# some questions about metals in solution. (edited)



## Martijn (Aug 25, 2014)

Hello, after i tried my first acquaintance tests from Hoke's book, I wanted to determine which metals my scrap consist of, so i dissolved some shots made of gold plated pins in nitric 53%, the color of the solution ended up dark blue. After decanting there was only purple powder and some un-dissolved shots, all the same color. 

My first thought it was a reaction with tin ("Purple of Cassius", tin paste or oxide) as it will give a dark purple color, similar to a stannous chloride test, or it can be because of the colloidal gold particle size. Apparently the particle size determines the color ranging from red to blue-purple according to this site: or am i completely wrong here in my assumption?
From Wikipedia: http://en.wikipedia.org/wiki/Colloidal_gold

The color looks very much the same as both. Any thoughts on how to see the difference between a tin reaction and coloring due to particle size? couldn't find anything on this in Hoke's book.


i think it has to do with tin, after AR treatment and addition of water I ended up with a thick layer of gelly-like white stuff. about 2/3 from the bottom up. 
[
if there was any silver in solution it will also be in the gelly stuff. (i was hoping not to encounter tin...after all i've read on the forum) or it is all silver or perhaps lead, from a tiny bit of solder on some of the pins, but can it be that much white gelly stuff? 
does anyone have a picture of silver chloride in a blue-ish AR solution? 

the solution was very diluted, but still slightly acidic and clear blue after decanting two times. no particles floating even when stirred. so i tried some smb precipitation, nothing happened no color change, nothing. measured Ph again and it was near neutral. i read smb needs acid or neutral solution to form SO2, to precipitate gold, but now i'm wondering if it's the copper still in solution or the too high Ph holding the gold by keeping the smb from reacting, so i tried to add 1ml of HCL to it, and again some white clogs appeared rather fast after addition. Ph is now acidic again. i know HCL pushes out silver chloride after AR treatment, but after diluting it about 50 times with water should have pushed out all silver right? can it be there's so much silver still in solution that the smb has no effect?

please advise, i want to figure out how to treat the rest of the scrap.
the picture of the flask is of the result after dilution with water: 6 ml solution with 100ml water at first in the flask, after two times carefully decanting a total of 750ml clear light blue liquid in a beaker.


----------



## Pantherlikher (Aug 25, 2014)

Not being able to give a good answer to your questions, sorry there.

Why would you waste $$$/nitric acid on a glob or plated pins?
A bit or research here on the forum describes those gobs of wasted $$$.

Ok so experiment with the loss. 
Start with HCL and measure the volume loss of the gob and see what goes into solution with HCL.

Next incinerate to rid gob of any HCL.
Now use nitric acid and let it dissolve all it will and measure volume left which hopefully will be enough to at least measure.

And do NOT use solder from pins or any used solder for that matter for testing solution. You have other unknowns in the mix which could give bad test results...

Not knowing what the "gob" of pins is made from makes it extremely difficult to determine anything.

Every post thread I've read through asked for extensive details of starting material to help "speculate" what is there and why.

Stop buying Gobs of crap and save yourself $ right off the bat and read the whole book before doing any experiments as well as reading through hundreds of thousands of posts here on the forum.

In other words...learn before you become an "expert" please.
I still would toss those gobs right in the trash pile as I know not nearly enough to attempt the whole process from start to waste solution's finish.

Good luck and hope for the best.

B.S.


----------



## Martijn (Aug 25, 2014)

Hi, thanks for the advice. i edited my post while you answered. 
to clarify matters, it's not for economic reasons, I got this scrap for free, saved it from the trash pile. Just a lot of evenings getting my hands hurt and cut on breaking connectors open and so on. paid for with blood! they are high quality completely plated pins (thick plated old style, 70's or earlier). Probably on brass, as i saw on the breaking edge. If i can get just one nice shining little button of gold i'm happy. it's more as a hobby and out of curiosity. 
i know it becomes less profitable for miners in America when gold goes below somewhere aroud 1300 an ounce, with prices now even slightly under, and refining scrap is even less profitable. so i dont expect a lot. just knowledge and who knows where it takes me.
there's no loss, i've melted only 200 gram of the pins and made 'shot'. put a couple of grams in a test tube, and spent 10 ml of acid in total, to get some experience first and figure out what to do with the rest. The rest remain plated pins. 

