The IEEE is warning that China’s export controls on rare earth minerals could start to impact datacenters, as shipments of some key materials are down 75 percent and Beijing is due to review its policies this November. The techie org's official publication, IEEE Spectrum, focuses on two rare earths in particular, erbium and yttrium, which are used in components for IT equipment. Exports of yttrium are down by about 75 percent this year in compar…