Sciencemadness Discussion Board

Crystal Heat Drain Opener

DFliyerz - 24-2-2015 at 20:09

I recently bought Crystal Heat Drain Opener assuming it'd be pure sodium hydroxide, seeing as Zep makes the best copper sulfate I've ever seen, but it turned out to be a mishmash of sodium hydroxide, sodium nitrate, and sodium chloride. Is there any way I could seperate the components, or at least recover the hydroxide/nitrate?

Pasrules - 24-2-2015 at 23:03

What size is the sodium hydroxide in relation to the other chemicals, it could be possible to screen filter your mixture?
At my workplace we make a mixture called sewercide which is a mixture of NaOH prill and aluminium turnings.

If your mixture is aqeous then I'm sure somebody else will give you method however I can't think of one.

DFliyerz - 25-2-2015 at 10:33

It looks like there are white pellets of what I'm assuming is sodium hydroxide in a large number of grey-ish pellets, but it'd be a huge pain to sort. Additionally, I was thinking that perhaps I could isolate the nitrate by using a copper salt to precipitate the hydroxide and carbonate and leave the nitrate in solution, since those are the main components of the mixture.

blogfast25 - 25-2-2015 at 11:05

Quote: Originally posted by DFliyerz  
I recently bought Crystal Heat Drain Opener assuming it'd be pure sodium hydroxide, seeing as Zep makes the best copper sulfate I've ever seen, but it turned out to be a mishmash of sodium hydroxide, sodium nitrate, and sodium chloride. Is there any way I could seperate the components, or at least recover the hydroxide/nitrate?


This kind of question has been brought up countless times already here. Please use the search facility before opening yet another thread.

This should be spliced onto an existing thread.
Quote: Originally posted by DFliyerz  
Additionally, I was thinking that perhaps I could isolate the nitrate by using a copper salt to precipitate the hydroxide and carbonate and leave the nitrate in solution, since those are the main components of the mixture.


The ratio of NaOH to nitrate (very high) makes that basically impossible, not to mention you'd lose all the NaOH to relatively worthless Cu(OH)2.

[Edited on 25-2-2015 by blogfast25]

Molecular Manipulations - 25-2-2015 at 11:13

I've bought something similar which is said to contain 30-60% sodium hydroxide and 30-60% sodium nitrate and 1-5% aluminum. If you knew exactly the concentration to be far more nitrate, you could fractionally crystallize some nitrate out who's solubility is 73 g/100 mL, 91.2 g/100 mL and 180 g/100 mL at 0 °C, 25 °C and 100 °C respectively. The thing is sodium hydroxide's solubility is far lower (41.8 g/100mL) at 0 °C, but I don't think it can be crystallized due to it's affinity for water.
Quote: Originally posted by DFliyerz  
I could isolate the nitrate by using a copper salt to precipitate the hydroxide and carbonate and leave the nitrate in solution.

Yeah, that would work, but isn't the sodium hydroxide what you want?
I've used barium nitrate to crystallize out barium hydroxide octahydrate who's solubility is 1.67 g/100 mL (0 °C). Then I added equal parts water by weight and boiled to dissolve it (solubility is 101.4 g/100 mL (100 °C)) and then added sodium sulfate to precipitate insoluble barium sulfate. Finally I had a solution of decently pure sodium hydroxide. It works but is hardly worth it, as sodium hydroxide is cheap and barium sulfate is far less useful than the nitrate. Plus getting sodium hydroxide out of solution is a trick, boiling it down in a nickel crucible has worked for me.

Amos - 25-2-2015 at 14:21

The tiny bluish pellets are sodium hydroxide, and the larger spheres in the crystal heat are sodium nitrate; I made the same mistake buying it but was able to remove almost all of the nitrate spheres with a sieve; they're actually really pure, you just need to dissolve them in water with a bit of nitric acid and recrystallize it once. I believe crystal heat also has some aluminum bits in it; they're the reason you can't really extract sodium hydroxide from the drain cleaner, as they react with it as soon as it's all wet.

