Magnetic separation

Magnetic separation and flotation are the two commonly used iron beneficia- tion processes and selecting the most effective process to treat low-grade ore de- pends mainly on the mineralogical structure of the ore especially the aggregation of Iron with gangue minerals [5]. Magnetic separation using wet high-intensity technique has become one of the most suitable methods for recovery of iron from low-grade ores [6], due to its better separation efficiency as compared to dry magnetic separation and gravity separation [7]. Flotation processes using either cationic or anionic collectors are therefore considered as the more most effective methods to separate iron-gauge minerals which are aggregated together and are weak magnetic particles [8]. Many studies on reverse magnetic flotation put across performances comparison between anionic and cationic collectors in terms of iron recovery and gangue separation efficiencies. In many cases, anionic collectors have lower recovery efficiencies due to poor selectivity while cationic exhibits low efficiency due to high viscosity and low foam mobility [9]. Cationic reverse flotation is usually pH dependent process and is done effectively at lower pH range from pH 9 to 10 as compared to anionic flotation which is done for pH range from pH 11 to pH 12 (Ana et al ., 2017) [10]. However, even with these technologies, it could not build a capable process of collecting high grade iron concentrate with high iron recovery from hematite-based ores.

The development of highly sensitive techniques for early detection of Pseudomonas aeruginosa is an important consideration of medical research [51,52]. Herein, we introduced an in situ PCR based on MNPs and a method of detection based on chemiluminis- cence and magnetic separation. The parameters for detection were optimized in this method. Finally, a highly sensitive and rapid detection method for Pseudomonas aeruginosa based on magnetic enrichment and magnetic separation has been developed with detection limits as low as about 10 cfu/mL, while the detection of a single Pseudomonas aeruginosa is also recognized. Automation of pathogen detection is a developing trend. The DNA enrichment and in situ PCR based on MNPs can simplify the process of de- tection, making automation more convenient.

Within the total number of publications regarding the usage of magnetizable particles and magnetic separation in bioengineering, only a little fraction is focused on the design of the separator itself. The reason for this could be that the separation in bench-scale was very simple and practicable with a permanent magnet. Normally, when the separation takes place in milliliters, either the magnet or the suspension container is removed manually for resuspension of the magnetic particle deposits. But when magnetic separation is conducted for several liters, a magnetic filter is required. The fluid is pumped through a filter chamber in which a matrix insert of highly mag- netizable stainless steel is placed [7]-[10]. Hereby the magnetic field is applied by permanent magnets or elec- tromagnets. The permanent magnets have the advantages that they have no power consumption and show no thermal load up. The disadvantage is the always active magnetic field which cannot be easily switched off as with an electromagnet. To overcome this disadvantage, a magnetic separator with a switchable magnetic field within the air gap of the yoke is published by Hoffmann et al. [11]. The separator was used in several studies for the separation of biomolecules from fermentations and biocatalytic processes [11]-[17].

The filter matrix can be built with various geometries as for example rods or plates with notches. Although cy- lindrical matrix filaments were more adequate for high-gradient magnetic separation in terms of fluid flow around the filaments, steel plates with notches and cuboid filaments were used here for the systemic study of filter matrices. With such filter matrices a higher magnetic force gradient could be generated at the edges of the notches. Moreover, the assembling of the magnetic filter, which will play a role for future use, is easier in this case. The manufacturing of filter plates requires techniques to produce the required notches without degrading the stainless steel at the cutting edges. Therefore filter plates were made by laser cutting, stamping and micro waterjet cutting (see Figure 4).

Plasmodium species to degrade haemoglobin (an Fe(II) diamagnetic complex) into haemozoin (an Fe(III) para- magnetic complex) was used, making possible the mag- netic purification of parasitized red blood cells containing haemozoin. The present study demonstrates the high degree of purity that can be obtained for the synchroniza- tion of in vitro cultures of Plasmodium falciparum, either on asexual or sexual erythrocytic stages, and the usefulness of magnetic separation for the enrichment and purification of Plasmodium parasitized red blood cells from infected malaria patients.

