European galvanisation sector produces more than 300,000 m3 per year of Spent Pickling Acids (SPAs), which are considered a hazardous waste with code 11 01 05 in accordance with European Waste List classification and may be of environmental concern due to their high content of zinc, iron and acids.
At present, this waste is mostly managed by neutralisation-precipitation procedures, in which large volumes of waste sludge containing metals are generated, being deposited in landfill.
The aim of LIFE-2-ACID project is to demonstrate a new technology that allows the selective recovery of metal zinc and iron chloride from SPAs generated in galvanizing processes, thus minimizing their environmental impact.
The innovative technological solution developed by LIFE-2-ACID integrates membrane based selective extraction (MBSEX) and electrowinning (EW):
- Separation unit based on reactive membranes that allows the selective separation of the SPAs in two independent streams enriched with iron in the retentate and zinc in the permeate
- Electrowinning unit where metallic zinc is obtained from the permeate stream.