Research Of Making Coagulant By Steel-pickling Waste Liquor And Its Utilization

By using steel pickling waste liquor as raw material, NaClO₃ as oxidant and taking advantage of the heat in the reaction, the high concentration Polyferric Sulfate (PFS) liquor were prepared in normal temperature and pressure without calefaction. The optimal operating conditions were obtained: n(Fe²⁺) : n (H₂SO₄) : n (NaClO₃) = 1 : 0.2 : 0.2, the way of adding material was adding gradually per 5 minutes. The concentration can reach 210g/L, alkalinity degree was 18.5%, the stability of PFS was relatively high.Condensed tannin-larch valonia and formaldehyde solution and dimethylamine water solution were used as raw material to complete the Mannich reaction for tannin modification and the production(cationic tunnin named CAT)was obtained. Then the Cationic tannin-polvferric Complex Coagulant were prepared by blending cationic tannin and polymerized iron. The optimal operating conditions under the standard of the removal of COD_Cr using the complex coagulant were obtained: m_CAT: m_PFS=1:4, reaction temperature 60℃ and reaction time 1.5h.The experimental results of treating clay solution showed that Polyferric Sulfate liquor had excellent effect in the removals of chaotic. The complex coagulant was used in paper making wastewater, the optimal operating conditions were: the amount of coagulant was 125 mg/L, pH 9.0, temperature at room temperature. The removals of filterable COD_Cr, chroma and chaotic were 51.2%, 60% and 80% above, respectively.It was proved that the removal of COD_Cr used by the complex coagulant was better than used by PFS through the compare experiments, which showed that the coagulating capacity of Polyferric Sulfate was reinforced by...