Gold will not drop

[Alondro]

Just curious about the source of your scrap. Here is the reason. Last summer, a bunch of gypsies claiming to be from Dubai, were all over Colorado. They had a song and dance about getting their ID's and money stolen, but they had a bunch of jewelry stamped 14k + 18K. They sold it for 1/2 of spot. Problem was, there is absolutely no gold in it. It assayed something like 70% Copper, rest Tin, Zinc, and to give it a high specific gravity, Actinium. When put in Nitric, the stuff practically explodes, it is so reactive. A lot of people got suckered by these a--holes. The residue looks just like what you have, hence the question about the source stock.

Actinium?! I think you mean cesium or barium, both of which are extremely reactive in water, and in acid would indeed produce an explosive reaction. Actinium is HIGHLY radioactive and has a half-life of only 21 years. It's produced in reactors in only milligram amounts.

 

[kurtak]

I put a about a foot of 1/2 inch copper tubing in the solution at 1ph to 2ph and no heat, using air to agitate. 95% of the copper dissolved and nothing dropped.

Per the bold print - If the copper is still dissolving then the cementing process is not done so you need to keep adding copper until it stops dissolving the copper --- the gold will not drop until the cementing process is done

The solution appears even blacker now.

yes the solution is going to get darker as more copper dissolves

How should I proceed at this point?

continue adding copper until you are sure no more copper is dissolving - then let it (the solution) sit for a day so any gold settles to bottom of beaker (you should be able to see the settled gold on the bottom of the beaker - because the solution is VERY DARK you may need to look up at the bottom of the beaker to see it- (IF - gold was in the solution) - decant &/or siphon the solution off & start the washing process of the settled gold (IF - in fact we end up with cemented gold)

We will discuss that washing process - IF - we actually find gold - at the end of the cementing process (which is not completed if copper is still dissolving)

Kurt

 

[kurtak]

Is this what cementing is supposed to look like? This only after about 2 hours of letting the copper sit in the solution with heat.View attachment 48442View attachment 48443

Sorry I did not see this until today - but yes - the brownish/tan that you see on the copper is clearly gold

Will talk about those pics when I get more time

one question though --- what did you do with that copper - as in did you put it back in the solution (to continue with cements process) & or clean it off first - if so how did you clean it

Kurt

 

[kurtak]

Opps - we need to back up just a bit from my first post today in which I said to continue with the cementing process

BUT - first you should do a stannous test - just like the one where I had you put two drops of the solution on paper - then put a drop of stannous on just one of the drops of the solution

If you get the same kind of result then where you get purple/black with the stannous - then continue with the cementing process

Clearly based on the pics you posted of the copper there is/was gold in solution

the whole purpose of stannous testing is to "first" see if gold is in solution - & then further test to see if/when all the gold has been dropped/recovered from solution

So you test until you get no more positive result

Kurt

 

[Alondro]

Opps - we need to back up just a bit from my first post today in which I said to continue with the cementing process

BUT - first you should do a stannous test - just like the one where I had you put two drops of the solution on paper - then put a drop of stannous on just one of the drops of the solution

If you get the same kind of result then where you get purple/black with the stannous - then continue with the cementing process

Clearly based on the pics you posted of the copper there is/was gold in solution

the whole purpose of stannous testing is to "first" see if gold is in solution - & then further test to see if/when all the gold has been dropped/recovered from solution

So you test until you get no more positive result

Kurt

I had an interesting result when I dissolved a small test batch of lightly-plated pins about a year ago (just 20 grams of low-grade pins, a test to see if total dissolution in nitric would permit recovery... it doesn't! Makes a lot of goo, insoluble aluminum nitride and tin oxynitrate from brass and so forth). I used some old hydroxyquinones (high purity, but too old for the lab I worked at to risk using for high-precision experiments any longer) to try and reduce it, and it created a thick dark red-brown ooze. So, I slowly dried it and had a brown, crumbly glassy material that resembled partially-burned sugar. On a whim, I crushed and mixed it with charcoal dust and heated it over an alcohol flame several times in a small steel dish, cooling and remixing with the carbon, heating each time to a red glow until the carbon all burned away.

