Abstract

During the treatment of white metal by pressure leaching with sulfuric acid and oxygen, the presence of iron in the leaching solution has a significant effect in the leaching rate. In this study, experiments were carried out in a titanium autoclave to clarify the role of iron in the leaching of white metal produced in a Teniente Converter reactor. The effect of iron (FeSO4) additions to the leaching solution was studied in the range 105 to 150°C, using oxygen partial pressure from 203 to 1013 kPa and 3 gpl of white metal. The results indicated that below the melting point of elemental sulfur (about 119°C) the addition of even 1 gpl of iron produced a large increase in the leaching rate (at 110°C the copper dissolution after 90 min increased from 49 to 73 %). However, at higher temperatures the presence of iron was detrimental to the leaching rate.