LIN Yan,LI Feng-chao,ZHAI Jun,et al.Treatment of Hydrochloric Acid Pickling Wastewater by Vacuum Distillation-Crystallization Process[J].China Water & Wastewater,2020,36(23 23):64-68.
Treatment of Hydrochloric Acid Pickling Wastewater by Vacuum Distillation-Crystallization Process
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第36卷
Number:
23 23
Page:
64-68
Column:
Date of publication:
2020-12-01
- Keywords:
- pickling wastewater; vacuum distillation; crystallization; ferrous chloride crystal; regeneration
- Abstract:
- A vacuum distillation-crystallization combined process consisting of four steps: pretreatment, vacuum distillation, cooling crystallization and centrifugal dewatering was developed to treat hydrochloric acid pickling wastewater from a hot-dip galvanizing workshop of an iron plant, and practical application of this process was conducted. Results of atmospheric distillation experiments and Aspen plus 7.2 software simulation suggested that the best performance could be achieved when evaporation ratio was 65% and vacuum degree of 0.065 MPa. In this case, the purity of ferrous chloride crystal (FeCl2·4H2O) was 97.10%, and the recovery rate of hydrochloric acid could reach 34.3%. A pickling wastewater treatment station with treatment capacity of 6 m3/d was designed and built. The treatment of 1 m3 waste acid solution could recover 97.40 kg FeCl2·4H2O crystal and 0.40 m3 regeneration acid with concentration of 4%, and the income could reach 69.31 yuan.
Last Update:
2020-12-01