• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
• /
• pp.30-33
• /
• 2001

Melting is one of the most effective treatments for stabilizing heavy metals and also creates high value by-products. In this study, authors evaluated the leaching characteristics of heavy metals in melting slag obtained from incinerator ashes. In order to evaluate the environmental compatibility of the recycled melting slag, the samples analysed various leaching tests of heavy metals were raw incinerator ashes, melting slag and the construction materials recycled from melting slag. As the results: (1) The leaching concentrations of tile melting slag were lower than those of the raw incinerator ashes in the experiment performed in accordance with Korea Standard Leaching Test (KSLT). (2) The result of leaching test with the method of RG Min-StB 93. FGSV Forschungsgesellschaft fur Stra $\beta$ en- und Verkehrswesen) met the requirements in German. (3) The compressive strengths of mortar samples used for evaluating the feasibility of recycling the melting slag as construction materials also showed the suitable range for recycling (4) Melting slag was considered the stable materials with respect to the chemical stability against chemical solutions with various pH conditions.

• Journal of the Korean Wood Science and Technology
• /
• 제42권2호
• /
• pp.157-162
• /
• 2014

This study was conducted to examine the functionality of the fire retardant treated wood. The hygroscopic property, leaching resistance, metal corrosive efficacy and gas toxicity of retardant treated wood were analyzed. Sodium silicate was penetrated to the wood for making fire retardant treated wood. The subsequent treatment agents such as boric acid, ammonium borate, di-ammonium phosphate were treated after sodium silicate treatment due to fixation. As results for the test, the leaching resist was improved by subsequent treatment. The fire retardant combination such as sodium silicate, boric acid and di-ammonium phosphate showed high hygroscopic property, metal corrosive efficacy. The gas toxicity was also satisfied KS standard.

• 산업기술연구
• /
• 제20권A호
• /
• pp.57-62
• /
• 2000

This experiment was done to investigate the leaching and adsorption properties of heavy metals on porphyry. The comparison with respect to the leachability of heavy metals from porphyry between the Korea Standard Leaching Test (KSLT) and the Toxicity Characteristic Leaching Procedure (TCLP) was carried out. The fractional composition of leachate and the total concentration of heavy metal of porphyry were studied through Sequential Extraction Procedure (SEP) and EPA Method 3050. Adsorption experiment of porphyry has pointed out that the optimum dosage of porphyry for 50ppm Pb was over 10g/L, the effective particle size for absorption was below 200 mesh and the optimum pH was about 7. From the Freundlich' adsorption equation, 1/n was 1.0722, and k was 0.0041. After adsorption, the fractional composition of Pb was changed. The exchangeable, carbonate, reducible fractions were increased, and the organic fraction was not changed, and the residual fraction was decreased.

• Journal of the Korean Wood Science and Technology
• /
• 제23권3호
• /
• pp.66-72
• /
• 1995

The rate of fixation of the components were evaluated in CCA-Type B and CCFZ-treated radiata pine sapwood by quantitative analysis of solution expressed from the treated wood. The leaching characteristics of radiata pine blocks treated with CCA-Type B and CCFZ were also evaluated by the AWPA standard leaching test. Both fixation and leaching charactersistics of CCA-Type B were compared with CCA-Type C treated wood samples. The rate of CCA-Type B fixation was a little faster than that of CCFZ. However, significant amounts of arsenic was unfixed in the CCA-Type B treated samples and consequently leached. These significant quantities of arsenic liberated from the CCA-Type B treated wood during service may pose some environmental concerns. Arsenic was no longer detectable from CCA-Type C treated samples when fixation was complete, even though the fixation of CCA-Type C was slower in some degree than CCA-Type B. In summary, it could be said that CCFZ was much safer preservative than CCA-Type B by the criterion based on the relative hazard assessed by absolute amount of unfixed element present in the treated wood. Also the decision that CCA preservative has to move from Type B to Type C should be made sooner or later for continuous use of CCA preservative in the future.

• 환경영향평가
• /
• 제22권2호
• /
• pp.135-145
• /
• 2013

The recycling of coal bottom ash generated from coal power plants in Korea has been limited due to heterogenous characteristics of the materials. The most common management option for the ash is disposal in landfills (i.e. ash pond) near ocean. The presence of large coarse and fine materials in the ash has prompted the desire to beneficially use it in an application such as fill materials. Prior to reuse application as fill materials, the potential risks to the environment must be assessed with regard to the impacts. In this study, a total of nine test cells with bottom ash samples collected from pretreated bottom ash piles and coal ash pond in a coal-fired power plant were constructed and operated under the field conditions to evaluate the leachability over a period of 210 days. Leachate samples from the test cells were analyzed for a number of chemical parameters (e.g., pH, salinity, electrical conductance, anions, and metals). The concentrations of chemicals detected in the leachate were compared to appropriate standards (drinking water standard) with dilution attenuation factor, if possible, to assess potential leaching risks to the surrounding area. Based on the leachate analysis, most of the samples showed slightly high pH values for the coal ash contained test cells, and contained several ions such as sodium, potassium, calcium, magnesium, chloride, sulfate, and nitrate in relatively large quantities. Three elements (aluminum, boron, and barium) were commonly detected above their respective detection limits in a number of leachate samples, especially in the early leaching period of time. The results of the test cell study indicate that the pollutants in the leachate from the coal ash test cells were not of a major concern in terms of leaching risk to surface water and groundwater under field conditions as fill materials. However, care must be taken in extending these results to actual applications because the results presented in this study are based on the limited field test settings and time frame. Structural characteristics and analysis for coal bottom ash may be warranted to apply the materials to actual field conditions.

