• Resources Recycling
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• v.19 no.5
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• pp.68-74
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• 2010

The aim of this study is to investigate the behaviors of synthesis of Calcium Chloroaluminte($11CaO{\cdot}7Al_2O_3{\cdot}CaCl_2$) under the melting temperature of municipal solid waste incineration fly ash(MSWI fly ash); $900^{\circ}C-1300^{\circ}C$ of sintering temperature. A sludge generated from a water purification plant (SW) was also used to fill up $Al_2O_3$ source, which might be deficient in MSWI fly ash. MF and SW were mixed at mixing ratio of 10 to 7, which is the mole ratio of CaO to $Al_2O_3$ of calcium Chloroaluminte. Mixed samples were sintered in the opened sintering reactor and the closed sintering reactor, respectively. The results showed that calcium chloroaluminte was formed at $1,000^{\circ}C$ in both reactors, but the temperature of decomposition of calcium chloroaluminte depended upon sintering reactor type; an opened sintering reactor and a closed sintering reactor, owing to the vaporization velocity of Cl.

• Resources Recycling
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• v.15 no.5 s.73
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• pp.26-32
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• 2006

The waste solution discharged from the LCD manufacturing process contains acids like nitric, acetic and phosphoric acid and metal ions such as Al, Mo and other impurities. It is important to remove impurities less than 1 ppm in phosphoric acid to reuse as an etchant because the residual impurities even in sub-ppm concentration in semiconductor materials play a major role on the electronic properties. In this study, a mixed system of solvent extraction, diffusion dialysis and ion-exchange was developed to commercialize in an efficient system fur recovering the high-purity phosphoric acid. By vacuum evaporation, almost 99% of nitric and acetic acid was removed. And by solvent extraction method with tri-octyl phosphate (TOP) as an extractant, the removal of acetic and nitric acid from the acid mixture was achieved effectively at the ratio A/O=1/3 with 4th stage of extraction stage. About 97.5% of Al and 36.7% of Mo were removed by diffusion dialysis. Essentially almost complete removal of metal ions and purification of high-purity phosphoric acid could be obtained by using ion exchange.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2006.05a
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• pp.90-94
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• 2006

The waste solution discharged from the LCD manufacturing process contains acids like nitric, acetic and phosphoric acid and metal ions such as Al, Mo and other impurities. It is important to removal of impurities to tess than 1ppm in phosphoric acid to reuse as an etchant because the residual impurities even in sub-ppm concentration in semiconductor materials play a major role on the electronic properties. In this study, we have been clearly established that a mixed system of solvent extraction, diffusion dialysis and ion-exchange technique, which made individually the most of characteristics is developed to commercialize in an efficient system for recovering the high-purity phosphoric acid. By applying vacuum evaporation, the yield of the process are almost 99% removal of nitric acid and acetic acid was achieved. And by applying the solvent extraction method with tri-octyl phosphate(TOP) as an extractant, the removal of acetic and nitric acid from the acid mixture was achieved effectively at the ratio O/A=1/3 with four stages and the stripping of nitric acid from organic phase is attained at a ration of O/A=1 with six stages by distilled water. About 97% and 76% removal of Al and Mo were achieved by diffusion dialysis. Essentially complete less than 1ppm removal of Al, Mo by using ion exchange ion resin and purification of the phosphoric acid was obtain.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.11
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• pp.1627-1633
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• 2012

This study was to evaluate the feasibility of recycling the solids separated from swine wastewater treatment process as a fuel source for heat production and to provide a data set on the gas emissions and combustion properties. Also, in this study, the heavy metals in ash content were analyzed for its possible use as a fertilizer. Proximate analysis of the solid recovered from the swine wastewater after flocculation with organic polymer showed high calorific (5,330.50 kcal/kg) and low moisture (15.38%) content, indicating that the solid separated from swine wastewater can be used as an alternative fuel source. CO and NOx emissions were found to increase with increasing temperature. Combustion efficiency of the solids was found to be stable (95 to 98%) with varied temperatures. Thermogravimetry (TG) and differential thermal analysis (DTA) showed five thermal effects (four exothermic and one endothermic), and these effects were distinguished in three stages, water evaporation, heterogeneous combustion of hydrocarbons and decomposition reaction. Based on the calorific value and combustion stability results, solid separated from swine manure can be used as an alternative source of fuel, however further research is still warranted regarding regulation of CO and NOx emissions. Furthermore, the heavy metal content in ash was below the legal limits required for its usage as fertilizer.

