question about gold recovery

I'm going to be hard on you because you need to take what I say seriously, in order to keep yourself any anyone else close enough safe.

The processes and acids used in the dissolution of precious and base metals can be dangerous and deadly, when I say deadly I mean exactly that, DEADLY. You have no business playing around with acids if you don't understand even the most basic concepts, for example, hydrochloric acid is not going to dissolve any gold unless there is excess oxygen present, that means there needs to be some type of oxidizer in solution. Matter of fact, hydrochloric acid at room temperature is not even going to dissolve the copper under the gold plating.

You have a lot of reading to do before you can even entertain conducting what are called familiarity tests. These are tests conducted in small test tubes so that you can observe the reactions and understand what is happening. A good portion of recovering and refining precious metals has to do with observing your chemical reactions and understanding the results so you can dynamically attend to your solutions. This isn't a recipe you follow, this is real life chemistry where you need to understand what is going on so you know what you need to do.

Even after you have read, performed tests, have confidently refined for years it's no guarantee that something will not happen. In no uncertain terms I can say that you have no business even asking these questions if your intent is to attempt the dissolution of metals in acids. Do not even try, not until you have read and learned enough to understand what you are proposing.

These are pictures of acids dissolving precious metals in a closed reaction system:







The brown rusty/red gas that you see in the pictures can be absolutely deadly. This is why I have them connected in an enclosed reaction system. If you notice, as well, they are vented through a condenser which pumps chilled water through a glass coil or tube and condenses some of the gases back into the solution. What you do not see is the extensive fume scrubbing equipment that the fumes go through before entering a catalytic converter fume scrubber, before being vented into the environment.

Aqua Regia alone (the solution used to dissolve gold) is deadly even before precious or base metals are added to it to be dissolved. Here is an excerpt of the MSDS on Aqua Regia.

Hazards Identification

Emergency Overview

POISON! DANGER! CORROSIVE!

CORROSIVE. LIQUID AND MIST CAUSE SEVERE BURNS TO ALL BODY TISSUE. MAY BE FATAL IF
SWALLOWED OR INHALED. INHALATION MAY CAUSE LUNG AND TOOTH DAMAGE.

Potential Health Effects
Nitric acid is extremely hazardous; it is a corrosive and a poison. In concentrated solutions it is an oxidizer.

Hydrochloric acid is a corrosive.

Mixtures of nitric acid and hydrochloric acid may form aqua regia releasing toxic nitrosyl chloride (yellow to
reddish-brown) gas.

Inhalation:
Corrosive! Inhalation of vapors can cause breathing difficulties and lead to pneumonia and pulmonary edema,
which may be fatal. Other symptoms may include coughing, choking, and irritation of the nose, throat, and
respiratory tract.

Ingestion:

Corrosive! Swallowing nitric acid and hydrochloric acid can cause immediate pain and burns of the mouth,
throat, esophagus and gastrointestinal tract.

Skin Contact:
Corrosive! Can cause redness, pain, and severe skin burns. Concentrated solutions cause deep ulcers and stain
skin a yellow or yellow-brown color.

Eye Contact:
Corrosive! Vapors are irritating and may cause damage to the eyes. Contact may cause severe burns and
permanent eye damage.

Chronic Exposure:
Long-term exposure to concentrated vapors may cause erosion of teeth and lung damage. Long-term exposures
seldom occur due to the corrosive properties of the acid.

Aggravation of Pre-existing Conditions:
Persons with pre-existing skin disorders, eye disease, or cardiopulmonary diseases may be more susceptible to
the effects of this substance.

I hope you take what I am saying seriously, and don't attempt to play around with dissolving any metals into any acids until you know enough to respect what you are proposing.

If you posted this on the GRF forum you would have been torn apart. If you seriously want to learn about this that would be the place to ask these questions, not here.

Scott

Phantom-
I have also done my reading and homework into the very same idea you had. Also came up with the same conclusion. Not having someone that has the knowledge and time to walk you through each step is asking for trouble.

Originally Posted by unknownk

MSDS sheets are designed to make common chemical sound worse then nerve gas

If you do a little reading, you will probably realize, in this case at least, that the MSDS doesn't express exactly just how dangerous what I am talking about and attempting to express, is.

Miners used to call the gases that evolve from this type of dissolution of metals "the red death", what we call NOx today. Metals were dissolved during the assay process and would float down to a miners tent who was often times sleeping. After breathing in the gas they just wouldn't wake up. Many miners died this way.

In this case the MSDS is dead right, there is no exaggeration. In the future, on these types of posts, you might want to think about what you are posting before you discount the MSDS or the seriousness of what a person is talking about. Attempting to make something seem less dangerous than it actually is may lead someone in the wrong direction, and cause themselves or someone else serious harm.

