pcm81 Posted June 14, 2015 Posted June 14, 2015 I was having some fun with chemistry, the end result of which was a handful of pure carbon. I decided to mill it and after separating it from ball milling media i noticed that media was dirty brown color; did not give it much thought and went on with my life. Today i put that dirty media with other media and just ran the ball mill with nothing but these two loads of media in hopes of cleaning the media up. At the end the media that was used to mill carbon came out with nice deep black sheen on it; almost as if carbon formed a thin layer on top of the media and the brown gunk i saw before was just some other contaminant that got cleaned off by 2nd milling. This got me thinking: milling pure carbon might result in thin protective film forming on the outside of the ball media; or at least a very high carbon content steel layer forming on the outside of the media. I am talking thin as microscopic. What do you all think about working the media in such a way and if the resulting media is now more inert to chemicals and rust? Or will resulting media be more prone to contaminating future material with carbon?
Arthur Posted June 14, 2015 Posted June 14, 2015 First thought is that few people use steel media, it's harder than lead but carries an increased risk of sparking so not good for mixes, yes I know steel is used for milling ingredients.
GMetcalf Posted June 14, 2015 Posted June 14, 2015 I don't think it's high Carbon Steel your media is now coated with, was your media steel to begin with? Carbon has some very interesting chemistry when it gets very small but if it's highly shiny then my thoughts are it's probably a fine layer of a graphite-like substance. Not sure how this would affect future milling though.
pcm81 Posted June 14, 2015 Author Posted June 14, 2015 First thought is that few people use steel media, it's harder than lead but carries an increased risk of sparking so not good for mixes, yes I know steel is used for milling ingredients.Yeah i agree, usually non-sparking media like lead or ceramic are used for flammable mixtures. I use steel for grinding non-flammable stuff .
pcm81 Posted June 14, 2015 Author Posted June 14, 2015 I don't think it's high Carbon Steel your media is now coated with, was your media steel to begin with? Carbon has some very interesting chemistry when it gets very small but if it's highly shiny then my thoughts are it's probably a fine layer of a graphite-like substance. Not sure how this would affect future milling though.Media was steel to begin with. It does rust so i'd guess high carbon steel to begin with. I suspect its a very file layer of carbon, but your guess is as good as mine what phase its in, probably graphite. Basically i dehydrated some sugar in sulfuric acid and ground the result.
GMetcalf Posted June 14, 2015 Posted June 14, 2015 That reaction produces amorphous carbon (non-crystalline). Depends how many free electrons are available when it goes it to the mill as to what you'll get out. Sounds like the brown stuff you found was probably reaction of the free carbon electron with any left over water/sulphate ions. I honestly have no idea if mechanical stress such as what you find in a mill jar can crystallise carbon, I know high pressures can and that's the basis behind artificial diamond production. Anyone have any ideas what the pressure between two mill balls is on average?
pcm81 Posted June 14, 2015 Author Posted June 14, 2015 That reaction produces amorphous carbon (non-crystalline). Depends how many free electrons are available when it goes it to the mill as to what you'll get out. Sounds like the brown stuff you found was probably reaction of the free carbon electron with any left over water/sulphate ions. I honestly have no idea if mechanical stress such as what you find in a mill jar can crystallise carbon, I know high pressures can and that's the basis behind artificial diamond production. Anyone have any ideas what the pressure between two mill balls is on average?In case if any one finds it interesting, here is a paper about DLC (Diamond Like Amorphous Carbon): http://carbon.utsi.edu/downloads/jrobertson_mser.pdf I have no Idea is the force between balls in ball mill is high enough to form a diamond, but if it is strong enough to break up sp2 bonds leaving larger fraction of bonds as sp3 bonds, then impregnating small (and i mean very small) DLC particles into outer layer of media is not out of the question.
pcm81 Posted June 15, 2015 Author Posted June 15, 2015 In case if any one is curios, here is how the balls look like: Left most is right after i ground some carbon yesterday. Middle one is the same as leftmost, but it has been additionally ball milled with just balls no media, Right most is like middle but it today's attempt with 0.75" balls and it has not been turning for as long. http://www.magicmrv.com/balls.jpg
Mumbles Posted June 15, 2015 Posted June 15, 2015 It may just be surface oxidation and pitting. It's very difficult to get all the acid out of carbon produced from sucrose and sulfuric acid.
pcm81 Posted June 15, 2015 Author Posted June 15, 2015 It may just be surface oxidation and pitting. It's very difficult to get all the acid out of carbon produced from sucrose and sulfuric acid. Ultimately you are probably right; but i'd rather think that i now have nano-diamond coated grinding media than just pitted media, especially since i spend half a day washing the carbon in RO water.
Recommended Posts