The daughter isotope Th-229, which is generated by the alpha-decay of the U-233 isotope, has shown great promise in medical research as a sustainable source of radioisotopes for the treatment of certain cancers. The Oak Ridge National Laboratory (ORNL) has demonstrated a laboratory-scale ion-exchange (IX) process for the recovery and purification of trace amounts of thorium from uranyl nitrate solutions. Testing was performed using surrogate solutions of depleted uranium (DU) containing ~50 ppm natural thorium (Th) to scale up and adapt the ORNL IX process from laboratory to production-scale. Testing using various diameter columns, resin bed depths, flow rates, and resin conditioning, loading, washing, and elution protocols led to a once-through demonstration in which column effluent samples consistently contained less than 0.5 ppm Th. Based on these conditions a five-day Thorium Extraction Prototype (TEP) test was performed. A five-day production schedule was executed using a four process-scale resin bed system to process Th-bearing feed solution. The five-day demonstration test was successful in every way. A total of 99% of the thorium input into process was recovered in the eluate solutions with only about 0.01% of the total uranium processed ending up in the eluate solutions. The column effluent solutions consistently had thorium concentrations below detection limits with only a few samples at levels up to 2 ppm after being processed through all three columns. As the columns were used, resin performance seemed to improve as all column effluent samples from Days 4 and 5 had thorium concentrations below detection limits. Operationally, no problems were encountered in maintaining acceptable flow rates for the various process streams. The overall analytical accountability for both thorium and uranium for this five-day process demonstration was 99.4%.