폐수처리 분야에서 자기 분리기술의 응용 현황 및 전망

저소웅 ( Shaoxiong Chu ),임봉수 ( Bongsu Lim ),최찬수 ( Chansoo Choi ) 한국물환경학회 2020 한국물환경학회지 Vol.36 No.2

Magnetic separation technology is an efficient and environmentally friendly technology. Compared with the traditional wastewater treatment technology, the magnetic separation technology has its unique advantages and characteristics, and has been widely applied in the field of wastewater treatment. In particular, the emergence of superconducting magnetic separation technology makes possible for high application potential and value. In this paper, which through consulting with the literatures of Korea, Chinese, United States and other countries, the magnetic separation technology applied to wastewater treatment was mainly divided into direct application of magnetic field, flocculation, adsorption, catalysis and separation coupling technology. Advantages and limitations of the magnetic separation technology in sewage treatment and its future development were also studied. Currently, magnetic separation technology needs to be studied for additional improvement in processing mechanism, design optimization of magnetic carrier and magnetic separator, and overcoming engineering application lag. The selection, optimization and manufacturing of cheap magnetic beads, highly adsorbed and easily desorbed magnetic beads, specific magnetic beads, nanocomposite magnetic beads and the research of magnetic beads recovery technology will be hot application of the magnetic separation technology based on the magnetic carriers in wastewater treatment. In order to further reduce the investment and operation costs and to promote the application of engineering, it is necessary to strengthen the research and development of high field strength using inexpensive and energy-saving magnet materials, specifically through design and development of new high efficiency magnetic separators/filters, magnetic separators and superconducting magnetic separators.

Sequential microwave roasting and magnetic separation for removal of Fe and Ti impurities in low-grade pyrophyllite ore from Wando mine, South Korea

Kim, Bong-Ju,Cho, Kang Hee,Chang, Bongsu,Kim, Hyun-Soo,Lee, Sang-Gil,Park, Cheon-Young,Lee, Soonjae,Choi, Nag-Choul Elsevier 2019 Minerals engineering Vol.140 No.-

<P><B>Abstract</B></P> <P>The applications and price of pyrophyllite are highly dependent on its Al<SUB>2</SUB>O<SUB>3</SUB> and impurity contents. Titanium as well as iron in pyrophyllite are impurities causing colorization of the final product. We investigated a method for removal of Fe and Ti impurities to improve the grade of pyrophyllite ore using sequential microwave roasting and magnetic separation. Pyrophyllite ore from the Wando mine (South Korea) contains Fe impurities, such as pyrite and hematite, and Ti impurities, such as rutile and Ti-oxides. This research demonstrate that the ore can be purified by the proposed sequential separation technique using microwave treatment and magnetic separation. The purification efficiency for the low-grade pyrophyllite ore was evaluated by conducting batch-scale sequential treatment tests. The microwave treatment magnetized Fe minerals in the ore due to mineral phase changes, and thus the magnetic impurities could be successfully separated by the subsequent magnetic separation. Iron and Ti were removed from the pyrophyllite ore with 86.3% and 68.3% efficiency, respectively, by 30 min of microwave irradiation and 2000 gauss of magnetic separation. The high removal efficiency of Ti impurity was resulted from association of rutile with Fe minerals, although weak. The efficiency of impurity removal was improved by lengthening the microwave irradiation time and increasing the magnetic field intensity. By applying a high magnetic intensity (>5000 gauss), it was possible to remove additional paramagnetic Ti impurities. The sequential separation technique using microwave roasting and magnetic separation may be a promising method for enhancing the grade of low-grade pyrophyllite ore.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Low grade pyrophyllite contained impurities, such as pyrite, hematite and rutile. </LI> <LI> Microwave roasting caused Fe impurities gaining magnetic property. </LI> <LI> Magnetized particles were isolated from pyrophyllite ore by magnetic separation. </LI> <LI> Association of Ti mineral with Fe mineral enhanced efficiency of impurity removal. </LI> <LI> Isolated Ti impurities was additionally separated under high magnetic field intensity. </LI> </UL> </P>

Magnetic separation device for paramagnetic materials operated in a low magnetic field

F. Mishima,N. Nomura,S. Nishijima 한국초전도저온학회 2022 한국초전도저온공학회논문지 Vol.24 No.3

We have been developing a magnetic separation device that can be used in low magnetic fields for paramagnetic materials. Magnetic separation of paramagnetic particles with a small particle size is desired for volume reduction of contaminated soil inFukushima or separation of iron scale from water supply system in power plants. However, the implementation of the system hasbeen difficult due to the needed magnetic fields is high for paramagnetic materials. This is because there was a problem in installingsuch a magnet in the site. Therefore, we have developed a magnetic separation system that combines a selection tube and magneticseparation that can separate small sized paramagnetic particles in a low magnetic field. The selection tube is a technique forclassifying the suspended particles by utilizing the phenomenon that the suspended particles come to rest when the gravity actingon the particles and the drag force are balanced when the suspension is flowed upward. In the balanced condition, they can becaptured with even small magnetic forces. In this study, we calculated the particle size of paramagnetic particles trapped in aselection tube in a high gradient magnetic field. As a result, the combination of the selection tube and HGMS (High GradientMagnetic Separation-system) can separate small sized paramagnetic particles under low magnetic field with high efficiency, andthis paper shows its potential application.

