Rapid iron extraction from nickel leaching residue by a hydrogen plasma smelting reduction

Abstract

The processing of limonite-type lateritic nickel ore through sulfuric acid leaching generates leaching residue that requires careful handling and treatment. This residue, which contains over 38% iron, has the potential to be an alternative raw material for the iron and steel industry. However, the direct use of this residue as a burden material in the steel industry faces challenges due to the substantial presence of sulfur, which exceeds 1%. In the pursuit of sustainability within the iron and steel sector, researchers have increasingly focused on advancing hydrogen plasma technology. Laboratory tests were conducted on the treatment of the leaching residue exposed to hydrogen plasma smelting reduction. The results revealed that within just 5 s of exposure to hydrogen plasma, the transformation of the residue into metal was initiated. After 30 s of exposure, the formation of metal had already occurred, but the sulfur content remained above 0.5%. However, when the residue was exposed to hydrogen plasma for 180 s, the sulfur content in the metal decreased to less than 0.1%. The presence of nickel and chromium in the resulting metal products should be taken into consideration, especially when special steels or stainless steel are being produced.