# Help with pins



## nmlfreitas (Jul 12, 2012)

Hey guys.
I've made a first try with pins. 
I had more less 800g of pins from motherboards and others.
I putted them on a jar with nitric, it released orange fumes.Turned blue and i have a lot of a dark grey powder on the bottom.
The pins are clean with no gold in it, the problem is that i don't see any gold flakes, have i done something bad?


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## philddreamer (Jul 12, 2012)

Did your jar had any traces of HCl in it?
Phil


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## maynman1751 (Jul 12, 2012)

There shouldn't be any pins left. A complete digestion would have dissolved them entirely. And like was mentioned, if there was any trace of HCl present it could have dissolved the gold and it could then cement out on the remaining pins.
There is also the chance that if the pins did not dissolve completely they may have simply cemented base metal over the gold on the pins.


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## nmlfreitas (Jul 12, 2012)

I don't have any traces of hcl on the jar.
The pins look like they have been burned. I only have the grey stuff and blue solution and no gold flakes.
I used only nitric acid, should the pins be dissolved and have no pins on the nitric bath?


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## Geo (Jul 12, 2012)

was there solder on the pins? did you sweat them off with heat or did you cut or shear them off.


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## nmlfreitas (Jul 13, 2012)

I gave them heat so they would come out, i guess some may have solder for sure.


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## Geo (Jul 13, 2012)

tin in nitric acid makes makes metastannic acid. it can be grey if theres a presence of sulfuric acid at all.http://en.wikipedia.org/wiki/Mosaic_gold

the precipitate will be in the form of white metastannic acid and brown stannic sulfide which will appear to be grey in color. most refiners add sulfuric acid to precipitate the lead from AR.


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## NoIdea (Jul 13, 2012)

Geo said:


> ....most refiners add sulfuric acid to precipitate the lead from AR.



Hey Geo, interesting, i personally, after ashing, after sulphuric acid digest, after hlc digest, the resulting material is treated with boiling sodium hydroxide, this will remove any lead or tin compounds, making them soluble in this medium as plumbates and stantates, hot filter, hot rinse wash, then re-ash, and then AR. Not sure if the last ashing is necessary though, hmmm.

Now why is the resulting sodium hydroxide solution brown?? Still working on that one. 8) 

Deano


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## nmlfreitas (Jul 13, 2012)

So what should i do to get my gold back?
Filter and give it a go with ar?


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## Geo (Jul 13, 2012)

chances are, the gold is still on the pins.theres some information missing that would help finding an answer. did you dilute the nitric acid or use it concentrated? we discovered there was tin in the mix, so theres got to be metastannic acid in there. when acid is introduced to mixed metals, it will attack the metal thats most reactive first. it wont effect any other metal until all of the first metal is dissolved. it could be, the acid was depleted before the foils was liberated. when you dissolve metal, it takes on a slight positive charge.metal that has yet to be dissolved still has a slight negative charge. some of the dissolved metal in solution will be attracted the negative charge and cement back onto the gold plate making it discolored.

filter the solution you have now and test with stannous chloride. check any solids for gold flakes. if you dont find any, its still on the pins. rinse them, dry them and rub with a piece of cloth to see if the gold color will show through.


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## Geo (Jul 13, 2012)

hey Deano, if i understand it right. strong bases will dissolve some values, especially if the temperature is high enough. when you get done with your washes and your sodium hydroxide is spent, try lowering the PH to below neutral and see if anything drops out.


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## goldsilverpro (Jul 13, 2012)

When dissolving pins with nitric, you generally have to do it completely to assure that you get all the gold. You had 1.76 pounds of pins and, therefore, it would take about 1.76 gallons of 50/50 nitric to do the job. That must have been a big jar.


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## nmlfreitas (Jul 13, 2012)

Geo 
My Nitric acid is concentrated. 
I checked the pins and they are all black, no sign of gold. On the jar i have the solution without the pins, i have on that jar the grey stuff below and i can see a very small and tiny gold flake or two.


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## butcher (Jul 13, 2012)

Remove a small portion less than a spoon full of the powder to another jar, add some dilute nitric to a small portion of the powder and see what happens.


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## nmlfreitas (Jul 13, 2012)

Thanks butcher
Will do that and then i will let you know.