Study on multi-stage magnetic separation device for paramagnetic materials operated in low magnetic fields

F. Mishima,Aoi Nagahama,N. Nomura,S. Nishijima 한국초전도저온학회 2023 한국초전도저온공학회논문지 Vol.25 No.3

Magnetic separation technology for small paramagnetic particles has been desired for the volume reduction of contaminated soil from the Fukushima nuclear power plant accident and for the separation of scale and crud from nuclear power plants. However, the magnetic separation for paramagnetic particles requires a superconducting high gradient magnetic separation system applied, hence expanding the bore diameter of the magnets is necessary for mass processing and the initial and running costs would be enormous. The use of high magnetic fields makes safe onsite operation difficult, and there is an industrial need to increase the magnetic separation efficiency for paramagnetic particles in as low a magnetic field as possible. Therefore, we have been developing a magnetic separation system combined with a selection tube, which can separate small paramagnetic particles in a low magnetic field. In the previous technique we developed, a certain range of particle size was classified, and the classified particles were captured by magnetic separation. In this new approach, the fluid control method has been improved in order to the selectively classify particles of various diameters by using a multi-stage selection tube. The soil classification using a multi-stage selection tube was studied by calculation and experiment, and good results were obtained. In this paper, we report the effectiveness of the multi-stage selection tube was examined.

Heavy metal removal from aqueous solutions using engineered magnetic biochars derived from waste marine macro-algal biomass

Son, Eun-Bi,Poo, Kyung-Min,Chang, Jae-Soo,Chae, Kyu-Jung Elsevier 2018 Science of the Total Environment Vol.615 No.-

<P><B>Abstract</B></P> <P>Despite the excellent sorption ability of biochar for heavy metals, it is difficult to separate and reuse after adsorption when applied to wastewater treatment process. To overcome these drawbacks, we developed an engineered magnetic biochar by pyrolyzing waste marine macro-algae as a feedstock, and we doped iron oxide particles (e.g., magnetite, maghemite) to impart magnetism. The physicochemical characteristics and adsorption properties of the biochar were evaluated. When compared to conventional pinewood sawdust biochar, the waste marine algae-based magnetic biochar exhibited a greater potential to remove heavy metals despite having a lower surface area (0.97m<SUP>2</SUP>/g for kelp magnetic biochar and 63.33m<SUP>2</SUP>/g for hijikia magnetic biochar). Although magnetic biochar could be effectively separated from the solution, however, the magnetization of the biochar partially reduced its heavy metal adsorption efficiency due to the biochar's surface pores becoming plugged with iron oxide particles. Therefore, it is vital to determine the optimum amount of iron doping that maximizes the biochar's separation without sacrificing its heavy metal adsorption efficiency. The optimum concentration of the iron loading solution for the magnetic biochar was determined to be 0.025–0.05mol/L. The magnetic biochar's heavy metal adsorption capability is considerably higher than that of other types of biochar reported previously. Further, it demonstrated a high selectivity for copper, showing two-fold greater removal (69.37mg/g for kelp magnetic biochar and 63.52mg/g for hijikia magnetic biochar) than zinc and cadmium. This high heavy metal removal performance can likely be attributed to the abundant presence of various oxygen-containing functional groups (COOH and OH) on the magnetic biochar, which serve as potential adsorption sites for heavy metals. The unique features of its high heavy metal removal performance and easy separation suggest that the magnetic algae biochar can potentially be applied in diverse areas that require biosorbents for pollutant removal.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Magnetic biochar derived from marine macro-algae was made for heavy metal adsorption. </LI> <LI> Physicochemical properties and isotherms were characterized using various techniques. </LI> <LI> Iron-loaded condition was optimized for Cd, Cu, and Zn removal and magnetic separation simultaneously. </LI> <LI> Magnetic macro-algae biochar had high selectivity for Cu with plentiful O-containing groups. </LI> <LI> Adsorption and recovery ability showed an opposite tendency as iron doping increased. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