Protein separation is one of the basic applications of this kind of bifunctional nanomaterials. To use these materials for protein separation, the sample was washed several times to make sure there is no free gold nanopar- ticle in the solution, and bovine serum solution was added in the sample. Then, by using external magnetic separation, the sample was divided to liquid and paste, which was redispersed in water, for SDS-PAGE electro- phoresis gel stained by Coomassie blue. Figure 2 shows

The Nome nickel laterite deposit is located in the North East of Albania. The ore deposit, devel- oped between ultramafic rocks and limestones during Early Cretaceous to Eocene, represents part of the Albanian Mirdita ophiolite zone. The lateritization of the deposit was observed mainly in three separate areas, the Has-Kukes-Lure in the North, Pogradec-Librazhd in the center and Devoll in the South. The main mineralogical components of the ore are goethite, hematite and quartz, while the secondary ones are chlorite (clinochlore, Ni-chlorite), kaolinite and lizardite. Nickel is mainly found in chlorite. The ore is characterized by the presence of spheroid particles, such as oval, pisoid, peloid and composite spheroid. According to the microscopical examination the ore is characterized in general as allotriomorphic, inequigranular and the texture is oolitic-pisolitic. For the mineral processing gravimetric and magnetic separation are used in the size fractions −8 + 4 mm, −4 + 1 mm, −1 + 0.250 mm and −0.250 + 0.063 mm. The chemical and mineralogical analyses, as well as the microscopic examination have shown that mineral processing by magnetic separa- tion gives the most satisfactory results for the size fractions −1 + 0.250 mm and −0.250 + 0.063 mm.

Boronic acid is also known as a typical adsorbent for cat- echolamine extraction because it can form cyclic esters with cis-diol compounds under alkaline conditions [21– 24]. Thus, boronic acid-functionalized materials exhibit strong affinity toward cis-diol-containing compounds, which leads to their applications for various functional materials and tasks, such as diagnostic sensing, magnetic separation, and targeted drug delivery [25, 26]. When preparing boronic acid-functionalized materials, how- ever, amine-terminated matrices should be conjugated with 4-formylphenylboronic acid via reductive amina- tion, which typically requires very long reaction times (more than 3 days) [27–30].

was investigated by repeating the adsorption-desorption cycle experiments. After each cycle, the SPE agent was recycled by magnetic separation, followed by washing with deionized water. After 100 times adsorption-desorption cycle, a good recoverability was obtained with the standard error <5%. These results confirm that the magnetic removable nanocomposite is not destroyed or poisoned during the adsorption-desorption cycles. Furthermore, after magnetic separation, the sample solution was analyzed for Zn, Ag and Fe using FAAS. There was no detectable value of these metals after each recycle, which was coincident with the results for stability studies. Consequently, the prepared magnetic SPE agent was found to be suitable for reuse without significant decrease in its adsorption capacity for Cd(II) ions until 100 cycles.

Abstract: In recent years, the outbreaks of foodborne diseases caused by pathogenic bacteria have made considerable economic losses and shown a threat to public health. The key to prevent and control these diseases is fast screening of pathogenic bacteria, which is usually performed with three procedures: sample collection, bacteria separation and bacteria detection. For sample collection, the national standard methods are often employed. For bacteria detection, currently available methods such as Polymerase Chain Reaction and Enzyme Linked Immuno-Sorbent Assay are often used. For bacteria separation, traditional methods such as filtration and centrifugation are not capable to specifically separate the target bacteria. However, food samples are very complicated and require efficient pretreatment for bacteria separation and concentration to achieve accurate and reliable results. The conventional immune magnetic separation method can be used to specifically separate the bacteria, but it still cannot meet the requirements for food sample pretreatment due to very low concentration of target bacteria in food. Therefore, this study developed an automatic and efficient immuno-separator of foodborne bacteria based on magnetophoresis and magnetic mixing, and E. coli O157:H7 was used as research model. A magnetic mixer was applied to facilitate the immunoreaction between the immune magnetic nanoparticles and the target bacteria cells, and a magnetophoretic separation tubing was utilized for magnetophoretic separation of the magnetic bacteria. Under the optimal mixing time of 20 min and the optimal flow rate of 50 µL/min, the separation efficiency of E. coli O157:H7 could be more than 90%, showing that the developed immuno-separator is promising to be applied for efficient separation of foodborne bacteria and can be easily extended for separation of other biological targets by using their specific antibodies.

