Primitive Technology: Roasted Ore and Shell Flux Smelt

Dear John. As a metallurgy engineer that handles ore into kiln, I have the following advice: I suggest you start with smaller fire and continuously build it up to increase the temperature, but it is important to keep a calm fire after starting it. Drying the ore slowly is the key to a nice and ready charge for the coal. Once you start adding coal (after 3-4 hours of drying the ore), I suggest you try making breaks while blowing, to let the coal and the charge cook well, like cooking a steak at a low temperature, because too much air will oxidize the iron earlier before it reaches a temperature near liquid phase before smelting, so that could be the problem why you are still getting small prills. Try making small pellets of 1 cubic centimeter of the ore. Burning the iron ore right from the start will cause the iron to pop and form into smaller prills into the slag. Also lime is added in liquid metal only (from my experience so far) Hope this helps!

I tested roasting the ore, using lime flux (shells) and recycling slag in 3 separate smelts. Roasting the ore improved the yield about 2 times though this might have been due to decreasing the volume and effectively increasing the concentration of the ore. Adding lime (snail shells) ruined the smelt and produced next to no iron. This may be due to the ore already being basic and chemistry and the lime made it so basic that the slag won't flow. Sand (an acid flux) or old slag might make a better flux for this type of ore, lime might be better used to flux iron sand (acidic due to the silica content). Finally, I tested re-smelting the slag from previous smelts (not the slag from the lime smelt). The result was about half the iron came out compared to fresh ore, which suggests that slag should be smelted again to recover any iron not obtained during the first smelt if fresh ore is hard to come by. Thanks.

Kind of crazy to think I've watched someone go from the stone age to the iron age over the course of a few years...on YouTube. Without any tricks or secret helpers, no clickbaity titles or mobile game plugs...just a mellow dude quietly and effectively reminding me of how absolutely useless I would be if everything went sideways. Thanks for the vids dude.

What's truly exciting about seeing him experiment like this is that it is EXACTLY how our ancestors learned. Yes, he got some hints. Yes he knew that flux was a thing. But that "What if I add this to the process?" and "What if I add this to the ore?" is how humanity began its exploration of metallurgy over hundreds of years. The "I heard that the guy two villages over sacrificed his shell necklace to god of the forge and barely any iron came out" exploration.

After 8 years, i still watch every single one of these videos within a day of them releasing. One of the greatest channels of all time, easily. Phenomenal!

The thing that always impresses me most is the patience he has. It would take a full generation cycle I think for humans not to be put off and constantly aggravated from these kinds of labors in daily life! Very enjoyable and educational. Thank you.

Stuns me that he has to build up a large reserve of charcoal between each smelt. The amount of work involved just in prep is huge! Incredible work!

I'd just like to add a comment of respect for the sheer amount of work that goes into producing what to us is an 18 min video. The bricks, the wood gathering, the many batches of charcoal production you must have done, the iron bacteria straining. You make it all look so easy but I know from personal experience that it is not. Best channel on youtube, I'm excited every time a new video drops.

8 years later and this man still finds new creative ideas to engage the audience, respect

I cannot begin to explain how much I love the fact that you include failures into the videos. That honesty and scientific approach is why it's so interesting.

Those huge nuggets are so satisfying to see after so many attempts yielding small ones over the years! Incredible work. Is it feasible to roast a larger quantity of ore at a time? Also wondering if you could load more of the roasted ore at a time into that tall furnace.

This is without a doubt the greatest channel ever produced on youtube. i could honestly watch this 24/7. Feels like my inner caveman is here to learn. Keep up the stellar work man.

Honestly incredible that humans figured out how to make metal at all, or even find out it existed in the first place. Cool stuff

The chemical used to lower the melting point of the slag (unwanted materials, also called dross) is calcium oxide. Wood ashes contain calcium oxide, as does pre-burnt shells, and limestone that has been baked into quicklime has the most calcium oxide. Since he's in an area with no limestone, he only has ashes and snail shells to work with. The failure may have been due to the fact the shells were merely crushed, and not pre-baked, as happened in a previous experiment (turning snail shells into the calcium oxide / hydroxide needed for making cement) several years ago. Or it simply could have been too much calcium oxide, because yes, sometimes too much of a good thing is actually a bad thing in the end.

This is my first time giving "super thanks" to channel in YouTube. I really love your contents for this past years. I wish you got healthy, and prosperous life despite your "life" on that primitive hut with all those bacteria and animals 😅. Once more thanks for amazing works you've done, i know it just small gift but this is my sincere thanks for you. Love from Indonesia ❤️

It's funny how the other primitive youtubers just happen to get iron so easily and forge it to tools in just one video. They show no process or failures, they just happen to succeed everytime :D I've been watching your videos since the beginning and happy to see that you still keep producing quality stuff no matter how famous you get!

I can't wait for the day he can actually make his first real iron lump to work.. This shows how much work it is to go directly from stoneage technology to iron age. And to boot it is such relaxing videos to watch...

just a reminder for those who don't know, these videos always (at least every one I have watched since learning this) have captions which explain what he is doing. they're a must have to watch these videos. :)

It is a beautiful take on not just primitive tech, but experimental chemical engineering as well. Thanks for this John.

You could tell he was proud of this one. Those were some good yields.