Papers by Keyword: Magnetite

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Authors: Si Qing Liu, Min Zhang, Wan Ping Wang, Xiu Juan Li
Abstract: In this research, a refractory iron ore is processed, according to the basic facts of mineralogical study. Mineralogy shows that the ore is characterized by the finely disseminated iron minerals with a small amount in the ore. Iron minerals in the ore are mainly hematite and magnetite. On the basis of the ore characteristic, a flowsheet of "stage grinding-low intensity magnetic separation-high intensity magnetic separation-gravity concentration by fine shaking table" was developed. An iron concentrate assaying 51.45% Fe at a recovery of 62.12% was obtained when the raw ore contains 18.61% Fe.
3273
Authors: Carlo Baldisserri, Davide Gardini, Carmen Galassi
Abstract: Cobalt ferrite (CoFe2O4) and magnetite (Fe3O4) nanoparticles suspensions in diethylene glycol were tested as candidate systems for the EPD of CoFe2O4 and Fe3O4. It was found that despite the high stability and high zeta potential of such suspensions and the occurrence of mass transport at the electrode, they are not viable systems for EPD, due to coagulation failure. However, dilution of both suspensions with ethanol caused film coagulation at electric field between 20 and 60 V cm-1. Combinations of electric field and DEG volume fraction in ethanol/suspension mixtures that allow EPD to take place are detailed, and a description of the outcome of EPD trials is provided. A qualitative discussion of the causes of film consolidation in the presence of ethanol is presented.
85
Authors: Irina A. Shikhman, Marina G. Shelyapina, Galina S. Kupriyanova
Abstract: Magnetite is a very promising candidate for hard electrode in magnetic tunnel junction devices due to its electronic and magnetic properties. Addition of a buffer iron layer improves required properties. Here we report on the results of our DFT study of the impact of the additional Fe buffer layer on the electronic and magnetic properties of magnetite.
288
Authors: P. Tserotas, E. Statharas, Ioannis Kartswnakis
Abstract: PEGylated, monodispersed, superparamagnetic, iron oxide nanoparticles (Fe3O4 / γ-Fe2O3) were synthesized by using a novel metal-organic approach in three steps. Ferric nitrate nonahydrate, Fe (NO3)3.9H2O, was used as iron source, which was sterically hindered among the interstices and / or in the cavities of β-Cyclodextrin (β-CD) molecules, following a modified complexation procedure. Via a polyol process the obtained complex system was first dispersed in polyethylene glycol (PEG) and under mild thermal treatment and in the presence of 1,12 dodecanediol, a new complex system of carboxylate type was formed, between ferric nitrate and PEG, denoted Fe (NO3)3.9H2O-PEG. This metal-organic precursor was thermally decomposed, forming the iron oxide nanoparticles. The obtained particles were characterized by X-ray diffraction spectroscopy (XRD), Fourier Transform Infrared spectroscopy (FTIR) and transmission electron microscopy (TEM).
693
Authors: P. Tserotas, E. Statharas, Ioannis Kartswnakis
Abstract: Monodispersed magnetite (Fe3O4) nanoparticles were obtained via an innovative three step synthetic approach. First, the formation of iron enneacarbonyl, Fe2(CO)9, a stable, solid organometallic complex compound, took place in a hexane solution, by the decomposition reaction of the unstable, liquid iron pentacarbonyl, Fe (CO)5, in the presence of sunlight and mild heating. In a second step, the dry compound Fe2(CO)9 was complexed with β-Cyclodextrin (β-CD) molecules, according to a combination of two modified complexation procedures. Steric hindrance of the organometallic molecules was achieved, among the interstices of the formed CD molecular network, which poses a novel, very crucial size control factor and stabilizing agent for the synthesized nanoparticles.
