• Resources Recycling
• /
• v.28 no.6
• /
• pp.96-105
• /
• 2019

Automobile shredder residue (ASR) is the final waste produced when end-of-life vehicles (ELVs) are shredded. ASR can be separated using mineral-processing operations such as comminution, air classification, magnetic separation, and/or electrostatic separation. In this work, trajectory analyses of conductors (copper) and non-conductors (glass) in the ASR have been carried out using induction electrostatic separator for predicting or improving the ASR-separation efficiency. From results of trajectory analysis for conductors, the trajectories of copper wire by observation versus simulation for coarse particles of 0.5 and 0.25 mm showed consistent congruity. The observed 0.06 mm fine-particles trajectory was deflected toward the (-) attractive electrode owing to the charge-density effects due to the particle characteristics and relative humidity. In the case of non-conductors, the actual trajectory of dielectric glass deflected toward the (-) electrode, showing characteristics similar to those of conductive particles. The analyses of stereoscopic microscope and SEM & EDS found heterologous materials (fine ferrous particles and conductive organics) on the glass surface. This demonstrates the glass decreasing separation efficiency for non-ferrous metals during electrostatic separation for the recycling of ASR. Future work will require a pretreatment process for eliminating impurities from the glass and advanced trajectory-simulation processes.

• Resources Recycling
• /
• v.17 no.4
• /
• pp.3-9
• /
• 2008

The total amount of fluidized bed incinerator ash, i.e. incombustion materials generated from the municipal solid waste incineration(MSWI) in Korea was approximately 14,000 tons in 2006. Most of the ash after ferrous metal separation is finally discard to the landfill sites. In the present work, possibility for recycling of the ash is studied to utilize the ash as raw materials for ceramic products. Incombustion materials obtained from the two different incinerators were used to recover the raw materials by applying the magnetic separation and screening process to remove metallic particles. The raw materials show relatively low heavy metals content obtained from the KSLP leaching tests. The ceramic products were prepared by mixing the clay with the various amounts of the raw material. The physical properties, i.e. shrinkage rate, absorbancy and compressive strength of the ceramic products sintered at $1,000^{\circ}C$ and $1,050^{\circ}C$, respectively were improved by increasing the addition amounts of the incinerator ash. Based on the leaching tests the ceramic products also be satisfied with the standard limits on the leachability of heavy metals because most of the metallic materials are effectively removed from the incombustion materials by appling the separation processes.

• Resources Recycling
• /
• v.8 no.3
• /
• pp.37-42
• /
• 1999

Ths sludy was canied out to recover gold and sllics from abandoned gold mine talings with about 4.5 ghonAu and 84.88 wt% SOz. Tl~bee nef~cialiop~ro~c esses including crushing, screening, magnelic and gravity (humprey sp~rals,h aking table) separation \ulcornervex employed. Results were Feasible to rccovn h e gold concentrates (307.1 gltoilon .4u . 0.60 wr%, 97.7 giton Au : 0.27 wl%, 15.3 &/ton Au . 5.23 wt%, 21.2 g/ton Au : 2.42 wl%) and silica (96.40 wi% SiO\ulcorner yield 60 65 ~ 1 % )

• Proceedings of the Korean Institute of Resources Recycling Conference
• /
• 2005.05a
• /
• pp.147-151
• /
• 2005

실리콘 잉곳의 절단공정에서 발생하는 폐실리콘 슬러지는 실리콘과 실리콘카바이드 등의 유가자원이 함유되어 있는데, 본 연구에서는 폐실리콘 슬러지 중의 실리콘 분말을 효과적으로 분리, 회수하는 방법에 대해 검토하였다. 폐실리콘 슬러지는 상당량의 절삭유와 소량의 철분말이 포함되어 있는데 절삭유는 유기 용매에 용해시켜 효과적으로 분리하였고, 철분말은 자력선별에 의해 제거하였다. 절삭유와 철성분이 제거된 잔사인 실리콘과 실리콘 카바이드의 혼합 분말로부터 초음파 분산 선별법을 사용하여 실리콘 분말을 효율적으로 분리회수 하였다.

• Resources Recycling
• /
• v.3 no.1
• /
• pp.38-43
• /
• 1994

The separation of valuable metals from IC chip scrap generated by domestic electronic company was carried out using the mechanical beneficiation such as shredding, crushing, screening and magnetic separation. The distribution of metals in various sizes of crushed IC chip scrap was investigated and metals present in crushed products was separated with the magnetic separator. The particle size distribution of crushed IC chip scrap was 7.5% for +3mm, 17.0% for 3~1mm and 75.5% for -1mm. The weight loss of crushed IC chip scrap was 18% when roasted at $700^{\circ}C$. The content of metals was 96% for +3~1mm, 13% for 1~0.595mm, 3.7% for 0.95~0.5. Au of 99% was present in -1mm crushed IC chip scrap. Ni, Fe, Cu, Sn and Pb were separated from crushed IC chip scrap by the magnetic separator under 700 and 2, 500 Gauss.

