Recycling of incineration ash generated from domestic waste incinerators is important from environmental and energy conversation aspects. The main components of bottom ash are CaO, Al2O3, SiO2, P2O5, MgO, and Fe2O3, similar to geological components. However, it also contains heavy metal ions such as Cu2+, Pb2+, and Cr6+. The ash material was sintered at 1100 ~ 1150oC by adding pink kaolin to stabilize those heavy metals. The study analyzed the crystal phase and absorption rates of the sintered material for application as a sub-base layer material for roads and conducted tests for the requirements for sub-base layer materials for roads, such as CBR test, quantity of abrasion, and liquid limit. Considering the plasticity, water absorption, and compressive strength of the road base, the mixture with 76wt% bottom ash and 24wt% pink kaolin after sintering at 1,120oC, showed CBR test result of 33.0, quantity of abrasion of 30.3, and liquid limit of NP (no plasticity). These result indicated the possibility of using bottom ash as a sub-base layer material, which satisfied requirements of the standard specification for road construction.

The purpose of this study was to analyze the physicochemical characteristics of bottom-ash recycling from municipal solid waste incineration (MSWI) and investigate the possibility of the use of bottom ash for Lightweight Aggregate for Structural Concrete and Bottom Ash Aggregate for Road Construction according to Korean Industrial Standards (KS). Samples were taken from the MSWI bottom ash collected at the resource recovery facilities “A” and “B.” In the results, both samples did not satisfy the criteria of the particle sizes. In particular, the two samples failed to comply with the physical and chemical characteristics criteria of the Lightweight Aggregate for Structural Concrete. On the other hand, both bottom ash samples met the physical characteristics criteria of the Bottom Ash for Road Construction. Therefore, the recycling of Bottom Ash Aggregate for Road Construction can be more a suitable method for recycling, provided that proper pre-treatment as a screening process for bottom ash is performed.

According to a report ‘2012 Present Condition of National Household Refuse Resource Recovery Facility’, about 582,178 tons/year of household refuse were processed in the incineration plant, and 465,087 tons/year of bottom ash and 117,091 tons/year of fly ash were produced respectively. As incineration ash contains many kind of heavy metals such as soluble salt, copper and lead, it may lead to the leaching potential of heavy metals according to the environmental change, so it requires special care in landfill and recycling. In this study CO2 was injected into the bottom ash, so that environmental stability such as leaching of heavy metals was reduced and increased the possibility of CO2 fixation ability of the bottom ash was analyzed. Bottom ash of the household refuse incineration plant of I City was used as the sample of the fixation ability particle size was divided into 3 sections to analyze its components before and after carbonation using XRF. Stability of the sample was identified by the leaching test through KSLT and TCLP, and CO2 fixation ability by the DT-TGA analysis. Test results of the fixation ability shows that stabilization of the bottom ash produced in the household refuse incineration plant by carbonation is evaluated as there is little environmental problem caused by heavy metals when it is utilized into the recycled aggregate, and economic profits can be expected due to securing new agents of the supply and demand for the recycled aggregates, the greenhouse gas emission reduction by CO2 fixation.

Municipal Solid Wastes (MSW) are disposed of three types (recycling, incineration, landfill). The ashes made after the incineration are also recycled to minimize the volume of waste owing to reducing the amount of landfill. However, MSW incinerations (MSWI) in Seoul are not satisfied with the policy of Korea as a result of experiments about the chemical characteristics of the ash (Ignition loss, pH, Chloride, Cyanide, metals leaching). So, according to the policy, the MSWI in Seoul must be pretreated so as to recycle the MSWI. There are many pretreatments, three pretreatments (washing, weathering, CO2 aging) of which are selected through the literature review. Through Washing, the value of pH and chloride decrease. The optimal ratio (S/L) and time of Washing treatment is 1 : 10 (S/L) and 60 minutes, respectively. The CO2 aging method compensates the defect of weathering method which is required to react long-period time. After CO2 aging, pH and some Heavy metals decrease. So, We will compare and evaluate pre-treatment methods and we find the best method or new method.

