Use Of Magnetite Research Articles

Myth and Reality Application of Magnetite Nanoparticles as Selective Contrasting Means of the Malignant Tumors in MRI Investigation

In an experiment it is shown on rats that biocompatible standardized nanoparticles of ICNB can be effectively used at MRI. It is well-proven that nanoparticles of ICNB for certain (р<0.001) strengthen a contrasting effect at MRI. Methodology of safe intravenous application of ICNB is excluding the use of magnetite of nanoparticles in the variant of independent contrasting means at MRI. It is set that in 24 hours after intravenous inject of ICNB the magnetite of nanoparticles for certain (p<0.001) selectively accumulate in tissue of malignant tumour and rise brightness of image.

Use of magnetite as anode for electrolysis of water

We have studied the oxidation of magnetite to Fe2O3 in an electrolytic cell in which the anode is magnetite and the cathode is platinum. We report cyclic voltammagram data consistent with the hypothesis that magnetite, without oxygen gas production but with hydrogen gas production at the cathode, is occurring. The reaction occurs at a potential at the anode of about 0.3 V vs SCE in 1 M NaOH electrolyte, consistent with colloid experiments which also estimated the equilibrium potential of the hypothesized reaction. Electrode characterization results using BET, XEDS, and macroscopic volume and mass measurements are reported, as well as the measurements of the amount of hydrogen gas generated per unit current. The quantity of gas generated is also consistent with our hypothesis concerning the electrode chemistry. Some samples exhibit evidence of two oxidation reactions occurring at the anode and a possible interpretation of these is also discussed. These results suggest the use of magnetite as an anode in a cell electrolysing water to produce hydrogen gas and Fe2O3. In such an electrolyser, the electrical energy cost of producing hydrogen gas could be significantly lower than the cost in a standard electrolyser. The measured steady state currents, equivalent to about 400 mA/g of magnetite, are too low to make a practical electrolyser. We briefly discuss several ways in which the currents might be increased to the levels required.

ChemInform Abstract: Magnetically Recoverable Osmium Catalysts for Dihydroxylation of Olefins.

AbstractA magnetically recoverable osmium catalyst is prepared by use of magnetite, quaternary ammonium salt, and potassium osmate(VI) and applied to the dihydroxylation of olefins.

Magnetically recoverable osmium catalysts for dihydroxylation of olefins

We prepared magnetically recoverable osmium catalysts by use of magnetite, quaternary ammonium salts, and potassium osmate(VI), and applied them to the dihydroxylation of olefins. By employing 2 mol% of the magnetic osmium catalyst, the dihydroxylation reaction proceeded smoothly to provide the corresponding vicinal diol in a good chemical yield. The osmium catalyst was readily recovered by use of an external magnet, and was reused repeatedly.

Evolution and possible storage of information in a magnetite system of significance for brain development

The initial evolutionary electromagnetic steps in the history of brain development are still unknown, although such knowledge might be of high relevance in understanding human degenerative diseases. All prokaryote organisms, one-celled or multicellular, must have an inherited system to process and store information activating instincts and reflexes, in order to give a quick response to external stimuli. We argue that magnetite is an obvious compound to be evaluated as an initial precursor from prebiotic Earth history in the evolution of such a system. Magnetite is a stable ferrimagnetic compound, present in organisms ranging from bacteria to humans. It occurred naturally in the early Earth environment and was later synthesized de novo in biotic organisms. We suggest that the use of magnetite has evolved to represent the main storage system for learned memory in all organisms living today.

Magnetite/maghemite mixture prepared in benzyl alcohol for the preparation of α″-Fe 16N 2 with α-Fe

Fine powder of iron oxide has been required in the preparation of ferromagnetic α″-Fe 16N 2 powder in low temperature nitridation. Magnetite and maghemite mixture was obtained by the reaction of iron acetylacetonate Fe(acac) 3 in benzyl alcohol. It was reduced to α-Fe in hydrogen at 400 °C. Particle size of the α-Fe was 300 nm in the reduction of iron oxides obtained from 2 g of Fe(acac) 3. It decreased to 100 nm in the preparation using 8 g of Fe(acac) 3. After the successive nitridation under ammonia flow at 160 °C, the highest yield of α″-Fe 16N 2 in 66 wt.% was observed on the nitrided product from the latter α-Fe, because of the smallest α-Fe particle size after the reduction in the present study. The yield and reproducibility of α″-Fe 16N 2 formation in low temperature nitridation was improved using the iron oxide prepared in non-aqueous benzyl alcohol compared to the use of magnetite obtained from aqueous solution.

