OREAS 467

OREAS 467 is an ore grade, rare earth element (TREO = 0.21%) matrix-matched certified reference material (MMCRM) prepared and certified by Ore Research & Exploration. The materials constituting OREAS 467 were sourced from both a quarry north of Melbourne (weathered barren siltstone) and Lynas Corporation’s Mount Weld Project (the ‘Central Lanthanide Deposit’) which is located 35 kilometres south of Laverton in Western Australia. The Mount Weld source materials (waste, low and medium grade REE ores) were found to be highly hygroscopic to the extent that significant analytical errors would likely result during analysis unless strict moisture handling procedures were adhered. To avoid this complication, the hygroscopic property was destroyed by roasting the materials at 900°C for 2 hours. Following re-equilibration of the materials to laboratory atmosphere the hygroscopic moisture content was deemed acceptable (~0.5% H2O-).

OREAS 467 has been characterised for REE’s, majors and traces using the following methods:

• Fusion XRF + LOI
• Full suit Peroxide Fusion ICP-OES/MS
• Full suit 4-acid ICP-OES/MS

Certified values for applicable analytes are operationally defined for each method, with results under OREAS ISO 17034 scope of accreditation.