A reverberatory furnace is characteristically used for which of the following metallurgical heating processes?

Introduction / Context:
Reverberatory furnaces heat the charge primarily by radiation from the hot roof and walls; flames do not contact the charge directly in the same way as in some other units. These furnaces are historically important in non-ferrous metallurgy and in certain pyrometallurgical operations.

Given Data / Assumptions:

• Furnace design with low roof and reflective lining directing radiant heat back to the hearth.
• Used for metallurgical processing of ores and concentrates.
• Operating temperatures typically sufficient for roasting and smelting of non-ferrous materials.

Concept / Approach:
Reverberatory furnaces are widely known for roasting and reduction/smelting of ores (e.g., copper, tin, and lead processes). Although “open-hearth” (a type of reverberatory) historically melted steel, the general association taught in furnace technology courses links reverberatory furnaces first to non-ferrous ore treatment, not to steel coil annealing or air heating.

Step-by-Step Solution:
Match furnace characteristics (radiant heating, shallow bath) to metallurgical duties.Identify core applications: roasting and reduction/smelting of ores.Select the best-fit choice.

Verification / Alternative check:
Reference descriptions of copper and lead reverberatory furnaces emphasize the radiation-based heating and ore-processing roles, confirming this as the canonical use.

Why Other Options Are Wrong:
Annealing steel coil: Uses controlled atmospheres and continuous annealing furnaces, not classic reverberatory layout.Heating air: Performed by air preheaters/recuperators, not a reverberatory furnace.Steel melting: Historically possible (open-hearth), but the more general and exam-typical association is roasting/reduction of ores.

Common Pitfalls:

• Equating all reverberatory designs with the open-hearth steel process; modern context favors non-ferrous applications.
• Confusing reverberatory heating with direct flame impingement designs.

Final Answer:
roasting/reduction of ores