http://www.hindawi.comThe latest articles from Hindawi Publishing Corporation© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2008/508617Rotating disks separators, mounted on single and double hollow shafts, are investigated experimentally. The shaft and disks were enclosed in stainless steel housing. Many parameters were measured to study their influence on the performance of single and double shaft disk filters at various rotation speeds. These parameters are pressure inside the housing, permeate flux, and electrical power consumption. The average velocity coefficient k˜ for single and double shaft disk separators was estimated and was found to be a good criterion of module performance as well. The comparison of measured and calculated filtration flow rate at various rotation speeds was in a good agreement. The estimated average shear stress is found to be about twice in double shaft filter disk. The feasibility of double shaft disk separator in treating filtration without filter cake is highly appreciated.Yazan Taamneh and Siegfried Ripperger© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2007/91740Sedimentation of organic fibres and inorganic particles can be observed in several industrial applications. Fibres are involved not only in wastewater treatment but also in other separation applications. In the paper industry, the separation of inorganic filler and coating particles from short cellulose fibres is still a challenge in the recycling process. During that process, particles have to be removed to obtain a purified fibre suspension. These fibres can be used again to produce new paper. With the currently applied techniques, like screening and flotation, the efficiency of short fibre separation is very poor. Moreover, also separation by sedimentation fails due to similar settling velocities of heavy-small particles and the light and larger fibres. This paper concentrates on the sedimentation of organic fibres and inorganic particles in water. The investigated suspensions are made by resolving two different and specially produced papers a coated and an uncoated one, as well as the single components used for its production. We observe a different sedimentation behaviour according to the concentration of fibres and particles in the suspension and the pH-value of it. The main result is that, according to the fibre rate, the sedimentation behaviour is particle dominant or fibre dominant.Markus Feist, Hermann Nirschl, Jörg Wagner, Georg Hirsch, and Samuel Schabel© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2007/34832The study presents the transfer of nanoparticles from the aqueous phase to the second nonmiscible nonaqueous liquid phase. The transfer is based on the sedimentation of the dispersed particles through a liquid-liquid interface. First, the colloidal aqueous dispersion is destabilised to flocculate the particles. The agglomeration is reversible and the flocs are large enough to sediment in a centrifugal field. The aqueous dispersion is laminated above the receiving organic liquid phase. When the particles start to penetrate into the liquid-liquid interface, the particle surface is covered with the stabilising surfactant. The sorption of the surfactant onto the surface of the primary particles leads to the disintegration of the flocs. This phase transfer process allows for a very low surfactant concentration within the receiving organic liquid, which is important for further application, that is, synthesis for polymer-nanocomposite materials. Furthermore, the phase transfer of the nanoparticles shows a high efficiency up to 100% yield. The particle size within the organosol corresponds to the primary particle size of the nanoparticles. Stefanie Machunsky and Urs Alexander Peuker© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2000/25381Using two models, namely the initial differential equation of motion and the reduced equation obtained from the initial one by neglecting the inertial force comparative calculations of the capture cross section of paramagnetic particles by a cylindrical ferromagnetic collector (a wire) were carried out. For various combinations of the particle diameter, the wire diameter, medium flow velocity, strength of the magnetic field, the error in the capture cross section caused by neglecting the inertial force in the equations of motion was determined. Approximate formulae for the determination of this error and of the ratio of the inertial force to the magnetic force as a function of the main separation parameters were proposed.Yu. S. Mostika, V. I. Karmazin, V. Yu. Shutov, and L. Z. Grebenyuk© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2000/29053A novel benefit of an ordered High Gradient Magnetic Separation (HGMS) matrix, made up of parallel ferromagnetic wires is presented. One shows that the magnetic force Fm depends on α, the angle between the wires of the matrix and the applied magnetic field H0 . There is a relation between the tilting angles and magnetic susceptibilities of particles pulled out from the mixture. This relation proves a practical possibility of separating a mixture only by