On the Use of Magnetite for Gold Recovery From Chloride Solution

The sorption of gold chloride () from chloride solution on synthetic and natural magnetite powders was investigated by batch sorption experiments. The effects of different parameters on the recovery were studied. The results showed that Gold (Au) uptake by magnetite was influenced by pH, contact time, chloride concentration, and initial Au concentration. Gold uptake by synthetic and natural magnetite was maximum at pH 6–7 with sorption amounts of 4.4 μmol/g and 5.0 μmol/g, respectively, after 24 hr at an initial Au concentration of 0.05 mol/m3. The Scanning Electron Microscopy–Energy Dispersive X-ray and Back Scattering Electron analyses of the magnetite particles after treatment confirmed the presence of Au precipitates on the magnetite (Fe3O4) surface.

Performance characteristics of pilot plant dense media hydrocyclone for beneficiation of coal and 3-D CFD simulation

Dense-medium separators have proven to be the most efficient processes for removing the undesirable material from run-of-mine coal. The application of high-pressure feed injection into dense-medium cyclones to provide an elevated centrifugal force has recently been found to allow efficient separation performances for the treatment of fine coal (i.e., <1000 μm). However, high-pressure injection requires specialized pumps and results in relatively high maintenance requirements. the Current study involves experimental investigation of separation performance characteristics of the dense media hydrocyclone (DMC). A pilot plant DMC has been designed and fabricated for performance characterization. Experiments have been conducted on 300 mm dense medium cyclone treating coal in the size range of −6 to +2 mm using magnetite as the medium under operating conditions. The operating variable was the specific gravity of the medium, feed inlet pressure and feed inlet flow rate. The ash contents of the feed coal reporting to the overflow and underflow have been analyzed qualitatively. The result indicates that the use of magnetite as dense medium in DMC resulted in the yield of clean coal, which is 5% more when the air core is suppressed as compared to the same conditions when the air core remains. A 3-D geometry is created in Gambit to support the experimental findings by using CFD simulation. It is interesting to observe that experimental findings agree well with the simulation results.

Bats Use Magnetite to Detect the Earth's Magnetic Field

While the role of magnetic cues for compass orientation has been confirmed in numerous animals, the mechanism of detection is still debated. Two hypotheses have been proposed, one based on a light dependent mechanism, apparently used by birds and another based on a “compass organelle” containing the iron oxide particles magnetite (Fe3O4). Bats have recently been shown to use magnetic cues for compass orientation but the method by which they detect the Earth's magnetic field remains unknown. Here we use the classic “Kalmijn-Blakemore” pulse re-magnetization experiment, whereby the polarity of cellular magnetite is reversed. The results demonstrate that the big brown bat Eptesicus fuscus uses single domain magnetite to detect the Earths magnetic field and the response indicates a polarity based receptor. Polarity detection is a prerequisite for the use of magnetite as a compass and suggests that big brown bats use magnetite to detect the magnetic field as a compass. Our results indicate the possibility that sensory cells in bats contain freely rotating magnetite particles, which appears not to be the case in birds. It is crucial that the ultrastructure of the magnetite containing magnetoreceptors is described for our understanding of magnetoreception in animals.

Magnetic separation of iron and heavy metals from water

A magnetic separation device is being developed for removal of iron and heavy metals from water. The device consists of a column of supported magnetite surrounded by a movable permanent magnet. The mineral magnetite, or synthetically prepared iron ferrite (FeO x Fe2O3), is typically supported on various materials to permit adequate water passage through the column. In the presence of an external magnetic field, enhanced capacity was observed in using supported magnetite for removal of actinides and heavy metals from wastewater. The enhanced capacity is primarily due to magnetic filtration of colloidal and nanoscale particles along with some complex and ion exchange sorption mechanisms. This paper will review some previous work on the use of magnetite for wastewater treatment and discuss the development and potential of the magnetic nanoscale filtration/sorption process for water treatment. Recent research results are also presented on preliminary experimental studies using the process with water samples containing iron.

Magnetite functional filler: a compounding study in polypropylene and polyamide

The mineral magnetite (Fe 3O 4) has been an important raw material for the iron and steel industry for over 100 years. The use of magnetite as a functional filler for plastics and rubbers is relatively new; the first commercial application in polymers was developed in the late 1990s. Magnetite's combination of high density, low scratch visibility and excellent ecological aspects prompted its use as a filler in EVA for the production of automotive sound dampening mats. Further polymer and rubber applications continue to be developed to take advantage of the unique properties of magnetite as a filler material. Peter L Duifhuis, business manager Polymers of Minelco B.V. and Jos M.H. Janssen of DSM Research describe how specific magnetite grades have been introduced for use in polymers and rubbers and summarize the results of a compounding study of the filler in polyamide and polypropylene undertaken by DSM Research.

