Fish milt used to glean rare earths

Kyodo

Japanese researchers said Friday they have found a better, cheaper way to smelt rare earth metals by using salmon milt, or sperm.

Rare earth ores can contain several of the 17 metals considered essential to manufacturing motors, phone parts and other high-tech products, but separating and recovering the metals from the ore is expensive and tedious because a special type of resin must be used.

The breakthrough made by researchers from Aisin Cosmos R&D Co., however, will make the process “low-cost and environment-friendly,” said Yoshio Takahashi, a professor of environmental chemistry at Hiroshima University who was part of the team.

The team, based in Aichi Prefecture, announced its findings at the Japan Sustainable Mining, Investment & Technology business forum in Tokyo.

After the team found a 2010 study that said phosphate groups found on the surface of bacteria can absorb and separate rare earths over 10 times more efficiently than the resin, it looked into the possibility of using milt, which is rich in phosphoric acids but mostly thrown away.

They performed an experiment in which salmon milt was dried, powdered and put into a beaker containing a solution consisting of rare earth metals.

The milt ended up absorbing the rare earth elements as well as bacteria does, especially the scarce and expensive elements thulium and lutetium.