choosing adequate tilting angles; the method is named separation in angular steps. Finally one shows two applications based on this principle: a separator which extracts successively and another one which extracts concomitantly different magnetic fractions from a granular mixture.Gh. Iacob and N. Rezlescu© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2000/45626In addition to engineering applications, magnetic fluids containing magnetic nanoparticles are being increasingly applied to biomedical purposes. Besides the well established use of magnetic particles for biological separation or as contrast agents for magnetic resonance imaging, magnetic particles are also being tested for the inductive heat treatment of tumors or as markers for the quantification of biologically active substances. The properties of magnetic nanoparticles usually exhibit a broad distribution, so in many cases upon application only a small fraction of the particles contribute fully to the desired magnetic effect. Therefore, magnetic fluids have to be optimized by fractionation techniques. This is preferentially achieved by methods that separate magnetic nanoparticles in accordance with their magnetic properties. Hence, a magnetic technique has been developed for the fractionation of magnetic fluids. Two different magnetic fluids were fractionated by this method. The fractions obtained and the original samples were characterized with respect to their magnetic properties as well as their particle sizes. They were investigated not only in terms of their magnetization curves but also in respect to biomedical applications. The magnetic fractions show clearly improved magnetic properties compared to the original samples and are therefore especially suited for distinct applications. Furthermore, the results indicate that the magnetic method fractionates the particles in accordance with their magnetic moment and has a good reproducibility.Thomas Rheinländer, Róman Kötitz, Werner Weitschies, and Wolfhard Semmler© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2000/71758Separability and separation mechanisms of small particles in modern rotating type eddycurrent separators (ECSs) were discussed in Part I. In order to address problems associated with this design concept, a number of novel ECSs, each with a unique design, have been developed. Part II reports on investigation into the separability and separation principles for various materials smaller than 5 mm, including fine copper wires, in three new devices: the redesigned Delft vortical ECS (VECS), prototype TNO ECS and a laboratory wet ECS (WECS). It is found that TNO ECS and WECS are more practical tools for separation of small metal particles. In particular, WECS is able to recover approximately 80% of very fine copper wires, with 0.5mm diameter and 2mm length. Separation principles for WECS are discussed in greater detail than other design concepts in the present study. It appears that the fledgling WECS will be most promising in the future for proccssing small particles. Further, aluminum separation from the —10 mm fraction of electronic scrap has been carried out using TNO ECS. It transpires that both the recovery and the grade of the aluminum concentrate are superior to those obtained with the rotary bolted-drum ECS of any type.Peter C. Rem, Shunli Zhang, Eric Forssberg, and Tako P. R. de Jong© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2001/10257Colemanite (2CaO 3B2O3 5H2O) is one of the commercially preferable borates for many industries, such as agricultural, metallurgical, nuclear and production of fibreglass, borosilicate glasses, soaps, detergents, fire retardants, enamels and frits, used directly or after being transformed to boric acid (H3BO3). This paper aims mainly to investigate the practical floatability of colemanite from the Emet deposits of Turkey using a conventional collector and to compare the concentration results with dry magnetic separation tests applied at high intensity.S. G. Ozkan© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2001/52860A. M. Turkenich© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2001/57434The idea to use magnetic techniques in biosciences is not new, but it has enjoyed a resurgence of interest especially during the last two decades. Magnetic adsorbents, carriers and modifiers can be used for the immobilization, isolation, modification, detection, determination and removal of a variety of biologically active compounds, xenobiotics, cellular components and cells. Magnetic separation and labelling have recently found many useful and interesting applications in various areas of biosciences, especially in molecular and cell biology, microbiology, biochemistry and bioanalytical chemistry. Special attention is being paid to the possible biomedical and clinical applications. Currently, the magnetic selective separation, represents the most often used magnetic technique. It can facilitate or accelerate many separation and purification processes especially in heterogeneous systems. To perform a biomagnetic separation an appropriate magnetic separator and magnetic particles or