# Sodium nitrite + molybdate



## witekprytek (Apr 3, 2015)

Hi,
I have access to few hundred litres of sodium nitrite doped with molybdate.
The liquid is used as corrosion inhibitor for closed circuit cooling installations.
Whole lot is surplus of requirement and has to be discarded due to lack of storage space.
I am not sure what other ingredients are in there, but can't imagine if there is anything else apart from water and maybe but unlikely ethylene or propylene glycol.

I'm thinking to save company money needed for disposal and take the whole lot for processing.
What I was thinking is maybe to evaporate water and collect sodium nitrite of which most/all would already convert to nitrate which in turn has multiple uses.
Easy to do, biggish fishtank (I have many of them) with cover to prevent rainwater dripping in, nylon mesh protected (insects) gap under the cover and placed in full sun outdoors. With one 100L tank I could evaporate 200-400L in one-two months. I'm not in a rush.


Few questions:
- not sure about molybdate even if there is tiny bit of it in solution. Would it mess things up? Can it be eliminated by cementing ?
- any other uses you can think of? I don't want to use it for dropping gold. By far prefer SMB (PS2) and have lots of it anyway.

Regards


PS. Edited to rephrase some part of it to avoid confusion or misundersanding.
PS2, I meant SMB, was thinking of few things at once


----------



## solar_plasma (Apr 3, 2015)

You are using tin(II) chloride to drop gold? How many years does this take? 

Your idea and the way you want to recycle this liquid shows you have no clue and should refrain from trying.


----------



## witekprytek (Apr 3, 2015)

Would be good if you produced something constructive or at least point out any flows.


You should refrain from posting meaningless comments like that in the future.


----------



## solar_plasma (Apr 3, 2015)

No way.

NaNO2 is toxic and nothing to play with in that amount in fish tanks that could break. Further you say you have no clue about what else ingredients are in this liquid. So, the only constructive answer can be: refrain.

You have been here more than 2 years and are posting, that you use SnCl2 to "drop" your gold. That shows that you are not here in order to learn. Sorry, to say this that directly.


----------



## Lou (Apr 3, 2015)

I would advise against accepting the material. Given the application, I don't see any precious metals to be had.


----------



## patnor1011 (Apr 3, 2015)

Lou, he perhaps want this to use it in recovery, not that there is anything to be recovered from it. 
Which seems rather strange as I assume he is from poland where proper chemicals and acids cost next to nothing.


----------



## witekprytek (Apr 3, 2015)

Hi guys,
please calm down and be serious.


I'm not about a rant, but clearly for opinion from whoever played with molybdate.

So,
1) I am not bothered by NaNO2. Don't know where the "toxic" thing came form. It is not more toxic than NaOH or CuSO4. In fact it is used as food additive. If you talking about concentration than even O2 is toxic. Besides in presence of O2 NaNO2 converts into NaNO3 without any help. Also it doesn't vaporize so open tank protected on top from rain and insects is perfectly safe.

2) I am not in Poland, I am in UK where proper chemicals are restricted or expensive and above all it is more about recycling unwanted chemicals and obtaining chemicals (NaNO3 as result is secondary

3) patnor is perfectly correct - It is not about precious metals, There are none in the liquid and I wont use nitrite for dropping any out of solution. Might however use nitrate for recovery (nitric) or even as fertilizer. (Just in case to cut short any possible main topic branching - molybdenum is not toxic and is necessary for plants - devils hides in concentration .

4) *Regarding ingredients*. I am not sure what *is* in it but I know what possibly *could* be in the liquid. What could be present is sodium nitrite, nitrate (from oxidation of nitrite), molybdate, possibly ethylene and/or propylene glycol. Bothe ethylene and propylene glycols do decmpose in water rather fast so are no problem at all. Besides, the liquid is new, sealed and I am intending to get % of the manufacturer and recipe (just in case another comment) it is not trade protected secret

5) *I do not use stannous chloride to drop gold*. I rarely do play with gold recovery nowdays and if I do I use SMB. Used to use SO2 when the stuff was cheap, readily available and I was using quite a bit of it. I have explained already but just in case I will do it again - I meant SMB and typed in tin chloride because I was thinking of few things at once


*solar_plasma*, I read your posts and they seemed to be sensible. Are you having bad day ?
From your comments I can see you have no clue about NoNO2 or fishtanks, so please refrain from further comments.


