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Double tuyere refining furnace

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The Past few months I have been experimenting with refining bloom slag, particularly the fluff / mother.  I had my first notable run which consolidated 8lbs of slaggy iron into 1.8lbs of high carbon steel.  The puck was weighed after the first weld.  Previously my attempts only hinted at victory so, with this furnace, I rolled the dice a little and overhauled almost every detail.  The most drastic change being the addition of a second tuyere.  In my opinion this solved 2 problems.  First it helped prevent slag from freezing under the tuyere.  Second it allowed for a higher pressure while maintaining a reducing atmosphere and a relatively even heat.  Higher pressure seems more important to me with this slaggy stuff vs normal iron.

Although I didn't achieve any reduction I'm still holding out hope that it is possible in these tiny furnaces.

First I crushed up mother, and mixed with flour/water to make little slag sausages.  Pieces that wouldn't break after a few hard hits were set aside along with clay heavy pieces.  This was well worth the time since it let all the action happen in a small and very controllable location.  From there the furnace ran pretty much like normal with the exception of tapping slag, which I did about every 1.5lbs of charge.

The daytime photos are from 2 metalic iron(mostly) remelts I did with Emiliano and friends, which were a ton of fun too!  You can see my nervous Nelly patchwork, but hey worst case is the furnace actually needed it.









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Thanks Alan!  I'm really happy with how this furnace ran, and look forward to future attempts.  Soon I should have a few folds done on my puck so i can get a test etch in.  I'm really excited to see what the steel looks like since it is behaving so nicely up to this point.(only 1 fold complete)

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  • 1 month later...

Very cool.. Why the two tuyeres ? 
 Every couple months I run all the bloom fluff through the regular tall stack. Like 30 -40 lbs at a time. 
 It always makes a great solid bloom/melt.. 
 I pick up everything around the compacting stump, and smelter, that will stick to a magnet.. 
 Of course, these days, every bit of dirt within 40 ft. of my smelting area, will pick up with a magnet ;)

 Great work Dan... Big fun. 

Mark Green


I have a way? Is that better then a plan?

(cptn. Mal)

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Thanks guys, much appreciated!  I have to do another run or two before I have enough material for a decent blade.  So it will be a while before some updates.

Mark, I went with two tuyeres because I was struggling with a single tuyere.  I thought with 2 apposing hot spots I would be less likely to freeze slag.  Also since remelting this material takes me a relatively long time, compared to pure iron remelts, I thought using 2 smaller tuyeres would help keep ash from building up so bad.  My main goal was to accommodate a 2-3lb bloom with as few cold spots as possible, while maintaining a reducing atmosphere. The floor of the furnace was roughly a 6" circle, 7"x10" at the tuyeres, and 6"x8" at the rim.  My single tuyere furnaces are normally 6" or 8" shafts.

I got a smelt or 2 planned between now and spring so hopefully I can try this more full scale like you describe!

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