98/01869 QGS2020 type piano-wire probability screen—An important matching equipment in the coal dry beneficiation technique with air-dense medium fluidized bed : Zhao, Y. et al. Min. Sci. Technol., Proc. Int. Symp., 1996, 801–804. Edited by Guo, Y. and Golosinski, T. S., Balkema, Rotterdam, The Netherlands

Dense-medium separators have proven to be the most efficient processes for removing the undesirable material from run-of-mine coal. The application of high-pressure feed injection into dense-medium cyclones to provide an elevated centrifugal force has recently been found to allow efficient separation performances for the treatment of fine coal (i.e., <1000 μm). However, high-pressure injection requires specialized pumps and results in relatively high maintenance requirements. the Current study involves experimental investigation of separation performance characteristics of the dense media hydrocyclone (DMC). A pilot plant DMC has been designed and fabricated for performance characterization. Experiments have been conducted on 300 mm dense medium cyclone treating coal in the size range of −6 to +2 mm using magnetite as the medium under operating conditions. The operating variable was the specific gravity of the medium, feed inlet pressure and feed inlet flow rate. The ash contents of the feed coal reporting to the overflow and underflow have been analyzed qualitatively. The result indicates that the use of magnetite as dense medium in DMC resulted in the yield of clean coal, which is 5% more when the air core is suppressed as compared to the same conditions when the air core remains. A 3-D geometry is created in Gambit to support the experimental findings by using CFD simulation. It is interesting to observe that experimental findings agree well with the simulation results.

The use of Magnetite as a Facilitator for the Microwave Heating of Contaminated Soils

ABSTRACTPrevious research work in the area of microwave heating for low temperature thermal desorption of contaminates has led to a novel method of delivering heat energy to contaminated materials (soils) that have poor electrical characteristics for the absorption of microwaves. This method involves the use of a heating facilitator. The facilitator, which in this case is a ferromagnetic material (magnetite), is admixed with the soil or sludge to be treated. When exposed to microwave energy, the facilitator preferentially absorbs the energy and transfers heat to the contaminated matrix. Using this method, it has been possible to achieve temperatures in excess of 900 °C (1650 °F) in test soils. At these temperatures, even the highest molecular weight hydrocarbon contaminants are compelled to desorb from the soil.The advantage of using magnetite is that it can be separated by conventional separation methods for recycle and reuse. The technology has implications of being useful in several chemical processing operations.

Monoclonal antibody-coated magnetite particles as contrast agents for MR imaging and laser therapy of human tumors.

Attempts to improve human tumor detection by non-radioactive magnetic resonance techniques have led several investigators to develop antibody-linked paramagnetic contrast agents. Initial studies focused on gadolinium conjugated to monoclonal antibodies. However, very high levels of this contrast agent were needed to significantly reduce proton relaxation times and obtain improved MR images. The use of magnetite (Fe 3O 4) as an MR contrast agent provides a magnetic moment that is approximately one order of magnitude larger than gadolinium. In this study monoclonal antibodies 44 x 14 (specific for squamous cell carcinoma) and 436G10 (specific for melanoma) were obtained from ammonium sulfate precipitation of tumor ascitic fluid. Equal volumes of magnetite solution (1.87 mg Fe/ml) and antibody solution 44 x 14 (5.24 mg protein/ml) and 436G10 (0.64 mg protein/ml) were mixed and sonicated. The 44 x 14-magnetite and 436G10-magnetite solutions were then added to equal volumes of M20 and P3 squamous cell carcinoma cell lines. T1 and T2 values were obtained on a Praxis II NMR spectrometer equipped with a 10 mm probe and 0.25 Tesla permanent magnet. The T2 relaxation times of the magnetite-antibody-cell mixtures were 31 ms with an R = 0.985 for both experimental samples. Our results demonstrate a significant decrease in T2 by binding of the magnetite-coated antibodies to these melanoma and carcinoma cells in vitro. The possibility of detecting subclinical local and metastatic disease with magnetite linked to monoclonal antibodies followed by MRI guided laser tumor ablation therapy may render this technique clinically attractive for treatment of deep-seated tumors.

