New Route for the Extraction of Crude Zirconia from Zircon

A commercial grade of zircon (ZrSiO4) concentrate was mechanically milled with MgO for up to 100 h in a laboratory‐scale mill. The resultant powders were subjected to thermal processing, chemical leaching, and X‐ray diffraction (XRD). There was no direct evidence of reaction during the milling step, with no new phases evident from XRD. Leaching of the powder showed that a reaction had occurred, and increased solubility with milling time was attributed to the formation of a nanostructured Mg‐Zr‐Si oxide, which dissolved congruently. Heating the powders resulted in a number of thermal events, including the formation/crystallization of ZrO2 and Mg2SiO4. Thermal treatment of the milled powders allowed selective chemical leaching of the magnesium and silicon, leaving a powder containing ∼90% ZrO2.