You can recycle tools, metal parts, weapons, jewelry and armor in a bloomery when you reach level 90 in smelting. These items must be kept in the bloomery with the temperature of 2,000 degrees in order to be recycled. Recycling will always return lumps of the metal the recycled item was made of. The amount of lumps that can be recycled from an item depends largely on the item and only to a lesser extend on the smelting skill. A smelting skill of level 100 will slightly increase the recycled amount of lumps (e.g. 6 instead of 5 lumps of iron from a single Light Chainmail Gauntlets, which needs one iron bar to be crafted). A Hardened steel pickaxe on the other hand returns only 1/80 of the metal which was used during the item's creation (two lumps of steel out of 4 steel ingots). The remaining durability of the recycled item doesn't effect the quality of the resulting lumps.
When recycling objects in a bloomery the quality of the resulting lumps will suffer a reduced quality from the object being recycled of roughly 50%.
Warning: Regional Effect is lost upon recycling Regional item.
At level 90, recycling will return 80% of the metal used to make a tool. This is rounded down if that returns a decimal.