# Depopulating Cell Phone Boards .. what is the best method ?



## ahmadbayoumi (May 7, 2016)

Dears,

I will buy about 25k of clean (boards with only ICs and without metallic parts) cell phone boards and will start processing them next week.

I have one important question her about removing or depopulating the components on these broads.

I know that there are many ways to do that:

1- Using heat gun but this way will consume a lot of time

2- Using hot sand bath but this also will take some time and will mix the depopulated components with sand

3- Using HCL or diluted HCL.

For me the easiest way is using HCL/diluted HCL as it will not cost me so much and it will be very quick but seems that the only concern her will be if HCL/diluted HCL will be able to dissolve some of the gold in these BCPs or not.

Some say yes and some say no so need your experience here and there is any other way that is more effective and efficient for processing large quantities


----------



## Topher_osAUrus (May 7, 2016)

Sand bath is your best bet.

Heat gun is very time and resource consuming.

HCl will most likely give you more problems than you would like.

Cell phones processed via wet method are very time consuming, but can be rewarding. Like all things in this field, study and patience are key.

There are other ways to skin this cat, im sure.

I believe most who have tried will agree sand bath, or smelting like the big-dogs do. But, to each their own.

Good.luck to you sir.

Topher


----------



## ahmadbayoumi (May 7, 2016)

Thanks Topher 

But what is the issue in using HCL .. does it affect the gold in the boards ?

I mean why you said that HCL would give more problems than I would like ?

The boards are free of any steal or nay other metal .. Only ICs and capacitors

Here, I'm just trying to find out an efficient way to deal with large quantities .. by other mean, a commercial way for depopulating cell phone boards what will do the required task with minimum resources and maximum output


----------



## ahmadbayoumi (May 9, 2016)

Dears, Still need you help and advise here

Is there any side effect from using HCL to depopulate cell phone boards rather than using to too much acid ?

PLS advise your experience ...


----------



## Topher_osAUrus (May 9, 2016)

ahmadbayoumi said:


> Dears, Still need you help and advise here
> 
> Is there any side effect from using HCL to depopulate cell phone boards rather than using to too much acid ?
> 
> PLS advise your experience ...



Theres a plethora or advice given for you dilemma all over the forums 200,000++ posts.

Its too wasteful of chemicals... Your waste will be a pain to deal with. 

You said they are already mainly depopulated though right?
How about some pictures?


----------



## ahmadbayoumi (May 9, 2016)

Thanks again Topher  

I know that there was 100s of post about this topic but really couldn't reach a conclusion about using HCL to depopulate cell phone broads

Some say it's OK and no problem is using HCL and some say NO as HCL will affect and may dissolve and waste some of the gold in these boards .. so I'm really confused

I have no issue dealing with waste HCL and even I have no issue in cost of the acid so my only concern here would be the effect of using HCL to depopulate these boards on the whole process or the on the yields of the process .. 

they are only depopulated from any metallic parts .. but ICs and all other components are still there

I don't have pics now but will share the pics once I got them.

So does depopulating boards with HCL affects the overall yield or have any other issue or side effect on the whole process ?


----------



## Topher_osAUrus (May 9, 2016)

Okay, so i have had my coffee and cigarette and I'm thinking much more clearly now. So-

You say the metal parts have been removed?
So its just the smd's and flatpacks on them?
Or just the big bulky iron and stuff thats left?

-either way, treating with HCl is wasteful
You will run into all sorts of chloride salts that would be best left alone/away from one another... Cadmiun chloride, silver chloride, lead chloride, and thats just the tip of the iceberg.

Do me a favor, go to google.com in the search bar type this EXACTLY:
Goldrefiningforum hcl depopulation

Read the first page or ten of the results... The professionals here have explained it many many times before in a much more elegant way than my simpleton mind can elaborate on.

I would think, depending on HOW they were depopulated previously (which, WHY would they only halfway depopulate them?) it would be much better in the end for you to heat gun or sandbath them then separate and categorize the smds and bgas and process them accordingly.