옹진군 해사의 선별공정에 따른 광물학적 특성

채수천 ( Soo Chun Chae ),신희영 ( Hee Young Shin ),배인국 ( In Kook Bae ),권성원 ( Sung Won Kwon ),이춘오 ( Chun Oh Lee ),김정윤 ( Jung Yoon Kim ),자영남 ( Young Nam Jang ) 한국광물학회 2011 광물과 암석 (J.Miner.Soc.Korea) Vol.24 No.1

경기도 옹진군부근의 근해로부터 채취된 해사로부터 비중 및 자력선별을 통한 중광물의 회수 공정을 실시하여, 광물학적 특성을 분석하였다. 옹진군 해사 내에 포함된 중광물로는 티탄철석, 저어 콘, 소량의 모나자이트 및 석류석 등이 있으며, 맥석광물로는 석영, K-장석, 사장석, 백운모, 보통각섬석, 녹염석, 녹니석 등이 있다. SIROQUANT 프로그램을 이용한 광물 정량분석 결과, 요동테이블 선별, 영구자석을 이용한 자력선별(rare-earth magnetic separation) 및 전자석 자력선별(Eddy current magnetic separation)로부터 회수한 유용광물인 티탄철석의 함량은 각각 0.8, 18.3, 48.7%로 증가되었다. 또 한 원사, 1차 비중, 2차 비중, 1차 자력 및 2차 자력선별 산물 중 대표시료 및 중광물군에 대한 화학분 석치로부터 재계산시, 티탄철석 및 모나자이트의 함량은 각각 0.23, 0.55, 5.22, 16.17, 44.99% 및 0.11, 0.02%, 0.16, 0.51, 1.19%로 증가하였다. 그러나 저어콘의 경우에는 0.13, 0.12, 0.11, 0.15, 0.10%로 큰 변화를 보이지 않았지만, 2차 비중선별시료 중 가장 미립인 -140 메시 입단의 경우 0.27%의 높은 값을 보임으로써 입도분리를 통한 선별 시, 회수율 증대가 기대된다. Mineralogical study was carried out for heavy minerals in the sea sand near Ongjingun bay, Kyonggi-do separated using the gravity and magnetic separators. Ilmenite, zircon and minor monazite and garnet were valuable minerals with gangue minerals of quartz, K-feldspar, plagioclase, muscovite, hornblende, epidote and chlorite. Quantitative analysis with SIROQUANT program showed that the contents of ilmenite separated with the gravity separation (the shaking table separation), the 1st step magnetic separation (rare earth magnetic separation) and the 2nd step magnetic separation (the Eddy current magnetic separation) were increased into 0.8, 18.3, and 48.7%, respectively. The content of ilmenite, monazite and zircon were recalculated based on the chemical composition of the representative and heavy fraction products of raw sand, the 1 step and 2 step gravity separations, and the 1 step and 2 step magnetic separations. The content increased to 0.23, 0.55, 5.22, 16.17, and 44.99% in ilmenite, 0.11, 0.02, 0.16, 0.51, and 1.19% in monazite. Although the zircon content did not differ over the processes (0.13, 0.12, 0.11, 0.15, and 0.10%), the improved recovery of zircon is expected by applying sieving process because of its high content (27%) in the fine grain size fraction (<140#) of the 2 step gravity separation.

Development of volume reduction method of cesium contaminated soil with magnetic separation

Yukumatsu, Kazuki,Nomura, Naoki,Mishima, Fumihito,Akiyama, Yoko,Nishijima, Shigehiro The Korea Institute of Applied Superconductivity a 2016 한국초전도저온공학회논문지 Vol.18 No.1

In this study, we developed a new volume reduction technique for cesium contaminated soil by magnetic separation. Cs in soil is mainly adsorbed on clay which is the smallest particle constituent in the soil, especially on paramagnetic 2:1 type clay minerals which strongly adsorb and fix Cs. Thus selective separation of 2:1 type clay with a superconducting magnet could enable to reduce the volume of Cs contaminated soil. The 2:1 type clay particles exist in various particle sizes in the soil, which leads that magnetic force and Cs adsorption quantity depend on their particle size. Accordingly, we examined magnetic separation conditions for efficient separation of 2:1 type clay considering their particle size distribution. First, the separation rate of 2:1 type clay for each particle size was calculated by particle trajectory simulation, because magnetic separation rate largely depends on the objective size. According to the calculation, 73 and 89 % of 2:1 type clay could be separated at 2 and 7 T, respectively. Moreover we calculated dose reduction rate on the basis of the result of particle trajectory simulation. It was indicated that 17 and 51 % of dose reduction would be possible at 2 and 7 T, respectively. The difference of dose reduction rate at 2 T and 7 T was found to be separated a fine particle. It was shown that magnetic separation considering particle size distribution would contribute to the volume reduction of contaminated soil.

