Foil removal/collection cell

[Topher_osAUrus]

P.S. very much enjoying Hoke's wonderful and practical book !

She wrote more than one book, links to downloading "Testing Precious Metals" is at the bottom of
http://goldrefiningwiki.com/mediawiki/index.php/Hoke

Göran

A little birdy told me, that one of these days we will be getting a new and improved scanned copy of her testing book..

..okay, it wasn't really a bird, it was Dave.

But, that book is great in its own right, as it contains a good bit of useful information that her refining book doesnt have.
Like the tolerance laws on karat alloys, discerning iridio platinum and ruthenioplat (i think thats how she "termed" them)

And how to price gold when buying, etc..
Except she uses dwt and a 35$/ozt price point..

But still... Great book!... I think I'm in love with Mrs Hoke :wink:

 

[aga]

I'd like to see if if your kit would work as well with plated pins!

Very poorly as it turns out.

Although this idea is fun to try, it's pretty much junk compared to the more accepted and 'normal' routes of stripping, even at the hobby level.

Having had a glimpse of some shiny gold, there is no option now but to collect it all and proceed to the really fun part : my first refining, melt and ... maybe solid gold !
(maybe just more toxic waste to render safe)

Made some Stannous Chloride test solution, as per lazersteve's post here :-
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=41&t=5271#p45030

The remaining connectors are dissolving in a kind of AR solution.
This is happening in a fume hood so that the NOx fumes are safely handled.
Never knew the acids did not have to be highly concentrated for it to work.

A few drops of the SC solution on some filter paper dipped in the dissolving pot goes almost black immediately, so the stannous chloride test must be very sensitive.

The connectors looked hard to break up easily/effectively and have lots of small holes to trap things in, hence going straight to AR as it seemed simpler (at least to separate the plastic/metals).

This will certainly make a Nasty mess of a liquid with a tiny bit of chloroauric acid in it.

After this first crazed (yet fun) rush to get started, following a well-known and documented procedure will certainly be the best way to go.

For this first try, i'd really like to see first hand how a completely botched 'refining' turns out, particularly the appearance and colours of solutions/muds/metal blobs. Botched it will certainly be.

A second or third Proper refining will definitely be needed, but if i didn't like doing this kind of thing, i wouldn't be here !

 

[g_axelsson]

Stannous is really sensitive and can easily detect sub gram per liter solutions of gold. SO₂ will give a false positive, but after a while you start to recognize the signs.

Be aware that some plastics break down in AR and creates a sticky mess, trapping the gold.

Göran

 

[aga]

Can't believe i messed about with salt 'n' vinegar.

A couple of hours in nitric works much better to lift foils from fingers.

 

[FrugalRefiner]

Is that a disposable plastic drinking cup you're running a nitric reaction in?

Dave

 

[aga]

Yep. [stt]PET plastic works fine for this kind of thing[/stt].
Edited: the cups turned out to be PP not PET.

HDPE would last a lot longer, probably.

Edit:
I have 3 1L versions of these laden with anywhere between 3 and 6g of gold between them, as i have no Large beakers yet.

For a bit of security they were placed inside another 1L cup.

So far so good (nothing leaked).

Edit days later: strikethrough incorrect PET statement.

 

[FrugalRefiner]

Yep. PET plastic works fine for this kind of thing.

No, it does not! Readers, do not rely on this advice!

First, PET does not stand up to nitric acid. You may have gotten lucky so far, but PET will soften and collapse.

Second, using things like beverage glasses for refining is a bad practice. All it takes is one careless moment to pick up a glass and take a drink.

Dave

 

[aga]

Personally i feel the rebuke unfounded, and i'm not offering advice, just saying/showing what i did.

Polyethylene plastics are impervious to water, which makes ionic reactions (such as happen in AR) very very slow indeed.

Concentrated Sulphuric, Nitric and Hydrochloric acids are routinely stored and shipped in HDPE (high density polyethylene) as is concentrated bleach (sodium hypochlorite).

This is because it reacts so very very slowly, and also retains it's mechanical strength for a very long time,. despite chemical attack and UV effects.

In any event, the Volume of solution i made required more than the available borosilicate 250ml beakers i have, so needs must.

The biggest downside to polyethylene versus 3.3 boro glass is that you can't heat it on a hotplate.
Heating it in a microwave oven works fine (that's what i did) although the oven will get corroded by the fumes.