• 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.

• Resources Recycling
• /
• v.11 no.4
• /
• pp.11-16
• /
• 2002

Analysis and separation of constituent materials of old car have been performed by using the industrial shredding line. For this aim, three old cars made by domestic automobile manufacturers, Sonata II, Sephia and Prince were chosen and delivered in pressed form without engine, tires and doors, etc. Shredding line was substantially composed of pre- and main-shredder. cyclone, magnetic separation, eddy current separation and man-power separation. From the separation of shredder products, iron scrap was observed to be the major material of old car accounting for 60.1 ％ of total weight and non-ferrous metals involving Al, Cu and Zn, etc. were about 2％. Light fluff, about 90％ of total fluff product, was comprised with plastic, fiber and sponge, etc. and the fraction of 5 cm undersize in light fluff was 70.5%. In case of heavy fluff, however. rubber and plastic were found to be the major constituent materials of it. Among the constituent materials of fluff, plastic showed the highest calorific value, more than 10,000 cal/gr and leather and rubber showed relatively high chlorine content, 10.3 and 2.55 wt%, respectively.

• Resources Recycling
• /
• v.12 no.3
• /
• pp.25-30
• /
• 2003

The synthesis of SiC used for the parts of the gas turbine and the heat exchanger, was carried out. In this study, wire cutting slurry of silicon wafer and the graphite rod of spent zinc-carbon battery were applied to the starting materials for the synthesis. The powders of Si or Si+SiC were obtained from the waste material by filtration, gravity separation and magnetic separation. Graphite powder was produced by dismantling, grinding and gravity separation from spent zinc-carbon battery. The synthesis of SiC could be completed from the mixture powders of Si and C or Si+SiC and C at the condition of equivalent ratio of Si and C, atmosphere of Ar or vacuum, temperature of above 1$600^{\circ}C$ and 2 hours reactions. The purity of synthesized Si-C was above 99%.

• Journal of Korea Foundry Society
• /
• v.29 no.1
• /
• pp.38-44
• /
• 2009

Magnetic separation of Fe contaminated Al-Si cutting chip scraps was performed for the recyclability assessment. It was also aimed to investigate the casting and solidification characteristics of the cutting chip scraps. The magnetically separated cutting chip scraps were adequately treated for the casting procedure and test specimens were made into a stepped mold inducing different cooling rates. The test specimens were evaluated by the combined analysis of ICP, Spectroscopy, OM-image analyzer, SEM/EDS, etc. Solidification characteristics of cutting chip scraps were examined as functions of Fe content and cooling rate. It is concluded that the magnetic separation process can be utilized to recycle the Fe contaminated Al-Si cutting chip scraps in the high cooling rate foundry process.

• Journal of Environmental Impact Assessment
• /
• v.28 no.5
• /
• pp.492-506
• /
• 2019

Heavy metal contaminants in the shooting range are mostly present in a warhead circle or a metal fragment present as a particle, these fine metal particles are weathered for a long period of time is very likely that the surface is present as an oxide or carbon oxide. In particular, lead which is a representative contaminant in the shooting range soil, is present as more fine particles because it increases the softness and is stretched well. Therefore, by physical washing experiment, we conducted a degree analysis, concentration of heavy metals by cubic diameter, composition analysis of metallic substances, and assessment of applicability of gravity, magnetism and floating selection. The experimental results FESEM analysis and the measurement results lead to the micro-balance was confirmed thatthe weight goes outless than the soil ofthe same size in a thinly sliced and side-shaped structure according to the dull characteristics it was confirmed that the high specific gravity applicability. In addition, the remediation efficiency evaluation results using a hydrocyclone applied to this showed a cumulative remediation efficiency of 71%,twice 80%, 3 times 91%. On the other hand, magnetic sifting showed a low efficiency of 17%,floating selection -35mesh (0.5mm)target soil showed a relatively high efficiency to 39% -10mesh (2mm) efficiency was only 16%. The target treatment diameter of soil washing should be 2mm to 0.075mm, which is applied to the actual equipment by adding an additional input classification, which would require management as additional installation costs and processes are constructed. As a result, it is found that the soilremediation of shooting range can be separately according to the size of the warhead. The size is larger than the gravel diameter to most 5.56mm, so it is possible to select a specific gravity using a high gravity. However, the contaminants present in the metal fragments were found to be processed by separating using a hydrocyclone of the soil washing according to the weight is less than the soil of the same particle size in a thinly fragmented structure.