A process for treating an ammonium fluorosulfate byproduct includes providing an ammonium fluorosulfate byproduct including primarily ammonium fluorosulfate and lesser amounts of fluorosulfonic acid and bis(fluorosulfonyl) imide, mixing the ammonium fluorosulfate byproduct with water, reacting the mixture of the ammonium fluorosulfate byproduct and the water at a hydrolysis reaction temperature to hydrolyze the ammonium fluorosulfate, the fluorosulfonic acid and the bis(fluorosulfonyl) imide to form ammonium bisulfate and aqueous hydrogen fluoride; and separating the ammonium bisulfate from the aqueous hydrogen fluoride.