One Bonus is that polyethylene will never shatter.

 

[jimdoc]

Reactions heat on their own.

 

[aga]

First, PET does not stand up to nitric acid. You may have gotten lucky so far, but PET will soften and collapse.

This is not a difficult experiment, yet you offer no data to support that statement.

I'm off on holiday next week, so tomorrow i will fill some cups with nitric, photograph them, then go and enjoy myself, come back, and photograph it all again a week later.

If i can find the rig, i'll do a tensile strength test on the 'before' and 'after' cups.

That's how Science works - just measure things before, test it, measure after, work out the difference(s).

Reactions heat on their own.

Some do, some don't.

If you're ever stuck with Hot beer on a warm day, stick it in a bucket of hot water, add ammonium nitrate, wait a few minutes then enjoy cold beer.

 

[FrugalRefiner]

First, PET does not stand up to nitric acid. You may have gotten lucky so far, but PET will soften and collapse.

This is not a difficult experiment, yet you offer no data to support that statement.

Instead of experimenting, why don't you try a little research. I'll make it easy by attaching a chemical resistance chart. There are others scattered all over the forum and the internet.

HDPE is very different than PET.

Putting refining solutions in a drinking glass is foolish.

While you may not have advised anyone to do what you did, you showed a picture, then posted that it's just fine. I don't want anyone else getting hurt because they read this thread some day in the future and followed your example, so I think the rebuke is totally justified. If you feel I'm out of line, you're welcome to take up your concerns with another moderator or Noxx.

Dave

 

[aga]

Point taken : Safety First.

Appologies if my reply caused any offence - i respect your view as a Mod and would never challenge it via the back-door so to speak.

The manufacturer's chart doesn't say what '"resistant" actually means, and has the disclaimer "dependant on time, concentration, and temperature".

Certainly PET will leak and fall to bits if heated to about 240 C.

I'll do the simple experiments and find out exactly how resistant it is to HNO₃ etc at common concentrations myself.

So far it has worked OK for me, although that is an un-scientific and subjective view.

 

[snoman701]

HDPE is polyethylene
PET is polyester (polyethylene teraphthalate)

The latter is readily, albeit slow, hydrolized by acidic (and moreso) basic solutions.

The prior, not so much.

Experiments are unnecessary, they've already been done and published.

Organic compounds and concentrated acids should really should be by the book, especially if you dehydrate your waste products.

 

[aga]

Experiments are unnecessary, they've already been done and published.

Would you happen to have a link to any published research on this ?

I've only found mechanical data, and chemical resistance descriptions such as 'Poor' and 'Good-Fair' - no actual facts.

 

[snoman701]

Just google it, polyester hydrolysis

Further though, appropriate labware is sturdy. You can get away with kitchenware that may not be completely resistant to acids, but it has to be sturdy.

 

[kurtak]

aga

Granted - a lot of the chems we use (acids included) come in plastic containers - but those containers are intended for ambient temp storage !!!

When you start using plastic containers for "reactions" you are introducing a whole other set of circumstances - heat (from the reaction) being one as well as oxidation being another --- heat is going to cause the plastic to become soft (period) which can/will lead to potential collapse &/or rupture --- oxidation can/will lead to potential of actual chemical break down of the plastic & again collapse or rupture

I understand getting set up with "real" lab ware (beakers, flasks etc.) is an expensive investment for the beginner - BUT - you can use a variety of "old" kitchen ware that will work perfectly fine for the beginner & you can get it CHEAP from second hand stores &/or yard sales

old coffee pots are nothing but a beaker - they are just shaped different :!:

Proceram can be used & it comes in many sizes & shapes including coffee pots :arrow: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=85&t=22043#p229317

Also - they make a glass cooking ware called VISIONWARE - I buy all I can get my hands on (CHEAP) when I see it second hand stores &/or at yard sales --- like pyroceram it will hold up to the heat of incineration

:arrow: https://www.amazon.com/s/?ie=UTF8&keywords=visionware+cookware&tag=mh0b-20&index=aps&hvadid=4967918444&hvqmt=e&hvbmt=be&hvdev=c&ref=pd_sl_5v0w119ae3_e

As far as reaction of nitric "only" - non-magnetic SS (Stainless Steel) works just fine --- I use 5 gallon SS pots for dissolving my silver all the time --- SS just wont hold up if chlorides are involved (like AR) but SS is perfectly fine for nitric "only"

There are MANY better CHEAP options of better stuff out there to get you started RIGHT in this rather then going down a path that amounts to nothing more then a DISASTER WAITING TO HAPPEN :!: :!: :!:

Consider your self LUCKY so far :!: :!: :!:

Kurt

 

[g_axelsson]

Experiments are unnecessary, they've already been done and published.

