Flux Skimming as a Source of Secondary Zinc

Flux skimming is generated as a by-product in hot dip galvanizing process, which contains about 45% of Zn. For significant quantity of zinc, flux skimming becomes a very remarkable source of it. With the purpose of recovering zinc, the flux skimming was studied. The presented paper deals with characterization and hydrometallurgical treatment of flux skimming obtained from 2 companies. Various zinc phases were identified by XRD analyses. The most presented phase in the first sample of flux skimming (VZ1) is ZnOHCl (96%). Different zinc phases were found in sample 2 (VZ2). The highest percentage of zinc phases analysed in sample VZ2 were 70.8% of Zn5OH8Cl2.H2O and 24% of (NH4)2(ZnCl4). Divergence in morphology and chemical composition of 2 studied samples of flux skimming caused different results after hydrometallurgical treatment of various samples. Both samples of flux skimming were leached in distilled water and hydrochloric acid (0.25M) at 20°C and 40°C, during 90 minutes. Using solution of HCl as leaching medium for flux skimming has shown better results than distilled water. During leaching treatment of VZ1, maximum extraction of zinc was 93% in the first minute at 40°C. At sample VZ2, the highest percentage of extraction was 62% at 40°C within 5 minutes