Stones in the coke

[Daniel Lea (AKA 99pppo)]

Hey Folks,

today I got two bags from a company called "PPS Stade" located in the near of Hamburg Germany. One bag bituminous coal from Sweden and one bag blacksmith coke. Of course I inspected the coal and the coke by taking one glass of each and look through it. The coal is very clean and has no "stuff" in it. But the one glass of coke contained three stones, one white one (I think quartz) with black dots and one looking like flint stone and one that looks kind of like basalt. Of course the stones originally appeared black from the dust but I felt that they are different from the coke and washed them.

My question now is whether that is normal and acceptable or whether I will have to raise a complaint against the coal supplier where I bought the stuff? I mean I actually paid money for stones that will have no heating function but clock up my forge...

Here are some pictures:










Thak you for your advise in anticipation!


- Daniel

[John B]

Hi Daniel, Stones in coke to me is not acceptable, it may be a packing/storage problem at the suppliers, and an isolated incident, in any case, they should not be there, and I would consult the supplier as to why they are there..

Personally, I would go with the coal, this will coke by itself when in use, make an easier fire to light and not require a constant air supply to keep it in.

I suggest you try each seperately and make your own mind up as to which you prefer, then make a calculated decision about which to continue with.

Good luck and have fun

[Daniel Lea (AKA 99pppo)]

Hi Daniel, Stones in coke to me is not acceptable, it may be a packing/storage problem at the suppliers, and an isolated incident, in any case, they should not be there, and I would consult the supplier as to why they are there..

Personally, I would go with the coal, this will coke by itself when in use, make an easier fire to light and not require a constant air supply to keep it in.

I suggest you try each seperately and make your own mind up as to which you prefer, then make a calculated decision about which to continue with.

Good luck and have fun

Tank you very much for the reply. Asking some people I found out that stones happen to actually often appear in coke. Joe even said that he had cast iron pieces in his coke... I will ask the supplyer why they sell such impure stuff. But I will simply have to test the stuff and decide what is most compfortable for me to work with...

[r smith]

I have heard the suppliers are allowed a certain percentage of "stones" by law and if they dont meet that amount they will add stones until they do- more coke to sell if it is cut with stones. :o

[Larry H]

if those are the only stones let it go, I always find rocks in my coke, it bothered me at first, especially buying two tons at a time, its not the cheapest solid fuel around, but it is the best. ( for me anyway )

[John B]

This stones in coke acceptability would appear to be a nationality thing.

Here in the UK I have never had any rocks in the coke I have been using for many years now, and know of no others in the UK who have this problem.

As to "a certain percentage is allowable", here in the UK as the Trade Description Acts are in force, if I purchase coke, I expect coke, and it must be fit for purpose, any rocks/stones would be pointed out to the supplier, and recompense demanded.

[Frank Turley]

Years ago, Tom Bredlow of Tucson would order his bagged coal from Phoenix Hardware. The coal always had stones mixed in. Tom sent the hardware company a postcard which read, "Please send the coal and stones separately; I'll mix them when they get here."

[ThomasPowers]

Out here our coal supplier had issues with getting rock in the coal so he started getting the coal in as large chunks which made sorting out the rock easier. He then crushes the coal and sells it as fines.

[John B]

Rock in coal is understandable, however coke is a byproduct from the chemical/coal industry and should be stone free

[Daniel Lea (AKA 99pppo)]

This stones in coke acceptability would appear to be a nationality thing.

Here in the UK I have never had any rocks in the coke I have been using for many years now, and know of no others in the UK who have this problem.

As to "a certain percentage is allowable", here in the UK as the Trade Description Acts are in force, if I purchase coke, I expect coke, and it must be fit for purpose, any rocks/stones would be pointed out to the supplier, and recompense demanded.

Coke plays a special role in the UK cause it is the only stuff you have in big enough amounts. Bituminous coal is traditional for Germany, Czech Republic, Sweden etc. I guess that is the reason why you have that kind of supreme coke.

[Dan P.]

I'm in the UK and sometimes get stones, the most common of various types of UFO I find in my coke.
Three stones per glass seems excessive to me, but then again, I don't usually use my coke by the glassful so perhaps I'm not entirely qualified to comment.
The main problem with stones is that they can explode and put your eye out.

[ThomasPowers]

John; if you have stones in your coal how do you not get stones in the coke made from that coal? GIGO!

(now petroleum coke is different...)

