关键词: 酸性含氟冷凝水, 沉淀, 膜分离, 废水回用

Abstract:

To address the problem of acidic fluorine⁃containing condensate treatment and reuse in the wet phosphoric acid purification process，a combined process of precipitation and membrane separation was studied as the purification and reuse process of acidic fluorine⁃containing condensate.The precipitation process was studied with the influence of precipitant and induced crystallization carrier on the effluent water quality.The membrane separation process was studied with the influence of operating conditions on membrane flux and effluent water quality during ultrafiltration and reverse osmosis，and membrane contamination and cleaning was discussed.Through the experiments，CaCO₃ was identified as the precipitant and calcite as the induced crystallization carrier.The optimal operating conditions of ultrafiltration was determined.The pressure was 0.4 MPa，the cross⁃flow velocity was 1.0 m/s，the inlet water temperature was 30 ℃，the recovery rate was 70%，and the cleaning and regeneration mode was physical and chemical cleaning，and the optimal operating conditions of reverse osmosis was determined，the pressure was 1.5 MPa，the cross⁃flow velocity was 1.5 m/s，the inlet water temperature was 25 ℃，the recovery rate was 85%，and the cleaning and regeneration mode was chemical cleaning.The effect of the combined process on the actual wastewater treatment was examined，and the fluorine content of the treated actual wastewater was lower than 2 mg/L，and the conductivity was lower than 50 μS/cm，which met the requirements of reuse process.The acidic fluorine⁃containing condensate was reused in the wet phosphoric acid purification process after treatment，which reduced the discharge of fluorine⁃containing wastewater and saved the use of demineralized water，and it had good economic benefits and ecological environmental protection value.

Key words: acidic fluorine?containing condensate, precipitation, membrane separation, wastewater reuse