| Crucible Furnace | Approximately 25–1,000 kg per batch, depending on crucible size and furnace design | Natural gas, LPG, diesel, or electric resistance heating | Usually about 700–800°C; aluminium melts at approximately 660.3°C | Small foundries, maintenance shops, laboratories, prototypes, and intermittent production | Relatively simple construction, low initial investment, flexible batch operation, and easy alloy changeover | Lower productivity for continuous operation; direct flame exposure may increase oxidation and metal loss; crucibles require inspection and replacement | Choose according to batch size, alloy-change frequency, fuel availability, crucible material, loading method, and required temperature control |
| Reverberatory Furnace | Commonly about 1–30 tonnes, with larger custom systems available | Gas or liquid fuel burners; electric versions are also possible | Generally about 700–850°C in the melting and holding zones | High-volume foundries, die casting, gravity casting, and continuous or semi-continuous production | Large capacity, high melting rate, compatibility with automatic charging, and separation of combustion gases from the metal bath | Large footprint, higher heat-up time, potential oxidation and dross formation, and greater need for burner and refractory maintenance | Evaluate required tonnes per hour, charging system, holding-zone control, flue-gas treatment, refractory life, and expected metal recovery |
| Rotary Furnace | Typically about 1–15 tonnes per batch, depending on shell volume and charge density | Gas or oxygen-enriched gas burners, with the furnace rotating around its axis | Usually controlled around 700–850°C for melting and treatment | Recycling contaminated aluminium scrap, chips, painted scrap, turnings, and dross-bearing materials | Strong material agitation, good contact between heat and charge, and suitability for difficult or low-density scrap streams | More mechanical complexity, possible oxidation during agitation, variable recovery depending on scrap contamination, and higher maintenance requirements | Prioritize scrap composition, oil and coating content, salt or flux practice, fume extraction, lining design, and metal-recovery targets |
| Induction Furnace | Approximately 100 kg to several tonnes per batch, depending on power rating and frequency | Electromagnetic induction supplied by an electrical power converter | Normally operated around 700–800°C for aluminium melting and holding | Clean scrap and ingot melting, controlled alloy production, laboratories, and operations requiring rapid heat-up and precise control | No combustion gases in the furnace, fast heating, strong electromagnetic stirring, compact layout, and accurate power control | High electrical infrastructure demand, sensitivity to charge composition and bath conditions, and potentially higher equipment cost | Check available electrical capacity, power quality, coil and lining design, stirring intensity, batch size, alloy cleanliness, and cooling-water requirements |
| Electric Resistance Furnace | Approximately 50 kg to 3 tonnes per batch; larger systems can be engineered for specific processes | Electric resistance elements, commonly positioned around the chamber or crucible | Typically about 700–850°C with programmable temperature control | Small-to-medium foundries, holding furnaces, heat-sensitive alloys, educational facilities, and low-emission indoor operations | Clean operation, quiet heating, good temperature uniformity, straightforward automation, and no direct combustion products | Heating can be slower than induction for some loads; electrical operating cost depends on local tariffs; elements and insulation require maintenance | Compare electricity price, required heat-up time, insulation quality, element replacement cost, atmosphere control, and holding-time requirements |
| Gas-Fired Holding Furnace | Approximately 200 kg to 10 tonnes of molten aluminium, commonly used after a separate melting stage | Gas burner with a controlled combustion chamber or immersion-style heating arrangement | Usually maintained around 680–760°C to limit unnecessary superheat | Die-casting cells and casting lines requiring stable metal availability and temperature between batches | Supports continuous casting supply, reduces temperature fluctuations, and can be integrated with automatic pouring or transfer systems | Not normally the most efficient choice for melting cold scrap; combustion emissions and heat losses require proper ventilation and control | Assess holding time, transfer distance, temperature-loss rate, burner turndown, automatic level control, and integration with the casting machine |