Furnaces & Smelting
What melts into what, at which temperature. Generated from game data.
Furnace types
| Furnace | Heat source | Speed | Notes |
|---|---|---|---|
| Basic furnace | wood / coal | 0.12 kg/s | your first smelter; wood burns cooler than coal |
| Furnace | coal / coke | 0.25 kg/s | the workhorse; coke burns hotter and cleaner |
| Blast furnace | coke (0.06 kg/s) + power | 1.0 kg/s | iron and copper only, needs electricity for the blast |
| Arc furnace | electricity only | 0.5 kg/s | no exhaust; heats ~50 K/s; best late-game smelter |
Fuel energy: wood 16 MJ/kg · coal 24 MJ/kg · coke 30 MJ/kg. Smelting consumes about 180 K of furnace heat per kg, so the furnace settles just under the recipe temperature and works continuously.
Coal furnaces exhale CO₂ (3.67 kg per kg of coal) through the chimney. Put a gas pump or tank next to the furnace to capture it, or keep smelting outdoors/ventilated.
Smelting recipes
| Input | Output | Min temperature | Needs coal/coke as reductant | Yield |
|---|---|---|---|---|
 Clay |  Brick | 927 °C | no | 100 % |
 Iron ore (hematite) |  Iron | 1227 °C | yes | 70 % |
 Copper ore (malachite) |  Copper | 1127 °C | yes | 60 % |
| Iron |  Steel | 1427 °C | yes | 100 % |
 Sand |  Glass | 1427 °C | no | 100 % |
 Iron concentrate | Iron | 1227 °C | yes | 70 % |
 Copper concentrate | Copper | 1127 °C | yes | 60 % |
 Gold dust |  Gold | 1067 °C | no | 100 % |
 Galena (lead ore) |  Lead | 1027 °C | yes | 80 % |
 Sphalerite (zinc ore) |  Zinc | 1027 °C | yes | 60 % |
 Cassiterite (tin ore) |  Tin | 1027 °C | yes | 70 % |
 Pentlandite (nickel ore) |  Nickel | 1477 °C | yes | 50 % |
 Ilmenite (titanium ore) |  Titanium | 1827 °C | yes | 50 % |
 Quartz |  Silicon | 1527 °C | yes | 45 % |
 Vanadium ore (V-magnetite) |  Vanadium | 1910 °C | yes | 45 % |
 Pyrite (sulphur ore) |  Sulphur | 827 °C | no | 50 % |
Ores can be crushed to concentrate first (see Processing): concentrate smelts with a better yield. The leaching plant is an alternative wet route with the best yields.