DMG + Methanol = explosive compounds ?

OK – I have a batch of silver nitrate that contains about 40 oz of silver that is testing positive for Pd with DMG (DMG dissolved by the old water boil method)

I burned out the 3.3 V 28 amp computer power supply I was using to run my Ag cell & have tried some lower amperage supplies but they only run a short time before burning up & now I am out of working power supplies. (so silver cell is not an option for me right now)

So I was thinking of dropping the Pd from the Ag nitrate using DMG then going with AgCL to recover my silver --- I read GSPs thread on DMG (under Chemicals) & was going to use irons method of dissolving the DMG with methanol (HEET in the yellow bottle) --- but then I got to thinking --- I know that alcohol added to acidic metal salt solutions can & will form explosive compounds. Example – mercury + nitric acid + alcohol = mercury fulminate --- so I did a Wiki search & came up with this

Mercury(II) fulminate is prepared by dissolving mercury in nitric acid and adding ethanol to the solution. It was first prepared by Edward Charles Howard in 1800.[1]
Silver fulminate can be prepared in a similar way, but this salt is even more unstable than mercury fulminate; it can even explode under water.
This compound (silver fulminate) can be prepared by the reaction of concentrated nitric acid with silver metal and ethanol, under careful control of the reaction conditions, to avoid explosion. Only very tiny amounts of silver fulminate should be prepared at once, as even the weight of the crystals can cause them to self-detonate.
Silver fulminate can be prepared unintentionally, when an acidic solution of silver nitrate comes in contact with alcohol. This is a hazard in the chemical silvering of mirrors.

So you can see my concern. My question is – how much of a hazard is there in dissolving DMG with methanol & then using it as a precip agent &/or even in testing.

In the above mentioned thread Harold suggested using just enough methanol to dissolve the DMG & then diluting with water to prevent evaporation – would this work to make a safe DMG precip reagent. Another words if you use “just” enough methonal to dissolve the DMG & then dilute with water – does the DMG cancal out the effect of the methanol to form a fulminate.

Just looking for a way around the old boil in water method – if possible --- thoughts, coments or suggestions welcome

Kurt

This is just an idea but what if I presume that your silver nitrate will be warm, not boiling just warm enough, you can dissolve a lot of dmg in just water if you heat that water.
Warm (again not boiling) water can dissolve and hold a lot of dmg. Dmg will drop out of water when it will cool to room temperature.

One thing to consider is to convert the silver to silver chloride, using HCl, then rinse it well, removing the palladium, which is still in solution. That could be accomplished with tap water. The real negative of this process (one I used a few times) is that it's pretty difficult to rinse out all of the palladium, but it can be reduced substantially. In any case, your silver would still most likely still need to be parted in a silver cell. You also end up with a large volume of solution which may require evaporation in order to recover the contained palladium. It might be well worth the effort considering the possibility of an explosion.

I would avoid even the slightest amount of alcohol were I in your shoes. From the information posted, it's clear that the compound is exceedingly unstable. Even if the resulting explosion was small, the thoughts of acidic solutions being tossed about gives me pause. I can see it all now----a face covered with silver nitrate, and the loss of eye sight, to say nothing of the potential for being cut to ribbons by flying glass.

Harold

Cover the DMG powder with distilled water and add NaOH prills slowly while mixing it. Keep at it until the DMG dissolve.
Add this coustic DMG solution to your silver nitrate while stirring, at first you will see silver oxide forms where the DMG drops hits the silver solution and it might show pink at the extremities, it will quickly redissolve upon stirring.

let it sit for 24-48 hours, if there's Pd, it will be at the bottom by then.

As Harold said, it is very hard to clean AgCl. This is why i have always favored to use DMG while the silver is still in solution.

edit: i have coverd this subject here

Here's a method for cleaning Pd from silver solutions posted by freechemist:

Removing Palladium from Silver Solutions

Steve

Thanks guys - This is what makes this forum so awesome! Time to head to the lab & give it a go. This has been a real difficult batch of Ag which I will try to explain later. Here is a pic of some of the Ag nitrate & the DMG test.

Harold - I understand the problem with preciping the AgCL first which is why I was asking about dissolving the DMG so I could precip the Pd first.

Also I agree about the concern of introducing alcohol to an acidic metal salt solution as I have been aware of Hg fulminate for many years now from my gold mining day 30 years ago when I lived in Northern California.

In fact it raised my eye brow when I first read about using alcohol to prepare DMG in that thread posted by GSP - but then I thought "they must know something I don't" - so I went & bought a bottle of HEET - but then I thought - no kurt - better throw it out on the forum first & see what comes back.

To be honest i was supprized it didn't come up on that thread - I would have brought it up but just read the thread a couple days ago. Maybe still need to post something there - I think it poses a danger even as a testing solution.

Kurt
edit to ad pics

kurt said:

..... I think it poses a danger even as a testing solution.

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I do not think so. If you test you usually use few ml of tested solution and few drops of testing solution. How dangerous a milligram of TNT might be?

patnor1011 said:

How dangerous a milligram of TNT might be?