Magnetresonanzspektroskopie der tumortragenden Rattenleber: Magnetitpartikel als Hilfe bei der Volumenselektion

Magnetite, an RES-specific contrast medium, has been used in animal experiments and in a few patients for MRI of the liver. We examined the use of magnetite particles for 31P-MR spectroscopy using a phantom, and perfused tumour-bearing rat livers and liver tumours in living rats. As expected, there is homogeneous uptake of the magnetite in normal liver leading to extinction of the signal when one uses suitable spectroscopic parameters. Since the ferrite particles do not penetrate non-hepatic tissue, such as metastases, a signal remains uniquely from the tumour and this can be used, for instance, for following the effect of cytostatic therapy. The use of magnetite produces a selective effect and interference from normal liver is thereby avoided. Multiple lesions with irregular configuration can be examined simultaneously by this method. It remains to be seen how useful the application of magnetite will be for avoiding motion artifacts during spectroscopy.

Superparamagnetic iron oxide nanoparticles as a liver MRI contrast agent: Contribution of microencapsulation to improved biodistribution

We have developed a new method of synthetizing superparamagnetic iron oxide nanoparticles, consisting in the modifications of Molday's method, which ensures high relaxivity (2.4 10 5 s −1·M −1·L), good chemical stability, singular biodistribution and a considerable safety margin. The ED (Efficace Dose) to LD50 ratio is 1 2400 instead of 1 50 for Gd-DTPA. In order to develop a magnetite-delivery system to the liver we have incorporated the nanoparticles into biodegradable synthetic microcapsules. Encapsulated 59Fe oxide nanoparticles are injected into rats; in these conditions the sequestration is 9-fold greater in liver and 6 and 5 times lower in blood and carcase, respectively. This modification of the biodistribution enables the use of magnetite containing microcapsules at only 0.3 mg/kg iron to obtain an improved contrast in liver.

The use of magnetite for estimation of microspheres in mice

For the use of magnetite as a tracer to estimate the biological fate of microspheres after injection, albumin microspheres containing magnetite were injected i.v. into mice; then they were examined for their biodistribution along with an in vitro test. Magnetite recollected from the homogenates of mice organs with a magnet was assayed by atomic absorption spectrophotometry.

蛍石鉱山廃水の高勾配磁気ろ過

Recently the output of fluorite has been increasing in China and environmental problems have been proposed accordingly by the waste water containing fluorine in the flotation plants of Dong Feng and so on. This paper describes the purification of artificial fluorite mill waste and colloidal calcium fluoride by high gradient magnetic filtration (HGMF) with the combined addition of magnetic seed particles and inorganic flocculant. The results are as follows.1) As fluorite and calcite particles suspended in water released calcium ions, the capture of suspended solids by HGMF and the hetero coagulation of each mineral and magnetite were estimated from their zeta potentials in the existance of calcium ions.2) The addition of magnetite which was prepared by the oxidation of ferrous hydroxide was the most effective for the removal of suspended solids in comparison with the use of magnetite prepared by grinding or coprecipitation.3) 0.2-0.5 T of external applied magnetic field was enough to capture suspended solids coated with magnetite. Theemployment of permanent magnet instead of electromagnet is possible, so that the energy cost will be reduced.4) Aluminium sulfate solution was added into suspension and pH was adjusted at 7 to 8 after the addition of magnetite. Thi s conditioning was very effective to purify artificial fluorite mine waste water or colloidal calcium fluoride by HGMF.

Magnetic bones in human sinuses.

Studies on the interaction of magnetic fields and biological organisms have centred on the influence of applied magnetic fields on the physiology and behaviour of organisms, including humans, and a search for magnetic sources within the organisms themselves. Evidence continues to accumulate that a wide range of organisms, from bacteria to vertebrates, can detect and orient to ambient magnetic fields (for examples see refs 2-4). Since the discovery that magnetic orientation by bacteria was due to the presence within the organism of magnetic particles of the ferric/ferrous oxide, magnetite, the search has begun for other biogenic deposits of inorganic magnetic material and ways in which the possession of such material might confer on the organism the ability to orient to ambient magnetic fields. Such magnetic material, often identified as magnetite, has been discovered in bees, homing pigeons, dolphins and various other organisms, including man. A variety of hypotheses for the use of magnetite in magnetic field detection have been proposed. We report here that bones from the region of the sphenoid/ethmoid sinus complex of humans are magnetic and contain deposits of ferric iron. The possible derivations and functions of these deposits are discussed.

Factors affecting the adsorption of polio virus to magnetite in water and wastewater

The process of magnetic filtration involves the use of magnetite for the removal of various pollutants from water and wastewater. A study was undertaken to investigate the interaction between magnetite and polio virus. It was found that the adsorption process was enhanced by the presence of cations, conformed to the Freundlich isotherm, and did not vary significantly when the pH was varied from 5 to 9. The influence of two wastewater effluents on the adsorption process was also studied and their interference with the adsorption of polio virus to magnetite is discussed.