How Does a Breaker Work?

Does any one know the mechanics of a breaker? Is it like a rock crusher? I did a search to try to find out how the coal breaker works and came up empty. Figure if any one knew it would be found here.

It's a three step operation. The raw coal and rock which consists of various sizes anywhere from "dirt" to pieces that can weigh hundreds of pounds are loaded into a hopper, it should be noted that the rock to coal ratio is very low. They can't make money sending a lot of material through the breaker that contains a lot of rock. On a side not this is one of the reasons its not very feasible to run culm banks, they can do it for a very low quality product suitable for a co-gen plants but not for consumers because the higher quality required yields very little product. A lot of rock also beats the crap out of the equipment.

Once it's loaded into the hopper the pieces that are larger than the largest sized final product are separated from smaller ones. These large pieces are then picked through by hand and they remove anything that is rock, wood or any other debris they come across. The large pieces are then crushed down to a maximum size of the largest size they make as final product and recombined with the smaller pieces separated earlier.

This is still a coal/rock mixture and this is where it will differ from a rock crushing plant. This coal/rock mixture is conveyed into a cone shaped device called a menzies cone. Basically this cone has water in it that has been mixed with magnetite. They lower the specific gravity of the water by adding enough magnetite so the coal floats and the rock sinks separating the two. This is an important step, the mixture has to be just right or you'll be either getting a lot of rock in the coal or vice versa throwing away a lot of good product . The coal is sent off to be screened and the rock is discarded. The magnetite in the water is recovered to be reused.

From there it is screened into different sizes. The largest size can be stove but not a lot of places make this. Hudson anthracite for example where I used to get my coal doesn't make any. The coal is also separated into Chestnut, Pea, Buckwheat, Rice, Barley and anything smaller than that goes into a single pile. The Barley is not much larger than coarse sand. The smallest sizes is generally sold for filtration and other uses which in turn is actually screened again at the plant that is using it filtration.

OK, But when it comes to the part where the rubber meets the road, just exactly what crushes the coal? Is it two steel plates in a V shape that occilate close and apart? Is it some sort of hammer? Is it 5,000 humans with lobster nutcrackers?

They have a rotating drum(s) with teeth, the coal is continually fed into it. It's either crsuhed against a steel plate if its a single drum or between two drums where the teeth would mesh together. This is actually the "breaker" part of the operation.

Richard S. wrote:They have a rotating drum(s) with teeth,

Yowza! Stephan King stuff!

Richard S. wrote: They lower the specific gravity of the water by adding enough magnetite so the coal floats and the rock sinks separating the two.

Richard,

Thats interesting, I always wondered how the rock and coal were separated in any volume. Magnetite occures naturally here and at one time was mined by hand. Just around the corner from my property there is what is supposed to be the oldest mine in NY. It is not much to look at until you realise that the material was probably all carted out in hand carts. When my oldest daughter was in school she did a display of local minerals. Magnatite was one and we scraped some up in the old mine still slightly magnetic.

That stuff is HEAVY... When they bring it in on flatbed truck I'll bet there isn't more than 12 pallets on it and they aren't stacked very high. They have them placed on the front and rear of the trailer over the wheels, nothing in the middle.

That cone is quite interesting. I work around crushers and asphalt plants and was always wondering how the separated it as well.

This is an important step, the mixture has to be just right or you'll be either getting a lot of rock in the coal or vice versa throwing away a lot of good product . The coal is sent off to be screened and the rock is discarded. The magnetite in the water is recovered to be reused.

At one breaker, at least, the "rock" is sent to the co-gen plant and is burned to make electricity. Isn't the specific gravity of the water raised to 1.6, or is that considered lowering?

Richard S
Do you have any more drawings of coal process like the menzies cone? That is cool and very informative.
Thanks for the information.

stoker-man wrote: Isn't the specific gravity of the water raised to 1.6, or is that considered lowering?

Yes I believe that is correct, I'm going the wrong way. I'll fix that.

Do you have any more drawings of coal process like the menzies cone?

That's not my drawing, there are few other drawings available here: http://memory.loc.gov/cgi-bin/ampage?collId=pphhs ... &maxCols=4