• Journal of Industrial Technology
• /
• v.20 no.A
• /
• 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.

• Korean Journal of Soil Science and Fertilizer
• /
• v.48 no.1
• /
• pp.64-71
• /
• 2015

Soil contamination with arsenic and heavy metals is a worldwide problem. Main objective of this research was to evaluated effects of reducing heavy metal leaching under reduced soil condition amended with industrial by-products. The contaminated soil was amended with 3% (w/w) of limestone (Ls), steel slag (SS) and acid mine drainage sludge (AMDS). Synthetic acid rain ($H_2SO_4:HNO_3=6:4$, pH 5.5 fixed) was used for feeding solution with flow rate of $0.78{\sim}0.88mL\;min^{-1}$. Results showed that similar pH and EC of leachate was observed in all treatments regardless of applied industrial by-products. However, arsenic concentration of leachate increased when industrial by-products were mixed. Meanwhile, concentration of heavy metal in the leachate decreased from 11.3 to 4.59 mg for Cd, from 92.3 to 7.93 mg for Pb, and from 11,716 to 1,788 mg for Zn via immobilization in soil with AMDS amended, respectively. Overall, application of industrial by-products can be an environmentally-friendly way to remediate soil and(or) leachate contaminated with metal(loid)s in metal mine site.

• Journal of Environmental Science International
• /
• v.26 no.8
• /
• pp.955-966
• /
• 2017

Amendment of multi-binders was employed for the immobilization of metal(loid)s in field-contaminated soils to reduce the leaching potential. The effect of different types of multi-binders (lime/diammonium phosphate, diammonium phosphate/ladle slag and lime/ladle slag) on the solidification/stabilization of metal(loid)s (Pb, Zn, Cu and As) from the smelter soil and mine tailing soil were investigated. The amended soils were evaluated by measuring Toxicity Characterization Leaching Procedure (TCLP) leaching concentration of metal(loid)s. The results show that the leaching concentration of metal(loid)s decreased with the immobilization using multi-binders. In terms of TCLP extraction, the mixed binder was effective in the order of lime/ladle slag > diammonium phosphate/ladle slag > lime/diammonium phosphate. When the mixed binder amendment (0.15 g lime+0.15 g ladle slag for 1g smelter soil and 0.05 g lime+0.1 g ladle slag for 1 g mine tailing soil, respectively) was used, the leaching concentration of metal(loid)s decreased by 90%. However, As leaching concentration increased with diammonium phosphate/lime and diammonium phosphate/ladle slag amendment competitive anion exchange between arsenic ion and phosphate ion from diammonium phosphate. The Standard, Measurements and Testing programme (SM&T) analysis indicated that fraction 1 (F1, exchangeable fraction) decreased, while fraction 4 (F4, residual fraction) increased. The increased immobilization efficiency was attributed to the increase in the F4 of the SM&T extraction. From this work, it was possible to suggest that both arsenic and heavy metals can be simultaneously immobilized by the amendment of multi-binder such as lime/ladle slag.

• Journal of Environmental Science International
• /
• v.1 no.1
• /
• pp.89-96
• /
• 1992

In this study , we have investigated leaching characteristics of heavy metals and alkalinity centering around steel mill slags by several extraction methods, for the purpose of risk assessment that exert influence on environment and offer of the foundation data of reuse by slags. Korean standard method, U.S.EPA Extraction Procedure, alkalinity extraction test and 9 step sequential fractionation experiment by Miller et al. were carried out for investigating teachability of steel mill slags. As a result of this experiment, heavy metals were little detected and it was considered that alkalinity does not exert a bad effect around environment in slabs with large particle size. By the result of 9 step fractionation experiment, heavy metal contents in slags were not plentiful, in addition, even comparatively plentiful contended heavy metals, for the most part, were likely to detained or bonded in silica matrix. Therefore, in case of slags with large particle size, it seems that teachability of heavy metals were next to impossible that is existed as a safety condition.

• Journal of Environmental Impact Assessment
• /
• v.16 no.1
• /
• pp.35-43
• /
• 2007

Vitrified aggregates obtained by using mine tailings were evaluated using various leaching methods to assess their environmental safety. The leaching tests in this study include continuous batch leaching, Dutch availability leaching, pH-stat and tank diffusion test as well as TCLP (Toxicity Characteristic Leaching Procedure), which is commonly adopted. Vitrification technique has successfully been applied treating some solid wastes containing high level of heavy metals, such as EAF (Electric Arc Furnace) dust and mine tailings. The potentially most leachable element among trace metals was As and theoretically about 7% of total concentrations in the aggregate can be released under extreme condition. Zinc was leached about 4% and the other trace metals including Cd, Cr and Pb were hardly released from the vitrified mine tailing aggregate.

• Korean Journal of Environmental Agriculture
• /
• v.19 no.3
• /
• pp.218-222
• /
• 2000

Wasted${\cdot}$rested mine areas give lots of effect on around-environmental changes after mining development. Leaching water at reclaimed land has been eluted from the solid components through physical, chemical, biological procedures by waters percolated through reclaimed site. The element analysis of waste tungsten ore tailing, leaching water analysis and removal of heavy metal by zeolite were performed to investigate the influent of acid rain on the released contents of H. M. The heavy metal contents in leaching water were determined to be As $1.21\;{\sim}\;1.54\;ppm$, Pb $0.11\;{\sim}\;0.15\;ppm$ and $SO_4\;^{2-}$ was $302\;{\sim}\;378ppm$. As deionized water and simulated acid rain (pH 3,4) were percolated through columns packed tungsten ore tailing, the amount of Mn, Na, Ca which were dissolved by pH4 solution was higher than those by distilled water. However, W and Mo were eluted easily by high pH solution. The change of heavy metal concentration by column experiment packed zeolite was effective a little because heavy metals were adsorved much more by zeolite.

