Speed is crucial here therefore from Alexis's blog

Bringing Ice Gloves into the Blast Furnace will help when using the bar dispenser, as they'll cool them off quickly for you to take. This will help you save time, instead of OSRS GP lugging buckets full of water repeatedly to cool the bars (and it will save space in your inventory as well).

Before you get started on getting to the Blast Furnace, it is worth noting that it's only accessible to those who live in these worlds 355: 352 three, three, three, and 387. Once you've spoken the Giant Dwarf , and then delved to Keldagrim the next step is to take a northerly direction and then make your way to the bridge. After you've crossed the bridge, keep going south until you find that Blast Furnace icon on the map. Enter the building marked go downstairs, and you'll be able to see the furnace.

Once you've finished this, it's much easier to go there in the future. You can make use of it by taking the Grand Exchange shortcut on the northwest wall, or take a trip in the minecart through Ice Mountain mines for dwarves, or use the minigame group finder to be able to enter the building.

It's a little difficult to get acquainted at first, but the minigame for the Blast Furnace is an easy task. To make use of the furnace you must follow these steps: Put your ore into the conveyor belt. Run down the ramp prepared with a bucket of water or ice gloves. Recool your bars, and then bank them.

Speed is crucial here therefore, make sure you wear gear to buy OSRS gold reduce weight as you travel through in the Blast Furnace. If you are a player who is less than 60 smithing the blast furnace, you'll require a stamina potion, and 25 ore, in addition to paying for your charge per 10 minutes.