crushing coal to a poweder

[BrokenBiker]

what is the easiest/cleanest way

 

[Paul.]

Its usually done in a ball mill (google it) a rotating drum with steel balls (grinding balls) and the coal / rock in it which get pulverised as it all tumbles round

 

[brightspark]

giz a clue what u making

 

[awemawson]

giz a clue what u making

Powdered coal

 

[brightspark]

Powdered coal

what for a coal fired powerstation they crush the coal and its blown in to the furnace as dust

 

[rtbcomp]

giz a clue what u making

An explosion

 

[rtbcomp]

Could you get your hands on an old gas cylinder? They crop up from time to time and would make an excellent ball mill - VERY noisy though.

 

[gulf]

coal merchants that bag the coal can give you sweepings,is it for sand casting you need it?

 

[Shox Dr]

An explosion

No need for coal dust, any old dust will do. Flour is good, and starch, and sugar. And your shotblasting dust, (hence the reason for Antistatic grounds) All have been the cause of some of the biggest explosions the world has witnessed

 

[norlander]

Its usually done in a ball mill (google it) a rotating drum with steel balls (grinding balls) and the coal / rock in it which get pulverised as it all tumbles round

easy then- coal and some granite rocks into wifes tumble dryer and heavy plastic sack over dryer exhaust vent.

 

[brightspark]

look at op/s other post and all will be revealed but it wont work

 

[Shox Dr]

easy then- coal and some granite rocks into wifes tumble dryer and heavy plastic sack over dryer exhaust vent.

Not yours by any chance

 

[brightspark]

Not yours by any chance

verry good

 

[rtbcomp]

No need for coal dust, any old dust will do. Flour is good, and starch, and sugar. And your shotblasting dust, (hence the reason for Antistatic grounds) All have been the cause of some of the biggest explosions the world has witnessed

The dust has to be flammable in the first place. Specification for grit blasting media should include inflammability. I use glass so that's OK, but I worry about the paint dust content, but I've had sparks from static and impact but no bangs yet!

 

[BrokenBiker]

i want to try it for case hardening to see how it does

 

[awemawson]

There are much easier things to use. On a small scale sugar works quite well - anything rich in carbon - treacle, molasses, or if you must, coal ! The modern equivalent of Kasenite I find a pain to use - the original stuck to the red hot metal as you withdrew it from the pot, the modern 'safe' stuff falls off so you have to heat the object already surrounded by it rather than the easy method of heating the metal in a torch flame, dipping, withdrawing then reheating.

Now sugar and treacle stick nicely - I keep meaning to mix some sugar in with my tin of Kasenite replacement to add the stickyness !

 

[BrokenBiker]

do you just use plain granulated sugar?

 

[bigegg]

Black laser printer toner is nearly pure carbon, and is a VERY fine powder.
It also becomes sticky when warm

 

[awemawson]

Any household sugar will do fine. In WW2 the POWs used to case harden mild steel using sugar to make wire cutters Proper case hardening compounds have additives to enhance the carbon absorption so will tend to be faster, but the basic principal stays the same. Heat the steel in the presence of excess carbon, and some of it migrates into the steel so that a mild low carbon steel core ends up with a higher carbon skin that will harden when quenched.

 

[BrokenBiker]

I will try sugar tomorrow after work see how it comes out.

I cant heat the metal up in the sugar though, so will it be ok getting the metal cherry red, dipping in the sugar and allowing to cool in the sugar, then heat and quench?