As far as waste is concerned, if you understand how to deal with it there is never any waste. So long as there is metal that is recoverable in solution that has value, the solution is not considered waste by the EPA. Using the reactivity series, you can cement each type of metal out of solution and then finally precipitate the last metals with sodium hydroxide and end up with what is essentially salt water, which is not considered waste material. But in order to understand what I just said, and how to do it, you would also have to understand enough about chemistry and have enough experience to be able to reduce solutions from acidic with metals, to just salt water.

Scott

Originally Posted by shendog

Thanks for the great input/warning/photos. It certainly makes life easier when someone with knowledge can share pertinent information on a topic of interest. The fact that you probably added years to the lives of many people is icing on the cake. Good job.

On a lighter note, I half expected to see Cheech and Chong on the other end of those tubes Scott.

Funny you should say that...

I know a refiner who has an employee who is a bit of an artist. With just marker pens he drew a picture of Cheech where the inlet pipe is to his fume scrobber, that makes it look like the clear pipe going into the scrubber is a pot pipe, and he's smoking it. Now that is a coincidence!

Scott

eesakiwi
That's where the saying "Sh*t happens" comes from.

Originally Posted by rckww7

WOW I'm not too sure what to say. What I am atempting to do is loosen the plating so I can separate it. I have researched this and have friends that do it.

If you have researched this, you would already know the process to remove, not loosen, the gold plating from the finger boards. You would know how to do it, or you would at the very least know that hydrochloric alone will not work unless under heat and under specific conditions. You would also realize that this is not the method of choice, nor the suggested method to do what you are suggesting to do.

Go to the Gold Refining Forum and search the process area for AP (Acid Peroxide). Check Laser Steve's site, you can get there off the forum, he is selling a video with instructions on how to use the AP process to remove gold foil from fingerboards, specifically.

So far as having friends that do it, if you do why are you asking on this forum how to do it, and not them. If you have a resource like that, then you should be utilizing it.

So far as your safety and process equipment is concerned, I would question how you were able to know what to purchase if you do not yet even understand the processes. I am fairly certain that you do not have the processing equipment for AP, which again would be the correct way to process finger boards.

If I embarrassed you by stating what to me is the obvious because I process and refine, I apologize, I don't want you to feel it necessary though, to suggest you have done anything you have not done, in order to save face. Frankly speaking, you have no clue what you are suggesting as evidenced by your first post, and you need to stop thinking you have any clue how to proceed and listen to my warnings and what I am trying to impart to you. I will stop trying to point you in the right direction if you do not stop trying to make it seem you know more than you do. I am here to help people and learn myself, I am not here to play footsie and coddle your ego if that is the case. I might hurt your feelings or upset you, but frankly helping you save your life is far more important.

When you say safety equipment what are you talking about? An acid spill kit? A plan to escape your work area in case you have a spill? A breathing apparatus with 15 min of air in case a bird flies down your vent pipe and blocks it, or the electricity goes out or your fan stops working for some other reason and fumes start building up? Do you have a fume hood, and is it far enough away from your emergency exit so that you can escape without breathing in poisonous, noxious, and deadly fumes?

Or are you talking about goggles and gloves?

When you say fumes will be directed and vented outside, are you taking into consideration how many feet above the ground that vent needs to be? Because these fumes we are talking about are heavier than air, and will fall to the ground, and need a specific amount of space between where they are vented, and how tall a human is so they can disperse enough not to affect breathing of any humans in the area, like next door neighbors, or even their pets.

And this is all just off the top of my head, I am serious about safety and doing things properly. Most of your budget being spent on safety equipment doesn't mean squat unless it's the proper safety equipment. If OSHA or the EPA were to inspect your suggested work area, would it pass muster, and if you say yes to that question, how do you know?

If you are doing this as a hobby, I can understand your not taking on the more extreme safety precautions, I don't agree with it but I understand, money might be tight and what I propose would cost a pretty shiny penny, and several thousands of dollars to boot.

And if you think I am mad, you are right, the fact you seem to be taking this all so lightly bothers me greatly and I want to make it clear for others that might read this post after, that your entire attitude towards all of this is a little bit self serving, and seems full of saving face rather than posting anything honest and useful for people that read later. I would have been far more impressed if you simply stated something to the effect of "You are right, I need to read more, thank you for trying to help me" rather than what you have posted.

I also would never say I am a long way off from killing myself, all that separates me from a fairly certain death is a little bit of laboratory glass. You are far closer to harming yourself and doing damage that could cause death than you ever would suspect. Until you realize just how seriously dangerous what you are proposing to do is, you shouldn't be doing anything at all!

Scott

Rck- I dont think you are going to get the answer you are looking for on this forum. I believe Noble said that if you have questions regarding refining, the gold refining forum is where you should be looking. If you are set up properly I am sure that if you explained your set up over there and explain exactley what you are looking to do and the process you are going to use someone might help you out. But trust me when I say this, the people there stress safety first and will smell out a newb in a split second just by the questions you ask. There people in the industry and lifelong home refiners that will not jeopardize their livleyhoods by giving out information to anyone that doesnt know what they are doing, causing someone to get hurt or worse, and then try to point their finger at them saying he told me to do it this way.