Everything on the forum is a tried and true method that these fine gentlemen have perfected over the years. I myself dont have the hubris to think that i could better the methods given as guidelines here.

But, i suppose innovation does come around inevitably.
The only issue I see with that, is that HCl depopulation, isnt an innovation, but a means to cut corners....that of which will surely make you pay in the end.

If you are just starting to refine, and you are kicking off your journey with 25kg of cell boards, i would tread lightly, and do my due diligence, and study.
We dont want you to be discouraged, or fail, we want you to thrive. That will not be possible without patience and study.

Please dont think this reply was meant to discourage or belittle, but think of it as a preemptive warning, that the ice you are walking on is thin, and should it break, it would be very very counterproductive as far as you getting, recovering, and refining, the little bit of gold that cell boards contain.

-topher

In regards to your reply-

HCl will never, ever, dissolve gold--(only exception being, when doing harolds wash procedure, and you accidentally leave the gold being cleaned on the hotplate with HCl overnight)

Gold CAN however, get lost, or trapped, by the chloride salts that you would undoubtedly be producing when depopulating the boards itself. Silverchloride, lead chloride can be a pain to get washed completely free of tiny little flakes of gold.

So, HCl wont make you lose the gold, the byproduct metal salts you are creating with the HCl WILL make you lose some gold... How much? I dont know exactly, some? Alot? A little? Perspective and point of view play the part in that answer, while, to me *any* gold lost is alot and too much, but to some, they care not about .004g of gold.. 

Best of luck to you in your endeavour.

Please keep us posted on your progress, as we all enjoy reading of one another's refining adventures

-topher


----------



## ahmadbayoumi (May 9, 2016)

Many thanks Topher  

You explained this perfectly .. and Yes, I do care about every 0.01g of my gold ..

Yes, it's time consuming but it worth rather than losing gold

You know, I'm just thinking about splitting the 25Ks boards into tow patches one (5Ks) will go in HCL and the other 20ks will go in sand bath.

This is for seek of experiment and to do the compromise

Sure will post and share my experiment here


----------



## FrugalRefiner (May 9, 2016)

Topher_osAUrus said:


> HCl will never, ever, dissolve gold--(only exception being, when doing harolds wash procedure, and you accidentally leave the gold being cleaned on the hotplate with HCl overnight)


Well... HCl, alone, will not dissolve gold. But HCl and an oxidizer will. HCl, if left open to atmosphere, will absorb enough oxygen to dissolve gold. Not a lot, but a little.

Dave


----------



## Topher_osAUrus (May 9, 2016)

FrugalRefiner said:


> Topher_osAUrus said:
> 
> 
> > HCl will never, ever, dissolve gold--(only exception being, when doing harolds wash procedure, and you accidentally leave the gold being cleaned on the hotplate with HCl overnight)
> ...



So, HCl + O2 from atmosphere is enough to dissolve a.miniscule amount of gold?

Or

Is it the NO2 in the atmosphere that is creating nitrosyl chloride?

I knew that HCl + time (atmosphere) will dissolve copper, it may take a week or 2 for it to oxidize it to copper chloride, but, is heat and atmosphere a determining factor in the gold dissolution as well?

Or, does regular climate temperatures (around 40 c max) not create a high enough temp to aid the little bit of oxidation that may occur with gold in HCl?

And how much might be a little?

I have about 50 more questions to ask, Dave...but, ill leave it to these for now :mrgreen:


----------



## upcyclist (May 10, 2016)

It's just like the AP process--the 'P' is the peroxide you add in the beginning to kickstart the oxidization reaction, but you can also just leave it out until your HCl absorbs enough oxygen from the environment (or from copper oxide on the surface of the metal). Sure, you might be waiting a while, but it will happen. That's why some like to refer to the process as 'copper leach' instead of 'AP'--it works with or without peroxide.