Along the increases of incineration bottom ashes emitted from the municipal solid waste incinerator, the issues, such as increased treatment costs, environmental problems and lack of land area for incineration treatment facility have raised. Therefore, this study was performed to analyze the incineration bottom ash to seek how to recycle the resources. The particles of bottom ash discharged as municipal solid wastes are not even and composed of inorganic substances such as iron and non-metals; in this study, therefore, the bottom ash are used as the basic data for the purpose of resource recycle. In this study, the waste incineration bottom ash emitted from the incineration treatment facility located in city C were analyzed. About 100 tons of municipal solid waste are incinerated in this facility on a daily basis. The particle size, XRF, TGA and ICP were analyzed for bottom ash. A LA-950(Laser Scattering Particle Size Analyzer) was used to perform a particle size analysis and as a result, the particle diameter of a large range was distributed and the particle diameter was shown to be wide so not evenly distributed. The distribution of particle diameter for each sample was shown to be inconsistent. XRF used an EDX-750 (Shimazu) to analyze the chemical components and as a result, the key components contained in the bottom ash included CO2, CaO, SiO2, Al2O3, B2O3, etc. The analysis revealed that CaO contained to be lower than other area. TGA / DSC 1 / 1600 LF(Mettler-Toledo AG) were used to analyze TGA and the heating rate of 10℃/min was applied up to the maximum temperature 1200℃. As a result, the sample of incineration bottom ash showed its significant reaction at around 700℃. In general, when temperature of bottom ash starts raising, the moisture started to evaporate at around 100℃ while a significant decline is observed in weight. However in this study, no significant change was observed around 100℃ followed by the pre-processed and bottom ash. ICP used 820 ICP-MS (Bruker, Germany) to analyze the heavy metal - As, Cd, Cr, Cu, Hg and Pb. 3 different bottom ash were divided into 3 samples and as a result, the average concentration of each substance was analyzed as As 0.0049ppm and Cu 0.006ppm, whereas the concentrations of Cd, Cr, Hg and Pb were observed to be less than the quantization limit; therefore, the concentrations of all 6 items were shown to be less than the hazardous level of the specified wastes.

In this work, we constructed the sulfur polymer cement(SPC) concrete using coal bottom ash from 4 thermal power stations in korea and investigated their practical data for production of industrial construction compounds. To manufacture the SPC concrete, we used batch concrete mixer with the heating jacket using hot oil. Also, coal bottom ash was used as a fine aggregate below 2 mm. When the SPC concrete were produced with diverse sulfur concentration (15, 20, 25, 30 wt%), compressive strength properties were analyzed. We got the compressive strength of the maximum 60 MPa. These experimental results could be effectively applied to the recycling technology of coal bottom ash.

A general method to expand the urban green space is to utilize the artificial ground that is unutilized in cities, such as buildings and rooftops. The processing technology of bottom ashes in thermal power stations shows a tendency to change from the wet process to the dry process. The dry process bottom ashes, which arise from the new process, are expected to be utilized as light-weight artificial soil, because they are poor in water, salt, and unburned carbon, which are not the characteristics of the existing wet process bottom ashes, and have a lower density than general aggregate. This study shows that the coefficient of permeability, saturation bulk density, pH, EC, and organic matter content of dry process bottom ashes are similar to those of perlite. Therefore, we conclude that dry process bottom ashes can be utilized as artificial soil.

화력발전소에서 2011년 약 123백만톤의 석탄을 소비하고 있다. 이 석탄을 연소하는 과정에서 석탄회가 발생되는데 이러한 석탄회는 Fly Ash(비산재)의 형태로 배가스와 함께 배출되거나 Bottom Ash(바닥재)의 형태로 보일러 하부에 잔류하게 된다. Fly Ash는 그 크기가 대략 10-30 μm으로 발생량은 시스템에 따라 다르나 전체회 발생량의 약 80~85%를 차지하며 나머지 약 15~20%에 상당하는 석탄회는 대략 1~2.5mm 크기의 Bottom Ash로 보일러 하부에 모인다고 보고되어 진다. 이러한 석탄회의 발생량은 계속 증가하여 2007년에는 한국의 석탄회 발생량이 620만톤이었지만 2011년에는 910만톤으로 증가하는 추세이다. Fly Ash는 전기집진기나 여과 집진기 등에서 배가스로부터 분리되어 콘크리트 혼화재나 시멘트 클링커 등으로 재활용되고, 보일러 하부에 모인 Bottom Ash는 Grinder로 분쇄 후 해수를 이용하여 대부분 회사장으로 폐기되고 있다고 보고되어 진다. 이와 같이 재활용되지 못하고 폐기되는 석탄회는 여러 가지 환경문제를 야기하고 있어 이의 재활용률을 높이고자 많은 연구와 개발이 수행되었다. 하지만 국내 석탄회의 재활용은 대부분 Fly Ash의 재활용에 의한 것으로서 Bottom Ash의 재활용은 매우 미미하며 대부분 회사장으로 폐기되고 있는 실정이다. 본 연구자는 회사장에 폐기되고 있는 Bottom Ash를 대상으로 미연탄소를 에너지자원으로 회수 하기 위하여 Bottom Ash 내의 미연탄소 회수 연구를 진행하였다. Bottom Ash내에 함유되어 있는 미연탄소를 비중분리와 체가름, 자력선별 등 물리적선별을 통하여 3283cal/g로 달성하였으며, 이후 물리화학적 선별인 부유선별을 통하여 pH변화, 기포제 첨가량 변화, 포수제 첨가량 변화, 광액의 농도, 부유시간에 따라 실험을 진행해본 결과 회수된 미연탄소가 5000cal/g을 넘는 부유물을 회수할 수 있었다.