other magnetic labels are needed. Several types of separators and a wide assortment of magnetic particles of different type and size (usually surface modified) are commercially available. The importance of biomagnetic (separation) techniques has increased in recent years and further development of new important applications is expected in the future. The purpose of this review is to summarise basic elements and prospects of biomagnetic techniques and to highlight possible applications in various bioscience disciplines.M. Safarikova and I. Safarik© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2001/95484A. M. Turkenich© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/1999/13573The results of a numerical solution of equations of the motion of a paramagnetic particle in the working gap of a magnetic separator for various values of magnetic induction (from 0.2 to 2 T) and the particle diameter (from 10 µm to 1 mm) show that along the particle trajectory various types of flow modes: e.g. laminar, transitional and turbulent can be present. It is also shown that some of the well-known formulae approximating the experimental dependence of the hydrodynamic drag coefficient on Reynolds number Re (the so-called standard hydrodynamic drag curve) as a step-smooth function, do not ensure the condition of continuity of the hydrodynamic drag on the boundaries of the range of values Re for which these formulae were obtained. One of the variants of approximation of the standard hydrodynamic drag curve for the case where along the same trajectory various types of regimes of flow-around a particle are present, is proposed.Yu. S. Mostika, V. I. Karmazin, V. Yu. Shutov, and L. Z. Grebenyuk© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2000/83676The separation principle and the advantage of using magnetic polymer particles in bioseparation is elucidated. After a short review of the presently used diverse magnetic microparticles as well as the basic differences of micro- and nanosized magnetic particles with regards to their physical properties in bio-separation, preparation and application of novel magnetic microparticles prepared from polyvinylalcohol are described. The performance of the novel product and their superior properties over established products in diverse bioseparation tests are shown. Furthermore, nanoparticles used for a new AIDS therapy approach are described. The basic principle is explained by which the AIDS virus (HIV) is destroyed through heat generated by inductively heated magnetic nanoparticles, which are specifically attached to the virus. Inductive heating tests with model magnetic colloids show that the required temperatures of > 50°C can easily be achieved.Detlef Müller-Schulte© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/2000/87250In this study, a superconducting high gradient magnetic separator (HGMS) with a matrix vibration system in dry mode was utilised to purify fine calcite and quartz powders smaller than 38 µm. The effects of the operating parameters (particle size, magnetic field/average air velocity (Bo /Vo), the amplitude of vibration as well as the aperture size of the expanded metal matrix) have been presented. The mechanicallybased matrix vibration with the air blowing was recognised to be effective for dry purification of fine powdered materials at high magnetic fields. The function of the matrix vibration has been discussed. In addition, the results have been empirically correlated with the operating parameters used for the purification in the separator.Yanmin Wang, Ann-Cathrine Johansson, Eric Forssberg, and Billy Chan© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/1999/56186Equations of motion of magnetic particles in the flow medium near a cylindrical ferromagnetic collector have been developed. A vector equation, expressing the balance of the inertia force and the vector sum of three forces: the magnetic, the gravitational and the hydrodynamic drag force of a particle was taken as the initial equation. Reduced equations obtained from the initial one by rejection of terms corresponding to the inertia or the gravitational force were also considered. Examples of numerical evaluation in which the motion trajectories calculated with the use of the initial equation were compared with the reduced equations of motion are given.Yu. S. Mostika, V. I. Karmazin, V. Yu. Shutov, and L. Z. Grebenyuk© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/1999/94239Magnetic separation of naturally occurring calcite (98.2% CaCO3) using selective coating of synthetic colloidal magnetite with sodium oleate has been investigated as a function of pH, concentration of colloidal magnetite, magnetic intensity and particle size. Colloidal magnetite treated with sodium oleate (oleate magnetite) is found to be a better coating agent than the natural magnetite. The mechanism of oleate magnetite coating has been investigated through adsorption and electrokinetics measurements. FTIR studies indicate that there is a possible chemical interaction between calcite and magnetite surfaces on which sodium oleate is adsorbed. Magnetic susceptibility