• International Journal of Concrete Structures and Materials
• /
• 제7권2호
• /
• pp.111-117
• /
• 2013

Heavy oil fly ash (HOFA) is a byproduct generated by the burning of heavy fuel oil. Chemical analysis showed that HOFA is mainly composed of unburned carbon with a significant amount of heavy metals. Due to toxicity, management of this waste poses a challenge to the industry personal. The present study investigates the possible use of HOFA as a black pigment or admixture in cement mortar aiming to produce ornamental brick. In order to investigate the change of cement mortar strength when HOFA is added, the standard compressive strength test with 50 mm cubes was performed. The results showed that the addition of 2-5 % of HOFA in cement mortar does not affect its strength. The leaching behavior of trace elements within HOFA and HOFA mixed mortar were investigated through laboratory batch leaching experiments. The results confirmed that HOFA can be utilized as a black pigment in ornamental brick, which is environmentally safe and provides good balance between color and brick properties.

• 한국결정성장학회지
• /
• 제17권3호
• /
• pp.133-137
• /
• 2007

화력발전소에서 발생하는 저회와 준설공사 시 발생하는 준설토를 효과적으로 자원화하기 위하여 인공경량골재를 만들어 경량콘크리트에 적용 가능한지 물리 화학적 분석을 진행하였다. 서울에서 20 km 서쪽에 위치해 있는 영흥도에서 발생된 저회와 준설토를 이용하여 인공경량골재를 제조하였으며, 모든 원료는 혼합 전 분쇄하여 사용되었다. 제조된 골재는 KS에 의거하여 입도시험, 표건밀도와 흡수율 시험, 안정성, 알칼리 잠재반응, 중금속 용출 시험을 진행하였다. 입도분석에서 굵은 골재는 적정 조립율 값을 나타내었고, 잔골재는 조립율의 범위를 벗어났다. 경량화 될수록 흡수율이 증가하는 사실을 알 수 있었다. 안정성 및 중금속 용출 시험 결과 무해한 것으로 판단되었으나, 알칼리 잠재 반응성 확인 결과 몇몇 조성을 제외하고 무해한 골재로 판정되었다.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2008년도 추계 학술발표회
• /
• pp.1647-1654
• /
• 2008

The characteristics of arsenic(As) contamination were investigated on soils of 3 abandoned metal mine sites in Gangwon-do, Korea. Total forty nine soils were sampled to conduct standard methods(extraction by 1HCl), sequential extraction and column leaching test. Concentration of As extracted by 1N HCl was ordered as follows: A mine > B mine > C mine, and the concentration of arsenic in the soils of A mine was significantly greater than that at any other cases and all samples of A mine were exceeded the national regulation of $6mg \;kg^{-1}$. In the results of sequential extraction, the potential contamination risk for groundwater and plants was ordered as follows: C mine > B mine > A mine because the C mine showed the relatively greater mobility and bioavailability of fraction than any other mines. And, in colume test, concentration of As was ordered as follows: C mine > B mine > A mine, and it was expected that these results were connected with fraction characteristics of the mine sites. Therefore adequate leaching investigations should be used to simulate the effect of natural leaching conditions, and to predict both the potential mobility of metals to groundwater and their bioavailability to plants under natural conditions.

• 산업기술연구
• /
• 제30권A호
• /
• pp.37-43
• /
• 2010

Polymeric materials in addition to Portland cement and hydrated limes were used to solidify heavy metal contaminated tailings from five abandoned metal mines in Korea. Mine tailings were mixed separately with Portland cement and hydrated lime at a concentration of 20-30 wt% and 6-9 wt%, respectively and Ethylene Vinyl Acetate(EVA) powder was added to each specimen at a ratio of 2.5 and 5.0 wt% to binders. Polymer-added and polymer-free solidified forms were evaluated for their appropriateness in accordance with the suggested test methods. Regardless of addition of polymeric materials, all solidified forms satisfy the uniaxial compressive strength(UCS) requirements(0.35MPa) for land reclamation and show remarkably reduced leaching concentrations of heavy metals such as As, Cd, Cu, Pb and Zn less than the toxicity criteria of Korean standard leaching test(KSLT). The addition of polymeric materials increased the UCS of solidified forms to improve a long-term stability of solidified mine tailings.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
• /
• pp.649-654
• /
• 2002

In order to suggest recyling and handling method of a tailing, observe it's physical and chemical properties, make an quality test of aggregates which are used a tailing and then examine a applied possibility in architectural materials. Tailing has a ununiform and many-side shape and it is organized quartz, muscovite, calcite, montmorillonite. pH is 6.86-7.28 and the result of leaching test is that Hg and Pb exceed of a standard. The specific gravity of aggregates which are used tailing is 1.95-2.23 and the absorption factor is 9-14.67%. The result of test for abrasion and crushing of aggregates which are used BFS is very excellent. The heavy metal is stabilized but a eruption property of Hg is similar to original sample.