer (TGA) and evaluated the degree of solubility of the epoxy resin for separation efficiencies of the WPCBs.

• Resources Recycling
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• v.26 no.5
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• pp.29-38
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• 2017

This study suggests optimal policy options for collection of used diapers through benchmarking of foreign countries and perception surveys. By conducting a survey, this study can identify the actual problems involved in the collection process and enhance the social acceptance toward diaper recycling policies. As a perception survey result, the economic burden of emission bags and sanitary issues were most important for the collection pilot test. Respondents thought that twice-a-week collection frequency was appropriate and that free emission bags might be preferable to participants. Currently municipal wastes are subject to waste management laws, which are applied by local governments. Diaper waste is categorized with municipal waste, so it seems to be treated by municipal waste systems. In terms of connection with government, possible alternatives were suggested to identify the relevant local government. Useful data could be obtained, to determine the economical viability of any future diaper recycling system implementation in the entire Seoul metropolis and adjacent areas of dense population.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.3
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• pp.20-26
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• 2013

We investigated practical methods of using recycled gypsum board paper in the paper industry. Gypsum board paper is used to produce construction gypsum board, and can be recycled through the recycling process of construction wastes. The experiments were carried out in two ways: One was the substitution of recycled gypsum board papers for KOCC, and the other was the use of recycled gypsum board paper powder. Recycled gypsum board paper was not disintegrated easily, but high temperature and the use of chemicals were able to improve their disintegration. The physical properties of handsheets made of the pulp of recycled gypsum board paper exhibited the same performance level as those made from KOCC except in the parameter of compressive strength. The powder of recycled gypsum board paper was manufactured using a grinder and handsheets were made with the powder and KOCC. The bulk was increased, but the strength properties were decreased by the addition of the powder.

• Clean Technology
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• v.2 no.2
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• pp.51-59
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• 1996

Billions of tons of industrial waste are generated annually in industrialized countries. Managing and legally disposing of these wastes costs tens to hundreds of billions of dollars each year, and these costs have been increasing rapidly. The escalation is likely to continue as emission standards become even more stringent around the world. In the face of these rapidly rising costs and rapidly increasing performance standards, traditional end-of-pipe approaches to waste management have become less attractive. The most economical waste management alternatives in many cases have become recycling of the waste or the redesign of chemical processes and products so that wastes are prevented or put to productive use. These strategies of recycling or reducing waste at the source have collectively come to be known as pollution prevention. The engineering challenges associated with pollution prevention are substantial. This presentation will categorize the challenges in three levels. At the most macroscopic level, the flow of materials in our industrial economy, from natural resource extraction to consumer product disposal, can be redesigned. Currently, most of our raw materials are virgin natural resources that are used once, then discarded. Studies in what has come to be called industrial ecology examine the material efficiency of large-scale industrial systems and attempt to improve that efficiency. A second level of engineering challenges is found at the scale of individual industrial facilities, where chemical processes and products can be redesigned so that waste is reduced. Finally, on a molecular level, chemical synthesis pathways, combustion reaction pathways, and other material fabrication procedures can be redesigned to reduce emissions of pollution and unwanted by-products. All of these design activities, shown in Figure 1, have the potential to prevent pollution. All involve the tools of engineering, and in particular, chemical engineering.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.3
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• pp.138-147
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• 2006

In this study, the composition and physico-chemical characteristics of municipal solid waste (MWS) which was treated in national park area kyungnam-do landfill were investigated. It is necessary to measure the characteristics of MSW and sludge to build a waste treatment facility, the data-base and total managing of the landfill. This MSW was composed of 34.62% of food wastes, 36.05% of papers, 15.37% of plastics & vinyls, 2.28% of textiles, 3.33% of wood, 0.49% of rubber & leathers and others, respectively. Most of MSW are composed of food, paper and plastic waste and more than 90% was combustible waste. For three components, moisture is 29.84%, combustible component is 62.30% and ash is 7.86%. The chemical element has the high order of carbon, oxygen, hydrogen on the dry basis of wastes. Also, the low heating value of the MSW which is measured by calorimeter is calculated as 2377.8kcal/kg. low heating value of the sludge is calculated as 338.06kcal/kg.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.3
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• pp.75-81
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• 2009

The industrial by-products market has increased at a geometric rate worldwide with the rapid economic growth. Among the wide variety of industrial by-products, fly ash which is generated by the combustion of coal is one of the more troublesome industrial wastes because they entail substantial disposal cost and also cause a shortage of disposal sites. In Korea alone, fly ash generation is expected to increase to 5.8 million tons by 2009, and to 6 million tons by 2010. Given the accelerated industrial development in developing countries, the amount of fly ash generation is predicted to reach enormous levels throughout the world. An increasing number of studies have currently focused on the feasibility of recycling industrial wastes i.e., fly ash in terms of environmental advantages. In this study, the optimized mix proportion of high performance shotcrete using fly ash was determined for the purpose of promoting recycling and reuse of resources.

• Resources Recycling
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• v.17 no.2
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• pp.30-35
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• 2008

Mixed acidophilic bacteria were approached for leaching of cobalt and lithium from wastes of lithium ion battery industries. The growth substrates for the mixed mesophilic bacteria are elemental sulfur and ferrous ion. Bioleaching of the metal was due to the protonic action of sulfate ion on the metals present in the waste. It was investigated that bioleaching of cobalt was faster than lithium. Bacterial action could leach out about 80 % of cobalt and 20 % of lithium from the solid wastes within 12 days of the experimental period. Higher solid/liquid ratio was found to be detrimental for bacterial growth due to the toxic nature of the metals. At high elemental sulfur concentration, the sulfur powder was observed to be in undissolved form and hence the leaching rate also decreased with increase of sulfur amount.