AirCowPeacock Posted September 20, 2012 Posted September 20, 2012 Can I mill Quartz Sand in my ball mill with Allumina Media? Corundum (which is Alluminum Oxide) has a Mohs Hardness of 9, and Quartz has a Hardness of 7. But Allumina isn't Corundum, Corundum is a naturally occuring mineral that has a different structure than the Allumina media we use. Does anyone know what is the actual hardness of the Allumina we use? Thanks. I want to grine the Quartz to around -200+350 mesh for use in thermite. with -325 mesh Alluminum. Right now the sand is probably -40+200 mesh.
brimstoned Posted September 20, 2012 Posted September 20, 2012 (edited) Pretty cheap food additive, might save a lot of wear and tear to your mill to just order a bit. http://www.americans...ilicon-dioxide/ Edited September 20, 2012 by brimstoned
AirCowPeacock Posted September 21, 2012 Author Posted September 21, 2012 Hey! Could I use that as an anticaking agent in potassium nitrate at 0.5%?
brimstoned Posted September 21, 2012 Posted September 21, 2012 Interesting idea, but it will probably slow down your BP, even at .5 %.
AirCowPeacock Posted September 21, 2012 Author Posted September 21, 2012 Probably. Shame, I hate the clumpy KNO3 I have now. It unclumps after practically 3 days in my dessicator, but it-shirts just so hydroscopic, and the air is fairly humid around now that a week or two later it gets just as bad again. I double bag it and put it in a PP plastic container. But the moisture still circumvents my futile efforts!! I love my KClO4 with 0.5% CMC anti-cake.
Mumbles Posted September 21, 2012 Posted September 21, 2012 If you ever actually milled quartz, I'd reserve that media and jar specifically for that purpose. I would never trust it to be completely free of crystalline quartz to ever mill BP again. I know plenty of people who use potassium nitrate with anti-cake and have never had problems. I really do not think that the performance issues would be all that great. If people can use agricultural grade potassium nitrate with good success, a little anti-cake is n't going to hurt anything. I would make sure to get good fumed silica however. Fumed silica is non-crystalline, and will not cause silicosis or spark via triboluminescense. M5 is the brand from Cabot that most people use. The following link is more pricy than the food stuff, but I do know that it's M5. People typically use it between 0.3% and 1%. I don't know how much is enough really. Only experimentation will tell. Be aware of how bulky it is. 1lb is approximately 2 gallons. http://apps.webcreate.com/ecom/catalog/product_specific.cfm?ClientID=15&ProductID=20897
taiwanluthiers Posted September 21, 2012 Posted September 21, 2012 I saw some Aer-o-sil (which is almost the same as Cab O sil) and its light... a 500g HDPE bottle of it weights only 40 grams. It's not the same as ball milled sand... I doubt a ball mill will ever get it that fine. The particle of fumed silica is only nanometers across, that's finer than microns! They feel like fluff.
Arthur Posted September 21, 2012 Posted September 21, 2012 Firstly are you sure of the chemistry of your intended thermite reaction. Usually it's iron oxide and aluminium to iron and alumilium oxide, are you hoping to get silicon flowing out. Have you checked that silicon thermite works. Secondly are you sure that you have chosen the best silica for your job. Silica sand is well used in industry and is sold in all filter mesh cuts, so find a specialist sand supplier and ask for the filter cut that you want. Fine silicas are less used in industry as they can become airbourne dusts and these can get into the lungs with harmful effects over long periods.
AirCowPeacock Posted September 21, 2012 Author Posted September 21, 2012 I've actually seen (atleast videos of) people making thermite with relatively course sand. But they also used finer Al or even Mg. I don't have any Mg and or any finer Al. So I'm worried it won't work. Either way, I'm sure I would get a better result wIth finer silica. I'm going to try it with the sand I have now, see if it works. If it doesn't, I'll go from there.
Mumbles Posted September 21, 2012 Posted September 21, 2012 Sorry, I missed the fact that you wanted to use it for thermite. Cab-o-sil or other fumed silicas probably isn't right for that. I was responded about the anti-cake thing. Try looking at ceramic suppliers. They will often sell very fine grades of silica that would save you the time and hassle of trying to mill sand. They also sell very fine flint, which is a silicon dioxide mineral, but I really have no idea how that would work.
Arthur Posted September 21, 2012 Posted September 21, 2012 Try seiving out some fines to make a booster thermite of fine silica and fine Aluminium. Once it's started the coarser material will burn
AirCowPeacock Posted September 22, 2012 Author Posted September 22, 2012 But my finest screen is only 20 mesh. Everything will fall through. I could try step priming with FP to SiO2-Al or FP to Fe2O3-Al to SiO2-Al.
Arthur Posted September 22, 2012 Posted September 22, 2012 You NEED the proper tools to be cometent and safe. If you can't buy fine mesh silica then you must seive it from mixed silica. The classic fuse for thermite is magnesium ribbon,
AirCowPeacock Posted September 23, 2012 Author Posted September 23, 2012 Yeah, I don't have Mg ribbon. FP has worked to light all the thermites I've experimented with so far, with the exception of ZnO thermite. However I suspect my ZnO has reacted with CO2 in the air since it was in a plastic container and about 5 years old (forming Zinc Carbonate.)
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