Zinc recovery from pickling acid solution
The zinc chloride is to be removed from pickling acid at 6N concentration.
Under these conditions, the ZnCl2 will form a stable complex and may be removed by PuriTech's ION-IX technology using an anion resin.
The resin is then eluted with water.
The CCIX process for zinc chloride removal comprises five zones :
- adsorption or zinc chloride loading zone
- adsorption rinse zone
- entrainment rejection zone
- a regeneration zone
- second entrainment rejection zone
All the zones operate continuously. The entrainment rejection (ER) zone is ment to concentrate the product, preventing the subsequent rinse stages from resulting in product dilution, and also optimising water usage.
The strong base anion exchange reactions that take place are shown below.
R-Cl- + [ZnCl3]- -> R-[ZnCl3]- + HCl Adsorption
R-[ZnCL3]- + H2O -> R-Cl- + ZnCl2 + H2O Regeneration
The overall process stoichiometry is represented by the reaction:
[ZnCL3]- + H2O -> ZnCl2 + H2O + HCl