To get a blacksmith's furnace or forge hot enough to smelt and extract ores, requires fuels that can burn to a higher temperature, and longer than firewood or coal (both of these have too many impurities, burn irregular and too fast). The use of a Metallurgical fuel is now essential in all elements of metallurgy.
A product of logs, Charcoal is made primitively in a charcoal pile, or in a charcoal kiln. Logs are heated with an absence of oxygen, pyrolysis or the charring begins, this removes the impurities and from this, approx. 45-55 Charcoal is produced from every input of 13 Logs.
A product of coal, Coke is 'cooked', much like charcoal; primitively in a piled coal hearth, where the coal is piled up and covered with earth, or in a beehive shaped coke oven it is produced faster. The process requires 13 mined Coal to produce approx. 45-55 Coke.
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