----------



## solar_plasma (Apr 3, 2015)

NaNO2 LD50: 85mg/kg http://de.wikipedia.org/wiki/Natriumnitrit

It is forbidden for pupils in Germany. NaOH and CuSO4 can be used for experiments for pupils older than 10. 

But you want to work with hundreds of litres of unknown composition.

And fishtanks, I have had anything from guppy over discus to saltwater, 40l up to 1000l and built a lot of them myself.

But even if you would know the exact composition, the fact that you don't know how to recover pure NaNO2 from the solution, beside your other comments, makes me sure, you should not do this.


----------



## solar_plasma (Apr 3, 2015)

If you were talking about some litres I might help you, but for what purpous do you want to use it since even don't know how to precipitate gold.


----------



## jason_recliner (Apr 3, 2015)

witekprytek said:


> I am not sure what other ingredients are in there, but can't imagine if there is ...


And I can't imagine why anyone in their right mind take on industrial waste, the ingredients of which they don't know.

You should listen to solar_plasma. He is well respected here because is advice is consistently sound. But you are effectively telling him to be silent because you don't like the answer.

You're already confusing your compounds. If you consider your safety, and that of those around you, is worth more than saving the company a fistful of disposal dollars, say no to this.


----------



## butcher (Apr 3, 2015)

NaNO2 sodium nitrite is often used in closed loop cooling systems as a water corrosion preventative.
Depending on the source and company it can be a pure sodium nitrite, or can be a mixture of other chemicals used in the closed loop cooling system.

You need to know what other chemicals are involved, and how much, if it contained ethylene glycol or some other antifreeze, or metal inhibitors...
Messing with unknown chemical compounds, can make a dangerous chemical conversion much more dangerous, by products of the reactions (from a chemical you make), used in recovery or refining process later, where metals are involved could even make possible explosive compounds, we just cannot mix chemicals willy nelly without knowing the dangers and possible reactions involved, or other possible reactions with the chemistry of the reactions we plan to use the chemical with in later reactions... 

Sodium nitrite can be made into sodium nitrate, and then to nitric acid, or decomposed to NOx (NO, NO2, and other nitrous oxide gases) which can be made into nitric acid.

But before using any chemical, like this from a chemical supplier, you need to understand what the chemical compound is and how other ingredient's that may be part of its makeup would adversely affect,t or even make what your trying to do dangerous. many company's now use a combination of chemicals to make up their own proprietary blend to sell the chemical at a higher cost, usually watered down in a barrel of water so your also buying a drum of water, with the chemical you need.

Get the MSDS, and post it. We can see if it is mostly just NaNO2, or if the blend of chemicals would cause problems in converting it to nitrate or nitric acid for use in recovery or refining.

You can convert the sodium nitrite NaNO2 to sodium nitrate NaNO3 a couple of different ways, with a slow oxidation (nitrifying bacteria), oxidation with air, or chemically faster with powerful oxidizers hydrogen peroxide H2O2 (slightly acidified to making it an oxidizing agent), sodium percarbonate Na2CO3-3H2O2 (Oxyiclean), several other oxidizers can be used to oxidize the nitrite to different nitrate compounds...

Nitrite has several routes of decomposition, oxidation is not a straight forward process, as factors of the process, like pH of some of the oxidizers, decomposition of gases in the reactions, temperatures, byproducts involved, and other considerations need to be taken into consideration...

I have used sodium nitrite in recovery and refining and have converted it to nitrate and nitric acid, several ways you can do it, it is not as easy as it sounds, but before we can discuss any details we would need to better understand what you have, what chemical composition, as it could be dangerous working with an unknown blend of chemicals, and then figure a plan to convert it to the chemical compound that can be used for recovery or refining...


