• Journal of Korean Society of Environmental Engineers
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• v.33 no.10
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• pp.767-773
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• 2011

The purpose of this study was to investigate the possibility of an alternative fuel resource by incinerating a mix of combustible MSW (municipal solid waste) and offals after separating recyclable material at the MRF (material recovery facilities) location. We analyzed the physical and chemical properties including the 3-contents, the calorific value, and chemical compositions of the separation rejects in MRF, and compared the results with combustible MSW. Moreover, we experimented the trend of combustible properties and the concentration change of air pollutants at mixed incineration in the MSW incinerator. According to the results of the experiment, the separation rejects showed higher heating value (5,865 kcal/kg), and lower moisture and ash content than combustible MSW. Since we have incinerated MSW in the MSW incinerator mixing the offals at 30% and 50% respectively, we know that the change of the concentration of dust, $SO_2$, $NO_2$, and CO did not appear significant, and not exceed the pollutants emission regulation. But, considering the enhancement of the HCl emission concentration (max. 33.7 ppm) at the co-incineration of the 50% offals, we believe that the proper mixing ratio of the separation rejects would become within 30%.

• Resources Recycling
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• v.25 no.1
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• pp.40-47
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• 2016

Nickel laterite ore is classified into two principal ore types: saprolite (silicate ore) and limonite (oxide ore). Saprolite-type ore characterized by high magnesia and silica contents is treated by pyrometallurgy process. On the other hand, limonite-type ore is subjected to hydrometallurgy process to produce nickel products. Hydrometallurgy process requires that a raw material to meet the demands that Si+Mg contents lower than 10% and Fe content over than 40%. It is therefore required that separation of saprilite-type ore to use nickel laterite ore as a raw material for hydrometallurgy process. In this study, separation of sparolite-type ore and limonite-type ore from nickel laterite ore from New Caledonia has been tried by dry classification. The results show that -5 mm size fraction and +5 mm size fraction of the nickel laterite ore contains mainly limonite-type ore and saprolite-type ore, respectively. To understand the moisture content of the raw ore on the dry classification, nickel laterite ore with different moisture contents of 23.0% and 9.1% were subjected to the dry classification. The results show that drying of the ore makes the separation more efficient as the amount of the fine product, that can be subjected to hydrometallurgy process without further separation or drying operations, was increased.

• Journal of the Korean Institute of Gas
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• v.25 no.3
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• pp.1-8
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• 2021

Among the flare systems that handle discharged substances from safety valves, the knockout drum was a key facility for safety, but the installation standards were not clear, so it was necessary to review the standards acceptable to the workplace and regulatory agencies. After investigating the domestic and foreign technical standards of knockout drums and the deficiencies of previous studies, research was first conducted on the degree of mass discharge, the installation location of the intermediate knockout drum, and the effect of changes in the composition of the discharged material. As a result of the study under the process simulation conditions, the gas-liquid separation of the knockout drum was completed in a small amount of less than 7,500kg/hr. However, when more than that was released, the gas-liquid separation effect was small even with the addition of an intermediate knockout drum. In addition, when the composition ratio of the material easily condensed was increased (molar fraction 10%), the gas-liquid separation effect of the knockout drum increased in the case of mass release. The gas-liquid separation effect was analyzed to be greater when the knockout drum was installed adjacent to the stack than the knockout drum was installed adjacent to the process equipment.

• Membrane Journal
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• v.33 no.3
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• pp.94-109
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• 2023

1,3-Dioxolane is an exciting material that has attracted widespread interest in the chemical, paint, and pharmaceutical industries as a solvent, electrolyte, and reagent because 1,3-dioxolane is not toxic, carcinogenic, explosive, auto-flammable, and multifunctional, and due to their excellent miscibility in most organic and aqueous solvent conditions. Recently, this material has received increasing attention as a CO₂-selective polymer precursor to separating CO₂ from flue gas and natural gas mixtures. Poly(1,3-dioxolane) (PDXL) possesses higher ether oxygen content than polyethylene oxide (PEO), which demonstrates superior membrane CO₂/N₂ separation properties owing to their polar ether oxygen groups exhibiting strong affinity toward CO₂. Thus, PDXL-based membranes displayed an outstanding CO₂ solubility selectivity over non-polar (N₂, H₂, and CH₄) gases. However, the polar groups of PDXL, like PEO, promote chain packing efficiency and cause polymer crystallization, thereby reducing its gas permeability, which should be improved. In this short review, we discuss the recent advancement and limitations of PDXL membranes in gas separation applications. To conclude, we provide future perspectives for inhibiting the limits of 1,3-dioxolane-based polymers in the CO₂ separation process.

• Resources Recycling
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• v.16 no.6
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• pp.3-9
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• 2007

Although the ferrous material was separated by the magnetic separation before the incineration process, the municipal solid waste incineration bottom ash generated during incinerator in metropolitan area consists of many iron products which account for about $3{\sim}11%$ as well as ceramics and glasses. The formation of $NiFe_2O_4$ and $FeCr_2O_4$ with a $Fe_3O_4-Fe_2O_3$ (similar to pure Fe) on the surface of iron product was found during air-annealing in the incinerator at $1000^{\circ}C$, because Ni and Cr has a chemical attraction about iron is using to coat with Ni and Cr metals for poish or to prevent corrosion. Therefore, Fe-Ni Cr oxide can be formed on durface of the iron product and it can be separated from bottom ash through the magnetic separation. So, in this study, the separation ratio of heavy metals as magnetic separation and mineralogical formation of Fe-ion(heavy metal) in ferrous metals corroded were investigated. As the result, the separation ratio of Ni and Cr based on particle sizes accounted for about $45{\sim}50%$, and Cu and Pb accounted for below 20%. Also, the leaching concentration of Ni and Cr in bottom ash separated by magnetic separation was lower than that in fresh bottom ash.

