possible iron ore/slag/bloom

[forgenorth]

I have found what I think might be (hopefully) some smeltable iron ore. The first 2 pictures are the same piece but different sides, I  found these near a stream, within a mile of a pig iron furnace so maybe this is what they used? The next 3 pictures were found around the foundation of the furnace previously stated. I believe these may be either slag or blooms, because they have anthricite inclusions and a white powder which could be limestone used as a flux I've heard. I read somewhere that they would put anthricite on the top layer of iron in the crucible, so the anthicite would oxidize before the iron. Is that where the anthricite came from? Also the peices in the last 3 pictures all hold a magnet very well.If anyone can confirm or deny any of this it would be greatly appreciated.

[Bentiron1946]

I can neither confirm nor deny but why not just put a piece in your forge and see what happens when it comes up to temperature and you whack it, could be fun to do.

[forgenorth]

@bentiron1946 I was thinking about trying that but my forge is temporarily out of service because I'm building a new bellows and going from side blast to bottom blast forge.

@Jammer  both of these  were found near the York Lancaster border in PA. I brought about 40 lbs of the ore back with me, I think that should be enough for a small scale smelt. What do you guys think? Also thank you for the links, Ive seen the wiki page but not the other until now, it's been difficult to find information on real iron ore and smelting. When i look up "iron ore" or "smelting iron" I get results for world of warcraft and the like. So far, the best resource has been the dvd ore to axe and wareham forge.

[ThomasPowers]

So search on bloomery and discard all results involving flowers. (Bloomery -Flowers)

 

Note that you will need to pretty much powder your ore to use it; why iron sand is often preferred.  We did a smelt once where we had to roast the ore and grind it down before smelting and it was a lot of extra work and hassle.

 

Also the book "Mastery and Uses of Fire in Antiquity", Rehder, has plans for a "fool proof" bloomery in the appendices---ILL a copy!

 

Note that while it only takes a few percentage points of iron content to turn a rock red your ore must have a higher iron content than the slag will to get actual iron out of the process.

 

Have you stopped by the geology department of a local college and ask if it was iron ore?  Holding it in your hand works a lot better for identifying stuff than a couple pics on the web.

[Nobody Special]

IF it's ore, roast it a fire, drop in water, then bust it up. Invite a friend, bring beer. You'll need it, this is incredibly tedious. And you're going to need a LOT of lump charcoal. Lots of variations on furnaces.

 

This site has some interesting info, but check around. http://iron.wlu.edu/ . The info's out there, on the process, but you have to adjust your searches to avoid WoW and Minecraft.

 

Not all ore takes a magnet well. I've got about 120 lbs sitting around my garage in buckets, and if the moon's in the right house, and the wind's blowing right, it's magnetic, a little bit. If you think you've got a bloom, why not cut a little off and take a look at the inside?

[forgenorth]

@ThomasPowers if it is ore, I would still crush it, this was just the inside of a big chunk.I always heard you should roast it any way to drive out moisture and sulfur is that true? Someone said that if the ore is too fine it can get blown around by the convection, is that true?Are there any kind of land forms to look for when looking for ore? I think I'm going to see if I can find a coppy of that book.

I know that it doesnt take much iron to make it rust but I don't have a way to test how much is inside.It seems pretty uniformly rusty the whole way through though.I like the idea of going to a college geologist, is iron ore something comon enough that they could ID it?

@Nobodyspecial why should you roast the ore and then quench it? I like the link it has good info. In regards to magnetism, the stonger the pull, the higher iron content right? What would a bloom look like on the inside?

 

 Thanks

[doc]

If you'd like to know more about and see the results of contemporary work into research on ancient smelting ? Here is a site you should visit  

 

http://www.leesauder...ng_research.php

[ciladog]

Lee is the man when it comes to ancient smelting.

[Nobody Special]

Roasting doesn't just drive out moisture, it changes the oxidation state. (or so I've read, only ever melted wee little amounts).  Dropping hot ore in cold water makes it crack/and or easier to bust up in my experience. More brittle. They'll be more brittle than to begin anyways, even without the quenching.  True of most rocks, stuff I ring the firepits where I burn leaves and make charcoal is Basalt and grabbo, with some iron inculusions, and it's all crumbly or cracked from the heat. May vary depending on the ore.

[ThomasPowers]

Pre processing of ore is dependent on what type of ore you have---if your ore doesn't include sulfur then roasting it doesn't convert it from a sulfide ore (eg Iron Pyrite to an oxide ore)

 

One thing I will mention: the pre processed iron ore "marbles" you can find along RR tracks in places are *designed* for use in blast furnaces and so contain way too much flux for a typical bloomery.

 

As early iron furnaces tended to be near the ore and fuel; if you found some ore nearby it is probably local and a local college should know about it.  Otherwise the state Geological Survey should have maps of ore bodies in your state---publishing such things has been part of their job for the last century or so.

 

As for what landforms to look for: well everything from bogs, to streambeds to mountains!

 

Magnetite Sand is a common find pretty much located anywhere there has been igneous or metamorphic rocks or has been glaciated from such regions.  It also comes in a good size to work with and requires no roasting or crushing.

 

We have used fine powdery limonite ores before with good results---of course we were using a hand crank blower for air input with a short stack scandanavian bloomery based on examples from the early medieval period

[forgenorth]

@Doc I like the link I'm going to look through all the links in detail now. Are you by any chance from upstate NY?