measurement shows a finite susceptibility of calcite by the addition of colloidal magnetite. In the investigation with calcite, calcite recoveries of > 94% have been achieved at a colloidal magnetite concentration of 0.25 ml/g and 7.1 kG of magnetic intensity. In case of synthetic mixture of calcite and quartz > 90% calcite recovery at a grade of 80.9% CaCO3 has been achieved at the optimum pH of 11.S. Prakash, B. Das, and R. Venugopal© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/1999/97902An analytic equation describing the torque between two magnetic dipoles is derived in this paper. We assume that the dipole sizes are small compared to their separation. Based on a previously derived force calculation between two magnetic dipoles, we derive an analytic expression for the torque. Note that the derived torque decreases with the third power of the distance between the dipoles. It is also interesting to note that the torque on the first dipole is not necessarily equal in magnitude and opposite in direction to the torque on the second dipole. This is due to the torque of both dipoles about a common center of mass.Peter B. Landecker, Daniel D. Villani, and Kar W. Yung© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/1999/63523P. de V du Plessis© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/1995/21871The radiation pre—treatment process makes possible the mineral properties modifications. In this paper theoretical principles of the influence of the radiation pre—treatment by means of accelerated electrons on the electrical conductivity and permittivity of selected minerals is analysed. The changes of specific conductivity, as well as permittivity in dependence on the radiation dose and the grain size of minerals are introduced. On the basis of these data the conditions of the above mentioned physical quantities changes using the radiation pre—treatment from the mineral processing improvement point of view are defined.Ivan Florek and Ingrid Murová© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/1995/26453This work considers a separation process and the attendant losses on the basis of thermodynamic analogies. Energy—oriented efficiency as a criterion of the process, and the entropy—oriented efficiency as a criterion of its results, are compared. An example shows that the values are close to each other. As a practical recommendation, a modification of the feeder system is suggested.I. J. Lin and A. Katyshev© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/1995/64594This paper describes some industrial applications of magnetic separation in Swedish mineral industry. Recent studies on magnetic treatment of minerals in Sweden are also presented. These studies involve selectivity of wet magnetic separation, wet magnetic recovery of mineral fines and ultrafines, sulphide processing by magnetic means, as well as dry magnetic purification of industrial minerals.Yanmin Wang and Eric Forssberg© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/1995/69167The application of centrifugal forces to a ferrofluid with finely grained particles located in a non—homogeneous magnetic field is the basis of the theoretical model of separation outlined in this paper. An analytical solution of the equation of the particle motion, its application under certain conditions, as well as the graphic representation of the results are presented.Annamária Mockovčiaková, Michal Lovás, and Štefan Jakabský© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/1996/15891Magnetogravimetric separation in a rotational device is a promising method for effecting sharp separation of minerals according to density. Separation is accomplished by two competing forces with opposite directions, namely the magnetic buoyancy and the centrifugal force. Magnetic buoyancy is experienced by particles which are suspended in a magnetic fluid when exposed to a non—homogeneous magnetic field. Since the magnetic buoyancy depends on particle volume whereas the centrifugal depends on particle mass, a purely gravimetric separation of non—magnetic particles can be accomplished. The process is able to achieve separation split—points up to densities of 20 g/cm3, but separation sharpness decreases with fine particle sizes. On a laboratory scale, magnetogravimetric separators can be used as an alternative to heavy liquid separation, and in industrial plants they may have promise as the final cleaning stage in gravity concentration circuits of precious metals.R. C. Bunge and D. W. Fuerstenau© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/1996/36045The magnetic flocculation behaviour of two kinds of iron oxide mineral (hematite—1 and hematite—2) was studied by using a new experimental device, in which a stirred container was set in an applied magnetic field. Magnetic flocculation of both minerals occurred in very low applied magnetic fields. Hematite—1 is a strongly paramagnetic mineral, the flocculation recovery improved with increased magnetic field strength and particle size. For hematite—2 the relationship between the flocculation recovery and magnetic field strength was more complex. It was