Electrostatic separation operating conditions

A variable-speed drive is usually used on the feed and cross-belt drives to exercise control in separator operation, although the speed is not usually changed once the optimum operating condition is estabUshed. Feed rates and the selection of the number of magnetic poles are usually deterrnined by preliminary laboratory tests. The mineral types involved in the feed largely determine the number of poles selected. High intensity cross-belt separators are frequendy used in combination with induced-roU or electrostatic separators. 

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. 

TABLE 19-26 Typical Operating Conditions for Electrostatic Separations... 

Fig. 6.11 A schematic drawing of new ion attachment mass spectrometer with the capillary sample inlet and a vacuum envelope with a wall separating ELS chamber fiom mass analyzer chamber. This capillary inlet is fixed on the front flange of the vacuum envelope. 1C ionization chamber, ELS electrostatic lens system, QMS quadrupole mass spectrometer, TMP turbomolecular pump, RP rotary pump. The vacuum envelope is pumped by a single 230 L sec" turbomolecular pump with two ISO-100 inlet flanges (Pfeiffer-Vacuum TMH 261-250-010) plus a 250 mL min" rotary pump. Ionization chamber is closed-type, with a 1 mm < ) aperture through which ionic species are passed. The typical operating conditions are IS pressure with nitrogen gas used as a buffer gas, 40 Pa pressure of ELS chamber, 8x10" Pa, pressure of the QMS chamber, 8 xlO"" Pa. (Reprinted with permission from Ref. [93]. 2012, Springer)...

Many anionic dyes (section 1.6) depend on their sulphonic acid groups for their solubility in water. Dye sulphonic acids have pK values within the range of pH 1-2 and are fully ionised under dyeing conditions as either the free acid or the sodium salt. The mutual electrostatic repulsion between dye sulphonate anions ensures their uniform separation and distribution in dilute aqueous solution. At higher concentrations, however, this repulsion is counterbalanced by mutually attractive forces of various kinds operating at shorter range [3] ... 

Electrostatic Precipitators The principles and operation of electrical precipitators are discussed in Sec. 17 under Gas-Sohds Separations. Precipitators are admirably suited to the collection of fine mists and mixtures of mists and solid particulates. Tube-type precipitators have been used for many years for the collection of acid mists and the removal of tar from coke-oven gas. The first practical installation of a precipitator by Cottrell was made on sulfuric acid mist in 1907. Most older installations of precipitators were tube-type rather than plate-type. However, recently two plate-type wet precipitators employing water sprays or overflowing weirs have been introduced by Mikropul Corporation [Bakke,/. Air Pollut. Control Assoc., 25, 163 (1975)] and by Fluid Ionics. Such precipitators operate on the principle of making all particles conductive wnen possible, which increases the particle migration velocity and collection efficiency. Under these conditions, particle dielectric strength becomes a much more impor-... 

---