I scrap all my house waste and stuff I get from friends, as iron, aluminum, copper and brass from electrical devices and, you name it. So I stumbled upon this lot of plated material, and after you tubing a bit found the gold ‘scrap site with the inquartation method, seemed feasible to me to try. I’m going to build a fume hood for the actual process, but I will use it for other purposes too, so it's not a total waste. Can always try a bit of miniature moonshining in there... :lol: 

I read the book, it's a lot to store at once and I re-read a lot, but not everything is in there and some information out there is confusing for, as I said, a newbie. The video's make it look so easy, I know, but I did a quite a bit of research before I even bought the first supplies and chemicals.
And as for throwing them away, nooooo! They’re way too shiny. I see gold on everything now.

The tin paste, I thought, if it stains the gold dust, might give an indication of gold present in solution as well. Since the tin is about the only thing that goes into this gel state after nitric treatment, it might be pretty pure or make it more pure. and if i get a big enough portion at once, i can make a standar testing liquid from that.It should give the same resluts provided that it's pure tin or i can separate it. I’ll research this further, not to be cheap and save money on a testing kit, but just out of curiosity. And throwing those less valuable metals in solution down the drain can't be good for the environment too. 
I want to have a plan of approach that will work and be safe before i start anything bigger than this, and have to read a lot, i hope some of you can point me in the right direction. 

As you might have figured out, I’m not English, so excuse me for any awkward use of language. :|


----------



## butcher (Aug 25, 2014)

Martijn,
I am glad to see you reading Hoke's book and doing the experiments, these will help you in many ways later as you learn to recover and refine metals, I can see from your lengthy post that you are confused on many details, of how to prepare recover and refine your scrap, you are also confusing some what of what happens with metals in solution...
you are taking a mix of metals and putting them into solution and trying to figure out the chemistry from this mess with very little understanding to go by.
small details like melting the pins and pouring shot was a mistake making recovering gold harder, and then you tried a process that would normally not be recommended...

You started off in the right direction with Hoke's book and doing the "getting acquainted experiments", but then you made a wrong turn trying experiments in an unknown territory.

I suggest getting back on track, with your study, and start off with a simple material like gold plated memory fingers, study how to prepare the scrap, and study how to recover the gold, and study how to put the gold into solution and precipitate it back out, use what you learned from Hoke's book in testing for gold in solution...

spend time learning with simpler scrap and processes, and work your way to more complicated materials and processes, using what you learn along the way, this will make learning this science of metal chemistry easier in the long run, you will also see how metals react, much like you did with the experiments you did with Hoke's book, as you go this will all begin to click in your mind, seeing much of what you read about or hear discussed on the forum...

Right now you have read some things and are trying to figure this out from what you think, and not what you know.
Spend time studying and practicing with what you study, and then when you see things it will begin to make more sense, and with the work you do while learning, you will begin to know more of what is happening, not just trying to figure out what you think may be happening...

Safety and dealing with waste are the first things to study, I did not see you mention these, But I am sure you have these in the top of your list of priority's to keep up with in your study.

I hope this helps you get back on track to getting that gold button, I have learned patience, so I can wait while you spend the time needed, but I still would like to see your first button in the gallery section...

I could not tell English was not your language from reading your post.


----------



## Harold_V (Aug 26, 2014)

Martijn said:


> As you might have figured out, I’m not English, so excuse me for any awkward use of language. :|


No, I didn't figure it out, and had it not for you having made the statement, I'm not convinced others would have, either. Very well posted information. 

Follow Butcher's advice. 

In regards to plated items. It's almost NEVER a good idea to melt them, as they can be processed by other means (stripping or dissolved directly, no melting) with far better success. 

When you melt gold in small volume with base metal in large volume, the resulting alloy will have the gold so finely divided that it will be difficult to manage. You are far better served to keep it as a thin solid (as plated, or otherwise applied), where it retains its form and identity, even though it may break up to tiny particles. They can still be easily recovered by filtration or settling. That may not be true of particles that result form being melted, as you've discovered. 

Always test your solutions with stannous chloride, even if you *think* they contain no values. That includes pale blue solutions, which most likely will be barren. Even small traces of silver or gold tend to shift the color towards green, but without testing, you may not know the status of the solution. 

If you suspect silver in a nitric solution, test a drop with salt or a drop of HCl, which you should remove from the parent solution. If you have silver present, you'll see a white cloud form, or even a clotty substance which resembles cottage cheese, assuming there is sufficient silver present. Do this test in a spot plate cavity, or a dark plastic spoon. 

