Jump to content
I Forge Iron

Lignite or Brown Coal as a forge fuel


Recommended Posts

From wikepedia:  Lignite, often referred to as brown coal, is a soft, brown, combustible, sedimentary rock formed from naturally compressed peat. It is considered the lowest rank of coal due to its relatively low heat content. It has a carbon content around 20-35% percent. It is mined all around the world, is used almost exclusively as a fuel for steam-electric power generation.

Lignite is brownish-black in color and has a carbon content from as low as 20-25 percent up to 60–70 percent, a high inherent moisture content sometimes as high as 75 percent, and an ash content ranging from 6–19 percent, compared with 6–12 percent for bituminous coal.

The energy content of lignite ranges from 10 to 20 MJ/kg (9–17 million BTU per short ton) on a moist, mineral-matter-free basis. The energy content of lignite consumed in the United States averages 15 MJ/kg (13 million BTU/ton).

Its high moisture content and susceptibility to spontaneous combustion can cause problems in transportation and storage. 

To give you an idea of the heat value of lignite at 10 to 20 MJ/kg (9–17 million BTU per short ton) The energy content of lignite consumed in the United States averages 15 MJ/kg (13 million BTU/ton).  The bituminous coal for blacksmithing in the US is in the 14 million BTU/ton range with good coal in the high 14 to mid 15 million BTU/ton range.  You can easily tell the difference in heat in the fire with a change of 1/4 to 1/2 million BTU/ton. My experience is when you drop down to the 13 million BTU/ton range it starts to be a problem with lack of heat. Here below 13 million BTU/ton does not do well as a fuel.

If you have experience using lignite or brown coal, please add to this information.

Link to comment
Share on other sites

  • 2 months later...

It’s a shame there are so few people who have even tried it. Seems most people just look at the stats and call it horrible without even trying it. Same thing with corn but when I tried corn I found it to be fairly nice to use. I’m sure bituminous is much better than lignite but I should think lignite would work. Might not be real fantastic for forge welding and probably fairly dirty. But for the price it would be interesting to try.
 

Being in North Dakota it’s 39$ per ton for lignite. where it costs about 800$ a ton to have bituminous shipped to me. So even if it’s a sub par fuel it’s probably worth it. I need to make the drive to go get some to do some testing with. 
 

I wonder if I could run it through a retort like with charcoal to burn some of the volatiles off. 

Link to comment
Share on other sites

  • 3 weeks later...

You can find lignite washed out of hillsides here in Ky pretty easily. I've heard it called cannal coal, sub bituminous,shale coal, and oil coal also. Whether those are technically correct terms I don't know. 

Back in the glory days of coal mining here in KY it was considered overburden. I think as profit margins have gotten smaller they no longer think of it as waste. 

Pnut

Link to comment
Share on other sites

  • 3 weeks later...

Found a source of stoker sized lignite for 110$ a ton. Expensive but it’s the right size to burn in a forge and is only an hour away instead of several hours like it would be to get from the mines. I’m thinking I’ll get some to try out. If I like it I’ll make the longer drive and buy in bulk for 39$ A ton from the mines 

Link to comment
Share on other sites

That would be interesting to see. I found a old analysis that’s probably too outdated to matter. But it’s of lignite from the same area. 

not sure how accurate this is now but here’s some numbers 


Carbon 65.56

Hydrogen  5.23

Sulphur .91

Nitrogen .87

Oxygen 21.08

Ash. 6.35

Link to comment
Share on other sites

I wouldn’t advise using it. Only for one reason. Once its heated the coal crumbles into dust which is easily airborne and rather annoying. This was fixed when I added a stove pipe to the side. Almost like a side draft hood. If you had a proper side draft hood it would probably be useable. But I’m still not going to keep using it. 
 

But as a whole it got metal plenty hot. I was able to melt/burn and also forge weld some wrought iron in it. Without flux. So it’s plenty warm. It doesn’t burn terribly fast. A lot slower than charcoal but faster than other coals.  I had no smoke. Other than a tiny bit when I first light it. A wood fire produces more often. There was no clinker. It does not convert to coke like bituminous would. 
 

overall the notion it doesn’t produce enough heat isn’t true in my experience. It’s pretty clean burning. More so than most of the bituminous I see people using in their forges. It’s perfectly useable but the flying chunks of coal are unpleasant 

FF5A7A69-A110-40B8-81C6-47AB71AB9D45.jpeg

3FE92ACE-4DAD-4D46-9773-410A22C00A20.jpeg

6701AE4D-05A9-49E1-9924-12E12A59F9D6.jpeg

Link to comment
Share on other sites

I tried to forge with lignite, you can vut you need wood to to combine.

That thing is like stone, it get hardly ignited and it hardly can get steel to yellow color, I can get it to red

 

Link to comment
Share on other sites

I don't know what is wrong with mine . It's like stone, you need a lot's of air  blowing in fuel, and again you need to blow it in small pieces.

It is realy hard to heat steel.

On my picture i heated using lignite some 10 mm rod  before, now it is harder i don't know why could be moisture..

And you have a lot's of smoke.

 

Link to comment
Share on other sites

Natkova:  Where did you get your fuel?  Was it sold as stove fuel?  This sounds very unusual to me and I am wondering if you got a load of bad fuel.  Lignite should be about as hard as a soft, non-resistant rock.  It should not be like gravel.  It should also burn fairly easily and get good and hot with an air blast to it.  What you describe sounds almost like carbonaceous shale which is sometimes interbedded with coal and lignite in the ground.  If it burns in a stove with just a natural draft it should get hot enough in a forge with a forced air blast to it.

Keep experimenting and I hope you are successful.

"By hammer and hand all arts do stand."

Link to comment
Share on other sites

Yes it.is for.wood stove. WE buy this coal  for  our stoves i can picture big chunk of it right now in my room :D

As i remember lignite is realy old rotten wood mixed with soil

 

Ita realy hard to forge with it I can get steel temperature get to red heat. But mode is harder.

I sont know how much role chimney play.

Mine chimney is just wood stove pipe that is 90angle knee than pipe three feet ling and again knee.

I use leftovers from this chunk to forge.

 

And this stiff make alots of clinkers.

IMG_20210104_235311.jpg

IMG_20210104_235405.jpg

Link to comment
Share on other sites

15 hours ago, Justin Topp said:

Yea that’s lignite alright. I must have higher quality lignite. I had very little smoke, enough heat to forge weld, and I get no clinkers. Weird 

I

 

15 hours ago, Justin Topp said:

Yea that’s lignite alright. I must have higher quality lignite. I had very little smoke, enough heat to forge weld, and I get no clinkers. Weird 

 Here is mine with lignite that I heated in summer

https://www.iforgeiron.com/uploads/monthly_2020_05/zutaboja.mp4.648a08210497f86092acbe1355e9c7ff.mp4

 

Link to comment
Share on other sites

  • 1 month later...

Well hou can forge but it nees to be as Frosty said smaller than fingernail pieces of lignite.

It looks frustrating to forge with  but it tolerate air more than charcoal because coal lignite is heavier

On 1/4/2021 at 4:47 AM, Justin Topp said:

With my lignite I could get it hot enough to burn steel on its own. 

Is your forge bottom blast?

Is there some deprh in your firepot?

 

Link to comment
Share on other sites

  • 1 month later...
On 2/13/2021 at 1:17 AM, Justin Topp said:

Yes my forge is bottom blast. My forge is about 4” deep. Coal was about 3/4” round. 

Maybe bottom blast give better results with lignitr?

Link to comment
Share on other sites

  • 7 months later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...