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

Hey man, thanks a bunch for this extensive response, this dude really needed this lesson. You just might have saved his and other lives. I never mess with anything dealing with chemical changes. I cheated in college to pass chemistry, its not my thing. I hope this guy listen and take your words seriously. Thanks again.