The Recovery of Non-ferrous Metals from Broken Light Bulbs using the Magnetic Liquid Based Separation

Viorica Chioran,Ioan Ardelean 한국자기학회 2010 Journal of Magnetics Vol.15 No.2

The paper presents results of a study on the selective separation technology of ferrous and non-ferrous metals from broken light bulbs. The proposed method is to use magnetic fluids to obtain a magnetic fluid based- separation. [1] The study was conducted using three types of waste materials: regular light bulbs, auto light bulbs and neon tubes. In order to process the waste materials, a six stages technologic flow was developed: a) separation of light bulbs components; b) Physical and chemical analysis of raw materials; c) grain conditioning of the raw material; d) dry magnetic separation of ferrous components; e) magnetic fluid separation of non-magnetic material; f) recovery of the magnetic fluid adhered to the surface of the separated material grains. [2] This study shows that magnetic fluid separation is only profitable for regular and auto light bulbs and is not profitable in the case of neon tubes.

대남광산 농경지 토양 내 중금속 특성에 따른 물리적 선별 처리효율에 관한 연구

박찬오,홍동호,이재영,이영재,이진수,ParK, Chan Oh,Hong, Dong-Ho,Lee, Jai-Young,Lee, Young Jae,Lee, Jin-Soo 한국지하수토양환경학회 2013 지하수토양환경 Vol.18 No.5

The main objective was to evaluate the efficiencies of different separation techniques, such as gravity separation, magnetic separation, and aerial separation. Zinc and cadmium removal efficiencies by gravity separation and magnetic separation were 28.3~29.3% and 19.1%, respectively, and were higher than the efficiency obtained by aerial separation. Results showed that the combination of gravity separation and magnetic separation in series which was to maximize the removal efficiencies gave removal efficiency of 21.5~38.7% for zinc and 22.1~23.4% for cadmium. The mass of soil meeting the regulation standards for zinc and cadmium after retrieval from the combined separation process accounted for approximately 80% of the treated soil that would be reusable without the pre-treatment procedure as the neutralization process using in the soil washing method. Physical separation techniques utilizing heavy metal properties are the alternative method to remediate heavy-metal contaminated soils in environmental and economic aspects.

자력선별법을 이용한 화력 발전소 매립회의 지오폴리머 원료화 연구

김강덕,Kim, Kangduk 한국결정성장학회 2017 한국결정성장학회지 Vol.27 No.5

화력발전소에서 발생되는 매립회의 지오폴리머 원료화를 위하여 자력선별 공정을 이용하여 자성체와 비자성체로 분리하였으며, 매립회의 입도 및 자석의 세기에 따른 미연탄소의 선별 특성을 관찰하였다. 3000 G 자석을 이용한 세립(0.15~0.84 mm)과 조립(0.84~2.4 mm) 매립회의 자력선별 결과, 매립회는 입도에 상관없이 비자성체의 무게분율과 강열감량이 자성체보다 높게 나타났으며, 세립 매립회의 경우 자석의 세기를 3000 G에서 10000 G로 증가시키면, 약한 자성을 띠는 물질들도 자성체로 분리됨에 따라 자성체의 무게 분율이 급격히 증가되면서 낮은 강열감량에도 불구하고 전체 강열감량의 32.6 wt%의 66.9 %(22.8 wt%)를 차지하였다. 자력 선별된 조립 매립회로 제조된 지오폴리머의 재령일별 압축강도 측정결과, 미연탄이 적게 포함된 자성체로 제조된 지오폴리머의 압축강도가 20 MPa를 나타내었다. Using a magnetic separation process, pond ash generated in thermoelectric power plants was separated into magnetic materials and nonmagnetic materials in order to make it into a raw material of geopolymers and unburned carbon; screening characteristics according to the particle sizes and magnet strength levels of the pond ash were observed. Based on the results of magnetic separation into fine particle (0.15~0.84 mm) and rough particle (0.84~2.4 mm) pond ash using 3000 G magnets, the weight fraction and ignition loss of nonmagnetic materials were found to be higher than those of magnetic materials, regardless of the particle size. In the case of fine particle pond ash, when the magnet strength was increased from 3000 G to 10000 G, even those materials that were weakly magnetic were separated into magnetic materials, leading to drastic increases in the weight fraction of magnetic materials, such that the ignition loss accounted for 66.9 % (22.8 wt%) of the entire ignition loss of 32.6 wt%, despite of the low ignition loss. Based on the results of measurement of the compressive strength levels of geopolymers made of magnetic-separated rough particle pond ash, the compressive strength of geopolymers made of magnetic materials containing small amounts of unburned carbon was found to be 20 MPa.