Recently, in our country has been heightened awareness of the performance of non-combustible construction materialsand eco-friendly. In addition, bottom ash can be used as a high-value, but it is a situation that is buried. Therefore, thebasic experimental study results on the development possibility of eco-friendly nonflammable floor finishing materialsusing the bottom ash, which is an industrial byproduct, are as follows: (1) As a test result of the compressive strengthof mortar conducted to review the use possibility of bottom ash as a floor finishing material, the standard mix that didnot use bottom ash showed 31.3MPa, a 25% replacement mix showed 33.7MPa and a 50% replacement mix showed33.6MPa. Consequently, higher results of the compressive strength of mortar were demonstrated up to the 50%replacement mix, compared to the standard mix. (2) As a flow test result by addition of superplasticizer, the flow was215mm in the 0.2% added mix, and 253mm in the 0.4% added mix. However, material separation was confirmed inthe case of the 0.4% added mix. Therefore, the addition meeting 190mm set forth in the KS F 4041 was 0.2%. (3) Asa result of bond strength test to review bond strength with concrete structure, it was 1.26MPa in case polymer powdercontent was 2%, except for 1.02MPa of basic mix, and it was 1.75MPa in the case of 4%, and all these met1.2MPaand more of bond strength set forth in the KS. (4) As a result of a wear resistance experiment conducted to review theuse possibility as a floor finishing material for parking lot, the mix meeting 0.15mg/mm2 or less of wear resistance setforth in the KS F 4041 was the case of 4% of polymer powder addition, which showed 0.13mg/mm2.

The components of municipal solid waste incineration bottom ash produced over 3 million ton every year are similarto the components of geological features, therefore it is suitable to be used as the raw materials of lightweight aggregate.Development of lightweight aggregate using this bottom ash will be helpful to solve landfill and environmental problems.Lightweight aggregate was developed at 1,110oC by using clay, kaolin, bentonite and silica as the raw material to 50%of municipal solid waste incineration bottom ash. Silicon carbide (SiC) was used as a blowing agent. Optimal mixingratio is bottom ash 50%, kaolin 22%, clay 22%, bentonite 6% and blowing agent 0.1%. As the result of quality test,produced lightweight aggregate met the all appraisal standards. The result of heavy metal leaching test was much lowerthan the elution reference value of ceramic manufactures made by using bottom ash.

최근 환경적 · 사회적으로 문제가 되고 있는 산업폐기물을 지반공학적 재료로 재활용하기 위한 관심이 확대대고 있는 추세이다. 따라서 본 연구에서는 화력발전소의 대표적인 산업부산물인 석탄회 중 저회의 도로 성토용 재료 및 구조물 뒤채움용 재료로의 이용을 위해 폐어망보강 저회의 CBR 특성을 분석하였다. 폐어망의 보강 방법은 지오그리드와 같은 층보강 형태, 그리고 단섬유처럼 불특정보강 형태를 이용하였고, 지지력 시험 결과 CBR 값은 짧게 잘라서 랜덤하게 혼합한 경우보다 층으로 보강하였을 때 더 높은 결과 값을 나타내었다. 또한 보강 층수가 증가할수록 보강효과도 증가하는 경향을 보였다.