685
Authors: He Nan Wang, Li Jie Wang, He Bing Wang, Guan Hua Men, Ye Liu, Hong Yan Liu
Abstract: In order to achieve aims of rapid real-time monitoring iron grade during sales process or mineral processing for the iron ores, a quick detection approach to magnetic iron grade of magnetite based on electromagnetic induction is explored in the paper. Information acquisition head is focused on an iron grade sensor, and the iron grade sensor is made up of coil-windings with magnetite core. Information acquisition circuits are given adapting mode of the transformer bridge type rectifier, and construction of the head is designed and machined. Testing mechanism is analyzed from the angle of magnetic field analysis, and the magnetic field model is also built up. Furthermore, magnetic iron grade of some testing samples are measured by the detection device above. It is showed that when the grade range of the magnetic iron of magnetite is varied from 20% to 65.3%, deviation is lower than 1.0%. By research above, it is shown that the detection method of iron grade based on electromagnetic induction is feasible, and it is also significant for improving the total testing level of mineral processing fields.
1443
Authors: Wei Zhi Wang, Li Ping Chen, Liu Bei Zhao
Abstract: This test used countercurrent bubble contact flotation column in reverse flotation to improve the grade of magnetic concentrate. By the tests of operating conditions and reagent system experiment, when the ore grade of concentrate after magnetic separation is 42.15%, after one roughing ,we can obtain the grade is 65.82% and recovery rate is 62.79% of the concentrate.
164
Authors: Yasumitsu Kondo
Abstract: Copper and nickel are accumulated in steels when steel scrap is used as steel sources. It is well known that copper causes hot shortness problem and nickel suppresses the effect of copper. In this paper, the behaviour of copper and nickel during oxidation is investigated. Steels containing copper and nickel were oxidized and the distribution of copper and nickel in the scale was examined. It was found that copper is not only enriched at the scale/metal interface but also exists in upper magnetite layer as a state of solid solution and along grain boundaries of the wustite layer as metal phase. From these results an assumption has been proposed that the liquid copper migrates from the scale/metal interface to the magnetite layer along the grain boundaries. On the other hand, nickel enriched in steel side near the scale/metal interface with copper. The metal particles containing nickel and copper remain inside the scale. Nickel also has an effect of the uneven scale/metal interface formation.
53
Authors: Yan Hua Guo, Hui Xin Dai, Jun Long Yang
Abstract: The run of mine ore grade of Gan Shang Yan is 47.83%, iron ore grade is higher, but harmful element sulfur and impurity silica content is relatively high. This experiment using a simple process low intensity magnetic separation-high gradient magnetic separation, for the ultimate index for comprehensive grade of iron concentrate is 58.41%, at a total recovery of 80.85%, and obtain good experiment index, the harmful elements and impurity content can meet the standard.
3029
Authors: M.G. Sagdieva, S.I. Borminskiy, Z.E. Rakhmatullaeva, A.K. Tonkikh, K.S. Sanakulov, B. Scott
Abstract: Two copper flotation tailings samples, one from the Almalyk Mining and Metallurgical Complex, Uzbekistan (sample designated AMMC) and the other from Whitehorse (WT), Yukon, Canada, were bioleached at laboratory scale. Acidophilic, iron- and sulphur-oxidizing cultures were enriched from the two tailings and these cultures were used for the testing. After 24 weeks of bioleaching in percolator columns 70-72% of the copper was leached from the AMMC tailings and 91-93% of the copper was leached from the WT tailings. The chalcopyritic nature of the copper and larger particle size of the AMMC tailings compared to the WT tailings were likely reasons that copper extraction was greater for the AMMC tailings. In-column, thiosulphate leaching of biooxidized residues yielded 90+% gold extraction for both tailings. In other testing the two cultures were subjected to an electromagnetic field during growth on ferrous iron. Compared to untreated controls, cultures subjected to the electromagnetic field oxidized iron more rapidly. Although magnetite, which exerts an electromagnetic field, was present in the AMMC tailings, there was no evidence that this magnetite had any effect on the bioleaching results. However, given the enhanced performance of the iron-grown cultures under the influence of an electromagnetic field, we believe that additional research should be performed to investigate this phenomenon
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