----------



## Lou (Apr 3, 2015)

FYI,

ethylene and propylene glycol do not decompose in water, in which they're almost infinitely soluble. 

Propylene glycol is fairly innocuous, but ethylene glycol is the same stuff that tastes sweet (most glycols do, as they're basically polyol sugars).

I would advise against taking this material for the following reasons:

1. Molydate shouldn't go down the drain. 
2. You need to completely profile the material.
3. Evaporating reducing alcohols with potentially oxidizing nitrite could be problematic.
4. Nitrite isn't really a fertilizer. Sure, it provides nitrogen, but that's what nitrates are for. 

As for the toxicity of nitrite: dose makes the cure, dose makes the poison. Nitrite solutions are usually used as antidotes to cyanide (and sulfide) poisoning. Also used in curing meats.


----------



## solar_plasma (Apr 3, 2015)

100kg NaNO2 in 100 000 tons of water (for example 4km of a river that is 10m wide and 2,5m deep) would kill the fishes. I tried to google if it is used as a fertilizer, but I could not find anything, - I doubt it is, since much of it would get washed into the rivers before it gets used by plants or at least gets oxidized to nitrate. And the farmer would probably kill himself when he inhales the dust. Even worse if it would reach the groundwater.

Ofcourse it is part of the nitrogen cycle in nature and agriculture, but this is a steady process and the nitrogen is spread over the whole scale of compounds. Though I am not sure, those might be some reasons, why I can't find any nitrite fertilizers.

If anyone can, I am always open to learn something new.


----------



## witekprytek (Apr 3, 2015)

OK, I've checked few things.

As I said before it might contain ethylene/propylene glycol but it is unlikely.
Both glycol and nitrite additives we are using on the same systems (thats why "might"), but for totally different reasons (thats why "unlikely").

It doesn't. Its nitrite doped with molybdate.

jason_recliner: it is not industrial waste. It is brand new unused product, solution of 2 simple salts dissolved in water. Wont turn your turtle into ninja and wont make another Chernobyl.

solar_plasma: 
1) check LD50 for NaOH, CuSO4 and NaNO2, just so you know for future reference.
2) statement that "tank can break" is more or less pointless. Casserole dish often recommended here for sulphuric cell is MUCH more likely to break than properly made fish tank. All tank I have have safety factor of at least 3, some have 1.5 but calculated for float and made out of tampered/laminated. I know because I made all of them.
3) if on a basis of mistyping explained above you judged that I do not know how to drop gold out of solution then all I can do is to congratulate you reasoning and application of logic
4) who said to use it as fertilizer ? Maybe you didn't read correctly when I said I might convert it into nitrates and then use as fertilizer ? Why don't you try to read and then think instead of trying to find flaw before you read ? 


Lou:
you are right that it should be checked before any action and that was original plan.
All concerns regarding glycols are off- there are none.



I do not know, maybe I should have started the thread in different manner.
I have chemical background including 3 years of chemistry as supplemental subject while doing biology degree.
In respect of precious metals I have done fair bit of recovery from jewelers wastes and refining. Few years of processing 50L a week on average.
Mainly pickling solution, but every now and then there were papers, pastes and swipes.

With all that I NEVER had anything to do with molybdates, save some dry theory and maybe few insignificant experiments at uni.


So the original question remains - anyone had any experiences with molybdates ? Is it easy to drop molybdenum?

If anything fails I'll use the same mechanism what makes it good corrosion inhibitor when combined with nitrite - just use bit of steel to collect and discard it.

Regards


----------



## solar_plasma (Apr 3, 2015)

Oh well, if I use the 0,01mg/l LD50 for fishes, which is stated by wiki, it would even be 80km river. :shock: 

Interesting what it tells about its toxicology: in seawater the nitrite competes with the chloride ions and has a much lower toxicity as usual.


----------



## witekprytek (Apr 3, 2015)

Just to add one thing - I still don't know concentration of nitrite and molybdate.
I can test nitrite concentration but I am not equipped for quantitive analysis of molybdate.
I will know that after easter break when I contact manufacturer.

