H5P Test

A simplified flowsheet for the Galvanox process is shown below. This process is being developed at UBC. Chaclcopyrite is the most abundant mineral of copper in nature. However, it resists leaching by conventional hydrometallurgical methods; the mineral rapidly passivates (after a short while it leaches very slowly) when leached in sulfate solution. In this process a copper concentrate is produced which contains pyrite and copper minerals, particularly chalcopyrite. If pyrite (FeS2) is present in the concentrate then chalcopyrite is readily leached. Pyrite, being an iron mineral, often occurs in sulfide mineral deposits. During leaching chalcopyrite is oxidized to form a solution of Cu+2, Fe+2 and solid elemental sulfur. Pyrite itself undergoes little reaction. (Mainly it seems to act as a catalyst for oxygen reduction.) After leaching the slurry is subjected to solid-liquid separation. The solids may be recycled to leaching to reutilize the pyrite. Much of the solution proceeds to solvent extraction, which is used to obtain a much purer copper solution. The details are not important here. Some of the solution lso proceeds to an oxyhydrolysis step (this is done in an autoclave) in which ferrous ion is oxidized to form hematite (Fe2O3) and sulfuric acid. This acts as an utlet for iron and prevents its build-up in solution. Hematite is a very suitable iron product for disposal. The solvent extraction process also generates acid, which together with that formed by hematite formation can be reused in the leaching step. The concentrated copper sulfate solution from solvent extraction proceeds to an electrowinning step. Here very pure copper metal is produced by electrolysis.