How gallium is recovered

Gallium melts in your hand, and none of it is mined on purpose. It is a by-product of making aluminum.

stations: 5
things upstream: 5
raw sources: 4
steps from the ground: 2

The short version

Gallium has no ore of its own. It collects as a trace in the sodium hydroxide liquor used to turn bauxite into alumina, and is pulled out with ion-exchange resin. At a typical 50 ppm in the bauxite, about 15 percent of the gallium can be recovered. Smaller amounts come out of zinc ores.

Dissolve bauxite in lye

In the Bayer process, bauxite is digested in sodium hydroxide to make alumina. Gallium in the ore dissolves and builds up in the circulating liquor.

Goes in
Bauxite Caustic soda
Capture it on resin

Ion-exchange resin pulls gallium out of the liquor. The remainder ends up in red mud and aluminum hydroxide.

about 15% recovered at 50 ppm
Tap the zinc side stream

A smaller supply comes from sulfidic zinc ores, where sphalerite hosts the gallium. Smelters recover it from process residues.

Goes in
Zinc ore
Refine to high purity

Crude gallium is purified until it is a very pure silvery blue metal. Electronics need that purity for gallium arsenide and gallium nitride.
Pour into ingots

The metal melts just above room temperature, so it is poured and shipped in small containers. A handful will melt at body temperature.

End of the lineGallium Next it goes into led.

Worth repeating

Gallium melts at 29.7646 °C, just above room temperature, and is a formal temperature reference point.
Only four non-radioactive metals are liquid at or near room temperature, and gallium is one of them.
Gallium nitride makes the blue and violet LEDs in modern lighting.