Then, I washed the results in a test tube and shook it gently for several minutes to settle anything heavy at the bottom... and viola! Tiny beads of gold had been produced! They were so small I had to use the best magnifying glass I had to see them, but there was a fair bit of it which collected into a little glittery yellow blob at the bottom of the tube. I was then able to use HCl and a couple drops of bleach to dissolve and recover it from the rest of the sediment.

I suspect the heating over and over gradually concentrated the diffuse gold bound to the organic material, and perhaps reduced a little more that was held in covalent complexes with other multivalent metal salts. I've heard that this process takes place in mountain woodlands where tannin-rich tree roots (like oaks) can leach out and deposit very fine gold dust as they dig into rocks, then die and break down. I've also seen papers describing processes by which certain bacteria and fungi can concentrate gold into finely-divided particles by similar organic chemical processes.

Further digging found a method using hydoxyquinones to create gold nanorods for biological and nanotech applications.

So, it appears hydroxyquinones can grab even slight amounts of gold from a very messy solution, BUT it takes a fair amount of work to recover it as it mostly comes out in nanoscale.

 

[sleepyman1]

@kurtak I will continue with the copper tomorrow. Thanks for the update.

@Alondro WOW, you're taking about using plants to find gold. You are WAY beyond my skills friend, thanks for contributing though.

 

[Barstool miner]

@Lino1406

I don't have any SO2 so I don't know what it smells like. It does have a strong odor though. Not as strong as HCL but its there. Probably because I have so much water and SMB in it???

@acpeacemaker

Thanks for all that but my gold has already been dissolved in the HCL bleach solution. I mixed my SMB with water and then added it. It's been on low heat for 2 days now and nothing has dropped. The solution is a light green color now. What the heck am I doing wrong? Getting nervous.

SO2 smells like burned matches , Lay man's talk "the gas is called Sulphur Dioxide

 

[Alondro]

@kurtak I will continue with the copper tomorrow. Thanks for the update.

@Alondro WOW, you're taking about using plants to find gold. You are WAY beyond my skills friend, thanks for contributing though.

Nah, I've just researched the heck out of various possible gold deposits and natural mechanisms of reducing gold in situ. When you actually get out into the field and look at the vast area of rocks and trees... it all becomes overwheming! It's simply a cool this to look for if you find a vein that look promising, especially if there are sulfides. Scrap some material around any oak roots (or black walnut) piercing the rock, especially if there's a lot of organic-looking brown staining from them, it might tell you something useful.

You can use black walnut husks and shells as a source of hydroquinones too. There are some protocols for the extraction. BUYING hydroquinones are expensive, and the high purity of lab-grade isn't necessary for this sort of method.

This autumn when there are lots of black walnuts, I may try the entire protocol from start to finish and see how it works on a modestly dilute gold solution to recover organic-gold complexes as the red-brown goo.

 

[Martijn]

Before you go using this compound that is made up of benzene look at the safety aspects.
From wiki:
"The FDA stated that hydroquinone cannot be ruled out as a potential carcinogen"
Burning that to ash might not be a good idea.

 

[kurtak]

I had an interesting result when I dissolved a small test batch of lightly-plated pins about a year ago (just 20 grams of low-grade pins, a test to see if total dissolution in nitric would permit recovery... it doesn't! Makes a lot of goo, insoluble aluminum nitride and tin oxynitrate from brass and so forth).

I am sorry but this post is absolutely FULL of mis-information !!!

First of all - lets talk about the pins (from electronic scrap) the pins can be made of "many" different metals

so what acid you use will depend on the pins

pins can be brass - an alloy of copper & zinc - the most common type pins - & will most certainly FULLY dissolve in nitric

or they can be made of phosphor bronze - an alloy of copper & tin - & although found in E-scrap are less common then brass pins - because of the tin in them - yes - nitric will cause the "goo" you saw - (we will talk more about that goo) therefore your 20 gram sample was likely phosphor bronze

my point is that just because you had 20 grams of phosphor bronze pins does not mean that nitric doesn't work to dissolve pins because the fact is MOST pins are brass which will fully dissolve in nitric

then - though rare - pins can be actual copper - which again will "fully" dissolve in nitric

