Blast-furnace fuel (4)
I believe the answer is:
coke
'blast-furnace fuel' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for coke that I've seen before include "something for heating" , "Fuel derived from coal" , "'Soft drink and hard drug, in short (4)'" , "Carbonised fuel residue" , "Fuel for heating" .)