• Applied Chemistry for Engineering
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• v.25 no.1
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• pp.103-106
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• 2014

Recycling of bottom ash from municipal solid waste (MSW) incinerator has been strictly limited due to its composition of high level chlorine and other unfavorable substances. The composition of MSW has been, however, changed after the introduction of garbage-bag sales system, extended producer responsibility (EPR) policy and the prohibition of direct landfill of food waste. Recent waste shows reduced moisture and chlorine content, increased calorific value due to the separation of food waste, incombustible materials and PVC. The main purpose of this study is to investigate the trend of composition changes of MSW incinerator bottom ash and to compare the analytical results with those before the separation system was introduced. CaO content of bottom ash, one of the major component of cement clinker, increased from 26.7% in 2001 to 34.0% in 2006. The chlorine content showed a dramatic decrease from 1.84% in 2001 to 0.00655% in 2006, which is closely compatible with that of the fly ash of coal-utilizing thermal power plants, which is mainly due to the changes of MSW composition. It is eventually considered that there is a possibility of utilizing the incinerator bottom ash as a raw material of cement clinker feed substances.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.2
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• pp.52-60
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• 2004

The basic approach to sewage sludge is organic waste minimization, promotion of energy recovery; volume and weight reduction by final treatment, and environmentally final disposal of natural circulation. Dry and pyrolysis of maize was experimentally investigated in full-scale rotary kiln in semi-continuous operation. The operational parameters varied are the operating temperature $160{\sim}175^{\circ}C$ of dry and $450{\sim}800^{\circ}C$ of pyrolysis, the solids residence time 9 min for pyrolysis. Important parameters studied include the running time, water content of sewage sludge, solids amount of sewage sludge(TS%) by the varied temperature. Also, with the increasing of temperature, how the yield of oil and char product change was observed, and the distribution of gas production components was observed. The gas of $C_1{\sim}C_3$ yield increased and oil of $C_4{\sim}C_6$ yield decreased along with pyrolysis temperature of $670^{\circ}C$ by the run time of 9 min.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.1
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• pp.43-46
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• 2010

As one of the methods for recycling the FRP used for the small and medium-sized waste ships, separation of the roving layer from the mat has some merit in a sense of the recycling energy and the environmental effects. Similar characteristics between the roving and the mat make the mechanically automatic differentiation difficult. They, however, contain different ratio of the resin and the glass and the thickness. In this study photo physical differentiation between the two layers has been made using (1) boiling concentrated sulfuric acid which can dissolve the resin in the FRP layer and (2) hydrogen fluoride(HF) solution which can reacts with $SiO_2$ fragments of the glass. Furthermore coloring the FRP sample with water-soluble dye following the HF treatment makes the roving layer more distinguishable photophysically. The implementation of HF treatment has been successfully tested in this study.

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.87-92
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• 2010

This study evaluates the laboratory properties of asphalt binder and mixture modified with R-EPDM(Recycling Ethylene Propylene Dien Monometer), which consists of R-EPDM as a main ingredient that is an industrial by-product made by manufacturing waste EPDM below 50 mesh as an additive. Superpave system was used to determine the PG(Performane Grade) and evaluate the property of R-EPDM modified binder. OACs(Optimum Asphalt Contents) of R-EPDM modified asphalt mixtures were determined by Superpave mix design using gyratory compactor and wheel tracking test and moisture susceptibility test were carried out with R-EPDM modified asphalt mixtures at OACs. The results from these tests, rutting-resistance and freezing and thawing resistance by moisture susceptibility of R-EPDM modified asphalt mixtures were superior to one of general asphalt mixtures(AP-5).

• Resources Recycling
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• v.25 no.6
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• pp.82-91
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• 2016

The framework act on resource circulation was got through the Korea National Assembly in May, 2016. It is the most important to analyze and understand its purpose, main contents, and policy direction of the framework act because this act will lead the resource circulation policy. Korea government is going to enact subordinate statutes such as its enforcement decree and regulation to enforce the act in January, 2018. No later than enforcement of the act, its subordinate statutes should be studied indepth and consulted without any bias in order to satisfy the intent - promotion of transition toward a resource circulation society - of the act. Therefore, in this study, the points in dispute in the act are indicated and the issues and specific directions of key articles are reviewed. The ideas to maximize the effectiveness of its subordinate statutes are also suggested.

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.1
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• pp.93-101
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• 2011

The modeling of SDR was carried out for the application of the solid waste incineration system. To find optimum operating condition for removal of acidic gases, computation fluid dynamic(CFD) model was used. In this study, the temperature profile of SDR(spray dry reactor) and the gas velocity profile for different models were investigated. In this model, the diameter of SDR was 3 meter and the height of SDR was 9 meter. The amount of inlet combustion gas of SDR was $6,125Nm^3/hr$ and the inlet temperature of SDR was 493 K. The amount of lime injection of SDR was 151 kg/hr. When the inlet shape of SDR was changed, the temperatur of SDR was changed and the gas velocity of SDR was 0.48 m/sec to 1.17m/sec and the outlet gas velocity of SDR was 6.9 m/sec to 7.42m/sec As a result of modeling, the average velocities in SDR and outlet were 0.489 m/sec and 7.424 m/sec, respectively, in which the temperature of outlet in SDR was 448 K.