Then there are pins made of kovar - most commonly found on CPUs - they will dissolve with ether nitric or HCl - kovar is very difficult to dissolve & the acid (nitric or HCl) needs to be HOT - straight "hot" HCl works better then straight hot nitric on kovar - however --- you can improve the dissolving of kovar by using nitric with the addition of some sulfuric - it takes VERY LITTLE sulfuric to improve the reaction of nitric on kovar

then there are SS (Stainless Steel) pins - also not real common - nitric does not react with SS so wont dissolve them - HCl however will - but slow doing so & creates a lot of waste - so there is another method that can/will recover gold from SS pins - it's call reverse AR --- reverse AR is a bit of a tricky process that uses MORE nitric & VERY little HCl - but it will strip (dissolve) the gold from the SS & leave the SS untouched by the acid (when done right)

Now then - lets talk about aluminum & nitric (& the supposed aluminum nitride goo)

Nitric - unless VERY dilute - does not react with aluminum - rather - what nitric does with aluminum - is it creates a VERY thin (few atoms thick) aluminum "oxide" layer on the surface of the aluminum - that (few atoms) oxide layer creates a passivation layer thereby preventing the nitric from reacting with the aluminum - in other words - prevents the nitric from dissolving the aluminum &/or turning it into some kind of goo

Now then - lets talk about this so called tin oxynitrate (or tin goo)

In the world of refining - that "tin goo" is called meta stannic acid (or stannic tin for short) - & yes - that goo is caused by the reaction of tin with nitric - which can be the result of solder or bronze (not brass)

Therefore - though yes - when processing pins with nitric - you may well encounter this problem of meta stannic acid (the goo) - whether as a result of solder - or bronze --- there is actually a "very simple" way of dealing with the stannic tin

First (like most every other process we do in refining) you wash the acid out of the solids --- in this case it would be the gold foils along with the stannic tin

Once you have washed the (nitric) acid out (at least MOST of it) you can then dry the foils & stannic tin

after drying you then incinerate the foils/stannic tin

the incineration process causes the stannic tin to convert to tin oxide - the tin oxide can then be simply dissolved away with HCl - which then allows you to dissolve your foils with AR or HCl/bleach

You can read more about dealing with stannic tin here

https://goldrefiningforum.com/threads/metastannic-acid-experiment.15324/#post-236142
as well you can do a search of other things I have posted about stannic tin using stannic tin as search words & my user name as I have posted much about dealing with stannic tin over the years

In other words - the rest of your post (& the B.S. about hydroxyquinones) is just that - pure B.S.

Therefore I will not even comment on the rest of your post - for there is a simple - long proven method for dealing with stannic tin - if/when created

Kurt

 

[Alondro]

I am sorry but this post is absolutely FULL of mis-information !!!

First of all - lets talk about the pins (from electronic scrap) the pins can be made of "many" different metals

so what acid you use will depend on the pins

pins can be brass - an alloy of copper & zinc - the most common type pins - & will most certainly FULLY dissolve in nitric

or they can be made of phosphor bronze - an alloy of copper & tin - & although found in E-scrap are less common then brass pins - because of the tin in them - yes - nitric will cause the "goo" you saw - (we will talk more about that goo) therefore your 20 gram sample was likely phosphor bronze

my point is that just because you had 20 grams of phosphor bronze pins does not mean that nitric doesn't work to dissolve pins because the fact is MOST pins are brass which will fully dissolve in nitric

then - though rare - pins can be actual copper - which again will "fully" dissolve in nitric

Then there are pins made of kovar - most commonly found on CPUs - they will dissolve with ether nitric or HCl - kovar is very difficult to dissolve & the acid (nitric or HCl) needs to be HOT - straight "hot" HCl works better then straight hot nitric on kovar - however --- you can improve the dissolving of kovar by using nitric with the addition of some sulfuric - it takes VERY LITTLE sulfuric to improve the reaction of nitric on kovar

then there are SS (Stainless Steel) pins - also not real common - nitric does not react with SS so wont dissolve them - HCl however will - but slow doing so & creates a lot of waste - so there is another method that can/will recover gold from SS pins - it's call reverse AR --- reverse AR is a bit of a tricky process that uses MORE nitric & VERY little HCl - but it will strip (dissolve) the gold from the SS & leave the SS untouched by the acid (when done right)

Now then - lets talk about aluminum & nitric (& the supposed aluminum nitride goo)

Nitric - unless VERY dilute - does not react with aluminum - rather - what nitric does with aluminum - is it creates a VERY thin (few atoms thick) aluminum "oxide" layer on the surface of the aluminum - that (few atoms) oxide layer creates a passivation layer thereby preventing the nitric from reacting with the aluminum - in other words - prevents the nitric from dissolving the aluminum &/or turning it into some kind of goo