As Dave said, HCl alone will not dissolve gold, but HCl with the help of an oxidizer can and will dissolve gold. That includes nitric acid, sodium nitrate, bleach, peroxide, and well, plain old oxygen


----------



## Topher_osAUrus (May 10, 2016)

upcyclist said:


> It's just like the AP process--the 'P' is the peroxide you add in the beginning to kickstart the oxidization reaction, but you can also just leave it out until your HCl absorbs enough oxygen from the environment (or from copper oxide on the surface of the metal). Sure, you might be waiting a while, but it will happen. That's why some like to refer to the process as 'copper leach' instead of 'AP'--it works with or without peroxide.
> 
> As Dave said, HCl alone will not dissolve gold, but HCl with the help of an oxidizer can and will dissolve gold. That includes nitric acid, sodium nitrate, bleach, peroxide, and well, plain old oxygen




That answers my question-Thank you!

I knew it was the O2 in the atmosphere that lead to the initialization of the copper II chloride leach, but since its the NOx that creates nitrosyl chloride when we make AR, I was curious if it was just the oxygen, or Nitrogen in the air we breathe...or any combination there of.. And, I was a tad bit curious as to how much would dissolve... say I had a chunk of 1 troy ounce of gold in a beaker with 1L of HCl, would it dissolve .1 gram after a year? or 10 grams? What if it was 1 troy ounce of precipitated gold?...not that I am going to test that...It's more of a satisfaction of curiosity more than anything.. I like to be a know it all, but to be that, I have to know it all... damn those catch-22's
 
Thanks upcyclist.

Your answer has lead me to another 50 questions lol. I guess I just might have to throw 10 grams in some HCl, and find out first hand....as I have a feeling, location, air polution, temperature, and 10000 other variables will determine the outcome

-topher, the-inquisitive


----------



## UncleBenBen (May 10, 2016)

I don't know if there would be much chance of solid chunk of gold dissolving at all in just HCl. It would be interesting to try. Maybe a small BB in just HCl, and another in HCl with aeration, and let them sit a few months and see what happens.

Let us know what your findings are with that Topher! LOL!  Just messing with you! :lol: 

Though, thank God for stannous chloride! I have managed to put gold powder back in solution with just HCl washes 3 or 4 times so far. One of the times it wasn't even heated. (Before I had read about Lou's cold washes) It was after a 2nd refine, several water washes, then on the 2nd HCl wash it was getting late. I poured in enough acid to cover the powder, put a watch glass on it and went to bed. By the next evening after work I had about a gram back in solution.

What ever the reason(s) may be, it made the lesson even more obvious to me that it always pays to test, test, test!


----------



## upcyclist (May 10, 2016)

UncleBenBen said:


> Though, thank God for stannous chloride! I have managed to put gold powder back in solution with just HCl washes 3 or 4 times so far. One of the times it wasn't even heated. (Before I had read about Lou's cold washes) It was after a 2nd refine, several water washes, then on the 2nd HCl wash it was getting late. I poured in enough acid to cover the powder, put a watch glass on it and went to bed. By the next evening after work I had about a gram back in solution.
> 
> What ever the reason(s) may be, it made the lesson even more obvious to me that it always pays to test, test, test!


Hahaha, that's also why often times I run waste through the stockpot, even when I think "there's no way there's any PMs in there..." :wink:


----------



## Topher_osAUrus (May 11, 2016)

upcyclist said:


> UncleBenBen said:
> 
> 
> > Though, thank God for stannous chloride! I have managed to put gold powder back in solution with just HCl washes 3 or 4 times so far. One of the times it wasn't even heated. (Before I had read about Lou's cold washes) It was after a 2nd refine, several water washes, then on the 2nd HCl wash it was getting late. I poured in enough acid to cover the powder, put a watch glass on it and went to bed. By the next evening after work I had about a gram back in solution.
> ...



I too, am the same way.

My gold is my precious! I dont want to lose it... Thats why my shop has like 15 5 gallon buckets in it.. 
I recently dropped au from a perfect auric chloride solution... Let it sit 3 days... Checked its turpidity, looked good to me... So, i decanted, set it aside..m a weeklater.. I gently stirred the solution for a minute... Then, in the center, a lovely pile of gold agglomerated, equalling .4 grams.

