Ion-exchange equipment

Ion-exchange equipment, 14 403-405 Ion-exchange hollow fibers, 16 15, 17 Ion-exchange lithium recovery processes, 15 126... 

In ion exchange equipment, cations or anions from the fluid deposit in the solid and displace equivalent amounts of other ions from the solid. Suitable solids are not necessarily porous the ions are able to diffuse through the solid material. A typical exchange is that of H + or OH ions from the solid for some undesirable ions in the solution, such as Ca++or SOa. Eventually all of the ions in the solid are replaced, but the activity is restored by contacting the exhausted solid with a high concentration of the desired ion. for example, a strong acid to replace lost hydrogen ions. 

One such example of a condensate purification system is the use of ion exchange equipment as shown in Fig. 3 for a typical paper-mill boiler cycle. The resin beds not only remove dissolved impurities by ion exchange, but also serve as filters to remove suspended solids, such as products of corrosion. It is necessary to backwash and regenerate such resin beds periodically. These resin beds can be purchased for in-place regeneration or for regeneration in external tanks. External regeneration facilitates more efficient removal of suspended metal oxides from resin beds. 

The ion exchange equipment, which is located on a metal rack (1.8 x 0.9 x 0.4 m) in one of the TRU hot cells, is maintained and operated with two master-slave manipulators that penetrate the 1.4-m-thick shielding wall. A flow diagram is shown in Fig. 1. 

Although the pressurized ion exchange equipment was patterned after systems being studied for biochemical separations, it was operated somewhat differently. For actinides, the speed of separation is critical because of radiation effects, and it was practical to trade off some resolution for a faster separation. 

Related Calculations. This example assumes standard cocurrent operation of the column with downflow feed and downflow regeneration. Countercurrent operation is a special case that is best handled by a manufacturer of ion-exchange equipment. 

Ion exchange equipment, 508,512,517 continuous processes, 515, 519,520 fixed bed arrangements, 512 performance. Uranium recovery, 515 sizing example, 513 Isoprene... 

During idle periods, fresh or partially exhausted ion-exchange equipment will be shut down, and flows will be discontinued. If the exchangers are not properly rinsed before being put back into operation, they can release hardness ions (or other unwanted ions) into the feedwater. 

One reason may be that since its inception ion exchange has been regarded more as a method of water production than as a method of water purification. Ion exchange equipment commonly resembles industrial plant much more closely than wastewater treatment plant. Ion exchange is also not considered a promising research area and, most importantly, it receives little attention in technical education courses. As a result, most progress in the application of ion exchange has been made by specialized companies, either resin manufacturers or producers of equipment for water treatment. 

A list of designers and manufacturers of ion exchange equipment is given in Table 18. The list is weighted toward those companies that operate in the United States. 

The pH sensitive reversible nature of the phosphate gel provides a continuously renewable surface for the entrapment of divalent impurities moving toward the membrane from the brine during operation and it eliminates the need for expensive ion exchange equipment for purifying the brine. 

Ion-exchange equipment. Three types of ion-exchange equipment used in U.S. uranium mills are the fixed-bed type, the moving-bed type, and the continuous resin-in-pulp (RDP) type. These will be described in turn. 

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