[Daniel Lea (AKA 99pppo)]

Washed one kitchen bowl full of the coke in the bathtub and found 6 little stones and some little pieces of slag. It seems like they are mixing some gravel into the coke in order to stretch it. Maybe there also is some very pure blacksmith coke out there. But what counts at the end is the performance in the fire pot. Will report about that as soon as I can test it. Thx for the replies so far!

[John B]

John; if you have stones in your coal how do you not get stones in the coke made from that coal? GIGO!

(now petroleum coke is different...)

The coke supplied in the UK as Blacksmithing Coke (Monkton) is a byproduct from the chemical industry and so is possibly the petroleum coke you refer to.

I also found that there were no stones in the coal we used to use, probably down to the particular coalfied/pit/seam it was sourced from and how it was extracted. (Grimesthorpe and Barnsley areas),

Other coal sources varied in quality, inclusions and performance so we stuck with the coal sources we were happy with,

[r smith]

I learned of "allowable stones" when a batch of coke came with river rocks in it. Several handfuls per bag. The only way they could get there would be to add on purpose so that was never purchased again.

[Frosty]

Finding stones and slag in coke is possibly a byproduct of stone in the coal, usually coal or oil shale. During the coking process the shale produces enough heat to help the coking process and ends up as slag.

Here in Alaska you're going to get stoker coal or coal shale suitable for furnaces that use powdered coal like gas in burners. If you want metallurgical coal you get to either order and ship it in from the lower 48 or go coal mining yourself. Every spring we have an event called "Art On Fire" featuring arts needing fire, we smiths put on a show but the big show is the iron pour. They fire the cupola melter with commercial coke and a big part of the event for the iron agers is scraping out the slag and ckinker stuck to the inside of the cupola. I don't know where Pat gets the coke, it may be petroleum or coal coke, I've never asked.

Frosty The Lucky.

[george m.]

Dear 99PPP0,

Some years ago I started using coke rather than coal because my supplier quit carrying blacksmith coal but still had coke. I discovered that it had about 5% or so stones (usually carbonaceous [black] shale) in it. I had to pick them out by hand with every shovel full that I used. I was saving them in a bucket so that I could go back and return them for credit on more fuel. Unfortunately, the supplier has gone out of business.

I've since gotten my coke from a different supplier here in the US and there has been no problem with contamination by rocks at all.

The only way that unaltered rock is going to get into the coke is the handling of the product after it leaves the coke oven. Any impurities in the raw coal will be melted during the coking process. I always figured that the crushed coke had been stored on a gravel pad and the stones had been scooped up by and unskilled front end loader operator.

As an old geologist I would say that your stones are pretty exotic for being naturally associated with coal or the coking process. The quartz and basalt (if you are correct in your identification) are igneous rocks which normally do not occur anywhere near coal deposits.

If it were me, I'd return the coke on the grounds that it has been contaminated, either accidentally or intentionally. If by a "glass" you mean a water glass of about 12 ounces (about 300 ml) I'd say that you have a pretty high level of contamination.

Geologically,
George M.

[Daniel Lea (AKA 99pppo)]

Dear 99PPP0,

Some years ago I started using coke rather than coal because my supplier quit carrying blacksmith coal but still had coke. I discovered that it had about 5% or so stones (usually carbonaceous [black] shale) in it. I had to pick them out by hand with every shovel full that I used. I was saving them in a bucket so that I could go back and return them for credit on more fuel. Unfortunately, the supplier has gone out of business.

I've since gotten my coke from a different supplier here in the US and there has been no problem with contamination by rocks at all.

The only way that unaltered rock is going to get into the coke is the handling of the product after it leaves the coke oven. Any impurities in the raw coal will be melted during the coking process. I always figured that the crushed coke had been stored on a gravel pad and the stones had been scooped up by and unskilled front end loader operator.

As an old geologist I would say that your stones are pretty exotic for being naturally associated with coal or the coking process. The quartz and basalt (if you are correct in your identification) are igneous rocks which normally do not occur anywhere near coal deposits.

If it were me, I'd return the coke on the grounds that it has been contaminated, either accidentally or intentionally. If by a "glass" you mean a water glass of about 12 ounces (about 300 ml) I'd say that you have a pretty high level of contamination.

Geologically,
George M.

The coal supplier apologized for that and they offered me a free bag of coal. The bituminous coal they get from Sweden is said to be splendid and I may buy a ton or so and I think I asked them whether they can discount the price for one bag off of the full prize.
Thanks for your reply.

- Daniel

[r smith]

Take the free bag and then work out the ton.