Now then - lets talk about this so called tin oxynitrate (or tin goo)

In the world of refining - that "tin goo" is called meta stannic acid (or stannic tin for short) - & yes - that goo is caused by the reaction of tin with nitric - which can be the result of solder or bronze (not brass)

Therefore - though yes - when processing pins with nitric - you may well encounter this problem of meta stannic acid (the goo) - whether as a result of solder - or bronze --- there is actually a "very simple" way of dealing with the stannic tin

First (like most every other process we do in refining) you wash the acid out of the solids --- in this case it would be the gold foils along with the stannic tin

Once you have washed the (nitric) acid out (at least MOST of it) you can then dry the foils & stannic tin

after drying you then incinerate the foils/stannic tin

the incineration process causes the stannic tin to convert to tin oxide - the tin oxide can then be simply dissolved away with HCl - which then allows you to dissolve your foils with AR or HCl/bleach

You can read more about dealing with stannic tin here

https://goldrefiningforum.com/threads/metastannic-acid-experiment.15324/#post-236142
as well you can do a search of other things I have posted about stannic tin using stannic tin as search words & my user name as I have posted much about dealing with stannic tin over the years

In other words - the rest of your post (& the B.S. about hydroxyquinones) is just that - pure B.S.

Therefore I will not even comment on the rest of your post - for there is a simple - long proven method for dealing with stannic tin - if/when created

Kurt

Well, there are gold-plated aluminum brass contact pins. In fact, they're still used today for AMP connectors. They aren't used for typical computer pins, but they do exist and people who get lots of AV equipment will end up with a lot of them. They tend to be very thick, so they're easy to identify. They were also used in some pin arrays from old electronics, and those are always embedded in hard plastic because the Al-brass is so soft.

And be careful of the 'pure' copper core pins. They may actually be BERYLLIUM copper, and beryllium ion is exceedingly toxic. It is a tiny, highly charged cation which displaces magnesium in many crucial enzyme reaction centers, interferes in DNA synthesis, as well as triggering a life-threatening hyper-immune syndrome called 'chronic beryllium disease' and 'berylliosis'. The body has no means to easily eliminate beryllium from itself, so it lingers far longer than even most heavy metals.

I would also urge you to look up the MANY scientific articles regarding the use of hydroquinones to create nanogold particles. I repeat: THIS WAS A PROTOCOL WE USED IN MY BIOLOGY LABORATORY to make nanogold for the DNA 'bullet' method of gene insertion. It is well-established and papers exist in Pubmed from the NIH laboratories detailing its methodology and applications. The formation of gold nanoparticles using hydroquinone as a reducing agent through a localized pH change upon addition of NaOH to a solution of HAuCl4

Note at the bottom of the article abstract that benzoquinone, the oxidation product, prevents aggregation of the nanoparticles. However, if a method as added to break down the benzoquinone, the particles WILL aggregate and fall out of solution. If the solution is dried, its a mix of gold, salt, and organic molecules. Thus, burning the organics away and washing away the salt will leave fine gold dust.

It's not usually recommended for typical gold recovery, because commerically-available hydroquinone is far more expensive than any other reagent. However, if you find a source of it, it's VERY efficient if the protocol is followed explicitly, and was used commercially for a time to recover gold from electronics manufacturing waste streams of metals dissolved in mixed acetone and HCl, since the hydroquinone reaction was not affected by the presence of acetone.

 

[orvi]

Yes, copper is very weak for general use in manufacture of pins. I never heard of the beryllium copper alloys used for pins (but could be the case in some old stuff, who knows) - much more frequently it is used as spring material in relay contact as holding metal "fingers/springs". As kurtak said, I mostly found the pins to be some sort of bronze (XRF mostly close to 90/10 CuSn), and these were difficult to process by classic AR procedure. I sticked with I2/KI method on them, despite some small loss of value due to reprecipitation. But from the first time, I learned, that you could very efficiently "sand off" the reprecipitated gold from the deplated pins with handful of coarser sand in tumbler for couple of minutes Getting close to 98% recovery of gold, compared to more painful AR. I cannot afford straight nitric leaching due to nitric "inaccessability" in larger quantity. So I improvised this approach. KI is not an issue for me to get and recycle. Processing is very quick following this route.

