Characteristics Of Magnetite Research Articles

Mechanical characteristics of magnetite as a function of particle size during column-based magnetic separation

ABSTRACT Column-based magnetic separation can concentrate magnetite while preventing magnetic particle agglomeration. Changes in the force characteristics during this process greatly affect the separation of different magnetite components. Here, the mechanical characteristics of magnetite with different particle sizes during column-based magnetic separation are studied. Upon reducing the particle size (passing 74 μm) from 45% to 90%, the magnetic force () required to separate the magnetite concentrate gradually increased. The difference in the magnetic force required to capture magnetite concentrate and rich interlocking concentrate by a magnetic field decreased from 39.53% to 13.92%. The difference in the magnetic force required to capture lean interlocking concentrate and gangue minerals by a magnetic field decreased from 75.87% to 54.26%. Verification tests showed that pre-separating magnetite concentrate and gangue from individual coarse particles reduced the workload of subsequent grinding and separation, making it easier to separate magnetite from the concentrate.

Synthesis of Magnetite Nanoparticles Using The Reverse Co-precipitation Method With NH4OH as Precipitating Agent and Its Stability Test at Various pH

In this study, the synthesis of magnetite was carried out through the reversed coprecipitation method with ammonium hydroxide (NH4OH) as precipitating agent. The aim of the study was to obtain the most appropriate moles ratio of Fe(III) and Fe(II) in obtaining the best characteristics of magnetite, considering that Fe (II) was easily oxidized to Fe (III). Characterization of synthesized magnetite was performed using a Fourier Transform Infrared (FTIR) spectrophotometer and X-Ray Diffraction (XRD). The results showed that the moles ratio of Fe (III) and Fe (II) that produced magnetite with high yield, FTIR spectra absorption and diffractogram peaks with high intensity was magnetite synthesized using a ratio of Fe (III) and Fe (II) = 1.5: 1. Yield of magnetite synthesized in this condition was 81%. Based on the stability test, magnetite was stable at pH 2-10.

Effects of divalent heavy metal cations on the synthesis and characteristics of magnetite

Despite decades-long research efforts, the remediation of groundwater contaminated by heavy metals has remained a significant challenge. Recent studies have demonstrated that in situ formation of magnetite might be an effective method to more permanently immobilize metal(loid)s. However, how the co-existence of additional heavy metals affects the synthesis of magnetite under environmentally relevant conditions and how it affects the associated heavy metal removal efficiency have remained unclear. Here, a common magnetite synthesis procedure was used to synthesize Cu-, Cd-, and Pb-substituted magnetites at circumneutral pH with variable heavy metal concentrations. The synthesized mineral products were then subjected to digestion, Mössbauer, XRD, SEM-EDS, magnetic susceptibility and surface area measurements, as well as isothermal adsorption experiments. The presence of additional divalent heavy metals during synthesis affected the characteristics of the Fe mineral products. Magnetite formed in the presence of heavy metals was poorly crystalline and impure. The mineralogy and morphology of the products was regulated by the surface affinity of the heavy metal. The co-existence of divalent heavy metal cations that have higher surface affinity than Fe(II) suppressed the mineral growth of more crystalline Fe oxides, including magnetite. Minerals synthesized in the absence of heavy metals had higher capacity and affinity for heavy metals than minerals synthesized in the presence of those metals because of the effects of altered mineral surface structure and surface area on adsorption. These results help us understand how different types and concentrations of heavy metals affect magnetite synthesis and its suitability for in situ groundwater remediation.

Protocol for the synthesis of Ba-hexaferrites with prefixed coercivities

The ferrite industry is one of the largest consumers of iron oxides, usually in the form of hematite from the roasting of steel pickling liquors or from mineral sources. In previous papers we have tested an oxidation process for obtaining magnetite and goethite from steel pickling liquors and two mathematical models have been proposed for synthesizing these two iron oxides. In this paper, the characteristics of magnetite and goethite are related with the coercivity of hexaferrites synthesized when the former are used as raw materials. Constant conditions were used for the ceramic method. Using goethite, Ba-hexaferrite is obtained only when the goethite is precipitated at the lowest oxidizer flow. When magnetite is used, a protocol with a statistically validated correlation is proposed for synthesizing hexaferrites with coercive fields between 230 and 450 kA/m. This correlation is valid for an oxidation process carried out at stirring speed of 1000 rev/min and with an air flow between 7.5 and 101/min. A second empirical correlation is proposed for obtaining final coercivities between 450 and 525 kA/m, for which it is necessary to increase the calcination time.

Characteristics of magnetite in submarine basaltic glass

SUMMARY We have compared the rock-magnetic characteristics of Cretaceous submarine basaltic glass (SBG) from DSDP/ODP Holes 417D, 418A, 807C and 543A to data from Holocene glasses from the East Pacific Rise. Both groups are very similar in that they contain single-domain, low-Ti magnetite as the carrier of a strong and stable remanent magnetization. The behaviour of magnetic hysteresis in SBG is, however, dominated by superparamagnetic grain-size populations. Transmission electron microscopy revealed spherically shaped grains of 10-20 nm diameter with crystal lattice properties consistent with magnetite. These grains could be responsible for the magnetic behaviour of SBG.

Secular changes in the magnetic characteristics of magnetite

Secular changes in the magnetic characteristics of magnetite