Magnetic Separation Experiments Research Articles

Development of High Gradient Magnetic Separation System for a Highly Viscous Fluid

It is necessary to remove the metallic wear debris originating from pipe of manufacturing line in industrial plant processing highly viscous fluid such as foods or industrial products. In this study, we developed a high gradient magnetic separation (HGMS) system which consists of superconducting magnet and magnetic filters to remove the metallic wear debris. The particle trajectory simulation and the magnetic separation experiment were conducted with polyvinyl alcohol (PVA) as a model material of which viscosity coefficient was 1 Pa · s. As a result, maximum separation efficiency over 80% was achieved by optimization of experimental conditions such as mesh number, flow velocity and the number of filters.

Development of high gradient magnetic separation system for removing the metallic wear debris to be present in highly viscous fluid

In the industrial plants processing highly viscous fluid such as foods or industrial materials, there is an issue of contamination by metallic wear debris originating from pipe of manufacturing line. It is necessary to remove the metallic wear debris in highly viscous fluid, since these debris causes quality loss. In this study, we developed a high gradient magnetic separation system by using superconducting magnet to remove the metallic wear debris. The particle trajectory simulation and the magnetic separation experiment were conducted with polyvinyl alcohol as a model material. As a result, ca. 100% and 92.2% of the separation efficiency was achieved respectively for the highly viscous fluid of 1Pas and 6Pas in viscosity, with 14 and 30mesh magnetic filters.

Magnetically applicable layered iron-titanate intercalated with biomolecules

We have prepared bio-inorganic nanohybrids consisting of magnetic inorganic nanolayers (iron-titanate) and protein molecules via exfoliation–restacking process in solution. It was found that the protein molecules were electrostatically and spontaneously incorporated into the interlayer space of the inorganic layered structure by adjusting the pH of the solution appropriately. The binding studies demonstrated the high affinity of the iron–titanate nanolayers for the proteins, and the immobilized protein preserved its activity after the hybridization. The catalytic activity measurement and magnetic separation experiment indicate the formation of magnetically applicable inorganic layer–biomolecule nanohybrids. The magnetic layer–biomolecule nanohybrid developed here would be a novel conspicuous material which shows different properties from those of conventional biomolecule-immobilized magnetic particles.

Fundamental study on magnetic separation of aquatic organisms for preservation of marine ecosystem

Recently, destruction and disturbance of marine ecosystem have been caused by changes in global environment and transplants of farmed fishes and shellfishes. To solve the problems, water treatment techniques to kill or to remove aquatic organisms are necessary. In this study, application of magnetic separation for removal of the aquatic organisms was examined in order to establish the process with high-speed, compact device and low environmental load. Techniques of magnetic seeding and magnetic separation using superconducting magnet are important for high-speed processing of aquatic organisms. Magnetic seeding is to adhere separating object to the surface of ferromagnetic particles, and magnetic separation is to remove aquatic organisms with magnetic force. First, we confirmed the possibility of magnetic seeding of aquatic organisms, and then interaction between aquatic organisms and ferromagnetic particles was examined. Next, for practical application of magnetic separation system using superconducting magnet for removal of aquatic organisms, particle trajectories were simulated and magnetic separation experiment using superconducting magnet was performed in order to design magnetic separation system to achieve high separation efficiency.

Study on magnetic separation of nanosized ferromagnetic particles

In recent researches in medicine and the pharmaceutical sciences, the magnetic separation technology using nanosized ferromagnetic particle is essential. For example, in the field of cell engineering, magnetic separation of nanosized ferromagnetic particles is necessary, but separation technology of nanosized particle using magnetic force has not been established. One of the reasons is that magnetic force acting on the object particles decreases as particle diameter becomes small, and makes magnetic separation difficult. In this study, magnetic force acting on the separation object was enlarged by the combination of superconducting magnet and the filter which consists of ferromagnetic particle. As a result of particle trajectory calculation and magnetic separation experiment, it was confirmed that the ferromagnetic particles of 15nm in diameter can be trapped in the magnetic filter under an external magnetic field of 0.5T. The ferromagnetic particles of 6nm in diameter which could not be separated under the same condition could also be trapped under 2.0T of external magnetic field.