What I did do later, and its seems a lot safer & simpler. But it takes months to happen.....
It takes the Copper & Brass pins away from the Gold, rather than trying to get the Gold off the pins. So the golds still in its plated state & form & shape & carat. Only its broken up a lot & will also be a brown powder as well as a gold flake looking Gold.

It is NOT refining gold. It will not be a higer carat than it started at & if melted, will probably be lower is its not going to get all the contaminents or plastic or carbon out.

--------------
Though I'm going to make a disclaimer just because I have found out from lots of experience..... That just because I can & have done it, doesn't make it safe for anyone else to do it, or even attempt to do it.
In fact I have seen lots of people fail spectacularly at what I have done, which probably means I hang out with ****heads... '
'Cous they can't even do what you guys here can do daily. Thats a complement for all you SMF members.

This is also what I have done, I'm NOT telling you to do this. I wear all the safety gear.
Again. Do NOT Do this. Or even attempt doing it.

---- example of failure
I went tramping when I was 13, on a two week trek & I carried all of my own food & gear etc. Big deal, atlas shrugs, so do I.

(just a word about 'tramping', tramping is when you go into the bush & tramp it, ie stand on the bush a tramp it down & make your Own track. In remote places where no ones ever walked before.
'Trecking', or 'bush walking' is when you have had a whole bunch of people go out & tame the area & make a flat track that someone in a bloody 4WD wheelchair could travel on.
Then you walk on that. Sorta like a walk in the park... Which it is)

So years later I'm talking with someone who is 35+ & a experienced tramper & he asks me about tramping & I mention my tramp & he thinks him & a bunch of others may do it.
Well if a 13 yr old kid can.....

I find out a lot later. They did try it, 3 days later they use their emergency ph to call up a private helecopter & pay good $$$$ to get them out.

Because, as soon as the absolutley flat track stopped, they relised they were not cut out to do what I could, as a 13 yr old....After their little 3 day wussy nature walk............boo hoo.

----------------------

Ok, back again.

My bench is rib height, that way I can't spill stuff onto chest area or above. Its in bright sunlight so I can see & theres plenty of fresh air & no breezes.

I put the cleaned pins, about a cups worth (washed in warm/hot HCL to remove the solder & washed again in water) in a glass jar. The jars a litre jar. Like a mason jar (yes yes a mason jar, sorry ^)
Added some HCL, about 5mm deep in the jar. I used the green stuff left over from the first, ah, learning curve.
New HCL would work.
Mixed it a bit to get the pins wet & I let it sit somewhere safe from disturbances (I live alone) & it will slowly corrode the pins. It took a while to start off.
Once its started it gives the HCL acid something to Bite or soak into. That will help keep the HCL up in the air & on the exposed pins.

The corrosion is like the rust on iron, except its light blue/light green/white, crumbles easyer & it happens only above the HCL acid level, like in the air only.
The wet HCL under the corrosion turns green/black if it wasn't allready like that (mine was green/black after the first, ah, chance)
It will dissolve the corrosion into the liquid if you stirr it in.

Once its started corroding I understood whats happening.

So, once its started, I gave it a little stir each day or two to get the pins wet again.
Some of the corrosion will be dissolved & once the pins were wet, I poured off the left over dark HCL acid into a taller glass jar.
That soon seperated out & the corrosion dropped to the bottom. I poured off the top green/black HCL acid layer back into the jar & got the pins wetter again..

I did that each day or two & added more HCL acid to the pins as it was needed to dissolve the corrosion.

For some reason, no matter how much HCL I poured off the tall corrosion jar, there would be more on top the next day. Reaction of some sort I guess.

So, weeks later the volume of the pins has dropped by a lot. Theres a lot more of the corrosion in the tall glass jar. I can see the loose flecks of gold in it & also on the pins.

Weeks later after doing all this, there was almost no pins in the first jar & a lot of the corrosion in the tall jar.

I poured all the corrosion into a bigger jar & added some more of the green/black HCL acid & stirred it a little at the same time.
It didn't take much acid to dissolve all of the corrosion.
Once the corrosion was dissolved, the Gold & the plastic & the other rubbish, like carbon etc, dropped quickly to the bottom of the jar.
I used a tapered measuring jar, but any tall jars good.

A day later I could see the thick layer of Gold flake at the bottom & another new layer of brown Gold dust & lighter rubbish on top of it.
I poured off the acid & added water & let it seperate out & then poured it off. Did that a few times. Dried it.

Now I have a mush of Gold flake, plastic, oxides, carbon & other unnamed stuff in the bottom of a jar.

This is not refined Gold. I didn't weight it before or after & I have no more acid left or a way to melt the Gold.

I live alone, so theres no one to move things when I'm not there or not. Theres no one to interupt me as I work & theres no one to ask annoying questions either.
In fact, I never have told anyone of what I do here or there. Its none of their business.