also found that the method used conventionally to calculate the magnetic interaction between particles is not suitable for strongly paramagnetic minerals, such as hematite—1.Y. Shao, T. J. Veasey, and N. A. Rowson© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/1996/42035The paper deals with the application of ferrofluids in mineral processing. The efficiency of primary and secondary raw material separation by the magnetohydrostatic method is dependent on convenient distribution and on the stabilisation of density of the ferrofluid. To determine this density, the effective dynamometric method based on measurement of the buoyant force was constructed. A density controller has been developed for stabilisation and control of the density. Influence of some factors on the separation process, as well as the results of magnetohydrostatic separation are described.Michal Lovás, Štefan Jakabský, and Slavomír Hredzák© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/1996/46596Magnetically treated water (MTW) is water passed through a magnetic field before being used. Applications of MTW are abundant in industry where it is used to prevent scaling on inner walls of pipes conveying fluids, especially water. In recent years scientists investigating the subject have concluded that the magnetic field interacts with the surface charges of particles in the fluid solutions affecting the crystallisation and precipitation of the solids in them. These processes are of significant effect on the translocation of minerals in irrigated soil.Rami Noran, Uri Shani, and Israel Lin© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/1996/58505Perlite of composition SiO2 73.6%, Al2O3 12.4%, Fe2O3 1.25%, MgO 0.15%, Na2O 2.99%, K2O 4.18%, H2O+ 3.17%, H2O- 0.2%, and found to contain 89.4% of amorphous phase and 10.6% of crystalline phase, the latter consisting of feldspars, biotite, quartz, magnetite and chlorite, was studied. Due to its largely amorphous nature, chemical composition and melting behaviour, perlite can be used in the manufacture of ceramics. For the glass industry, on the other hand, an impediment, albeit the only one, is the iron content, so that the iron—bearing minerals must be removed, which can be accomplished by dry magnetic separation. Laboratory and pilot—plant separation experiments carried out with these minerals showed that the Fe2O3 content cannot be reduced to below 0.65% owing to small inclusions of iron—bearing minerals that remain in the other minerals, or in the amorphous particles. Perlite with an Fe2O3 content below 0.7% and grain size of less than 1 mm can, however, be used in the production of coloured glass containers.D. Herskovitch and I. J. Lin© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/1996/29648Flocculation of fine paramagnetic particles rendered hydrophobic by absorption of surfactants in external magnetic field in aqueous suspension, called simultaneous hydrophobic and magnetic flocculation (SHMF), has been studied through a theoretical approach and experiments. All interactions between fine paramagnetic particles in the case of SHMF are being discussed in this paper. Through extension of the classical DLVO theory, the theory of stability of fine particles in aqueous suspension in the case of SHMF is proposed. Potential energies of interaction between fine rhodochrosite particles rendered hydrophobic by absorption of sodium oleate in external magnetic field have been calculated from the theory. Experimental results of SHMF of fine rhodochrosite and siderite particles showed that SHMF exhibits much stronger and faster aggregation then either hydrophobic or magnetic flocculation alone. Two examples of SHMF applied to fine particle processing are given.Shaoxian Song and Shouci Lu© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/1996/34321Four different iron minerals were selected for study, and five size fractions of each mineral were prepared. The magnetic properties of these minerals were measured. The effect of particle size and magnetic susceptibility on wet high intensity magnetic separation was studied simultaneously. It was found that hematite—1 was a strongly paramagnetic mineral, and the effect of particle size in WHIMS was not significant. Goethite and limonite were weakly paramagnetic minerals, and could not be effectively recovered by WHIMS. The magnetic properties of hematite—2 were between hematite—1 and goethite and limonite, and the effect of particle size on WHIMS for hematite—2 was significant.Y. Shao, T. J. Veasey, and N. A. Rowson© 2008, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/GetArticle.aspx?doi=10.1155/1996/80708The physical foundations and theoretical determination of conditions for formation of a slurry flow in form of a film along ferromagnetic plates of a rotary high—gradient magnetic separator are described. It is shown that this new hydrodynamics allows to increase not only the reliability of the separator thanks to the increase of the width of gaps between the plates, but also to improve its metallurgical efficiency.A. M. Turkenich© 2008, Hindawi Publishing Corporation. All rights reserved.