[Edited on 2-25-2015 by Amos]

DFliyerz - 25-2-2015 at 14:49

Quote: Originally posted by Amos  
The tiny bluish pellets are sodium hydroxide, and the larger spheres in the crystal heat are sodium nitrate; I made the same mistake buying it but was able to remove almost all of the nitrate spheres with a sieve; they're actually really pure, you just need to dissolve them in water with a bit of nitric acid and recrystallize it once. I believe crystal heat also has some aluminum bits in it; they're the reason you can't really extract sodium hydroxide from the drain cleaner, as they react with it as soon as it's all wet.

[Edited on 2-25-2015 by Amos]


Well, at least it wasn't a complete waste, considering my local Home Depot keeps saying that they have potassium nitrate, but never seems to have any.

DFliyerz - 25-2-2015 at 20:32

Upon closer inspection after screen filtering it, it appears that the aluminum is not homogenous with the rest of the crystals, which is interesting. Now, if only aluminum was magnetic...

Also, a crazy idea: using a non-water liquid/solvent like mineral oil to seperate the sodium hydroxide and aluminum by density.

And finally, continuing crazy ideas that are totally money/material inefficient, it's apparently possible to regenerate sodium hydroxide from sodium aluminate.

[Edited on 2-26-2015 by DFliyerz]

Molecular Manipulations - 25-2-2015 at 20:42

I think if you shake it sideways in a tray panning it, the aluminum should sink to the bottom and you can slowly pour off the hydroxide and nitrate. Then separate that with a seve.

Darkstar - 25-2-2015 at 20:55

I've always gone to Lowe's for OTC potassium nitrate. If you haven't already, look for a product called Spectracide Stump Remover. According to the MSDS, it's 100% KNO3. As far as I can tell, this seems to be true. You can use their website to check if your local store carries it. Comes in a black, 16-ounce container with a big orange label and a grey nozzle for a cap. Should be around $7.

Also, while you're there, look for Roebic Laboratories Crystal Drain Opener. It's a little on the expensive side, but it's 100%-pure NaOH. No aluminum or any other BS in it. Comes in a black, 32-ounce bottle with a red cap. Usually ~$15 or so.


Amos - 26-2-2015 at 04:00

Quote: Originally posted by Molecular Manipulations  
I think if you shake it sideways in a tray panning it, the aluminum should sink to the bottom and you can slowly pour off the hydroxide and nitrate. Then separate that with a seve.


I tried this idea, which seemed to work pretty well for removing a significant of the aluminium, but unless you're in a very dry environment, it doesn't take long for the whole thing to become goopy, frothing mess from humidity alone. And for the record, you do NOT want to be around this stuff when the reaction runs away, as a caustic aerosol of NaOH forms.

Molecular Manipulations - 26-2-2015 at 08:39

I guess it depends on where you are, but it's winter now, so outside even if the relative humidity is high, there won't be much water in the air. So it wont absorb too much if you do it in five minutes or less. It's pretty cold there in New England I'm sure.

[Edited on 26-2-2015 by Molecular Manipulations]

DFliyerz - 26-2-2015 at 12:08

Quote: Originally posted by Darkstar  
I've always gone to Lowe's for OTC potassium nitrate. If you haven't already, look for a product called Spectracide Stump Remover. According to the MSDS, it's 100% KNO3. As far as I can tell, this seems to be true. You can use their website to check if your local store carries it. Comes in a black, 16-ounce container with a big orange label and a grey nozzle for a cap. Should be around $7.

Also, while you're there, look for Roebic Laboratories Crystal Drain Opener. It's a little on the expensive side, but it's 100%-pure NaOH. No aluminum or any other BS in it. Comes in a black, 32-ounce bottle with a red cap. Usually ~$15 or so.




Home Depot's website says that they always have ~10 bottles of Spectracide, but whenever I go there they never have any... :P

aga - 26-2-2015 at 13:44

Think more sideways and, AISTR, aluminium goes all Kinetic when placed in the field of a Linear Motor.

DFliyerz - 27-2-2015 at 10:53

Update on how the separation of sodium nitrate is going:
I sieved out as much of the sodium hydroxide and aluminum that I could, and dissolved ~150g of the mostly sodium nitrate in about 350ml of water. Interestingly, the mixture separated into a blue layer at the top and a clear layer on the bottom, with lots of pieces of aluminum in a pile. Also interestingly, a simple filtration got all of whatever was coloring the top layer, so the filtrate was completely clear. I then just boiled the filtrate down to about 125ml, and left it over night. When I checked on it in the morning I had some very nice crystals of what I'm assuming is nitrate, so I put that in the fridge and will check on it later.