For now I am guessing it wont be worth recovering molybdenum as such, so main focus is to take it out, discard it and use nitrAte to make nitric.


----------



## Lou (Apr 3, 2015)

If you really want the Mo out, keep load it onto Purolite A172 or some other weak base resin. Can elute it off with a base, and recrystallize as a molybdate salt. There are some insoluble salts that can be made.

Nitrite can be oxidized to nitrate with peroxide, or electrolytically with a stainless or titanium anode.

I guess if this is your idea of fun, go for it.

Might notice that Mo will give you a false positive for platinum via stannous!


----------



## solar_plasma (Apr 4, 2015)

I think plastic tub would be safer and more comfortable, but if it has to be a fish tank, I would place in in another bigger fish tank. Friends of mine had a sudden leak without any visible reason with a 530 l fish tank. So, this happens.

If I would want to do this, first of all, I would get the msds and post it together with an accurate description of my process, to let others check, if there is anything I overlooked.

For the resin I would probably use a fish tank filter pump, since the liquid should not be corrosive. Nevertheless I would try to check the durability of the used materials.

Then I would vaporize the water using a fish tank heating element and crystallize the nitrite, filter off and recrystallize. A possibility here is to oversaturate the sodium cations with another sodium salt, sulfate might be a better choice, if this method were used, than chloride as I would not want to risk to have any chlorides in my nitride. 

Definately I would not want to have any poly-ols or at all any organic compounds left in my nitrite.

I do not see the need for oxidizing to nitrate, since the nitrite can be used as basematerial for many purpouses, can be stored as is safely and processed when and for whatever needed.

In the end I would test qualitatively for any possible contaminants.

I still think it is an inconsiderate idea, especially since you obviously do not have the knowledge, a proper setup and experience to do this and you do not know how to react if anything unexpected happens, but since the moderators have been very lenient with you, I share my ideas, too. My advice is still: Don't.

Counting the working time, materials (and waste, if you recrystallize with another salt), this will probably be quite expensive (and still only technical grade) nitrite.


----------



## butcher (Apr 4, 2015)

No way I would use this or try to convert it to a fertilizer.

Nitrites and nitrates in our water supply can be bad news for us all, it kills fish and Aquatic life, nitrite in our water with bacteria converts to nitrates which kill fish with brown blood disease, depleting the oxygen supply, it can cause blue baby syndrome in babies.

Molybdate (like chromium compounds) are used in the cooling systems to help prevent corrosion of metals like iron copper and aluminum, they can be part of a proprietary blend of the nitrate solution used for water treatment of closed loop cooling systems.
Molybdate Azole blends are often used, although the water soluble molybdate can be in other forms some blends use 200 to 300 PPM.

Although like many metals we need a little in our body to survive (like iron or copper) too much becomes a poison.
We would not want too much water soluble molybdate in our water supply.

These blends of chemicals used in industrial cooling systems and cooling towers, can use several chemicals added separately or as a chemical blend,like antifreeze glycols added to the cooling system as part of the blend or as a separate chemical to prevent freezing of the cooling system in winter.

These chemicals added to the different systems in an industrial plant, with boilers and water cooling systems, can be added as individual pure chemicals or proprietary blends of chemicals sold by the water treatment companies, supplying your chemicals used in the plant, like pure sodium nitrite can be added as a pure NaNO2, added to the cooling system by the engineer working at the plant, as well as the molybdenum, chromium, or 
ethylene glycol or some other type of antifreeze, or they can be a blend of chemicals, which is becoming more and more popular with chemical companies supplying chemicals these days, they can sell the watered down chemical blends at a higher profit, as most engineers nowadays have little clue to as what they are actually buying or adding to do the water treatment in the plant and are relying more on their chemical supplier (salesman) to suggest how to chemically treat the waters in the industrial plants...

I would not use a chemical blend of nitrate ( containing molybdate, chromium, antifreeze...) to make nitrates or nitric acid.

