Hot and Cold

A (hopefully) CLEARER GUIDE:

1. 
   
2. From the questgiver, exit East (up the camp's slope) to the frozen lake, Frostfield Lake. There, kill Brittle Revenant and loot Essence of Ice until you have 5.
3. 
   
4. Then, head farther East (maybe South-East) toward where Fjorn's Anvil used to be.
5. 
   
6. On the path leading to the anvil, look for tiny black things with smoke coming up from them. They are easier to spot in the snow. Get near one, use an Essence of Ice, then right-click loot the metal scrap. Do this until you have 5.
7. 
   
8. Go back west to where the anvil actually is and turn it in. Yay.
9. 
   

Kudos to posters below who supplied the bulk of this information.

You get Essence of Ice from Brittle Revenants at Frostfield Lake.

Just to clarify - by Fjorn's Anvil, the quest means the subzone called Fjorn's Anvil, not the anvil you get the quest from. I thought the scraps would spawn around the actual anvil in Dun Niffelem.... hehehe.