The term SMELTER REFUSE is related to the process of smelting, which is the process of extracting a metal from its ore. The crossword solution for this term is SLAG, which is a byproduct of the smelting process. SLAG is a glassy material that is created when impurities are removed from the ore during the smelting process. It is usually composed of silicates and oxides and can be used in construction materials or as a fertilizer.