Makes me sad to think of how careless, wreckless, and (most importantly) -*impatient*- i was when i first started.

Which, brings another question -completely unrelated to depop w/HCl.. What causes the re-dissolution when doing the HCl wash as prescribed?

-oxidizers clinging to the glass after ppt?
-oxidizers in the atmosphere?
-heat from the "simmer" on the hotplate?
-something im missing?

-topher, the ever curious


----------



## Anonymous (May 12, 2016)

Topher.

Minute residues of Nitric cause this. I throw my first acid wash into a jar as the base of my next refine religiously. Alternatively if I have enough remaining liquid that is "dropping" I throw it straight back into that. I used to get all bent out of shape about it however now I just accept it as part of the process.

It's certainly more of an issue if you are refining very small quantities because otherwise the economies of scale kick in.

Jon


----------



## Topher_osAUrus (May 12, 2016)

spaceships said:


> Topher.
> 
> Minute residues of Nitric cause this. I throw my first acid wash into a jar as the base of my next refine religiously. Alternatively if I have enough remaining liquid that is "dropping" I throw it straight back into that. I used to get all bent out of shape about it however now I just accept it as part of the process.
> 
> ...



Thank you Jon!

One of the first times i refined with AR, i did not use a clean stir stick when stirring my HCl gold wash, and to my surprise, even though i *rinsed* the stir stick off, it still had enough HNO3 (or NOCl?) on it to dissolve HALF of the gold i had in my baby beaker (1.3 grams [estimated])

So, from then on, i was very mindful of good labware hygiene.

And Ben, I most certainly will do that...no joke. It probably wont be for another month or two, but, i will share my experiences here with everyone, just for "S's and G's"

In the name of science!

-toph


----------



## UncleBenBen (May 12, 2016)

Topher_osAUrus said:


> And Ben, I most certainly will do that...no joke. It probably wont be for another month or two, but, i will share my experiences here with everyone, just for "S's and G's"



Please do, Topher. This enquiring mind would certainly like to know what happens!

With what little I have actually recovered and refined so far, including what I lost, I think I have put gold back in solution with just HCl as much as I haven't. And that is with no nitrates involved at all.


----------



## UncleBenBen (May 13, 2016)

I think it may have just dawned on me why I was redissolving so much gold powder with HCl.

It was pretty much all happening around the same time, and I remember being down to maybe 1/2 a liter of HCl left in the jug. If the fumes are heavier than air, then slowly turning the jug to pour what little I needed each time would also pour out fumes. As the fumes poured out they would get replaced with fresh air. The air would get trapped in the jug and with that last little bit of acid sloshing around it probably absorbed a fair amount of O2.

Then there I was, washing gold powder with HCl plus an oxidizer. Or maybe it was something else, but it kind of makes sense in my big ol' cranium.


----------



## Topher_osAUrus (May 13, 2016)

UncleBenBen said:


> I think it may have just dawned on me why I was redissolving so much gold powder with HCl.
> 
> It was pretty much all happening around the same time, and I remember being down to maybe 1/2 a liter of HCl left in the jug. If the fumes are heavier than air, then slowly turning the jug to pour what little I needed each time would also pour out fumes. As the fumes poured out they would get replaced with fresh air. The air would get trapped in the jug and with that last little bit of acid sloshing around it probably absorbed a fair amount of O2.
> 
> Then there I was, washing gold powder with HCl plus an oxidizer. Or maybe it was something else, but it kind of makes sense in my big ol' cranium.



I had that thought once or twice (i think alot of odd thoughts though :lol: )

But, i did just read that some choose (say, do) just cold HCl while doing their precipitated gold wash instead of the hot. As, when HCl gets hot, it breaks down. Which, could, in turn, dissolve some of those good bits at the bottom of the beaker.

And i truly will do that test, i am still fixing up my messes from last years youtube blunders... After i get done with that... And fixing my blunder from 2 nights ago (im stupid, left a solution on the burner and it evaporated to crystal... Then i did it again....idiot)..but, whatever cements out of my buckets, im going to rerun in AR, then melt them down. And those nuggets will be my sacrifice in the name of science.


