Assertion: heavy metal | /r/HasProperty | obtained
Facets:
value: by roasting their sulphide ores
type: MANNER
Source sentences:
text: Broadly speaking, and with some exceptions, lithophile heavy metals can be extracted from their ores by electrical or chemical treatments, while chalcophile heavy metals are obtained by roasting their sulphide ores to yield the corresponding oxides, and then heating these to obtain the raw metals.[n 24] Radium occurs in quantities too small to be economically mined and is instead obtained from spent nuclear fuels.