From the above studies it can be concluded that indium was incorporated into the particles. The magnetic separation provides the proof that for all the loadings of the indium the nanoparticles still remain magnetic in nature. Also one can readily control the loading of indium in the particles by varying the amount of indium chloride during the starting of the reaction. Because of the moderately short half life of 111 In, its commercial availability, its easily achievable radiation protocol, and its ability to be incorporated into magnetite, this isotope makes an excellent starting point for radiotracer studies with magnetic nanoparticles. Once preliminary expectations are proven, a multitude of future radiotracer studies with 111 In and longer lived species will follow in both the biomedical field and the environmental field.

Impedance biosensor is one type of electrochemical biosensors and often featured with compact design, rapid detection, relatively low cost and easy integration, which generally relies on the electrochemical impedance change on the interface of an electrode under an alternating-current potential with a direct-current bias. The bacteria detection strategy based on electrochemical impedance biosensors often includes immunomagnetic separation for isolating the target bacterial cells from the food sample and biosensor detection for determining the concentration of the bacteria. The conventional magnetic separation is based on antigen-antibody reaction and has been widely used for specific separation of various biological and chemical targets [23]. Compared to magnetic microparticles, magnetic nanoparticles (MNPs) with higher surface-to-volume ratio, less steric hindrance and more uniform distribution are often modified with the antibodies against the target bacteria and used to capture the bacteria, followed by magnetic separation by a magnetic field and enrichment in a small volume of buffer solution. So far, immunomagnetic separation are often performed by manual operation and not suitable for separation of the target bacteria from a large volume (10 mL or larger) to increase the sensitivity. Besides, interdigitated array microelectrodes with low ohmic drop, short detection time, high signal-to-noise ratio

magnetic solid phase extraction adsorbent coupled with fluorescence spectrophotometry to separate Congo red in food samples. PILs as possible environmentally friendly solvent can obtain good extraction efficiency. The magnetic separation greatly improved the separation rate and reduced the analysis time. In conclusion, poly ionic liquids immobilized MNPs could be considered as a promising alternative for the extraction of Congo red. This introduced method for the separation of Congo red from real samples was proved to be satisfactory.

355 μm sieves size fractions [1] [18]. For the tailings results significant percent content of the niobium mineral was observed to be contained in the various sieve size fractions, but with poor recoveries values when compared to that of the concentrates. This trend reveals that the niobium minerals do not respond effectively to the separation process of the air floatation when compared to the rapid magnetic separation method. Reason been that [18] [21] have reported in different forum, that critical size factor of a particle is a very important parameter that if attained, particles of minerals will respond to the effect of the mechanism use to separate or agglomerate the particles. Hence, the above stated condition is not made by the mineral particles of the various sieves size fractions and thus, the poor response to the separation test of the air floatation separation method. From the tests conducted using the single stage processes, none of the processes used in the single stage produces the required grade of 50% Nb 2 O 5

of large surface area and high magnetic properties, which cause high adsorption efficiency, high removal rate of contaminants, and easy and rapid separation of adsorbent from solution via an external magnetic field. After magnetic separation, the contaminants can be easily separated from MNPs by the desorbent agents, and the recovered MNPs can be reused [13]. In last decade, magnetite nanoparticles have been used for some organic and inorganic pollutants without and after surface modification [12-16].