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## nmlfreitas (Jul 16, 2012)

As promised here it is:
I did what butcher told me, dilute nitric with water and added small portion of the grey mash that i had, it got with this colour


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## butcher (Jul 17, 2012)

seperate the blue liquid from the powder, filter this liquid hang a bar of copper into the solution to cement any metals of value, the silver powders I would wash again in dilute HNO3.


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## ashir (Apr 12, 2020)

butcher said:


> seperate the blue liquid from the powder, filter this liquid hang a bar of copper into the solution to cement any metals of value, the silver powders I would wash again in dilute HNO3.



Having q long time in refining, even nearly saperating hardest metals like rh IR from ores but I process pins 100 times and every time is was fail :x :x 
Many time saperate magnetic, non mqgnatics, process saperate. Failed.
Recently I mix up all the pins, not saperate magnetic or non magnetic.
Use battery acid with nitric to dissolve copper and iron based pins. 
Acid is green with a lot brown gray powder, not white, wash the pins. 
Pins are still there and nothing happens to them. Reincinirate and use HCl, nothing happen. Still pins are same, a lot pins sho copper on Thiers surfaces some are still white shiny, 
Have gold plated watch bands many kg, some clean saperate pins, want try sulfuric cell next time but it's on now what should I do to these pins.?????

Once earlier happens while processing another batch of pins. Use HCl+water, small increment nts of nitric, solution becomes black, filter the solution, using urea was unreactive. So Aqua failed. Leave the pins. They turn first gresn yellow on surface as copper oxidise then a layer of copperash irony look. Today I reincinirate and crush them, maximum pins are gone, gold flakes are mix in sludge!!!! Is here any post that can describe pins processing with different methods, with expecting errors. And their solution?


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## Yggdrasil (Apr 12, 2020)

Hi Ashir.
This may be blunt, but I have no bad intentions her*e*:

All the information you need is in here: search, read and study.
I'm not sure we are doing you any favors by guiding you step by step, better that you study and gather an understanding of what you have been studying.
You have been all over the forum, asking and asking in ways that make me cautious about if you read and take in the information you are given.

Regarding pins, the AP and HCl leach is just to remove the base metals before you dissolve the remains in whatever method you prefer.
If you use AR on pins directly you have to dissolve all until all base metals are gone, the black powders could have been your gold precipitating back on the base metals.

PS!!
Just another thing, if the solution has taken color and there is a lot of powders, something has happened to the pins, excactly *what* is the question. 
If you are having issues with a process, mixing in other uncertain factors from other processes you are having issues with, don't make it easier to identify your initial issues. 
(POOH sorry about that sentence :wink 
For instance, if the pins are SS then nitric may passify them.

Edited for writing error in red


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## butcher (Apr 12, 2020)

ashir,
I don't think I will be much help, without seeing what's happening in person, it is hard to tell by reading what all is going on or what that is giving you problems...

Pins can be made different, some are mostly very pure copper a thin coating of nickel and gold, other pins are made from copper alloys like brass mostly copper and zinc alloys, some naval or red brass can be made with up to 30% tin and contain other metals such as lead iron and arsenic, there is also nickel silver alloys used besides copper about half of the alloy can be made of nickel or zinc, and we also have phosphor bronze alloys or beryllium copper alloys.

Some pins the gold is very thick which can make them difficult to process by normal means, not because of the base metal but just because the gold is so thick the acids have a hard time getting to the copper or base metals...
Too much gold can make it hard to get to the base metals.
Too much base metals if dissolving gold and letting it plate back until everything is in solution.

With pins having tin in the composition of the alloy, it is risky to put the gold into solution with the tin involved there is a good chance some of the gold will be lost to colloids.

I cut these pins in small pieces and use them to make nitric acid, cutting them gives the acid plenty of surface area of the base metals to attack, helps to speed reactions...

