Considering temperature capability, fuel-fired furnaces are generally limited to about 1700°C. Up to what approximate temperature can electric furnaces be used in industrial practice?

Introduction / Context:
Electric furnaces (arc, induction, resistance) can achieve much higher temperatures than most conventional fuel-fired furnaces, because they do not depend on combustion equilibria with diluent nitrogen. Knowing the typical upper range is important for material selection and process feasibility.

Given Data / Assumptions:

• Fuel-fired furnaces are practically constrained to about 1700°C by combustion limits and refractory service.
• Electric furnaces can concentrate energy directly into the charge or via resistive heating elements.
• Practical, widely cited upper range in industry is about 3000°C (especially for specialized arc furnaces).

Concept / Approach:
While laboratory plasma systems may momentarily exceed these temperatures, standard industrial electric furnaces capable of sustained operation and reasonable refractory life typically top out near 3000°C. This range enables melting of refractory metals, calcination of specialty ceramics, and high-temperature treatments that combustion systems cannot reach economically.

Step-by-Step Solution:
Contrast combustion vs. electrical heating mechanisms.Recognize industrially achievable, sustained temperatures.Select 3000°C as the representative upper bound.

Verification / Alternative check:
Equipment vendor literature and metallurgical handbooks often list electric-arc furnace hot-spot temperatures in the several-thousand-degree range, with 3000°C being a conventional reference point for maximum capability in MCQs.

Why Other Options Are Wrong:
2000°C: Achievable, but not the upper bound.4500°C or 6000°C: Beyond typical industrial furnace practice and refractory limits; such temperatures relate to plasma/arc cores, not sustained furnace operation.

Common Pitfalls:

• Confusing momentary arc column temperatures with usable furnace wall or charge temperatures.
• Ignoring refractory/electrode constraints that limit continuous operation.

Final Answer:
3000