• Resources Recycling
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• v.27 no.1
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• pp.74-83
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• 2018

This study conducted the Life Cycle Assessment(LCA) on waste rubber recycling technology for recovering rubber product from the waste tires. Environmental impacts were assessed for the five categories of impacts: global warming, resource depletion, acidification, eutrophication, photochemical oxide production, and ozone layer depletion. When recycling 1ton of waste tire containing rubber, global warming impact was 1.77E+02 kg $CO_2-eq.$, resource depletion impact was 1.23E+00 kg Sb-eq., acidification impact was 5.92E-01 kg $SO_2-eq.$, eutrophication impact was 1.23E-01 kg $PO{_4}^{3-}-eq.$, photochemical oxide production impact was 3.42E-01 kg $C_2H_4-eq.$, and ozone layer depletion impact was 1.87E-04 kg CFC11-eq. In terms of overall environmental impacts, carbon, softener and electricity the greatest impact, so it is necessary to compare the environmental impacts of the raw materials to replace carbon and softener, and a method to reduce the filler usage in the process is needed. In addition, it is necessary to improve energy efficiency, change to low-energy sources, and apply renewable energy.

• Resources Recycling
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• v.33 no.2
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• pp.3-15
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• 2024

Environmental awareness is rising worldwide. however, cement manufacturing facilities use recycled resources to improve raw material and fuel substitution rates, contributing to environmental issues such as waste disposal. The emission of sulfur oxides (SOx), an air pollutant, has been regulated by limestone as raw material in cement manufacturing. However, the impact of increasing use of recycled resources on future facility processes and environmental changes is unclear. Therefore, the cement manufacturing facilities require desulfurization-related technologies and research. In this study, we investigated the applicability of desulfurization technology to cement manufacturing facilities and demonstrated various approaches to applying this technology using byproducts generated in cement manufacturing.

• 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.

• Resources Recycling
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• v.6 no.3
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• pp.28-35
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• 1997

Adsorption properities of hcavy metals (Cd, Cu, Fe, Mn, Pb, Zn) and organic compounds (Trichloroethylene and T Tetrachroethy len려 on sh$\xi$1I( oyster and ark shell) were investigated using wat$\xi$r treatment matenals, The shell powder (m띠or C crystal structurc is calcium hydroxide) showed the preference adsorption for heavy metals in order of Mn > Zn > Fe > Cd > eu > P Pb. The high removal capacities of heavy metals arc helicved to be largely due to precipitation by foonation of metal c carhonat,잃 and hydroxides at high pH caused by the $Ca(OH)_2$ component of sl1ell, immobilizatIon of heavy metals in a solid I matrix by calcium‘ and fixation by insoluble organic materials in the oystcr and ark shell. The use of sh려I in water treatment h has the potential to bc benefIcial as a source of inexpensive matcrials‘ moreover, not only treatment of waste but also e environmcntal business including environmental-purification ceramics could be better off by utili낌ng high-valued waste and d developed puri'fication ceramics and media.

• Resources Recycling
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• v.5 no.3
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• pp.24-30
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• 1996

The computcr s~mulatiun model in vanaus s~nelllng process for melling waste cashhg sand was developed by using energy and malcrial balance concept. This modcl can prcdict the coal, flux and oxygen conaumptron and thc volume and temperature of off-gas The ~niljor critical varlablcs for smclting process can be crplained by using the analysis of energy and malc~ialb alance. Thc Innst lmportarlt variables lor smelting process were h i ~ hpo st-combust~anr atla, high heat transfer crficiency and refractory pratcclion lechnalogy. For saving encrg), in this smelting proccss, selection of caw marerials i.e coal, flus was important, cspacially ubi~go f low volatile coal was prufitahle.

• Resources Recycling
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• v.25 no.2
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• pp.17-24
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• 2016

This study aims at evaluating environmental impacts on recycling process of used small household appliances. The recycling process mainly consists of manual dismantling, crushing and various sorting processes to effectively recover valuable resources and to minimize environmental impact. In this study, life-cycle assessment (LCA) methodology is applied to analyze major environmental parameters such as GWP, ADP, POCP, EP, etc. One of the major impact categories on the weight basis in the recycling process is global warming (GWP) 57.1%, next to ADP 35.4% and POCP 4.8%, respectively. As a result of environmental impact on recovery of valuable resources/ton, the GWP of plastics for ABS is highest (33.7%) compared to ferrous metals (9.4%). The effects of environmental and economical benefit are also analyzed to compare with the amount of virgin materials to be recycled by recycled materials. In addition, recycled materials are also more economical in comparison to virgin materials due to the environmental avoiding effect by recycling. In conclusion, the key environmental issues related to the recycling of e-wastes are analyzed and therefore, the effective recycling process will contribute to mitigate global warming potential in the near future.

