is Ge a good main breaker?thats what i want to replace my federal pacific one with, i looked for square d 16 circuit ones but i could not find any for 150amp. thanks

Hi, I hope this isn't considered off topic but I'm not sure where else to post this. One of my favorite ways to unwind is breaking down old computers. I separate them into sheet metal, aluminum, copper, and strip out the larger chips, capacitors, and resisters. I take the resulting metals to a recyclers. It usually cover the cost of gas, it helps relax me, not make me rich plus I'd rather see the stuff recycled than thrown in a landfill. My question is what is the metal that surrounds the wound copper center in transformers. It's a shiny dark gray, brittle, magnetic, and doesn't rust. When it is broken the interior is very grainy. I know that it is used to create a field with the copper. It's too brittle and slow to show rust to be iron. I thought it might be graphite but then is magnetic (ferrous?). Can they recycle it? Also found a collar of the material (Yoke?) used with the copper windings around a monitor tube. I believe they use magnetic field to control the beam characteristics in the CRT. Thanks