I will answer part of the question and let Ms. Viger answer the one about residual materials.
In the case of anode sludge, for example, the price of a barrel is the same as that of a Ferrari. So it's not waste, it's a valuable product. In fact, Canada recovers silver, gold, platinum, palladium, tellurium and bismuth. These are the very elements and metals that we need. In fact, they are very valuable and we take great care of them.
That said, when they are processed, there are sometimes residues. Ms. Viger could tell you about that now.