Design of vanadium trioxide wastewater treatment

1. Nature and composition of wastewater

The acid wastewater discharged from V2O3 workshop sedimentation section contains V5 +: 100-120mg / L, Cr6 +: 100-250mg / L, Na2SO4: 42-57g / L, pH value of wastewater is 1.8-2.5, temperature is 70-80 ℃, and the maximum flow of wastewater is about 35m3 / h.

The quality of V2O3 wastewater treatment and drainage shall be in accordance with the first level discharge standard in the national integrated wastewater discharge standard (GB 8978-1996).

2. Wastewater treatment process

At present, the following two processes are generally used in the treatment of vanadium containing chromium acid wastewater at home and abroad: first, the ion exchange process mainly aimed at recovering vanadium in wastewater, the recovered mother liquor contains a large amount of chromium and sodium sulfate and other components, and the waste liquor needs to be treated again, so the waste liquor discharge will cause environmental pollution; second, the reduction process aimed at treating up to standard discharge Neutralization process. For reduction and neutralization process: Ruqi company in Germany adopts ferrous sulfate reduction sodium hydroxide neutralization method, Thyssen company in Germany adopts SO2 reduction sodium carbonate neutralization method, and IMCO company in Italy adopts ferrous sulfate reduction lime neutralization method.

Combined with the production practice of Panzhihua Iron and Steel Co., Ltd., the wastewater treatment system of V203 workshop adopts ferrous sulfate reduction lime neutralization method through comprehensive analysis and comparison. V2O3 waste water treatment station is composed of regulating tank, waste water pump room, reduction tank, neutralization tank, concentration and sedimentation tank, filter, pressure filtration room, laboratory, lime milk preparation system, etc.

3. conclusion

It is feasible to treat V2O3 acid wastewater containing vanadium and chromium by ferrous sulfate reduction lime neutralization method, which has stable operation effect and good effluent quality. Reduction and neutralization reaction are the core of V2O3 wastewater treatment process. Through pH value automatic monitoring of lime milk, ferrous sulfate dosage automatic control and lime milk two-stage neutralization, the wastewater quality can be guaranteed to meet the discharge standard. The production practice shows that the process is simple and the equipment is highly automated. It can not only effectively remove pollutants, but also realize the recovery and utilization of vanadium resources in wastewater, which has good environmental and economic benefits.