Assertion: metal's ore | /r/HasProperty | roasted in the air
Facets:
value: to oxidize it
type: PURPOSE
Source sentences:
text: The ore is then roasted in the air to oxidize it to the lanthanide oxides: while most of the lanthanides will be oxidized to the sesquioxides Ln 2 O 3 , cerium will be oxidized to the dioxide CeO 2 .