Abstract: In recent years, China imported about ten sets of equipment for hydrofluoric acid alkylation in oil refineries. Analysis shows that both the waste alkaline liquid and waste residue of CaF₂ discharged thereform contain mainly sodium fluoride, and some calcium fluoride in the residue. The result reveals the unreliable environmental safety assurance of the manufacturer. The key to solving this problem lies in recovering NaF, a useful chemical, in which the authors have succeeded at laboratory scale, A new waste treatment plan will save 40 tons of CaCl₂ and recover 40 tons of NaF for each installation.