석탄은 풍부한 매장량과 공급원의 안정성 등으로 화력발전의 근간이 되는 연료광물이다. 에너지를 생산하기 위한 과정에서 지속적으로 석탄회가 발생되는데, 석탄의 연소과정에서 발생되는 석탄회의 발생량은 약 840만톤에 달한다. 석탄의 연소과정에서 발생되는 석탄회는 포집되는 장소에 따라 플라이애쉬, 신더애쉬, 바텀애쉬로 구분되어진다. 바텀애쉬의 경우 보일러 노벽, 과열기, 재열기 등에 부착해 있다가 자중에 의해 보일러 바닥에 떨어진 애쉬로서 플라이애쉬에 비해 입도가 굵으며 총 석탄회 발생량의 약 10 ~ 15%를 차지하고 있으나 발생량에 비해 이를 처리하기 위한 매립지나 처리시설의 확보가 어려워 바텀애쉬의 처리에 대한 문제가 크게 대두되고 있으며, 선진국의 경우 바텀애쉬를 활용하기 위한 연구가 활발한 반면에 국내의 경우에는 이에 대한 체계적인 연구가 미흡한 실정이다. 또한 석탄회 중 약 75 ~ 80%를 차지하는 플라이애쉬는 시멘트와 포졸란 반응의 효과로 콘크리트 혼화재로 재활용이 되고 있지만 바텀애쉬는 단순 매립용 자재로만 활용되고 나머지는 전량 매립되고 있어 이를 활용하기 위한 연구가 절실히 요구되고 있다. 본 연구는 바텀애쉬를 부가가치향상을 시키기 위한 기초연구로서 화력발전소 바텀애쉬 시료의 물리적 특성을 연구하였다. 입도분석결과, 50*100 mesh 입도구간에 무게비 21.60%로 가장 많이 분포하고 있었으며, 100mesh이상이 약 85%였고, 평균입경(D50)은 약 535 μm로 나타났다. XRF 분석결과, 대부분의 입도 구간에서 Fe₂O₃의 함량이 높게 나타났고, 입도가 큰 구간(4*8, 10*16 mesh)의 CaO 함량이 입도가 작은 구간(50*100, 100*170, 270*325 mesh)에 비해 CaO의 함량이 더 높은 것을 확인할 수 있었다. XRD 분석 결과, 석영, 방해석, 트리디마이트, 크리스토발라이트, 명반석, 마그네타이트, 헤마타이트가 주요 구성광물로 나타났다.

In this work, lightweight brick was prepared from aluminum dross, MS and MBA. Aluminum dross is discharged as by-product through the process of aluminum smelting. It can be used as foaming agent, because it produces hydrogen gas due to the reaction with alkali activator. In this study, the specific gravity and compressive strength of prepared brick was discussed with the addition of aluminum dross. Compressive strength, flexural strength and specific gravity was 36 MPa, 2.6 MPa and 1.48 at mixing ratio of 0.9wt% aluminum dross, respectively. The physical property of brick was debased with the addition of aluminum dross. Because the pore size was bigger in accordance with the addition of aluminum dross.

Recycling the bottom ash from MSWI (Municipal solid waste incinerators) ash is required to reduce the secondary pollution. We characterized the bottom ash and investigated the possibility of application for subsidiary ceramic raw materials. Major components of bottom ash are analyzed as CaO, Al2O3, SiO2, P2O5, MgO, Fe2O3, which are the same components of the earth’s crust. This similarity of components implied that bottom ash could be recycled as ceramic products through systematic treatment. Considering the plasticity and water absorption results, the ceramics, which are the mixture with 74 wt % bottom ash and 26 wt% Pink Kaolin, showed 1.39% water absorption after sintering 1150oC for 1h. This result indicated the possibility of recycling of bottom ash for subsidiary ceramic raw materials.

Recycling of bottom ash which is the part of the non-combustible residues of waste combustion is very important for saving energy and resource recycling. In this research, we tried to develop recycling method for the bottom ash as the roadbase, the layer of aggregates under the paved layer of a road. We first removed ferrous and non-ferrous metals from the bottom ash with a 20 mm mesh strainer. After grinding ceramics and glass using jaw crusher, we mixed them with the bottom ash, and then they were further finely grounded up to the particle size less than 150 mm with ball mill. XRD analysis of the final ground material showed that the main ingredients were CaO, SiO2, Al2O3, P2O5, Fe2O3 and MgO. Also there were some heavy metals such as Cu2+, Pb2+ and Cr6+ in it. To make roadbase out of the processed bottom ash, we mixed it with purified sludge, pink kaolin (from Hadong, Gyeongnam, Korea), and silica sludge, and fired in an electric kiln at 1150 ~ 1200oC. Finally, the usefulness of the roadbase made of bottom ash was analyzed by testing absorption rate, crystallizing and strength as well as indoor California Bearing Ration (CBR) test, abrasion test, sand reduction test. The developed material from recycling the wasted bottom ash satisfied the requirement of roadbase properties.