----------



## Anonymous (May 13, 2016)

Ben the process of dissolving gold into HCl with the air from pouring the jug as an oxidiser isn't a rapid one. I don't think you have a real problem there in the context you're using it. 

Just remember lads- until you pour it away you've still got it. Whether you stockpot that wash liquid, or use it for your next dissolve you're literally "golden" 8) 8) 

I'm glad things like this get brought up.

Jon


----------



## UncleBenBen (May 13, 2016)

spaceships said:


> Ben the process of dissolving gold into HCl with the air from pouring the jug as an oxidiser isn't a rapid one. I don't think you have a real problem there in the context you're using it.
> 
> Just remember lads- until you pour it away you've still got it. Whether you stockpot that wash liquid, or use it for your next dissolve you're literally "golden" 8) 8)
> 
> ...



You are correct, Jon. It really isn't a problem, especially with the religious use of stannous. Just kicking it around out of curiosity more than anything.

That and to get Topher riled up!! :mrgreen:


----------



## Topher_osAUrus (May 13, 2016)

UncleBenBen said:


> spaceships said:
> 
> 
> > Ben the process of dissolving gold into HCl with the air from pouring the jug as an oxidiser isn't a rapid one. I don't think you have a real problem there in the context you're using it.
> ...



Haha!
It doesnt take much to get my cogs upstairs a cranking around (eventually filling my head and house with smoke)

But, i too, am glad the little things like this get discussed.
Will it ever be something that is *needed* to know?
-probably not.. But, I'd rather know and not need it, than need it and not know.

But, besides the small nuances and idiosyncrasies of this little tid-bit...

Who here *really* doesnt use stannous?
Yes, the new guys think its just a *suggestion*...but, for those in the know...we all *know* it is something to live by.

Or we should anyways...right? :roll: :mrgreen:


----------



## Geo (May 13, 2016)

UncleBenBen said:


> I have managed to put gold powder back in solution with just HCl washes 3 or 4 times so far. One of the times it wasn't even heated.


It's hard to remove nitrates with just rinses. Even sodium hypochlorite is hard to destroy and solutions must be brought to a boil to decompose it completely (214 °F). Sodium nitrate decomposes at 716 °F which is a very big difference. Unless you neutralize the acids, you will always dissolve some values using hot HCl washes. To neutralize the acids, you can use a base which leaves a byproduct that is soluble in water. You can also incinerate. Incineration is recommended. Generally speaking, if you can't roast the precipitated gold powder for whatever reason, that reason should also exclude you from dissolving it in the first place.


----------



## Anonymous (May 13, 2016)

Incinerate powder before washing it? Never. Bad advice Geo. I agree with so much that you say and respect you a great deal but that's just garbage. 

Most guys on here have a gramme or two at a time. Incineration just adds to the losses at that point. 

Jon


----------



## Geo (May 13, 2016)

When you can't incinerate, neutralize the acid with a base. That's why I gave two options. I use sodium bicarbonate. Follow the base with several water rinses before moving to any other step.


----------



## Geo (May 13, 2016)

spaceships said:


> Incinerate powder before washing it? Never. Bad advice Geo. I agree with so much that you say and respect you a great deal but that's just garbage.



There are many proponents of incinerating gold powder before rinsing on the forum. It's the way I was taught to do it. When I was first starting out, I worked with small amounts. Now, when I work on small amounts of gold powder, I add the small amounts together and refine a larger amount at once. It takes the same amount of time and effort and the losses seem to be less. Incinerate foils and powders to save in headaches later on in the process.


----------



## Topher_osAUrus (May 13, 2016)

spaceships said:


> Incinerate powder before washing it? Never. Bad advice Geo. I agree with so much that you say and respect you a great deal but that's just garbage.
> 
> Most guys on here have a gramme or two at a time. Incineration just adds to the losses at that point.
> 
> Jon



I have never incinerated my ppt'd powders.
But, i have only dealt with a max of 20g at a time, while i finish getting my feet wet, so to speak.