• Resources Recycling
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• v.26 no.1
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• pp.69-77
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• 2017

Used small household appliances(small e-waste) consists of a variety of complex materials and components. The small e-waste is mainly composed of plastics and an important potential source of waste plastic. The black plastics, particularly are very difficult to separate by resin type and therefore these are mainly recycled in the form of a mixtures. In the present study, the sorting technologies such as gravity and electro static separation, near-infrared ray(NIR) and IR/Raman optical sorting separation on mixture of black plastics were analyzed and their limitations on sorting process were also investigated. The Laser Induced Breakdown Spectroscopy(LIBS) spectrum of each black plastics was used for identification of black plastics by resin type, and after analyzing the normalization operation, Principal Component Analysis(PCA) was carried out. The spectrum data was optimized through PCA process. In order to improve the identification accuracy and sorting efficiency of black plastics, it is necessary to design a classifier with high efficiency and to improve the performance and reliability of the classifier by applying the field of intelligent algorithms.

• Resources Recycling
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• v.20 no.1
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• pp.28-36
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• 2011

More than 50% of refractory materials generated from high-temperature melting furnace was not carbonized and could be recycled by adopting proper separation process. In the present work, the separation of refractory materials has studied by adopting color sorting technology to promote the recycling of waste refractory. Purity of the refractory materials was obtained with at 97.2%, color temperature of sorter light source 6,500K, which gives less interference of surrounding light source. Purity and separation efficiency were improved as size is setting bigger and lower conveyer belt speed. It is revealed that optimum conditions were color temperature 6,500K, conveyer belt speed 1,000 mm/sec, particle size -20 mm, etc. To improve purity and separation efficiency on below 10mm size, the resolution of should be fixed camera and it narrow recognition range. As a result of the study, color sorting technology could be used for separation of waste refractory materials and will contribute to promote the waste recycling.

• Resources Recycling
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• v.29 no.6
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• pp.15-26
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• 2020

In recent years, there is an increasing interest in environmental friendly treatment of waste-plastics in terms of the generation of microplastics. Accordingly, the recycling of waste-plastics is very important because it provides advantages of volume reduction, mitigation of carbon dioxide emission, and reproduction of value-added products. In particular, in order to recycle the eco-friendly waste-plastics, it is necessary to use a physical separation methods, and among them, flotation separation, which can separate material (i.e., polymer component) in waste-plastics is well known as a very effective separation method in terms of material recycle. Therefore, in this review, the research trend of flotation separation for effective separation of mixture waste-plastics was investigated. In addition, through the reported research results, approaches to use as new functional materials from polymers, which are raw materials for waste-plastics, are summarized.

• Resources Recycling
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• v.6 no.2
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• pp.22-28
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• 1997

In recent yean thc problem of wastc plastics arc greatly incrcascd with ihe result uf lndushial growth. As a rcsult the amount of wastc plaslics in domestic area is appraxhnately 2,300,000 t<~nin 1996 base and contmuously increasing more than 12% cvcry ycar. Thc disposal way of these waste plastics arc dlLl malnly rely~ng on landill1 or partially incinuralion So that it hss become a senous social problem due to the second envirnmentd pollution. The tcchnologics iar prducing oil from the waste plastics have hccn dcvelopcd far along pennd and currently some of them are in a commercialiration stage Pyrolysis process in one of the major process m heating waslc plaslics bul still has some restlichons for the cammcrc~dizatian duc lo 11s emnom~cal problems assaciated with a systcmiltlc lecd collcctionidispnsJ ways. Cansldenng cnvaomcnld problems, thc inclease m the charge for waste matcds trcatmcnt and thc lmlitarion ni disposal area, it is inteicstcd that the wastc plastics treabncnt by pyrolysn. which would be the safest and the most eilic~ent process for cnnvcrting fecd wastc to rc-usablc rcsourccs. would he predomhant m ihe near h~lurc Thc shldy aims inr the development of haslc ted~nolagy for scaling up to a com~nercial sire through pyrolys~s process which is cnnduclcd under the absence of air. Furthern~orc the waste plastics can be recycled as iual gas or oil wilhout harmful effects in enviroment, The waste w e d plastics arc pyrolyzed in (he fluidized bcd rcaclor under continuous way and thc ail ylcld gives approx~marcly 47 4%.