I had 2 potato plants that I dug up after I accidently put charcoal powder on them. After I harvested the potatoes I want to replant them with new soil. I have three questions to ask all the gardeners:
1. Can I replant them?
2. After I plant them will they die on me?
3. Will I get more from them?

I'm tring my hardest!

Good question, I don't think the plant itself would do much, tell us what part of the country you are, people from your specific area may have some answers.

Are the potatoes themselves mature (have eyes, thick skin?) Your best bet is if they are, sprout them and plant those. Depending where you live, might get another crop of new potatoes this year off the new plants.

The original plants are going to be very, very unhappy from being pulled up -- you've ripped off a lot of small roots / root hairs. They've already flowered, and spent their energy making potatoes. I think of when I transplant bushes / flowers -- you trim back the top growth considerably to make up for the smaller roots. And you know it'll be next year before the plant is thriving again. Not good for annual vegetables!

Also, what is "Charcoal Powder" -- the only stuff I know by that name is Activated Charcoal used for certain poisons to "bind" with them until the stomach pump is ready. Can't imagine that would hurt plants Ashes from a charcoal grille maybe? I could see some mild level of concern because of the garbage used to make most charcoal briquettes...

That's okay. I got few potates out of the plants