Abstract: Flocculant PAFSC was prepared by aluminium alloy waste slag as raw material.Through the single factor experi- ment，the optimum conditions to leaching aluminium waste slag in hydrochloric acid were as follows：reaction time was 20 min，reaction temperature was 80 ℃，hydrochloric acid concentration was 6 mol/L，and amount-of-substance ratio n（HCl）∶n（Al）= 3∶1.The leaching rate of aluminium was more than 95% under these conditions.By leaching aluminium waste slag to get the aluminium chloride solution to produce the PAFSC and PAFSC was applied in pulping waste water treatment.Using 400 mg/L of the PAFSC to deal with the pulping wastewater，the COD removal rate and decolorization rate of pulping wastewater could reach 68% and 92% respectively.The effect of PAFSC was better than that of PAC（polyaluminium chloride）.

Key words: aluminium waste slag, leaching, flocculant PAFSC, treatment, pulping wastewater