Subcomputer
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CeO2 -> useful salts?
I had an idea to use Cerium as a semi analogue to Thorium for exploring what seemed to be a rather empty area (as far as I could tell, given my
newbishness), as it is above it on the periodic table and lacks certain minor legal and safety issues.
TFSE told me that CeO2 polishing compound could be broken down with strong sulfuric acid and heat, with several papers on google even breaking it down
some rather obvious seeming math on heat of solution and size of CeO2 particle.
Surprisingly, two samples of CeO2 - one light orange powder from an old rock tumbling kit, and another supposed 99% light beige powder from eBay -
both "worked" (scare quotes) with battery refill grade sulfuric acid. The "99%" turned the solution light yellow after a few hours room temperature,
and tangerine after some time on a candle warmer.
At this state, I seem to have succeeded. This leads me to a few questions. First, how do a make sure I have Cerium (IV) Sulfate? Next, what's this
about it decomposing back to CeO2 in non-acidic environments? Finally, what are some leads I should be looking up to create CeCl3, Ce(OH)3?
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Brain&Force
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Neutral solutions of cerium sulfate will slowly convert to cerium dioxide. If you want to make CeCl3 you can add hydrochloric acid to the
cerium dioxide, but this generates chlorine. Then you can convert it to cerium hydroxide by hydrolyzing it (this generates HCl). Do these steps in a
fume hood. Cerium(IV) sulfate is a good redox titration indicator and becomes clear when a reducer is added.
Thorium is less likely to go into the +3 state and prefers to remain as ThO2.
At the end of the day, simulating atoms doesn't beat working with the real things...
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sasan
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if your CeO2 is calcined,then it wont dissolve in HCl(aq).it just dissolve in hot concentrated sulfuric acid.take care of sulfuric.it is completely
corrosive
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blogfast25
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My thread on Cerium salts, including sulphates:
http://www.sciencemadness.org/talk/viewthread.php?tid=24638#...
Effectively dissolving commercial CeO2 is far from easy and crystallising salts of Ce, apart from Ce (III) sulphate is no sinecure either. Battery
acid H2SO4 and a candle warmer will yield very little.
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Subcomputer
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I've created enough light orange "something" then to get some minor crystallization, both on the sides of the reaction vessel and where I started
trying to crystallize some out (now going to settle for crystals with acidic fluid on top) in another vessel at slightly above room temperature.
Additionally some of the CeO2, or rather settled monochromatic material in the reaction vessel, has become like a gum that is a pain in the ass with a
glass stirrer. This is only with the eBay "99%", not the rock tumbler stuff. Maybe the eBay stuff was a (good|bad) batch? I certainly wouldn't say
I'm getting an appreciable yield, of course.
This is definitely a work of patience. I could potentially move the setup to a hot plate and higher grade sulfuric acid, but I'm not quite set up to
deal with the full safety needs to my satisfaction.
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