Salmon fishing… for rare earths in Japan

Asia – It’s not rare to encounter a recycling breakthrough that is based on a rather peculiar method. The latest example involves rare earth elements (REEs) and a Japanese delicacy much like caviar – namely salmon ‘milt’, or semen. A research team led by Yoshio Takahashi has found that the DNA within the substance has a way of binding with metal fractions in ores, e-scrap and magnets.

According to the University of Tokyo, results to date have showed that salmon milt has a sufficiently high affinity to adsorb REEs; indeed, its adsorption capacity is 1.04 mEq/g, which is comparable with that of commercial cation exchange resin. ‘Heavier REEs have higher affinity for milt,’ the researchers note.

According to the University of Tokyo, results to date have showed that salmon milt has a sufficiently high affinity to adsorb REEs; indeed, its adsorption capacity is 1.04 mEq/g, which is comparable with that of commercial cation exchange resin. ′Heavier REEs have higher affinity for milt,′ the researchers note.

Neodymium has been successfully separated from a synthetic solution of neodymium magnet waste by a batch-type method using salmon milt, according to Takahashi. A key factor is the phosphate present in the salmon milt powder used, paired with an acid and centrifugation process. Recovering and separating REEs in this aqueous solution is claimed to offer a sustainable and economic alternative to the chemical extraction methods currently in use.

The salmon used for testing was sourced off the coast of Hokkaido, which is Japan′s second-largest island.

The report can be found at www.bit.ly/RareEarthsFishJapan