• Journal of Environmental Science International
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• v.17 no.11
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• pp.1235-1241
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• 2008

Membrane separation is extensively used for water/wastewater treatment because of its efficiency separation processes. However, particles in the feed water can deposit and accumulate on the membrane surface to created cake layer. As a consequence, the selectivity of the membrane and flux through the membrane are decreased, which is called fouling/blocking phenomenon. In order to solve fouling problem, we developed a novel membrane named Carbon Whisker Membrane (CWM) which contains vapor-grown carbon fibers/whiskers on the surface of the membrane and a layer of carbon film coated on the ceramic substrate. We firstly employed polymethyl methacrylate (PMMA) as a testing material to investigate the fouling mechanism. The results suggested that Carbon Whiskers on the surface of the membrane can prevent the directly contact between the membrane body and particles so that the fouling/blocking could not occurred easily compared to the membrane without carbon whiskers. We also researched the relationship with the diameter, density of carbon whisker on the membrane surface and total flux of solutions. Finally, we will be able to control the diameter and density of carbon whiskers on the membrane and existence of carbon whiskers on the membrane, it is important factor, might be prevent fouling/blocking in the water treatment.

• Journal of Hydrogen and New Energy
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• v.26 no.1
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• pp.45-53
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• 2015

The objective of this study is to develop a gas pro-treatment system for DME synthesis, wherein this system separates $CO_2$ from Flaring gas as Membrane, in order to save raw material ($CH_4$) cost of DME. In this study, hollow fiber membrane is developed, which is able to separate high-pressure gas, supported by polysulfone and coated with amorphous fluorinated polymer. Throughout the evaluation of the membrane's separation characteristics, the membrane is applied to this system. The membrane is designed by 2 stages for over 90% removal rate of $CO_2$ and over 90% recovery rate of $CH_4$. The bench scale of pro-treatment system is developed as $25Nm^3/hr$.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.193-197
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• 2001

This study was carried out to recover gold, silver and other valuable metals from the printed circuit boards (PCB) of waste computers. PCB samples were crushed to under 1mm by a shredder and initially separated into 30% conducting and 70% non-conducting materials by an electrostatic separator. The conducting materials, which contained the valuable metals, were then used as the feed material for magnetic separation where it was found that 42% was magnetic and 58% non- magnetic. The non-magnetic materials contained 0.227mg/g Au and 0.697mg/g Ag. Further leaching of the non-magnetic component using 2.0M sulfuric acid and 0.2M hydrogen peroxide at 85$^{\circ}C$ extracted more than 95% copper, iron, zinc, nickel and aluminium. Au and Ag were not extracted in this solution, however, more than 95% of Au and 100% of Ag were selectively leached with a mixed solvent (0.2M ammonium thiosulfate, 0.02M copper sulfate, 0.4M ammonium hydroxide). Finally, the residues were reacted with a NaCl solution to leach out Pb while sulfuric acid was used to leach out Sn. Recoveries reached 95% and 98% in solution, respectively.

• Elastomers and Composites
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• v.33 no.1
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• pp.37-43
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• 1998

The permeation of gas through polymer membrane at temperatures above its glass transition, generally occurs by a solution-diffusion mechanism. This mechanism is performed by the affinity difference between polymeric materials and gas molecules, and various technologies, such as copolymerization, impregnation and so on, have been researched to improve the affinity of polymeric material for the gases. In this study, permeability and selectivity for some gases were obtained from steady-state rates of gas permeation through silicone rubber membrane which is prepared by supercritical fluid extraction method. The permeability was measured by the volumetric method proposed by Barrer. Permeability was increased generally with temperature and permeation pressure. Silicone rubber membrane shows a higher permeability to $CO_2$ than to $O_2$, $N_2$. This results probably reflect the relatively high solubility of CO_2 in silicone rubber membrane, which is due to the affinity of $CO_2$ molecules. Since separation powers of $CO_2/N_2$, $CO_2/O_2$ were more than 200, and 100, respectively, it is able to separate $CO_2$ from the air, and the optimum temperature and pres-sure was 328.15 K, 60 cmHg respectively. In future, it is possible that the silicone rubber membrane can be used for separation or concentration of $CO_2$ through experiment for mixed gas separation.

• Journal of the Korean Electrochemical Society
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• v.1 no.1
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• pp.18-23
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• 1998

Theoretical model has been derived in the electrophoretic separation system where an electric potential is applied to the system in the axial direction. The effect of electrophoretic convection in the polymeric media is significantly contributed to separate large ionic-molecules because the conformation of large ionic-molecule quickly orients in the field direction. The dependence of the transport in the polymeric media upon field intensity and molecular size aids in understanding the transport of large ionic-molecule in the system, since the convective velocity of large ionic-molecule is accelerated inside a porous material. The separation of two different large ionic-molecules is predicted with a value of $(Pe_t/Pe_g)$ of individual large ionic-molecule using an operator and the reptation theories.