Towards zirconium metal production from zircon concentrate and zirconia powder using hydrogen plasma smelting reduction

- Zirconium is a critical metal for advanced technologies, which finds extensive applications in corrosion-resistant alloys, aerospace materials, and nuclear fuel cladding. Its industrial production by the Kroll process includes the high-temperature chlorination of zirconium oxide, a process that emits toxic chlorine gas. In this paper, a cleaner method for zirconium production is presented, which makes use of hydrogen plasma smelting reduction (HPSR), utilizing both zircon concentrate (ZrSiO 4 ) and zirconia (ZrO 2 ) as feedstocks. The treated samples are pre-compacted briquettes exposed to an 80% H 2 - 20% Ar thermal plasma at 5 L min -1 for 2.5 - 10 minutes, during which significant reduction and metallization have been obtained. It has been demonstrated that with a prolongation of plasma exposure, the effectiveness of reduction was substantially improved. For the ZrSiO 4 briquettes, the content of zirconium increased from 77.79 wt% to 93.54 wt%, while the oxygen content decreased from 20.20 wt% to 5.09 wt%, silicon being entirely volatilized (> 98% removal). Better results were obtained for ZrO 2 briquettes, with higher Zr enrichment, reaching up to 95.60 wt%, and lower residual oxygen, as low as 3.60 wt%. The experimental results show that ZrO 2 can be reduced to ZrO 0.2 by hydrogen plasma smelting reduction. Further research should be undertaken in order to obtain metallic zirconium.