Too much gold can make it hard to get to the base metals.
Too much base metals if dissolving gold and letting it plate back until everything is in solution


http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=38&t=6199


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## ashir (Apr 12, 2020)

Thanks yggdrasil and butcher
Aqua reigia is batter if I get a lot HCl, I can get nitric and sulfuric but hard to find HCl. 
A strange thing I find is 
Sim jacket covers partially plated. Not magnatic. Not dissolving in HCl, not in nitric not in sulfuric. I test 3 pieces and put them in 3 acids. 
Well every one has a weak point and yes " pins are mine" 
Cell will be batter idea but pins in mobiles are inside plastic and too much time consuming to saperate them from plastic. 
Looking for HCl, will try Aqua regia, 
Butcher I read some where on forum to put some nitric and wait few weeks to oxidise base metals , 
What you say about this?


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## butcher (Apr 12, 2020)

HCl should be plentiful and cheap, I would keep looking for a source.


you could always improvise and make caveman muriatic acid surely you can find rock salt
2NaCl + H2SO4 = 2 HCl + Na2SO4 
distilling off the gas into ice-cold water, or bubble the gas into the flask of a cold very diluted nitric solution with the metals in the flask cut or in small pieces which will react more easily with a large surface area, leaving you with the sodium sulfates for other uses...


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## ashir (Apr 13, 2020)

butcher said:


> HCl should be plentiful and cheap, I would keep looking for a source.
> 
> 
> you could always improvise and make caveman muriatic acid surely you can find rock salt
> ...


Awesome idea, never think to make it by myself? Will try this, the matter is to dissolve the pins in ar take so much free HCl.


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## ashir (Apr 13, 2020)

If I use 50/50 HCl + water and small increments of nitric.
What if nitric increases thank HCl?


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## butcher (Apr 13, 2020)

I do not understand the statement I use 50/50 HCl + water.
HCl azeotropes at around 20% HCl and 80% water.

Basically, it really does not matter how dilute the acid is if you use heating and evaporation in your processes the water is removed by heating and the acid concentrates.
If you need stronger HCl (up to azeotropic) you can evaporate the water off the dilute HCl Acid to concentrate it up to around 20% HCl concentration.

When you get nitrate ions or acids higher than the HCl ions in the solution we call it reverse aqua regia,
HCl will become the limiting reagent for the reactions to take place to completion or move to the right side of your chemical equation in this case you will need more HCl to dissolve gold as a chloride salt, the nitric may be able to budge an electron from a gold atom but it will not share a bond with three chlorides (because you have no free chlorine or chloride ions in solution for a newly formed gold ion to bond to (with no place for the electron to go or no chloride to bond with you) you no longer are moving electrons or dissolving gold.

So basically unless you add chloride ions (even table salt NaCl at this point would do to provide chloride ions), you will not dissolve any more gold, nitric will be hard to eliminate without the additions of HCl or some acid even H2SO4, the base metals will make nitrate salts when evaporated, we need the acid to convert them back to nitric and then with the heat drive the gases of the acid from solution thus de-NOx-ing the solution...


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## ashir (Apr 13, 2020)

That's the logic. 
So the simple concept is to add much HCl so that small increments of nitric as reach to 1 3rd of HCl also its quantity should be enough to dissolve all the matels at same time!


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## anachronism (Apr 13, 2020)

ashir said:


> That's the logic.
> So the simple concept is to add much HCl so that small increments of nitric as reach to 1 3rd of HCl also its quantity should be enough to dissolve all the matels at same time!




I'm not sure that you're understanding what people are telling you. If you did, you'd not be suggesting that we are trying to get to 1/3 Nitric.


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## butcher (Apr 13, 2020)

Because you read hokes book and are not just wasting our time asking questions that you would not understand the answer we gave until you have read her book, Hoke stated it takes approximately 1 fluid ounce (29.57 ml) of 68% HNO3 and four fluid ounces ( 118.28 ml)of 32% HCl to put one ounce of gold into solution.


Note: 
Here she is working with karat gold and gold from all different kinds of sources, and so even here, she is recommending using more nitric than you need to do the job, but she also explains how to evaporate three times to remove the excess nitric later in the process... 

So we will not normally use as much nitric as she calculated.
So we should be able to dissolve an ounce of gold (31.103 grams of gold) in less than 5 ounces (150 ml) of an acid solution...

So for each ounce of gold, we can add 118ml 32% HCl and with heat adding the HNO3 in slow increments and drops at a time, until the gold is converted to salts dissolved I the liquid (but we should not have to add as much HNO3 as the 29.5 ml of 70% nitric we calculated) if you do, you know something is wrong... or you know you are using more than needed...

