• Journal of Industrial Technology
• /
• v.21 no.A
• /
• pp.257-261
• /
• 2001

The separation of rare earths minerals is very difficult because of their similar chemical properties. The rare earth minerals are used as the mixed rare earth minerals or the misch metal without separation to each element. However, the high purity rare earths are recently produced commercially to each element so they there are used as the materials for high tech. Based on the characterization results for the raw minerals, we have developed a combined process containing gravity seperation, magnetic seperation and flotation. The result obtained from this study is monazite concentration of TREO grade 69.11% and Recovery 56.02%.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.2
• /
• pp.445-450
• /
• 2016

This paper studied on the influence of naval vessel shape on vertical magnetic field after the vessel was demagnetized. The triangular shape, the rectangular shape and circular shape were adaped from vessel's structual drawings. Magneto-static FEM analysis was performed to obtain the iduced magnetic field due to earth magnetic field for those shapes. During demagnetization process, magnetic field of residual magnetization was observed. The holizontal and vertical magnetic field were calculated depending on vertical bias magnetic field through magnetc component seperation. To demagnetize naval vessel ship, demagnetizing coils shoud be wound more finely in the vow and stern of the ship than it should be in the mid-part of the ship.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.360-360
• /
• 2008

Steelmaking industry is widely known to use a lot of water and same amount of wastewater is generated. Although toxicity of wastewater from Steelmaking industry is low, it contains an amount of various organic materials and Fe-Oxides. It is important to recycle the wastewater because of water shortages and water pollution. In general, large-scale equipment is necessary to process the wastewater. On the other hand, superconducting high gradient magnetic separation (HGMS) system can process the wastewater in the small space. Superconducting HGMS system that had a purpose to purify the wastewater was assembled. Cryo-cooled Nb-Ti superconducting magnet was used for magnetic separator. This system can operate continuously because contaminated filters can keep on returning after cleaning. The various magnetic seeding reactions were investigated to increase the reactivity of coagulation. Filter cleaning system was developed to decrease the quantity of clean water. This research was supported by a grant from Korea Electrotechnology Research Institute, Republic of Korea.

• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.7
• /
• pp.683-687
• /
• 2008

When suspended solids are removed by natural sedimentation, it is necessary to use mainly huge equipments and waste great cost. This is a problem that must be solved certainly as soon as possible. In this study, suspended solids of yellow soil water were rapidly removed by controlling pH and amounts of magnetic powder, organic and inorganic flocculants. In the case of the suspended solids of 0.3% yellow soil water, the most excellent turbidity was achieved at pH between 7 and 7.5.

• Proceedings of the KOSOMBE Conference
• /
• v.1997 no.11
• /
• pp.517-527
• /
• 1997

Magnetic Resonance Spectroscopic Imaging is a methodology combining the imaging and spectroscopy. It can provide the spectrum of each areas of image so that one can easily compare the spectrum of one position to another position of the image. In this study, we developed pulse sequence or the spectroscopic imaging method, RF wave forms or the saturation of water signal, computer simulations to validate our method, and confirmed the methodology with phantom experiment. Then we applied the spectroscopic method to human subject and identified a few important metabolites in in vivo. To develope a water saturating RF waveform, we used Shinnar-Le-Roux algorithm and obtained maximum phase RF waveform. With this RF pulse, it could suppress the water signal to 1:1000. The magnet is shimmed to under 1.0ppm with auto-shimming technique. The saturation bandwidth is 80Hz(2ppm). The water and fat seperation is 3.3ppm(about 140Hz at 1 Tesla magnet), the bandwidth is enough to resolve the difference. But we are more concerned about the narrow window in between the two peaks, in which the small quantity of metabolites reside. We performed the computer simulation and phantom experiments in 8*8 matrix form and showed good agreement in the image and spectrum. Finally we applied spectroscopic imaging to the brain of human subject. Only the lipid signal was shown in the periphery region which agrees with the at distribution in human head surface area. The spectrum inside the brain shows the important metabolites such as NAA, Cr/PCr, Choline. We here have shown the spectroscopic imaging which is normally done above 1.5 Tesla machine can be performed in the 1 Tesla Magnetic Resonance Imaging Unit.