How is iron removed from nickel matte in a converter?

In the process of refining nickel from sulfide ores, iron is removed from the matte using a rotating converter, similar to those used in copper production.1

During this stage, the iron within the molten matte is oxidized to form iron oxide. A silica flux is added to the converter, which combines with the iron oxide to form a slag. This slag is then drawn off, effectively separating the iron from the nickel-rich matte. This process is carefully controlled to produce a matte containing approximately 70 to 75 percent nickel, as converting nickel sulfide directly to metal would require excessively high temperatures.12