Molecular Manipulations - 27-2-2015 at 12:17

I'd recrystalize the sodium nitrate at least once more. It will still contain hydroxide ions like it is.

Amos - 27-2-2015 at 14:07

How do you know it's not carbonate? Sodium carbonate has a much lower solubility in water than sodium nitrate.

DFliyerz - 3-3-2015 at 20:21

Because there's lots of it. I did a second recrystallization and it looks great, burns well too.

e14 - 23-10-2016 at 15:54

Do not buy ZEP unless you want to unclog something. Separating anything from it is like reinventing the wheel. NaOH is hygroscopic and reacts with aluminum. Take the bottle and pour it into your bathtub with the drain shut and add some water and watch out!

Melgar - 24-10-2016 at 10:46

Actually.... in a very dry environment, try placing the mixture on a flat, vibrating board, or make something like a plastic pool table with pockets on only one side, covered with glass or plexiglass. The various particles will eventually separate based on how they respond to the frequency of the vibration according to their physical properties. You can vibrate the board manually, or attach a motor to it with an off-balance weight in such a way that you can control the speed. When they've separated sufficiently, use some sort of scraping device to push the particles into their correct pockets. This is how those old electric football games worked; the little guys were weighted so that they'd move a certain way when the table was vibrating. it doesn't work as well for spherical particles that tend to roll, but if you textured tub surround, you can minimize rolling. It sounds crazy, but I actually used something like that to successfully separate ammonium phosphate and urea in yeast nutrients.

The aluminum should separate out very easily, in any case, because it has a much different density.

Alternately, put the whole mix into chloroform, then gas with dry chlorine. If there's no side reactions that I don't know about (and there probably are), the aluminum should dissolve as AlCl3, leaving the insoluble salts behind. (Note: this was a brain fart, do not actually do this)

e14 - 30-10-2016 at 16:36

I read somewhere sodium nitrate is much more hygroscopic than potassium nitrate. ZEP probably uses it for its added hygroscopicity? Either nitrate is used as an oxidizer. I do not know the exact reaction that would take place with sodium nitrate. Anyways, unless I knew the exact reason for the nitrate, I wouldn't bother with it, IMO - too dangerous. Just place some in your bath tub with a little or a lot of water and it looks pretty scary.

Melgar - 31-10-2016 at 12:37

Quote: Originally posted by e14  
I read somewhere sodium nitrate is much more hygroscopic than potassium nitrate. ZEP probably uses it for its added hygroscopicity? Either nitrate is used as an oxidizer. I do not know the exact reaction that would take place with sodium nitrate. Anyways, unless I knew the exact reason for the nitrate, I wouldn't bother with it, IMO - too dangerous. Just place some in your bath tub with a little or a lot of water and it looks pretty scary.

The nitrate might actually be there to SLOW the reaction, of all things. Other than glass, one of the few materials that can store nitric acid is aluminum. This seems crazy at first, because of how easily nitric acid dissolves most metals, and because of how easy aluminum is dissolved by other acids, particularly hydrogen halides. But nitric acid passivates aluminum, by thickening the Al2O3 layer, making the underlying aluminum even more inert to oxidation.

Likewise, nitrate salts act as oxidizers when they're heated, so they could be there to passivate the aluminum if the temperature gets too hot. Though, a passivating layer probably wouldn't protect against NaOH... I guess it could just be there to oxidize organic material?

[Edited on 10/31/16 by Melgar]

e14 - 31-10-2016 at 19:53

Depending upon aluminum's mesh an ATFE license may be required. Simply looking up pyrotechnic aluminum will show this. So, what is ZEP's mesh? It is a proprietary formula. ZEP could be a type of water gun powder? What would happen if you added some ATFE aluminum to its mixture? Or is the aluminum in there already ATFE? Interesting just to separate the aluminum then if possible. Illegal aluminum. And yet the sodium carbonate is also hygroscopic. It acts as an electrolyte and attacks aluminum according to Wikipedia.