99chemicals
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Boiling Chips
I made some calcium sulfate boiling chips today by hydrating calcium sulfate with water and letting it hardening.
I am wondering if there are any chemicals that react with it under high temperatures. I made it for nitric acid production in the future.
If you want to see the video https://www.youtube.com/watch?v=h1TNyOmU0Os
Am I correct when saying that usually insoluble sulfates are pretty nonreactive.
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vmelkon
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Why do you need it for nitric acid production? Usually, people add conc H2SO4 to a nitrate and heat to drive off the nitric acid and no boiling chips
are needed.
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unionised
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It's generally a good idea to add some sort of boiling chips to a distillation.
Calcium sulphate is generally fairly inert.
Unfortunately I think it dissolves in conc H2SO4 to form Ca(HSO4)2.
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99chemicals
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Would there be any problems using this in a nitric acid distillation? I am going to add Conc. sulfuric acid to KNO3 and distill the acid.
Would these be usable for making bromine.
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Hexavalent
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There may be a chance of;
2HNO3 + CaSO4 → Ca(NO3)2 + H2SO4
Very nice video and idea BTW - I'll be sure to make some soon.
[Edited on 1-7-2012 by Hexavalent]
"Success is going from failure to failure without loss of enthusiasm." Winston Churchill
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99chemicals
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Quote: Originally posted by Hexavalent  | There may be a chance of;
2HNO3 + CaSO4 → Ca(NO3)2 + H2SO4
Very nice video and idea BTW - I'll be sure to make some soon.
[Edited on 1-7-2012 by Hexavalent] |
I don't think that Nitric acid is a strong enough acid to dissolve a soluble sulfate and make sulfuric acid. It may exist in equilibrium. From what
I know Sulfuric acid is the strongest acid that is commonly encountered. It would take a stronger acid to make sulfuric acid or am I confused?
This is off topic but how do you get the arrow? Usually I use ->. Did you copy and paste or is there a code?
[Edited on 7-1-2012 by 99chemicals]
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Hexavalent
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Calcium sulfate is extremely insoluble in water, Wikipedia quotes 0.21g/100ml (anhydrous) and 0.24g/100ml (dihydrate) at 20°C .
BTW, there is a code for the arrow. User 'bfesser' referenced it in a thread in 'Forum Matters';
http://www.sciencemadness.org/talk/viewthread.php?tid=15528
It is really useful for showing reactions, symbols, superscript etc.
[Edited on 1-7-2012 by Hexavalent]
"Success is going from failure to failure without loss of enthusiasm." Winston Churchill
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bbartlog
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For nitric acid distillation, maybe these will be fine. But in general, I don't think calcium sulfate is a good material for boiling chips. The
solubility is low, but hardly so low as to prevent some contamination of aqueous solutions. And further, CaSO4 will react with soluble carbonates or
oxalates to produce the insoluble calcium carbonate/oxalate and corresponding other salt. I don't know where you got this idea but I would suggest
sticking to more conventional boiling chips.
The less you bet, the more you lose when you win.
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99chemicals
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| Quote: Originally posted by bbartlog | | For nitric acid distillation, maybe these will be fine. But in general, I don't think calcium sulfate is a good material for boiling chips. The
solubility is low, but hardly so low as to prevent some contamination of aqueous solutions. And further, CaSO4 will react with soluble carbonates or
oxalates to produce the insoluble calcium carbonate/oxalate and corresponding other salt. I don't know where you got this idea but I would suggest
sticking to more conventional boiling chips. |
I made aluminum oxide boiling chips by thermal decomp of aluminum hydroxide. Those work great but I wanted some that would be more resistant to atack
by acid and base. You can dissolve the Al2O3 in ammonia, NaOH, HCl, H2SO4, HNO3 the list goes on.
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Arthur Dent
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I have to admit that the "boiling chips" I use are made of inert material... and are quite inexpensive to obtain.
At the dollar store, those little glass beads they use for arts and crafts and necklace-making, they come in various formats, but the 2/3mm beads are
most useful.
But the "ghetto" version is to smash a piece of tempered glass... the "rock salt"-sized chunks of glass are perfect for such an application.
Robert
--- Art is making something out of nothing and selling it. - Frank Zappa ---
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Mailinmypocket
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Speaking of dollar store, I bought a cheap ugly dinner plate and smashed it to bits - The porous porcelain pieces with sharp edges work great!
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liquidlightning
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I generally use broken bits of glassware. Stirring rods tend to work the best. I just swirl them in some sandblasting sand for about a minute to get
rid of the sharp edges.
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dann2
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Pieces of pumice stones.
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malcolmf
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Hydroleca = Little pellets of porous, fired clay. Sold cheaply in UK garden centres, for greenhouse moisture trays, or just plain hydroponics.
For boiling chips, pick out a handful of the smallest pellets and use the rest in the greenhouse. (The easiest way I've ever seen for tomato
growing!)
Pellets are available in 4mm, 6mm, 11mm, in sacks starting at 5l up to commercial greenhouse quantities.
Available in the rest of Europe, apparently , so probably available everywhere in some form.
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achem500
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I often use pieces of chipped concrete. I tried porcelain once, (from an electrical insulator, actually) but it wasn't porous enough. Concrete chips
worked well, but I'm not sure how inert they are. They worked for isopropanol distillation 
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platedish29
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Was just looking for this, Thanks!
Currently I make use of smashed dirty quartz stone, which works pretty well, specially in circunstances at which salt solutions boils annoyingly
harsh.
The only problem is that it suffers some discoloration everytime it is heated up in solution. Should it be discarded? I'm not sure if it is porous
enough??
[Edited on 3-9-2012 by platedish29]
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vmelkon
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I used pieces of granite. It works fine. It isn't very porous but I think having a lot of rough surfaces is good enough. I think it is quite inert to
acids.
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