elementcollector1 Posted December 18, 2011 Posted December 18, 2011 I recently found some Cerium (IV) Oxide as a polishing powder, and have a lot of calcium metal chunks to spare. What is the best way to start this reaction in a thermite-like manner? Should I grind up the Ca into powder, or leave it as these 1 cm chunks? The reaction is: CeO2 + 2Ca -> 2CaO + Ce Molar ratios: 172.115 + 80.156 -> 112.155 + 140.116 (numbers correspond to reactants and products above them) So, for every 17 grams of CeO2, I would use 8 grams of Ca (either powder or chunks) to get 11 grams of CaO and 14 grams of Ce, correct?
chem student Posted January 6, 2012 Posted January 6, 2012 (edited) i'd probably powder the calcium, mix it with the oxide and ignite it using a magnesium fuse rod. Edited January 6, 2012 by chem student
elementcollector1 Posted January 6, 2012 Author Posted January 6, 2012 (edited) Right, but the hesitation is because Ca could be dangerously pyrophoric as a powder. EDIT: The polishing powder I have is NOT ceria, it is Tripoli. Luckily, I made some ceria on my own. Would this be better to convert to the hydrated chloride or leave as the oxide? Edited January 6, 2012 by elementcollector1
chem student Posted January 9, 2012 Posted January 9, 2012 Right, but the hesitation is because Ca could be dangerously pyrophoric as a powder. EDIT: The polishing powder I have is NOT ceria, it is Tripoli. Luckily, I made some ceria on my own. Would this be better to convert to the hydrated chloride or leave as the oxide? i don't see the need to convert to chloride. powdering the calcium shouldn't be much of a worry , it will oxidise real fast though? you'd have to powder it in an oxygen free atmosphere. unfortunately i don't know how.
elementcollector1 Posted January 9, 2012 Author Posted January 9, 2012 i don't see the need to convert to chloride. powdering the calcium shouldn't be much of a worry , it will oxidise real fast though? you'd have to powder it in an oxygen free atmosphere. unfortunately i don't know how. I don't exactly have the tools to do that. Perhaps just igniting it might be enough. Or melting it?
chem student Posted January 22, 2012 Posted January 22, 2012 heating it would increase the oxidation rate, as well as powdering it. the only thing i can suggest is that you only expose it to air right before you do the reaction, (assuming it's kept under oil).
elementcollector1 Posted February 9, 2012 Author Posted February 9, 2012 heating it would increase the oxidation rate, as well as powdering it. the only thing i can suggest is that you only expose it to air right before you do the reaction, (assuming it's kept under oil). Er... it's not. The metal is still fairly shiny though, so unless my United Nuclear canister is filled with argon (not likely, it has been tipped over before), this calcium doesn't seem to oxidize as fast as I thought it would. Give it a year or two. I've worked with magnesium and aluminum powders, and these are fairly stable from my viewpoint. If I had an argon tank, this would be really easy. I know a welding store nearby, so we'll see.
Suxamethonium Posted February 9, 2012 Posted February 9, 2012 Calcium chunks are usually stored in an air tight container. After long storage you end up with calcium oxide/hydroxide/carbonate instead- but it takes a while- filling the container with argon or nitrogen would prolong the life considerably- but its not necessary. As for the reaction, calium chunks wont work very well (if at all). You would be much better off using powdered metal, noting that Mg or Al are readily available in such form. Alternatively you could try to melt the calcium (probably once mixed with the cerium oxide) to start to reaction- you'll probs need the blow torch (approx 850C) and a container that can withstand to reaction temp.
elementcollector1 Posted February 10, 2012 Author Posted February 10, 2012 Calcium chunks are usually stored in an air tight container. After long storage you end up with calcium oxide/hydroxide/carbonate instead- but it takes a while- filling the container with argon or nitrogen would prolong the life considerably- but its not necessary. As for the reaction, calium chunks wont work very well (if at all). You would be much better off using powdered metal, noting that Mg or Al are readily available in such form. Alternatively you could try to melt the calcium (probably once mixed with the cerium oxide) to start to reaction- you'll probs need the blow torch (approx 850C) and a container that can withstand to reaction temp. So, would ceramic work? Also, are either Mg or Al reactive enough to reduce the ceria?
Suxamethonium Posted February 10, 2012 Posted February 10, 2012 Last time a performed a thermite reaction in ceramic it shattered. You could try a heavy walled ceramic- but you'll probs need to go with something like cast iron (and hope the reaction doesn't exceed 1200 degrees C. Mg and Al should be reactive enough, at the very least you will get some cerium (but you may have to use excess Mg/Al).
elementcollector1 Posted February 10, 2012 Author Posted February 10, 2012 Righty-o, then. Off to thermite some more oxides!
elementcollector1 Posted April 27, 2012 Author Posted April 27, 2012 Well, it's been a while since I tried this. Anyway, I now have 25 grams of CeO2 very fine, pure, nearly white powder and 10 grams of Mg turnings, dark gray in color. The turnings of Mg should ignite, according to my teacher, with a magnesium rod, but is there any way to powder the thermite without setting it off? Mortar and pestle does not work, but ball milling is a possibility. Also, there's the consideration that Cerium (IV) Oxide is relatively inert, and as such might not even be reduced. Ideas, anyone?
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