Editing Gadolinium (section)

==Production==
Gadolinium is produced both from monazite and [[bastnäsite]].
# Crushed minerals are extracted with [[hydrochloric acid]] or [[sulfuric acid]], which converts the insoluble oxides into soluble chlorides or sulfates.
# The acidic filtrates are partially neutralized with caustic soda to pH 3–4. [[Thorium]] precipitates as its hydroxide, and is then removed.
# The remaining solution is treated with [[ammonium oxalate]] to convert rare earths into their insoluble [[oxalate]]s. The oxalates are converted to oxides by heating.
# The oxides are dissolved in [[nitric acid]] that excludes one of the main components, [[cerium]], whose oxide is insoluble in HNO<sub>3</sub>.
# The solution is treated with [[magnesium nitrate]] to produce a crystallized mixture of double salts of gadolinium, [[samarium]] and [[europium]].
# The salts are separated by [[ion exchange]] chromatography.
# The rare-earth ions are then selectively washed out by a suitable complexing agent.<ref name="Greenwood" />

Gadolinium metal is obtained from its oxide or salts by heating it with [[calcium]] at {{convert|1450|C}} in an argon atmosphere. Sponge gadolinium can be produced by reducing molten GdCl<sub>3</sub> with an appropriate metal at temperatures below {{convert|1312|C}} (the melting point of Gd) at reduced pressure.<ref name="Greenwood" />