I’m not very familiar with the ellconomics of recycling, but I doubt that this process to recover an additional 2% will be cost effective.
Considering spot prices for cobalt are dropping quickly and are now back to pre-2019 levels... not sure it makes sense to invest heavily in this.
Do they keep a huge deposit of these tailings hoping for it to be profitable some day?
BTW referring to it as “huge deposits” is likely exaggerating. There are currently only a small number of battery packs that have failed to the point of being processed. Even with larger number of EVs, the number will climb slowly and will probably never be enough to produce huge slag deposits.
Dump it in the nearest river.