Harold


----------



## Martijn (Aug 26, 2014)

Read Hoke's book again last night, especially the silver chloride parts, and I think the white stuff is just that, since it came down after addition of water and also with HCL. Once it's completely digested it will be much easier to separate things. I’ll store the little bit for later in the 'silver pot' and store the Cu / Au nitrate as well. 

The NOX fumes that came off that small test tube were so unpleasant and scared me a bit, knowing what’s in the MSDS. I don’t want any of that to reach my neighbors. So I’ll go for some kind of scrubber and fume hood first. Even for small tests, and never outside again. I was thinking about a water sprayed mist or vacuum venturi / eductor system with flasks and marbles. Lots to study.

The reason I melted the pins, is because it’s too well plated, and there is no bare metal on the surface for the nitric to start eating away under the gold, I thought. An AR digestion would get me everything in one solution, so that's why. Any other tips on how to treat this? Cutting up 10.000 pins is a lot of work. I have other scrap that’s partially plated, and also gold fingers, as Butcher mentioned, so that won't need melting first. After the fume problem is solved, I’ll try those first.
I'm searching for ways to detect NOX concentration in an airstream to test if the setup is effective enough. Any hints? Like a piece of filter paper treated with some detection fluid to place in the exhaust. 

Stripping? Read this reply from Pantherlikher in another post: 
"What I've been kicking around for thin plating is to watch it soak in HCL + Bleach until visible gold is gone. Then remove bulky base metal and drop gold. Of course this would be dirty and needing refining but might be a way to get gold out." 

I will look in to this. A link to a description of this process would be much appreciated. Can't find it in Hoke's book.


----------



## Martijn (Aug 26, 2014)

Just found Lazersteve's posts about HCL + chloride treatment, very interesting reading!


----------



## Claudie (Aug 26, 2014)

Martijn said:


> Just found Lazersteve's posts about HCL + chloride treatment, very interesting reading!



He has some informative videos on his site too!
You should check those out as well.


----------



## butcher (Aug 27, 2014)

Martijn,
You have just found this vast subject, and have barely opened this vast chemistry book, looking at only a few pages so far, you have many more pages to see, before you even begin to see what all this book contains, and what is all about, or even what the book of recovery and refining of precious metals is all about, and how it is done, and the many different ways to do this chemistry, and the complications of it all. 
Keep studying, and searching for those answers to your questions, it will open many new pages and discovery's.

Begin with things like the guide to the forum (found in the general chat section), and other suggestions you will see in the forum, reading the forum and working on simple projects.

We need to learn to walk, before we will be able to run, enjoy learning to walk through the forum, and its vast resources, and with that you will learn to run.

Copper chloride is another white salt, as well as lead chloride, you could have silver chloride, but my guess it may not be, (there can be many different white salts, yours will be of the metals and acids used in your experiment), considering your beginning scrap material and process, I do not see silver that likely, save the salts. 
Test the solution, you may need to cement gold from it with copper, or the gold may already be with those white salts, test your solution, and deal with it how you learn to in the safety section (see dealing with waste), while reading the forum you will learn how to separate and identify these white salts, and if they just happen to contain gold or silver you will learn how to deal with that also...

You will also learn how to recover and refine precious metals from many different types of scrap, with the many different processes we use...

You have only begun to see a small glimpse of this vast forest, spend some time exploring it. and enjoy the journey.


----------



## Martijn (Sep 15, 2014)

I've found an interesting pdf about 'Qualitative Analysis of Metal Ions in Solution' link to pdf: http://src.gov.jm/wp-content/uploads/2013/02/2-3-qualanalysis.pdf 
To me, it explained a lot about what happens with precipitating the different metals in solution, in whitch order to do it, and why. 

Some of the reagents seem a bit dangerous to work with, like H2S,i know this one from petrochemical plants i worked at, but surely there are other more safe options.

Still reading a lot, and for my fully plated pins, I am considering two options: nitric acid for the base metals, and AR to get the gold out. Or HCL with Hydrogen peroxide and HCL with bleach to get the gold. The AP method as i believe it is referred to, is said to take a lot of time on pins. and i'm not sure the HCL peroxide mix will eat away some gold and precipitate right back out on the copper underneath. this is mentioned in another post. I guess running tests will be the only way to know.
I will run some small tests if it can be done without melting first with both methods, because they're completely plated, no other surface to start eating away underneath the gold. 
An electrolytical cell is being advised also, but i don't know if that takes a lot of other chemicals and equipment? 

While reading and gathering materials for the hood, i've been scrapping like crazy and now have some 20 different kinds of gold plated scrap sorted to figure out how to treat them. i demolish everything shiny... :lol:


----------

