Recovery from scrub solutions

This paper describes a process for the recovery of actinides from Na2C03 scrub waste solutions which involves the extraction of the HDBP and H2MBP from acidified solutions using a water-immiscible aliphatic alcohol. All the actinides remain in the aqueous phase, which may then be processes using conventional TBP or DHDECMP procedures (3). We refer to this process as the ARALEX (Argonne alcohol extraction) process. This paper also describes the extraction equilibria measurements performed in the development of the process. 

Figure 6. Conceptual flowsheet for the recovery of actinides from TBP-Na2COs scrub solutions basis one MTHM.

When using acid scrubbers, the amine is transferred to the scrubbing solution, which then needs further treatment. However, recovery of the amine from the solution is possible. This is discussed in Section 4.6.5. 

The R D department has also measured the solubility of Ge and Si in scrubbing solutions at various pH values. The results are presented in a table (available from the AIChE) and may be useful in the design of a germanium recovery system. ... 

If required, relatively pure carbon monoxide can be recovered by cryogenic separation (i.e. condensation at very low temperatures), use of selective scrubbing solutions (for example CUAICI4 in toluene, the COSORB process) or solid adsorbents, and by other methods. Some CO recovery techniques are also applicable to the CO-rich (c. 70% molar) off-gases from basic oxygen furnaces and the leaner off-gases from air blast furnaces produced in steel manufacture, though operations of this type are still limited. 

Separation of Pb(CH3)4 by distillation is improved when THF is used as the solvent [76]. For the separation of Pb(CH3)4, the same yield is reported for steam distillation or extraction [93]. Extraction can be accomplished with toluene [80, 85, 87, 88, 99, 107]. An anhydrous method of recovery involves the vaporization of Pb(CH3)4 with a preheated inert gas or CH3CI [142]. Pb(CH3)4 can be recovered from the gas phase and vent gases with an organic scrubbing solution [143, 144]. 

The extractors are York rotating disc contactors, 3-inch ID by 48-inch long. Three contactors are to be used, one each for extraction, scrubbing, and stripping. The system will be used to investigate the recovery of plutonium and americium from MSE waste salt solutions using 30% DHDECMP in diisopropylbenzene. 

The purpose of such scrubbing operations may be any of the following gas purification (eg, removal of air pollutants from exhaust gases or contaminants from gases that will be further processed), product recovery, or production of solutions of gases for various purposes. Several examples of applied absorption processes are shown in Table 1. 

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