The resulting "UNH" (uranium nitrate hexahydrate) material pumped out of the vats was then processed through extraction to purify the solution. The UNH solution was passed through a multistage liquid-liquid counter current tower with tributyl phosphate and kerosene to extract the uranyl nitrate. The impurities exit the tower as the raffinate stream for further processing. The extract solution was passed through another counter current extraction tower to re-extract the uranyl nitrate from the kerosene into deionized water. The kerosene was then processed through a wash to be recycled back through the extraction process. The resulting UNH solution was now ready for further concentrating and thermal denitration.