Electrostatic separation process

It may be added here that electrostatic separation suffers from more or less the same disadvantages as dry magnetic separation in that both require a perfectly dry feed, and both have a relatively small capacity for finely divided material. For most efficient operation, it is necessary that the feed be processed in a layer (one particle deep), but this severely restricts the throughput of the electrostatic separation process. 

To avoid generation of waste brines and the associated serious problem of brine disposal, the potash industry in the former FRG began converting some operations to electrostatic separation, a dry process for separating potassium salts from other soluble salts (24,25). 

Typical Operating Conditions Table 19-26 presents some typical values oF important operating conditions For the separation oF several diFFerent types oF Feed materials. In considering candidate processes For a given separation job, the table can sometimes be help-Fiil in showing that materials oF similar properties and/or economic v ahie can be treated bv electrostatic separation. 

Magnetic separation for ferrous materials eddy-current separation for aluminum electrostatic separation for glass from wastes free of ferrous and aluminum scrap magnetic fluid separation for uouferrous materials from processed wastes... 

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. 

Stalk is removed by the use of electrostatic separators. The process is effective because of the higher moisture level of stalk as compared to leaf after emergence from the drier. Fiber and dust can be eliminated by winnowing. 

The ilmenite production from heavy mineral sands exclusively utilizes a physical separation method using magnetic separation, gravity concentration and electrostatic separation. Flotation is practiced mainly for beneficiation of fine mineral sands containing rutile, ilmenite and zircon. The ilmenite that is produced in a number of operations in Western Australia, India and the USA is high in chromium, which makes the ilmenite unusable. This section discusses a new process that was developed for chromium removal from ilmenite concentrates. 

Rotor bodies, in steam turbines, 23 231 Rotor electrostatic separators, 16 643-644 Rotor rotating converter, 16 151 Rotors, molecular, 17 59-61 Rotor spinning cotton yarn, 3 17 Rotor-stator devices, 10 127 Rotor-stator disperser, 3 701 Rotor-stator mills, 13 65 Rotor-stator mixers, 16 674-675 Rotosil process, 22 412 Roughages, as ruminant feeds, 10 863 Roughing, in mineral separation, 16 604 Roughing services, magnetic drums used in, 15 446... 

The PET and aluminum chips require further drying so that they can be electrostatically separated. This is the most expensive part of the entire process. "The aluminum cap is only 1% by weight of the bottle," explains Dittman, "but the equipment to remove it represents about 30% of the investment in the plant. It s out of balance, and we are trying to remove the aluminum more cheaply." The process-which at the CPRR plant can handle about 600 lb per hour, or a potential capacity of about 5 million lb per year—generates clean, well-separated (99.9%) granulated plastic chips that can be sold to a manufacturer who uses the resins. 

The electrostatic forces in many systems play a dominant role, such as the separation process (filtration) in wastewater treatment. 

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