Would you happen to have a link to any published research on this ?

I've only found mechanical data, and chemical resistance descriptions such as 'Poor' and 'Good-Fair' - no actual facts.

https://www.google.se/search?q=pet+nitric+acid+compatibility&ie=utf-8&oe=utf-8&client=firefox-b&gfe_rd=cr&ei=MLvCWJzNI-yO8QeE2bHgBg

According to the first hit : http://www.plasticseurope.org/Documents/Document/20100705182216-050303GeneralChemicalResistanceofPET-20050303-003-EN-v1.pdf

Nitric acid <10% = PET exhibits good resistance to attack; chances of successful testing are very good.
Nitric acid 10-20% = PET has marginal resistance to attack; significant chance of container failure.
Nitric acid >20% = PET exhibits poor resistance to attack; should not be considered for this application.

Recommendations from manufacturers is also facts. Not everything have to be published research.

Göran

 

[aga]

Thanks very much for the link.

At the very top they clearly say (about the information):-
"... should not be construed as implying a legal guarantee for specific properties of the products or for their suitability for a particular application"

Unfortunately they do not state the actual application (e.g. rotor vanes, bulk container, reaction vessel) nor do they say what a 'significant chance' means, so at best it is a guideline, not fact.

This list has 2 ratings for each concentration, one at 20C the other at 50C, and explain some of their ratings :-
http://sevierlab.vet.cornell.edu/resources/Chemical-Resistance-Chart-Detail.pdf

Again there is no application-specific detail.

The experiments are very easy, so i'll establish the facts about the use of PET containers with the chemicals/materials used in e-scrap gold recovery myself.

Edit:
Oops. Setting up for the experiment i noticed the number in the recycling symbol was a 5 not a 1.

These are poly proplylene, which is much more resistant to acids and bases than PET.

Sorry for not checking that earlier

 

[kurtak]

The experiments are very easy, so i'll establish the facts about the use of PET containers with the chemicals/materials used in e-scrap gold recovery myself.

aga

I am not sure what you are trying to prove here (other then you are some sort of self proclaimed master mind) but it has already been stated by a number of us that have been members of this forum for "many" years (compared to your 2 - 3 month) AND that have been doing this MUCH longer then you & as well on a MUCH larger scale then you --- that using small thin walled plastic containers as reaction vessels - is NOT advisable &/or acceptable & should therefore be considered BAD advice NOT TO BE FOLLOWED

Though you may get away with it on a small "experimental" level --- It is a DISASTER WAITING TO HAPPEN

aga

Having read other things posted by you - I see you like to be argumentative &/or defiant expressing your self as someone with a great deal of experience &/or knowledge when in fact it is clear you still have a GREAT deal to learn - one of which is that this BIG chip you have on your shoulder does NOT serve you well :!:

In case you are not getting the picture aga - you have "stormed" into this house with little or no experience as if you own the place & are someone to recon with even to the point of being confrontational with "long standing" members that have MANY more years experience then you & experience on large scales you have yet to even dream of :!:

You seem to a smart individual aga capable of learning & doing this - but as a word of good advise I suggest you get rid of this big chip you carry on your shoulder --- or you may find your welcome here short lived

Kurt

 

[aga]

Thank you for taking the time to offer the detailed advice Kurt, and for defending this excellent forum.

1. I am not trying to prove anything to anyone else.

2. My experience at PM recovery/refining is still basically Zero (no metallic gold yet).

3. The combined Centuries of actual experience that the members here posess overshadows anything i might even imagine i know.

4. When someone says 'unsuitable' or 'gets warm' i automatically want to know 'why' as in what happens, and 'how warm' as in degrees C.

Re-reading some things i've said here, i agree with you about the chip-on-shoulder thing and will go and work out why that is.

Until i've completed the recover/refine/melt process i'll not post anything else.

Without even being able to show my first gold button, i don't really have any right or reason to be posting anything about any part of the process. Same as for any noob on this forum.

Apologies for any offences caused.

adrian.