Iron Prills

I smelted iron bacteria in a short furnace and produced a small quantity of iron prills (small iron spheres). In my ongoing quest to reach the iron age, further experiments were conducted concerning furnace design and the treatment of ore. I began by making a very short furnace. A pit 25 cm wide and 25 cm deep was dug and the tuyere of the forge blower placed in a 15 degree downward angle into the pit. Onto this, a furnace stack made of mud and grass was built 25 cm above ground level. The furnace was fired at various stages to help dry it. It took less than a day to build.
Eucalyptus wood was collected dead off the ground and stacked into a re-useable charcoal mound I had made previously. The top was sealed with mud and the mound lit. It took about 2 hours 30 minutes for fire to reach the air entries, at which time the holes were sealed and the top closed with mud.
Iron bacteria from the creek was gathered and brought to the smelting hut for processing. Charcoal was ground into a powder and mixed with the ore and water in the proportions of 1:1 char to ore by volume. This mixture was formed into 59 pellets 2.5 cm in diameter and then dried on top of the furnace.
To make the smelt, a wood fire was made in the furnace and allowed to burn for about an hour by natural draft and blowing. When the wood burnt down to the tuyere the furnace was filled with charcoal and 10 pellets were added to the top and the blower was engaged. Three handfuls of charcoal and 10 pellets were added at about 7 minute intervals totaling about 42 minutes. Charcoal was then continuously added after the last charge until the basket was empty. It took a total of about 3 hours working the blower until the operation ended.
The mass of slag and iron prills was prized out of the furnace using a log and wooden tongs. It was hammered flat while hot but no large bloom was made. Instead many small iron prills were found. These mostly seemed to be cast iron.
So far this is the largest amount of iron I’ve made in the wild and it used less charcoal than previous attempts, so I consider it a success of sorts. The ore must be mixed with carbon to ensure the correct reduction chemistry normally provided by carbon monoxide in a taller bloomery furnace. The fact that cast iron was produced suggests that next time less charcoal powder be added to the ore pellets or perhaps none at all considering that dead iron bacteria may also contribute some carbon to the ore. Alternatively, cast iron can be re-melted in a “finery” furnace, a small highly oxidizing furnace, to remove excess carbon, producing steel or iron. Alternatively cast iron can be converted into malleable cast iron by heating it in an enclosed container at 800-1000 c for long periods. Further experiments will be conducted.

 

18 thoughts on “Iron Prills

  1. I absolutely love the stuff you do . I’ve been a huge fan of bushcraft for years but you show that it’s not just eating bugs and going to the toilet in a hole . Please keep it going I love reading these and watching the videos . It’s incredibly relaxing . I would love to be able to do what you do . Kind regards . A fan

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  2. I’ve been watching you for a long time, what made you want to do this type of stuff. because you inspired me to get up get outside and do what you do so thanks mate. if your reading this and it makes no sense its because my school cant teach for sh*t sorry thank cya.

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    • Minor injuries such as pulled muscles and superficial scratches. I also got sick once and think that was from the bush. My property gets flooded once a year restricting access. I know climate change is real but I don’t know the extent to which it effects me v.s. if it was not occurring. I work around problems as they arise. Thanks.

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  3. I love your channel they need to give you a t.v show all the bird sounds sound like Australian birds what part of Oz do the videos take place ??? Keep up the good work mate

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  4. Still got some lovely Western Australian raw copper ore rocks sitting at home that I’d gladly trade for some pottery and baskets my neighbor! If long distance trade for tens of thousands of years was good enough for the blackfellas then it should be a good enough compromise to furnish your projects needs!

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    • Thanks for the offer. But I should really stick to the rules I’ve set for my self. After all scarcity encourages creativity- I may come up with a novel means of collecting copper from the environment. I’ve actually accidentally smelted copper and gold from iron bacteria before though only in a very small amount. My theory is the bacteria find these metals toxic (unlike the iron they live off) and concentrate them on the outside of their cells. I’ve also gotten sulfur from them too, it condenses on the inside of the furnace. Thanks.

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      • Thanks for the reply! (I’ve made the offer before but my comments never stuck somehow, using an alternate e-mail worked!) I really hope you manage to work something out, stone age technology in Australia is really hamstrung by the lack of accessible metals! Unless we actually do have native bog iron or copper sands or such that I’ve not heard about…

        Also I think if/when you do have a useable quantity of metal you’ll blow your options wiiiiiide open and have too many projects to consider!

        Really enjoy your work and format mate, I’ve actually attempted my own copper/charcoal smelt here in southwest WA inspired by your good self!

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  5. Awesome, as always! Hope you can do a lot of stuff in the iron age! Do you have more iron around? Is that hard to find/identify? Looks like it has a very unique color.
    Regards! Huge fan!

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    • Yes, I’m slowly accumulating more ore. Also, slag from previous attempts can be re-used to get more iron out so that’s what I’ll start doing as well. I keep the old slag in a pile in the smelting hut. The stuff I use is iron bacteria and is more common than people think. Check for it in creeks, it’s an orange paste that oozes out of waterlogged soil. Thanks.

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  6. Hello! I homeschool my kids and after seeing this video, I think this would be a cool project for us to try out as I’ve seen the iron bacteria here and there in our area. When you say you take the bacteria to the smelting hut for processing, what does that include? Basically, I’m wondering how you get it into powder form. Thank you for all you do!

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    • Mix charcoal powder with it 1:1 by volume. To get a powder just let it dry out. You can mix it charcoal while it’s still wet if you want, it doesn’t make a difference. Though the ore pellets should be dry before going into the furnace to save charcoal. Thanks.

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  7. Hoping you and your loved ones are safe up there with the fires they have had up north, I have family on the other side of baffle creek to the deepwater fire, and it’s beena hell of a time for them, but better than for those in its path.

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