If you cannot use this ( chemical blend) in your cooling system, then you should dispose of it properly, at a proper chemical waste treatment facility...

If what you have is pure sodium nitrite (normally in powdered form, sometimes dissolved in water), then you can use it to convert to nitrates (sodium or potassium), or nitric acid for use in recovery or refining...


----------



## witekprytek (Apr 5, 2015)

Lou said:


> If you really want the Mo out, keep load it onto Purolite A172 or some other weak base resin. Can elute it off with a base, and recrystallize as a molybdate salt. There are some insoluble salts that can be made.


Good hint, thx. I'll check pricing, if not bad or can be reused later on for other purposes (unlikely) then I might go for it.

-------------------------------------------------------------------------------


Lou said:


> Nitrite can be oxidized to nitrate with peroxide, or electrolytically with a stainless or titanium anode/


Possible but unnecessary, got plenty of space and time, if anything I'll let _Nitrobacter_ do their work. Once Mo is out the bacteria should be fine with plentiful food source 

-------------------------------------------------------------------------------


solar_plasma said:


> I think plastic tub would be safer and more comfortable


It wouldn't outdoors unless plastic was UV stabilized or extra thick. Not likely to find tub made out of UV stabilized plastic and I don't have any extra thick walled tubs. Glass container is perfectly safe unless we have hailstorm with egg size ice balls 

-------------------------------------------------------------------------------


solar_plasma said:


> If I would want to do this, first of all, I would get the msds and post it together with an accurate description of my process, to let others check, if there is anything I overlooked.


Will get it after Easter. For now I am 99% positive its NaNO2 + Na2MoO4 in unknown concentration and with no additives.
Based on info from work mate who works with it on daily basis. To be confirmed.

-------------------------------------------------------------------------------


solar_plasma said:


> I do not see the need for oxidizing to nitrate, since the nitrite can be used as basematerial for many purpouses, can be stored as is safely and processed when and for whatever needed.


 Good point. Can't think of any use for now, but might just store it away. You never know ... 

-------------------------------------------------------------------------------


solar_plasma said:


> In the end I would test qualitatively for any possible contaminants.


 That will be in msds. Its brand new and sealed, so no after sale contamination possible.

-------------------------------------------------------------------------------


solar_plasma said:


> I still think it is an inconsiderate idea, especially since you obviously do not have the knowledge


 So he graduated incompetent chemist -> http://chemia.amu.edu.pl/en/main-pa...-members/prof.-zw.-dr-hab.-grzegorz-schroeder

-------------------------------------------------------------------------------


solar_plasma said:


> a proper setup and experience to do this and you do not know how to react if anything unexpected happens


 True, I do now own full blown lab stretched over few acres and wasn't doing this mixture for last 50 years day in day out. However doing chemistry as hobby since I was 10 (started with electrolysis of NaCl), several years of chemistry at Uni, electroplating for living for 8 years, doing precious metal recovery and refining for several years and having small plating workshop kitted out and running for few years might have given me fraction of *YOUR KNOWLEDGE AND EXPERIENCE* ...



Disposal of any chemical costs arm and a leg. Even if it is distilled water in industrial containers you will be charged hefty price.
If that stuff was a weird mixture, contained aromatics, chromium (VI) or anything what is *actually dangerous* I wouldn't even think of touching it.
The msds might prove it is weird mixture then obviously I'm not gonna get involved.
From what I know about this brand new sealed containers is that they contain water solution of 2 simple salts which are not dangerous if not used for bathing, making drinks or dumping in the drain or on veggie plot.

I mentioned I am not equipped to do quantitative analysis of Mo but can do qualitative.
I'll submerge steel bar and test for Mo after few days.
If potassium ethyl xanthate (already ordered) test shows no pink then waht's left is just NaNO2 left.
Might try weight steel before and after, but complexity of Mo reactions with Fe oxides might be too much for reliable results.


In case of high concentration of Mo ideally I would like to find a way to drop some Mo salt or oxide. If not viable then steel bar or the resin Lou mentioned might be the way to go.


