Process energy of the chemical uranium enrichment process is discussed using the dynamic enrichment factor, avoiding a cluster of commonly used equations that correlate relevant engineering parameters. An advanced process, whose process energy was found to be much smaller than in the original process in both laboratory and bench tests, has been recently developed and applied to a pilot plant. The basic principle underlying the improvement is an inverse redox reaction induced by the increased sorbability of multicoordinated metal-complex ions onto an ion-exchange resin. The energy requirement for the advanced process will be reduced to <100 kW·h/kg·separative work unit.