Abstract: An apparatus and method for reprocessing waste piranha containing contaminated H.sub.2 SO.sub.4 from, for example, a semiconductor processing operation is described. The apparatus and method include a first distillation flask which are maintained under a substantial vacuum. The first distillation flask includes a first column with a column packing means and a reflux means to retard loss of H.sub.2 SO.sub.4 in the first distillation. The second distillation flask boils off substantially pure H.sub.2 SO.sub.4 through a column which is coupled to a condenser which condenses substantially pure H.sub.2 SO.sub.4.

Abstract: A two-step distillation process provides semiconductor purity, concentrated hydrofluoric acid. Further, the distillation process, occurring under reduced pressures eliminates essentially pure water after the first distillation step. The product output of the second distillation process provides an acid of weight percent greater than 27 weight percent. The product acid is carefully diluted to the required concentrations during the dilution step.