A three-column ion exchange test program on Vitro leach liquors was run to compare the performance of IRA-400 and XE-75 resins with respect to loading, elution, and poisoning characteristics. When a high molybdenum liquor was used as feed to the columns, molybdenum poisoning was shown to occur with both IRA-400 and XE-75 resins; however, this poisoning action was much less rapid and less extensive in the case of XE-75. In this respect the XE-75 was found to be similar to Permutit SE. The use of a six percent caustic regenerant completely restored the ion exchange properties of the poisoned XE-75 resin. A cyclic resin-in-pulp process for recovery of uranium from Vitro leach liquors and pulps was studied. The Winchester cell was employed for this investigation in conjunction with XE-123 resin - - a plust 20 mesh resin with the exchange characteristics of XE-75. Performance data, including the effects of molybdenum poisoning, indicate that a 12 cell string may be used effectively with seven cells on exhaustion and five on elution.