It's sketchy enough trying to incinerate foils, or filters.

Roasting my powders :shock: 
I may lose sleep over that.

Not to say it shouldn't be done at times. I believe i read harold(maybe harold, maybe another founding guru - not that i dont consider you a guru Geo, -as i have watched a great many of your videos, and have "creeped" your posts for wisdom and insight- )

I just kind of fear incinerating period.
-no, fire doesn't scare me-
Losses because i dont have a filtered fume hood for incineration.

Ahh, the nightmare...the horror :evil: 

-on a more seriois side-

*Neutralizing the powder.*
Would this be acceptable/are there any that do this?-
*precipitate gold
*hot water wash
*ammonia wash
*hot water wash
*HCl wash
*hot water wash
***borax water wash
*melt barely damp in borax coated/already seasoned melt dish

I know some use ammonia *after* their hcl wash/water washes for remaining AgCl and copper. But would it be beneficial to do such *before* the initial HCl wash of powder gold.

***I read a thread where GSP actuslly washed his silver cement with borax water (and i think also nitrate water), which made the silver "melt like butter"...Would this be a good practice for gold too? Especially if one (me) is using the borax from wally-world where it *PopCorns* up under heat until it decomposes and loses some water? 

I always feel i lose gold when it begins to popcorn...but, I am using a cruddy MAPP gas torch and I don't have a good melting tip for it, or a good fire brick set-up to retain the heat (Ive been using corning ware dishes stuffed with fiberglass insulation)

But, then again, ever since i found this forum, i have believed i have lost gold *everywhere* at *everyturn*... My mind is more at ease now after learning a thing or three, but still.. I was curious if this is done by anyone?

-toph


----------



## Geo (May 13, 2016)

The best way to avoid excess nitrates is to not use an excess to begin with. If you consecutively dissolve values when you do HCl washes, it is a problem of pre-treatment or the lack thereof. You will need to include a way to neutralize the excess oxidizer before the wash. Ammonia is a base but using ammonia with nitrates is not recommended for beginners (at least by me). Ammonium nitrate is formed by adding nitrates to ammonia. The dry crystals is a strong oxidizer. It forces organics to decompose at a high rate of speed (with light and heat) under the right circumstances. There's little chance of forming an explosive compound as long as you study and understand what is happening. Ionized gold can be very, VERY unstable under the right circumstances. It's more explosive than silver. Silver was used in the primers of bullets until it was deemed too unstable. There are chemicals that seem benign enough and are normally, but when reacted upon can be very dangerous.


----------



## Topher_osAUrus (May 13, 2016)

So remaining (stubborn) nitrates that stick around after precipitation is the reason that ammonia isn't used after a few hot water washes on precipitated gold powder?

I thought i read on here from Lou or 4metals, that once gold is precipitated, the nitrates in the powder have effectively been ridden away, otherwise gold would redissolve in solution right there (leaving the red fumes in its wake - im going to look for that thread in a second)

I was just more curious as to if that order would be acceptable, i, in no way, was trying to belittle or diminish your statement Geo. And, in my list above i forgot number of times. Which could be important i.e.

*precipitate gold*
*decant
*rinse hot water x3
**rinse in warm ammonia
*rinse in hot water x3
*rinse in HCl
*rinse in hot water x3
*#*#*rinse in borax water
*melt

The **'s is what i was curious about, if that would be an acceptable practice which could aide in neutralizing the clingy NOCl/NO3/Cl/O whatever is left and taking up gold in the HCl wash?

The *#*#* is what I'm really *really* curious about.?.
Is it something that could be done for gold?(of course it can *be* done, but would it aide melting?) 
I really just hate the laundry borax with my torch setup.
With my family's oxy/acetylene torch, its no big deal, but this crummy MAPP with its even crummy-er tip, just literally makes the stuff *pop*... Even if the dish is red hot, the heat from the top just sucks (for lack of better word..)

