| 摘要 |
Purification process for spent, preferably hydrochloric acid based pickling baths, which have been used for pickling of steel articles in a hot dip galvanization process. Metal ions present in the pickling bath in the form of iron chloride complexes or zinc chloride complexes are brought in contact with an anion adsorbing material, preferably a conventional chloride ion-saturated anion exchanger, whereby the zinc chloride complex is selectively adsorbed. The solution containing the iron chloride complex can be used directly for the preparation of water purification chemicals. The ion exchanger is eluted or washed with water, whereby the zinc chloride complexes disintegrate, hydrochloric acid and zinc chloride are obtained in the washing solution, at the same time as the ion exchanger is regenerated while maintaining the same activity. The washing solution can, by a multistep washing in counter-current, be given a high enough concentration of zinc chloride so that it can be recirculated without further treatment to the flux bath in the hot dip galvanization process. If the chloride content of the spent pickling bath is not sufficient sot hat all metal ions will be present in complex form, this can be adjusted simply by addition of hydrochloric acid. |