I was aware of hydroquinone use, because of small particle/nanogold formation. And also because I known very well about benzoquinone irritating properties nasty lachrymatory stuff. If you are doing the thing in a hood, you should be OK, but I must warn that benzoquinone penetrates gloves. Not very quickly, but it does. And it sublimes very easily, filling the room with unbearable irritating itchy vapors. If you do not pay attention, you will be crying uncontrollably (a lot) if you let that benzoquinone saturated aceton somewhere on the bench

As organic chemist, I cannot see how you easily break down the benzoquinone. This won´t be a trivial task to do, I assume. Maybe some nucleophile will do the trick, but pouring more chemistry to the pot isn´t most clever way how to do recovery. Altough, somebody with easy access to old photographic chemicals stuff maybe appreciate it

 

[sleepyman1]

All of the copper has dissolved so I put another 8 inches of 1/2 inch copper tubbing in it. Nothing has dropped.

 

[sleepyman1]

All the copper dissolved again. I put another 8 inches of copper tubing in today. Nothing has dropped.

 

[sleepyman1]

@kurtak

Kurt, you mentioned way back that some gold could be trapped inside the solids, the crystals. What should I be doing with those? Could I start processing those? With your instructions of course.

 

[Geo]

Any pins that are springy, in other words it holds pressure against the other contact point, will be phosphor bronze. Header pins, like ide pins that are straight and pointy, are just brass for comparison. There are also copper-beryllium (CuBe) pins in old electronics. CuBe is also used as spring metal that carries an electrical current. While Be has been phased out of commercial electronics, it is still used in non-sparking tools used in explosive atmospheres or other applications where sparks are prohibited. Remember, if the pin is naturally curved or bent, it holds pressure against something and will be phosphor bronze.

 

[Geo]

If you dissolve copper into AR, at the end of it all, you will have CuCl2. Not really suitable to use as AP because of the contamination of free oxidizer. CuCl2 will dissolve copper until the solution is saturated. If there is the slightest amount of free oxygen or oxidizer in the solution, it will continue to dissolve copper AFTER the solution is saturated with copper. Naturally the solution can't hold that much copper in solution so it expels the excess copper out of solution as CuCl1 (CuCl) which is a white powder. It looks green from the color of the solution but is actually white. It's a heavy, white solid that settles relatively quickly. To test if white solids are indeed CuCl, place a sample in the small container and add fresh HCl to it. If it dissolves into green solution, it was CuCl. Any solids that are not dissolved in fresh HCl will be something else. Metastannic acid (hydrated tin oxide) will not dissolve in fresh HCl to any noticeable extent. It also will not dissolve in water. It is reasonably easy to deal will after you have to a few times.

 

[kurtak]

All the copper dissolved again. I put another 8 inches of copper tubing in today. Nothing has dropped.

If you are still dissolving copper then the cementing process is not done

Also - are doing the stannous testing as I asked

if you are you did not post the results as I asked

As a reminder here is what I asked

Opps - we need to back up just a bit from my first post today in which I said to continue with the cementing process

BUT - first you should do a stannous test - just like the one where I had you put two drops of the solution on paper - then put a drop of stannous on just one of the drops of the solution

If you get the same kind of result then where you get purple/black with the stannous - then continue with the cementing process

Clearly based on the pics you posted of the copper there is/was gold in solution

the whole purpose of stannous testing is to "first" see if gold is in solution - & then further test to see if/when all the gold has been dropped/recovered from solution

So you test until you get no more positive result

Kurt

 

[kurtak]

@kurtak

Kurt, you mentioned way back that some gold could be trapped inside the solids, the crystals. What should I be doing with those? Could I start processing those? With your instructions of course.

Sorry but it has been a VERY LONG time since we last discussed the solids - so I will have to go back & review what was discussed

I don't have time to do that right now but will do my best to do so

In the mean time - Do the stannous test & post the results like I asked - AND - if you get the same result from the stannous test that you got the first time I had you do it --- continue with the cementing until it stops dissolving the copper

Kurt

 

[Martijn]

To help Kurt out, maybe this thread should be copied in to one without all the sidetracks to stay focussed and keep it manageable.
This is turning into a monster for Kurt.
And way to confusing for sleepyman imo.