• KSBB Journal
• /
• v.16 no.4
• /
• pp.389-397
• /
• 2001

The effect of sludge digestion on the leaching efficiency of heavy metals from sludge by bioleaching with Thiobacillus thiooxidans MET was investigated. The used sludges were a non- and anaerobically digested. The leaching efficiency of heavy metals was strongly dependent on the pH of the sludge solution rather than the sludge condition and stolid concentration. The lower the pH the more heavy metal was leached from 3.0 of pH. The sequent orders of leaching heavy metals were Zn, Cu, and Cr. Although the buffering capacity of non-digested sludge was similar to anaerobically digested sludge, the pH decrease rate of the anaerobically digested sludge solution was faster than that of the non-digested sludge solution due to the higher sulfur oxidation rate of T. thiooxidans MET in the anaerobically digested sludge. The amount of leached heavy metals from the anaerobically digested sludge showed higher than that of non-digested sludge at the same pH value. This result might be caused by the difference of the insoluble metal types, which were contained in the sludge. An increase in sludge solids concentration decreased the leaching efficiency of heavy metals in the range of solids concentration 10 g/L to 70 g/L. The optimum ratio of S° to sludge stolid was 0.1 in both the sludge. The bioleaching process of heavy metals with T. thiooxidans MET showed the disinfecting effect over 90% as well as the reduction effect in sludge weight of 20%.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2000.05a
• /
• pp.46-51
• /
• 2000

Environmental quality regulations are used to establish the maximum permissible concentrations of heavy metals before a site can be deemed to be polluted or contaminated. This paper compares the results obtained by 0.IN HCl extraction and acid extraction method(HNO$_3$+HClO$_4$.HCl). The leaching efficiency of 0.1N HCl extraction is directly proportional to the final pH of leachate, due to the different solubilities of the heavy metals at different pH values, The severe differences between 0.1N HCl-extractable and total metal contents result mainly from the buffering effect of carbonates, present in sediment. samples. Application of sequential extraction experiments to some sediments collected from gully pot in Seoul illustrates a much stronger scavenging effect by Fe and Mn-hydroxides, carbonates and organic phases. As deduced from both sequential extraction and leaching experiments, the relative mobility of heavy metals is found to be: Mn>Zn>>Co>Cd>>Cu>Pb>Cr>Fe, in spite of large differences in heavy metal content and localization. Changes in the physicochemical environments (such as acidification) caused by a traffic accident may result in the severe environmental pollution of heavy metals of surrounding area( surface water and rivers).

• Journal of the Korea Organic Resources Recycling Association
• /
• v.17 no.1
• /
• pp.88-95
• /
• 2009

This study is for understanding the domestic possibilities of the high temperature incineration of waste containing Polychlorinated Biphenyls (PCBs) with the analysis of normal operation case and waste gas, fly ash, dioxin about bottom ash, Total-PCBs, Co-PCBs, and the for analysis the heavy metal leaching feature included by bottom ash and fly ash, heavy metal leaching experiment was implemented. The result shows the dioxin density of the waste gas from waste containing PCBs was $0.00699{\sim}0.00763ng-TEQ/Nm^3$, which is lower than $0.0192ng-TEQ/Nm^3$ from the normal operation case. And each Co-PCBs and total PCBs shows $0.00043{\sim}0.00112ng-TEQ/Nm^3$ and $3.06{\sim}3.87ng/m^3$ respectively. The bottom ash test result shows Dioxin 0.00225~0.00630ng-TEQ/g, Co-PCBs 0.00027~0.00082ng-TEQ/g, Total PCBs 0.9~2.6ng/g, and the fly ash shows Dioxin 0.00164~0.00344ng-TEQ/g, Co-PCBs 0.00053~0.00054ng-EQ/g, Total PCBs 0.64~0.84ng/g. The bottom ash and fly ash experiments for heavy metal leaching did not show any leaching but when it comes to the ingredients of the fly ash, Pb elements shows 31.01~237.7ppm, higher than leaching criterion. The analysis of the density of all air pollution material from the waste gas shows the lower value than permissible criterion.

• Economic and Environmental Geology
• /
• v.45 no.2
• /
• pp.121-135
• /
• 2012

Soil dispersion and heavy metal leaching with two heavy metal-contaminated soils were studied to derive the optimal dispersion condition in the course of developing the remedial technology using magnetic separation. The dispersion solutions of pyrophosphate, hexametaphosphate, orthophosphate and sodium dodecylsulfate (SDS) at 1 - 200 mM and the pH of solutions was adjusted to be 9 - 12 with NaOH. The clay content of suspension as an indicator of dispersion rate and the heavy metal concentration of the solution were tested at the different pHs and concentrations of the dispersion solution during the experiment. The dispersion rate increased with increasing the pH and dispersion agent concentration of the solution. The dispersion efficiency of the agents showed as follows: pyrophosphate > hexametaphosphate > SDS > orthophosphate. Arsenic leaching was sharply increased at 50 mM of phosphates and 100 mM of SDS. The adsorption of $OH^-$, phosphates and dodecysulfate on the surface of Fe- and Mn-oxides and soil organic matter and the broken edge of clay mineral might decrease the surface charge and might increase the repulsion force among soil particles. The competition between arsenic and $OH^-$, phosphates and dodecylsulfate for the adsorption site of soil particles might induce the arsenic leaching. The dispersion and heavy metal leaching data indicate that pH 11 and 10 mM pyrophosphate is the optimum dispersion solution for maximizing dispersion and minimizing heavy metal leaching.