A comprehensive hydrofluoric acid (HF) acidizing radial-flow model describes deep-matrix mixing and backproduction of spent acidizing fluids. The model has matched published ionic returns profiles of several HF acidizing treatments. A hypothetical HF acidizing treatment was modeled that demonstrated approximately two treatment volumes of aqueous production are required to recover most of the original treating fluid. The full-length paper contains four case studies where published field acid returns were matched with the simulator.