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About as dangerous as 4.6 appels falling together from a tree :mrgreen:

As far as burning out your power supplies. The possible reason is because you have too large of an anode and it is causing too uch of a load on the power supply. Maybe make your anodes smaller and this might solve your problem.

Patnor/Sam – I am willing to agree that using alcohol as a DMG solvent for testing poses “small” problem for the more experienced refiner that is only going to use a drop or 2 to test a couple ml of Ag nitrate solution for PD (or as stated “About as dangerous as 4.6 appels falling together from a tree”) so I am not trying to be argumentive here.

However – that said – I have a great deal of experience working with all kinds of explosives. I spent 20 year working in mining, logging & road building operations in Northern California & we were blowing things up on a regular bases. I have spent years doing my own ammo reloading – have made my own black powder gun powder - & yes I have worked with mercury fulminate to make my own percussion caps for black powder shooting (I didn’t make the Hg fulminate, just helped drop it in the bottom of the caps to make them)

Fulminate & TNT are two different things. TNT is very stable - fulminate is not. Most explosives are not shock sensitive & in fact many of them wont even explode when you put a match to them – they will only burn very hot & rapid – they only “explode” when the burn occurs in tight confinement (due to rapid pressure build up – or – if there own burn rate is accelerated --- that’s where fulminate comes into play & why it is used to make blasting caps, percussion caps & primers. It (fulminate) accelerates the burn rate of more stable explosives to “make” them explode instead of just burn fast.

It only takes 1 ml gram of Hg fulminate to make a black powder gun percussion cap – Ag fulminate is less stable then Hg fulminate.

Here is the problem I see with giving instruction to use alcohol to make DMG test solution (without a warning to go with it) --- I can see the less experienced (or inexperienced) refiner taking a couple ml of Ag nitrate – adding a drop or 2 of alcohol prep DMG – not get the result he is hoping for – then thinking maybe its not enough. So he ad’s more Ag nitrate & more DMG – the next thing you know – he has created a potential minor mishap. --- And worse yet – he decides to use it to precip a liter or 2 of Ag nitrate.

In fact – that is exactly what I “almost” did! --- I went & bought the yellow bottle of HEET to do it. --- It was only my prior knowledge with Hg fulminate that made me question the possibility of making “other” fulminate that made me research it – that prevented a potential “major” mishap in my lab.

My personal opinion is (for safety) The thread by GSP needs a warning added (&/or any thread instructing alcohol DMG prep) but I will leave that to others to decide being as how I am the “About as dangerous as 4.6 appels falling together from a tree” guy

By the way Sam – thanks for the DMG NaOH instruction – it worked great & is much better then the old water boil method.

Kurt

Barren Realms 007 said:

As far as burning out your power supplies. The possible reason is because you have too large of an anode and it is causing too uch of a load on the power supply. Maybe make your anodes smaller and this might solve your problem.

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Barren - thanks for the reply. I was running a 3.3 VDC 28 amp supply 1 liter cell 5 oz anode & cathode a little more then 2 times anode size. I tried going to a 2 liter cell to get more distance between anode & cathode so I wouldn't need to attend it so much to keep the crystle knocked down.

I assume its the greater distance between anode & cathode causing more resistance causing the supplies to heat up & burn out after about 30 - 40 minutes of running.

Granger has a variable programable 3 - 15 VDC 0 - 40 amp power supply listed in there cataloge for $460

I want to get a hold of the manufacture & talk to them about their oppinon of using it for a cell &/or how large a cell it might be able to run.

Hi Kurt

Please know, i wasn't mucking you. Sorry if it seemd that way.

I think you have a good point as every fast moving objects (expanding gasses included) is a force that should be reckon with.

I have done a little search on the web about what would 1 mg of TNT resemble to, and found it to equal about 4.6 joule or 4.6 nm.
Then i have searched, what would 4.6 nm would resemble in real life and found a nice website with a short list (which now seems that i can't locate anymore), it had a long explenation about how the masurments works and more... they put together a table, under the 1 newton meter it said equal to 1 apple falling from a tree...
Not very scientific, i know. I only did it to give my self some proportion and i really liked the falling apples description

Now, i don't know how exact this information really is, but i do know this, no matter how little energy is packed in a material, when confined or even partially confined it may cause serious damage.
So yes, i do agree with your point and think a warning should be accompanied to the use of methanol+DMG.

p.s. - Glad it eventually worked out and you were able to test your solution.

kurt said:

I assume its the greater distance between anode & cathode causing more resistance causing the supplies to heat up & burn out after about 30 - 40 minutes of running.

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It doesn't work that way. Higher resistance may increase temperature in the solution, but should drop temperature in the power supply, as higher resistance leads to lower amperage at any given voltage. However, I'm of the opinion that you didn't alter the resistance of the circuit by much by spacing the anode/cathode a greater distance. The electrolyte is quite conductive.

What may work for you is to parallel two or more power supplies, so each is producing a proportionate amount of the required amperage. That could be an inexpensive way for you to continue refining, assuming you have access to a couple more power supplies. If you parallel enough of them, they'd run quite cool. Two should drop the temperature considerably.

Harold

I believe most Computer PSU's have different buses inside them, and you shouldn't have any issues running separate ones (both are in 1 psu) in the same solution, I would think. May have to be a new PSU though...