@nobodyspecial I was kind of thinking that it would help make it brittle, I saw somewhere that people used to put flint in fires to make it easier to knapp for certain applications.

@Thomas Powers I think the ore i have has some sulfur because when I've crushed it up it has a very faint sulfur smell. I figured it would make sense that there's a source of ore near the furnace so they would have to haul it very far. Did that powdery oreget blown out at all?

Thanks allot guys

[forgenorth]

Also would a double chamber bellows be enough air for a smelt?

[Steve Sells]

doubel bellows is a style, that wont mean a lot, its how much air it can move, its the size that matters.. ;)

[ciladog]

You're going to need some help if you intend to use bellows for a smelt. They last 4-6 hours of constant even air flow.

[forgenorth]

The bellows is 4 feet long and 2 feet at its widest point. I have a couple freinds who can help, how many would be needed?

[ciladog]

I think how many friends you need will be up to you. It's a lot of work doing an iron ore smelt.

First you have to build the bloomery   Then you need to roast and break up the ore. Then you need to make or buy a few hundred pounds of charcoal and break that up into small pieces.

And then you get to start the fire to dry out the bloomery and pre-heat it. And then you charge it with charcoal and start the air blast. When the bloomery dry enough and is hot enough you start charging it with ore and charcoal every 10-15 minutes (depending on how fast it is burning down) for about 4 hours.  When it's almost finished, you tap the bloomery and drain the slag. Now if you have done everything correctly, you may be lucky enough to get an iron bloom instead of cast iron.

Watch Lee's video.

[ThomasPowers]

The smelting experiments at St Fagan's in Wales used a bellows for air----look at http://www.geoarch.co.uk/experimental/experimental.html  and go down to the smelting bit.

 

The powdery ore did not blow out as we would add it and then add the charcoal on top each charge and the shaft furnace was about 4' high so by the time it got near the tuyere it was already covered over by more than a yard of other ore/fuel charges.

[Chuck in Ms]

Hey Forgenorth, I hope it is ore. Smelting is not really my thing but I did help do one this past weekend at Fire In The Swamp. We had about 45 pounds of ore and got a bloom over 8 pounds. It took a lot of dry wood to get the bloomery going and drying out then two 30 gallon barrels of charcoal, maybe more, for the process. The time went over five hours but wasn't that hard to do. Seems like keeping track of the time was a big deal. Add so much ore so much charcoal wait so long and start again. The one man doing the demo did it basically by himself with a little help here and there. At the end once he got the bloom out two of us compressed the bloom with light blows using 8 pound mauls. He directed the hammer blows and turned the stock.
I admit the resulting bloom was very worth while.

[forgenorth]

@ ciladog I make my own charcoal and will build a furnace once I confirm i have ore. Are you one of the guys who was in ore to axe your setup looks very similar.

@ Thomas Powers there bellows is about half the size of mine by the looks of it. I also have a shop vac that going to modify as a backup.

@Chuck in ms That sounds epic! If he used 45 lbs of ore then I probably have enough ore right now to smelt.I think the most time consuming part is going to be  producing enough charcoal mostly because I can only make 15 -20 gallons at a time. My brother is going to bring a sample to a geology professor at his school soon so I can confirm it.

Thanks guys

[ThomasPowers]

We used to buy charcoal from the manufacturer in the 20# sacks for the smelts in PA

 

For my smelts I usually screen all output from our woodstove all winter and add store bought as needed.

 

Collaborative smelts often have an "entry fee" of a couple of bags of real charcoal per person...

[Chuck in Ms]

The charcoal was no problem. He used pieces like split fire wood but only about half the normal length (12-14 inches) . That was stacked neatly on end, round and round, until the barrel was full. Then clamped the top on the barrel, built a small brush fire all around and over the barrel and cooked it. Kinda cool clean up the spring pruning mess and make charcoal out of left over fire wood at the same time.

1. The small hole was open in the barrel top and there was a punched hole in the center of the barrel.

2. The barrels were on there side during the burn.

3. Once opened the was about 5-10% not charcoal, but most was perfect even the bark was intact and identifiable just charcoal now.

4. One barrel tried to start burning once we opened the lid (this was two days after the burn)

5. We put the fire out and chopped into small pieces mostly as we used it.

Hope some of this is helpful. Chuck

[ciladog]

@ ciladog I make my own charcoal and will build a furnace once I confirm i have ore. Are you one of the guys who was in ore to axe your setup looks very similar.

 

No I was not in the video but I have participated in one of Lee's smelting classes at Peter Valley 3 years ago. The pictures were of that smelt.  And I went to observe the smelt last year.  A very good time both times.  Lots of ice cold beer to cool off while charging the furnace. :)  :wacko:

 

Do you know about the tradition of biting the stem off a hot chili pepper and throwing it into the bloomery at the start of the smelt?  If everyone that is there charging the furnace doesn't do it you get cast iron.  And you have to eat the pepper to make it a successful smelt.

[Frosty]

I don't know if this has been mentioned seeing as I only skimmed the thread so far. However be VERY careful putting ANY stone that's been in water in a fire, a steam explosion can result and those are B-A-D things. Seriously, even a rainy day can allow enough water into cracks to cause a steam explosion.

 

Warm it slowly beside the fire before you put into the fire. Better safe than sorry.

 

Frosty The Lucky.