That's why many scrappers don't let cast iron through. The cost per pound of this scrap can add up pretty quickly, making it worth taking it to the recycling depot. The prices offered by junkyards for cast iron scrap are usually very low. Prices depend on the quality of the metals and their origin.
Cast iron in relatively good condition can get better prices than old, rusted and worn cast iron. It is mainly found in the form of castings and pipes, although it is used in several other forms.