I figure about 3.8ml 32% HCl per gram of gold and expect to use approx 0.95ml of 70% HNO3 to get that gram of gold into solution

Read Hokes and study, Study the forum, this has been explained in much better detail in the past and you get much more informed by studying than asking a member to explain this again something he has tried to explain to almost every new member we get...
You will not get the details from asking questions that you will get from doing the study yourself, we do not have the energy to write a book to answer the same question to thousands of new members questions.
So you do not get all of the information unless you do the work to study.


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## ashir (Apr 13, 2020)

Oh yes, there must be free acid to hold the base metals. Use as low nitric as possible. 
Reading hooks is always helpful as reading it every time explores new things. 
The reason was to ask is AP mathod was not suitable for me at the moment and even many time it was said to be not best mathod for pins
Watching some videos of regular refiners, all use direct HCl, small increments of nitric, 
They do its do e, 
I do it gone wrong, 
One thing I point out that I use so less HCl (to extra nd use of HCl) that's not enough ,
2nd I delay so long after adding nitric, and let the solution wait some time for days to go further, ( its my ganuine error)


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## ashir (Apr 16, 2020)

So here the gold.
4 kg mixed pins. Divided in two batches
Process: (first batch)
Use battery acid with small increments of nitric. 
Solution positive for silver.
Alot White powder, Here lead makes problem

So filters incinirate. Dip in HCl. 
White powder,
Wash incinirate
Dip in HCl , small increments of nitric
Solution turns black and assurely gold was cemented back on base metals, filtered , tested for gold, negetive 

Again add HCl, small increments of nitric , same happen
Re processed same happen. ( error was to use less acid)
Finally added 10 liter HCl for 2kg pins and small amount of nitric,
got the solution positive for gold

2nd Bach
Add 12liter HCl. Small increments of nitric. Untill all metals dissolve. Filtered tested positive for gold

The both process are not suitable for pins. (But the sources were limited to only this process)
I was looking for my eroor, reading the topics on pins, was forcing to know your materail, copper, brass,nickle,coper,iron, steel . ! Out of that you have to use too too much acids for little little values, this not profit me but teach me to not do this again, untill there is no other source avail. Thanks every one to help me


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## butcher (Apr 16, 2020)

Glad to see you recovered some gold from your efforts.

It is good to see the gold, but I am not as interested in seeing pictures of the gold, as I am of seeing pictures and getting tips on how to treat the waste solution properly from extracting the gold from these salts, that is what I wish to learn more of, see more discussions of how the toxic solution is handled after the gold is melted...
keep studying and you will get better at these skills.
Keep studying and keep yourself and your family healthy so you can enjoy the gold.

The author of the book is not HooK, Her name was Miss Calm Morrison Hoke or C, M. Hoke, the book is Hoke's book not the Hooks book.

Read the title of her book to get her name right. Read the book to get your gold right.


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## ashir (Apr 25, 2020)

butcher said:


> Glad to see you recovered some gold from your efforts.
> 
> It is good to see the gold, but I am not as interested in seeing pictures of the gold, as I am of seeing pictures and getting tips on how to treat the waste solution properly from extracting the gold from these salts, that is what I wish to learn more of, see more discussions of how the toxic solution is handled after the gold is melted...
> keep studying and you will get better at these skills.
> ...



Thanks for correction. It was a side process while I am interested in ewaste manually saperate parts. Especially in IC chips and mlccs. 
Small scale , to learn the metals as basic experiments. 
And yes it's hoke's book that's the key to learn basics. Thanks,
There was less experience on metals that were used in pins,( find some brass,copper. Steel even some kovar) 
At the time concentrating related to ores, 
For next time to process pins , sulfuric cell is to be said best and also find a geo's post about sodium thiosulphate leach
https://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=19973&p=204853#p204853

But will take ores to be preffered as I am in there from 3 years, thanks


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## solarnevo1 (Apr 28, 2020)

Maybe you should use more nitric acid. Take few pins from lot and trow it in hot nitric. After some time pin's will disolve and if copper is cemented on gold surface you will be able to see gold flakes. If you have this case filter solution and add more nitric. For 800 gr of pins you will meed atound 3,2 l of nitric and 3,2 l of water.


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