----------



## solar_plasma (Apr 5, 2015)

> So he graduated incompetent chemist -> http://chemia.amu.edu.pl/en/main-page/Faculty-of-Chemistry/faculty-members/prof.-zw.-dr-hab.-grzegorz-schroeder



That's you? And hey, when you first wrote about precipitating gold by lots of SnCl2, you wonder why I got the impression, that you have no clue? In an online forum everybody is what he writes, at least in the recognition of the reader of an actual post.

Further you could have 10 doctors and still having no clue. But at least if everything you wrote is true, you have convinced me, that you will not likely cause an environmental disaster. :lol:



> Casserole dish often recommended here for sulphuric cell is MUCH more likely to break than properly made fish tank.



The casserole dish is not glued with silicone. It is extremely thick in relation to volume. It is not simple glass, but glass ceramic. Only best quality is chosen. We are always prepared for the risk of any vessels could break or boil over, so there is an adequate vessel placed beneath, that would catch the whole volume of liquid used (at least this is the teaching).


----------



## witekprytek (Apr 5, 2015)

Nope, its not me, I am a bit younger 
He is the one who signed my graduation papers.
Very tough task to make him happy, but that's how it supposed to be.

I explained I was thinking of SnCl2 in other context that's why I wrote it down instead of SMB.

Fish tank style vessel is not meant to be heated from outside and to higher temperatures. I would say 40-50 DegC would be the limit I am comfortable with.
Sun would do the work over time - expense and hassle free. I am not in a hurry.
Silicone is very chemically resistant, save hydroxides in higher concentrations and hydrofluoric acid/salts. Even acrylic is not so bad.
In this application either one is an overkill really.

Have few self made "vaporizers", but all are glass cabinets in which you place beakers with your solution.
Work like a charm.
Two of them can nearly boil water in beakers on hot summer day 
I might actually glue new "vaporizer" with drain and proper vented lid. Not double glazed and insulated, but something what looks just like fish tank with lid.

Got plenty of glass, sealant, tools and really enjoy working with it, so its not work but pleasure.
Once it gets warmer I'll be outside workshop all day long 
I wouldn't glue a tank indoors, not worth the dent in health .


----------



## solar_plasma (Apr 5, 2015)

> That will be in msds. Its brand new and sealed, so no after sale contamination possible.



This is not what I meant. The msds will tell you what contaminants MIGHT be left AFTER purification. Those ARE to test qualitatively AFTER purification. If not, you don't know, if you have removed them. Also you need to know your test, sensitivity and cross-sensitivity, can it be used in the given situation and so on. If you have studied chemistry, then you know the difference between believing and knowing. You also need the msds in order to know, WHAT to test for, since you can't test for 1000 (even then you would need to know which 1000) possible chemicals qualitatively. And most of them you wouldn't even be able to test for unless your an analytical chemist or similar with a million$ equipped lab.


----------



## Lou (Apr 6, 2015)

Solar_plasma, 

Appreciate the focus on safety and your devil's advocacy but goodness, let the man experiment in peace. I think he knows enough at this point to be ok with it! He's seen all manner of suggestions.


----------



## solar_plasma (Apr 6, 2015)

Yap, of course.

I guess, what made me wrought-up was, that I thougt to read a light-minded undertone in his lines, which I just can't stand when people handle several hundred litres of chemicals without making clear that they do it in a professional environment. As there has been written elsewhere on the forum: new process, start with small setups. But it's not my affair.


----------



## goldsilverpro (Apr 6, 2015)

I'm a big believer in starting every project with a beaker size sample. I've been doing this stuff almost daily since 1966 and I still run a small test lot on almost everything substantial that I want to process.


----------



## Lou (Apr 6, 2015)

goldsilverpro said:


> I'm a big believer in starting every project with a beaker size sample. I've been doing this stuff almost daily since 1966 and I still run a small test lot on almost everything substantial that I want to process.




Voice of reason. Pennyweight of prevention is worth a pound of cure!


----------