Desulphurization of Lignites by Slow, Fast, and Flash Pyrolysis and High Intensity Dry Magnetic Separation

Slow, fast and flash pyrolysis followed by high intensity dry magnetic (HIDM) separation experiments were conducted to obtain improved solid fuels. Pyrolysis experiments were performed in three different apparatus, and important parameters of processes, temperature, particle size, residence time and heating rate were studied to determine the optimum conditions. Desulphurization of lignites by flash pyrolysis is more successful than slow and fast pyrolysis. At optimum conditions of pyrolysis, up to 58.15, 60.24, and 62.31% sulphur reductions were obtained in slow, fast and flash pyrolysis, respectively. Char, obtained from the pyrolysis experiments, was further cleaned by a Permroll HIDM separator. Sulphur reduction enhanced up to 82.68, 84.40, and 86.55% in the char of slow, fast and flash pyrolysis, respectively.

Removal of Aerosol by Magnetic Separation

We concluded high gradient magnetic separation experiments of iron (ferromagnetic) nano-particles with a nominal diameter of 50 nm by using a superconducting magnet. In the experiment, we fabricated fine iron particles using a thermal reactive plasma method in argon and hydrogen mixed gas and sent them directly to the magnetic separator. We present the experimental results, functions of the capture ratio on the magnetic flux density, and velocity of flow. We conclude that high gradient magnetic separation can separate nano-particles and is useful for nano-technology

Magnetic evaluation of nanostructure of gold–iron composite particles synthesized by a reverse micelle method

Iron–gold nanocomposite powder was synthesized by sequential reduction of Fe 2+ and Au 3+ in reversed micelles. The UV–Vis absorption spectrometry and magnetic separation experiment indicated that the powder is composed of composite nanoparticle containing both iron and gold. XRD indicated that gold exists as metal, and X-ray absorption near edge structure showed that the magnetic phase was Fe 3O 4. TEM observation indicated that the nanocomposite was single-nanosized and has a sharp size distribution. The magnetization was measured with a SQUID magnetometer and found to be superparamagnetic. The magnetic moment size was evaluated by fitting the lognormal distribution function and the Langevin function to the magnetization data. These results were discussed taking account of the core–shell structure.

永久磁石式ロール型磁選機の分離特性に関する基礎的研究

Magnetic separation experiments were carried out using a rare earth magnet type of magnetic roll separator and hematite, chalcopyrite and pyrite as feed material. The effects of feed sizes, their magnetic susceptibility and belt speed on the performance of the magnetic separator were investigated.The difference in magnetic susceptibility of the three minerals was a little, however the order of their values was hematite>chalcopyrite>pyrite. Irrespective of feed size and belt speed, hematite was recovered as magnetic product, and pyrite as non-magnetic product. Chalcopyrite was collected as non-magnetic product at high belt speed or with coarse feed size, but with decreasing belt speed and feed size its collecting region was shifted to magnetic product zone. Under a suitable condition chalcopyrite concentrate with 96.4% recovery and 85.0% grade was obtained from the mixture of three minerals.Based on the experimental results mentioned above, a mathematic model of particle movement in magnetic separation zone was derived, considering magnetic force, gravitation, centrifugal force, and frictional force and drag force. The movements under various conditions were calculated using the model, and the calculation results were in close agreement with the experimental results.

A Study of the Parametric Effects on Magnetic Coal Ceaning

A coal-cleaning technique was evaluated to determine its effectiveness to remove sulphur and ash contents of dry pulverized coals before combustion in power stations. Dry high-gradient magnetic separation (HGMS) experiments were conducted on a British coal from Coalfield Farm North using ferromagnetic stainless steel wire meshes as the separator matrix which was located in the bore of a superconducting solenoid magnet. The parametric effects of magnetic field, air velocity and separator length on the process were investigated. Increasing magnetic fields and separator lengths and decreasing air velocities each individually increases the percentage reductions of pyritic sulphur, total sulphur and ash. Reduction efficiencies up to 91, 65 and 61 per cent for pyritic sulphur, total sulphur and ash respectively were obtained. These results have at least shown that dry HGMS could possibly provide a simple and economic alternative to flue gas desulphurization to reduce sulphur dioxide emissions to the atmosphere from coal-fired power stations, with the additional benefit of an ash removal capability.