-topher


----------



## Geo (May 13, 2016)

It can be done the way you describe. I am saying that if you are dissolving gold with the HCl rinses, you need to change what you are doing. I don't like following HCl with ammonia or the other way around because of the ammonium chloride smoke created. I neutralize the acid before adding the ammonia or I acidify the ammonia with vinegar before washing with HCl. 
There should not be a set number of rinses and washes. The main thing is to repeat the rinse or wash until the rinse or wash stays clear. Any color change means you still have more to do. It may be on the first rinse or the tenth, but when the rinse stays clear, move to the next step.


----------



## Anonymous (May 13, 2016)

Topher

Why would you rinse in Ammonia as a standard procedure if there's no silver present? It's only present in certain recoveries from ewaste. I have never used it as a wash apart from experimentation. Yes in inquarting it's more of an issue however there are other methods of removing it. 

Geo whilst your comment regarding incineration and amalgamating multiple recovery drops may have merit I can assure you that regardless of whether you may have been taught that method originally, it is not required. Regardless of whether your drop is 1g or 100g if you neutralise the Nitric correctly, the dissolved gold should be negligible. The only issue arises when people haven't removed the vast majority of the Nitric, and the people who don't are more likely to be those who both recover very small amounts, and don't understand the processes. 

We're talking to people here who don't get that bit wrong, and yes I agree that using less Nitric is something that comes with experience but Sulphamic acid and an 85 degree cook should remove it to an almost insignificant level. It's that insgnificant level that I am referring to, not an overly abundant excess in the powder. 

I trust that clarifies what I meant.

Jon


----------



## Topher_osAUrus (May 13, 2016)

I have only used ammonia 1 times in my powder wash procedure. And that was because i had AgCl troubles my first couple of melts.

Patience (and dilution) cured that problem so i no longer use it.

It was more of a curiosity, that if it (ammonia wash, pre HCl), would be a decent candidate for a two-for-one process, -stop the small dissolution of gold- and -remove other impurities like copper and silver- 

Not something i plan on doing anytime soon.
Really i just wanted to know if it was a viable option should the circumstance arise.

I like to use sulfamic acid at times just because it serves multiple purposes in one fell-swoop

-topher


----------



## Anonymous (May 14, 2016)

Thanks for clarifying Topher 8) 

Jon


----------



## Topher_osAUrus (May 14, 2016)

spaceships said:


> Thanks for clarifying Topher 8)
> 
> Jon



No worries.

Many a times, my mind works a million times faster than my fingers (most people's brains do-as neurons fire around 280mph, -we also emit around 80-120watts of power-which could effectively be picked up by the new James Webb space telescope..from very...very..far away)
And when i finally am able to peck my way through a thought, several have passed that i wanted to put, but got omitted by accident.

I need to get my laptop out of my kids room and use it... The 130 words per minute i can type on it, is much better than the msybe 50 on my phone... Sure isnt 280mph, but, every little bit helps lol.


----------



## UncleBenBen (May 16, 2016)

Geo said:


> UncleBenBen said:
> 
> 
> > I have managed to put gold powder back in solution with just HCl washes 3 or 4 times so far. One of the times it wasn't even heated.
> ...



As I said earlier in the thread, there were no nitrates involved. I only recently made some cold nitric to help with testing material. The hypochlorite I was using as an oxidizer should have been destroyed as you said, as it was after several boils of the powder in water before washes in HCl. And then it was usually on the 2nd or 3rd wash that gold would go back in solution.

Another example of why I suspect it was that almost empty jug of HCl was when processing almost powder fine gold foils in several filters, along with all the filters, paper towels, Q-tips, etc, that were in my filter bucket. Incinerated, crushed and placed in a beaker. I poured in the last of the HCl from that old jug and sat it aside as I was setting up my hotplate and catchpan and what not.

I remember going in the house for about 30 minutes to help the wife. When I got back outside I noticed the HCl in the beaker had a familiar yellow tint to it. Tested with stannous and sure enough it was positive for gold. The picture is after stirring it for a few minutes with a piece of 8awg copper wire.