In this paper, by making use of the chiral kinetic equation, we derived a closed set of anomalous Maxwell equations relevant for the study of relativistic plasmas with chiral asymmetry and inhomogeneities. By utilizing an expansion in powers of electromagnetic fields and deriv- atives, we derived electric and axial currents as well as a closed set of the coordinate-space equations for the electric (or fermion number) and chiral chemical potentials. We studied the two regimes in which the zero order distribution function is given by the standard Fermi-Dirac distribution function and a boosted one. The latter realizes the drifting state where the plasma drifts as a whole with the drift velocity perpendicular to both electric and magnetic fields. In this case, the expansion proceeds only in powers of the component of electric field parallel to the magnetic field whereas the perpendicular component of electric field is taken into consideration exactly. In addition to the Hall current for the electric current, we found its analogue for the axial current generated by the axial density. The chiral magnetic effect current is reproduced exactly in the drifting state. What is surprising is that we also found two addi- tional electric and axial currents of a possible topological origin. They resemble the chiral magnetic/separation cur- rents, but flow perpendicular to the magnetic field and are driven by the perpendicular component of electric field, as well as the scalar product of the electric and magnetic fields.

contrast, Cu and Zn removal did not apparently increase with the applied magnetic field because of their nonferromagnetic characteristics. However, during magnetic separation, parts of Cu and Zn were still removed with Fe from the waste. This phenomenon is because the fragment generated from sawing wire contained not only Cu and Zn but also Fe. Eventually, the removal fractions of Zn and Cu were lower than that of Fe.Increasing the cycle number of magnetic separation should enhance Fe removal from the waste. Figure 4 illustrates the effect of increasing cycle number on metal removal at 0.44 T. When the cycle number increased from 1 to 3, the Fe removal fraction increased linearly from 0.48 to 0.73. Because parts of Fe fragments contain Cu and Zn, Cu and Zn removal can be slightly enhanced by increasing the trap of Fe fragments in the magnetic filter. When the cycle number exceeded 3, the Fe removal fraction was saturated. Although the cycle number increased to 5, the Fe removal fraction increased to only 0.79.

MINERAL PROCESSING TABLE OF CONTENTS RESEARCH AREA 3.1 : PHYSICAL SEPARATION TECHNIQUES 559 Contract MA1M-0041-C The application of high intensity magnetic separation to the beneficiatio[r]

An evaluation of existing insulation and remediation technologies for solid mineral waste storages is carried out. Results of field observations at one of the largest tail- ings in Russia are given. A quality of atmospheric air, and surface and ground water are estimated in the impact areas of a magnetic separation waste storage at an iron ore deposit of the Kursk Magnetic Anomaly. An effective method of landfill’s surface insulation using polymeric materials is offered. The technological insulation process by means of a self-propelled screening machine is described. The suggested method will allow preserving an artificial deposit until the time of its rational mining, stopping water and wind erosion from its surface. Environmental conditions in its location area will be improved and pollution of atmosphere, soil, and natural water will be reduced. Keywords: waste repository; adverse impact; technogenic deposit; reclamation; con- servation.

mm 3 /TAs respectively. The corresponding trajectories are shown by dash"dot lines. In present approach, these mobilities are obtained numerically which are also consistent with equations (16"18). If the particles with mobility m m =12.0×10 "4 mm 3 /TAs ( m 1 < m m < m 2 ) enter the separation channel through the inlet a, they will be collected at the outlet b without sticking to the wall regardless of their initial entry positions. The possible trajectories of these particles will be between the two solid lines marked by m m . Figure 5 also confirms that any particle with mobility, m m , satisfying m 1 < m m < m 2 , will be totally separated without sticking to the wall. The flow rate Q is 10 ml/min and B 0 is 0.775 T in this figure. Therefore, the most important factor for optimisation of