Study: leaching of zinc dust from electric arc furnace waste using oxalic acid

A study has been conducted on the process of leaching of zinc dust using oxalic acid by hydrometallurgical method. The sample preparation process starts from the dust zinc washing. The leaching process was started by mixing the sample with solution of 5 M oxalic acid. There were three variations; the ratio of mole, temperature and leaching time to know the optimum condition. From the variation of leaching process that has been done, an optimum condition was obtained where the ratio of zinc mole dust to 5 M oxalic acid solution is 1:10 with temperature 90°C and leaching time for 150 minutes. The leaching filtrate was precipitated to obtain zinc oxalate with a solution of sodium hydroxide up to pH 7. The FTIR and XRD analysis showed that the leaching products confirmed as hydrozincite (Zn₅(CO₃)₂(OH)₆) and sodium bicarbonate (NaHCO₃). The carbonate compound may be caused by decarboxylation during the leaching process. The calcination of leaching products to convert hydrozincite turn out zinc oxide was done at 600 °C. The results of the XRD analysis show that there were zinc oxide and still found zinc carbonate and sodium carbonate.