Once it all cemented out I decanted and continued with a new jug of HCl and didn't have any more problems. That's why I figured the HCl had to have absorbed THAT much oxygen, or was contaminated from the start. Also, most of the accidental dissolving happened around the same time, just within 2 or 3 weeks time. Didn't have any trouble with it before or since, but I think my filter bucket was one of the last things I processed before I put it all on hold.



Geo said:


> Generally speaking, if you can't roast the precipitated gold powder for whatever reason, that reason should also exclude you from dissolving it in the first place.



My studies here have taught me that unless there is a need to incinerate, like powders mixed with a tin mess, then precipitated gold never leaves the beaker until it's ready to melt. But I do agree that I don't have any business dissolving gold. Which is why I packed it all away months ago until I can get a lab put together with a working fume hood.

I'm still keeping my test tubes and tiny beakers busy though. I love testing new materials for PMs!! :mrgreen:

I was going to use ammonia once back around October. It was some Au powder that came from gold clad over silver relay contacts and I just couldn't bring myself to do it. I don't think I could even with a hood. Ever since my 'ammonia incident', as my wife calls it, last July when I accidentally drank some thinking it was vinegar, I can't take the slightest of a smell of ammonia now without instantly vomiting. Made for one heck of a scary night in the ER.

Remember kids, just because all your friends are doing it, drinking ammonia won't make you cool!!!


----------



## Topher_osAUrus (May 16, 2016)

Hello Ben,

Ive been thinking of you! -and your theory!(mainly the theory)

So, Lou said that heat can/will decompose HCl.

Whats the weather like in your neck-of-the-woods?

Had any really hit days that your jug has been subjected to? Or direct sunlight?

Im wondering if the O2 in the atmosphere has aided this dissolution, or if the HCl has decomposed a bit giving some Cl in solution thats free to oxidize the powder easily?

Just a thought, about the only one ive had.

-topher, the thinker-er-err


----------



## UncleBenBen (May 16, 2016)

Hi Topher,

There is no telling what the jug may have been through before I bought it. The Lowe's I by it from seems to run through their stock pretty quickly. I probably bought that one around the beginning of October. I was down to the last of it by mid November, which was around the time I was redissolving gold so easily.

So while I had it the hottest days were in the 70s. The jugs are white. They stay in the basement in an old refrigerator with the gasket still on the door. And I get sunburned looking out the window, so when I was outside refining it was dark or I was in the shade.

I thought about what you and Geo discussed about traces of oxidizer on a stir sticks. I used a sturdy plastic one for a while which could explain it. But when I found the picture I posted last post, I had already bought new beakers which meant I had new glass stirrers too. I was pretty meticulous about keeping my glass clean.

I might just have to chalk it up as just one of those things. Unless it starts happening again when I get back to processing. If nothing else it was definitely a good lesson in the importance of testing!


----------



## Geo (May 16, 2016)

HCl alone, whether heated or not, should not oxidize gold. I know that things happens that can't be explained easily but from a purely scientific standpoint, you have assume that there was an oxidizer introduced somehow. It was either on the glass, in the HCl or in the material itself.


----------



## UncleBenBen (May 16, 2016)

Geo said:


> HCl alone, whether heated or not, should not oxidize gold. I know that things happens that can't be explained easily but from a purely scientific standpoint, you have assume that there was an oxidizer introduced somehow. It was either on the glass, in the HCl or in the material itself.



EDIT: Hahaha! I'm sorry Geo. I just now saw that the reply I had typed didn't make it to the post! :roll:  

I think what I had written was along the lines of I agree with that whole paragraph. Y'all gave me some good ideas as far as possible reasons for the problem.

I'm almost certain my HCl had gotten contaminated somehow. I haven't had a problem since with accidentally dissolving gold in all the small tests I've done. Even though I was working with tiny amounts of powder at a time. Hopefully it will never be a problem again.

I was saving all those tiny amounts of powder in a 50ml beaker for months. It was usually barely enough to even see when I would wash it from the test tube. But it all added up to my latest button!!




I didn't try to weigh it. I heated the dish back up and let it get stuck in some borax so I wouldn't lose it.


----------

