Slag Furnace

The Slag Furnace is a Factorization furnace which is similar to the vanilla Furnace, except it requires double the fuel input (Coal will only smelt 4 items instead of 8).

Slag Furnaces have a a 120% yield when smelting ores, except when Silver Ore is smelted, in which case it will produce a Silver Ingot and a 120% yield of Lead Ingots. With other ores, there is a chance of obtaining smooth Stone together with the respective ingot.

However, rather than smelting any ore directly, it is better to grind it in a Grinder first, and use Slag Furnaces as part of the Factorization ore processing chain, either smelting Dirty Gravel (from a Grinder) or Clean Chunks (from a Mixer).