Electrostatic separation applications

The common types of other industrial electrostatic separators employ charging bv conductive induction anchor ion bombardment. Figure 19-56 illustrates the principles of application,... 

TABLE 19-25 Machine Capacities of Electrostatic Separators for Mineral Applications... 

Plastic and Metals Recycling Electrostatic separation has been inereasinglv applied to recover nonFerroiis metals From industrial plasties (telephone and eornrniinieation scrap). It also is an important step in the reeveling oF beverage bottles to reject anv remaining nonFerroiis metals. Both oF these reeveling applications make use oF roll-type ion-bornbardrnent separators (Fig, 19-61/ ),... 

The electrostatic separation method is the exclusive choice in some specific situations, for example in the cases of rutile and ilmenite deposits. These deposits generally contain minerals of similar specific gravities and similar surface properties so that processes such as flotation are unsuitable for concentration. The major application of electrostatic separation is in the processing of beach sands and alluvial deposits containing titanium minerals. Almost all the beach sand plants in the world use electrostatic separation to separate rutile and ilmenite from zircon and monazite. In this context the flowsheet given later (see Figure 2.35 A) may be referred to. Electrostatic separation is also used with regard to a number of other minerals. Some reported commercial separations include those of cassiterite from scheelite, wolframite from quartz, cassiterite from columbite, feldspar from quartz and mica, and diamond from heavy associated minerals. Electrostatic separation is also used in industrial waste recovery. 

Electrostatics, effect on weighing, 26 243 Electrostatic self-assembly (ESA), of thin-films, 1 724-725 Electrostatic separators, 16 642 Electrostatic separation, 16 642-644 Electrostatic spray coating, 7 56-58, 74-75 Electrostatic stabilization, 10 119-121 of latex, 14 708-709 Electrosteric stabilization, 10 122 Electrostream (capillary drilling), 9 600 Electrostrictive coefficient tensor, 11 93 Electrostrictive devices, applications of, 11 103-104... 

Electrostatic-Separation Machines The first electrostatic machines to be used commercially employed the principle of contact electrification. These were free-fall devices incorporating large vertical plates between which an electrostatic field was maintained. Tribo-electric separation (contact charging) has experienced an increase in applications due to advances in mechanical self-cleaning and electrical design as well as the development of efficient precharging techniques. 

Mineral Beneficiation Electrostatic methods are widely used in the processing of ores with mineral concentrates. Generally, electrostatic separation is used as a part of an overall flow sheet comprising various combinations of physical separation procedures. It is particularly well established in the processing of heavy-mineral beach sands from which are recovered ilmenite, rutile, zircon, monazite, silicates, and quartz. High-grade specular hematite concentrates have been recovered at rates of 1000 tons/h in Labrador. Applications also include processing tin ores to separate cassiterite from columbite and ilmenite. Refer to Fig. 19-61 . 

Although electrostatic separation (static or high intensity) has not been applied widely in solid waste treatment at the industrial level, it is expected to be of wider use in the future in certain sectors of applications. This separation has been successfully applied to separate plastics from paper, plastics from each other, shredded copper wires from their plastic insulation, glass from plastic, nonferrous metals from plastic, or glass, for example. 

The equivalent spherical particle diameter of an aggregate of irregularly shaped particles can be found by studying the inertial motion of particles in a medium. This inertial motion behavior is used in many applications, such as sedimentation vessels, electrostatic separators and precipitators, and particle collectors. The various forces that affect particle motion, shown in Figure 4, are briefly discussed below. 

The selection of a suitable zeolite adsorbent for CO2 removal from flue gas (mixture of CO2 and N2) has been carried out. The limiting heats of adsorption, Henry s Law constants for CO2 and N2, CO2 pure component adsorption isotherms and expected working capacity curves for Pressure Swing Adsorption (PSA) separation application were determined. The results show that the most promising adsorbent characteristics are a near linear CO2 isotherm and a low Si02/Al203 ratio with a cation in the zeolite structure that has strong electrostatic interaction. 

Electrical properties of grain have been utilized for quick moisture tests based on the measurement of resistance, capacitance, or electrical conductivity. Many studies have been devoted to the development of density-independent functions of the dielectric properties that would permit on-line measurement of moisture content [74-76]. Also, measurements of electrical properties of grain and seed have been employed for purposes other than determining moisture content. For example, viable seeds of corn were sorted from dead seeds by measuring the current conducted by individual soaked kernels between electrodes connected to a 6-V dc source [77]. Another application of electrical properties is electrostatic separation where the ability of a seed to hold a surface charge is determined mainly by its conductivity. 

Anderson, J. M., Parobek, L., Bergougnou, M. A., and Inculet, 1.1.1979. Electrostatic separation of coal macerals. IEEE Transactions on Industry Applications lA-15 291-293. 

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