Non-Chemical Volume of gold to refine?

[Fragum]

Hey Guys,

I imagine that most of you have settled into a process that suits you when recovering and refining gold. I was wondering about the volume of scrap to process (such as fingers in AP) at one time.

Is there a limit as to how much scrap you will process at one time, and why?

Thanks in advance!

 

[Noxx]

The only limits are the volume of your containers you can handle and the volume of toxic gases released.

Your neighbours wouldn't be very happy if you make +50 liters batches
There is a lot of NOx released when using 1 liter of AR, I don't imagine it 50 times more lol.

 

[lazersteve]

Fragum,

I typically process 5-8 pound batches of fingers with AP in a 5 gallon bucket. The key is agitation. The more scrap in the bucket the harder it is for the AP to dissolve the copper due to the shielding effect of adjacent fingers to one another. They tend to press together and protect each other from solution exposure.

Another set of problems come about when filtering, rinsing, and disposing of the larger volumes and masses of material you will be handling. If you process more weight than you can lift you will need an alternate means of moving the scrap and solutions.

As Noxx pointed out increased fumes and chemical safety are always a concern when scaling up any reaction.

If you are setup properly you can scale up just about any chemical reaction.

Steve

 

[Fragum]

Thanks for the replies!

One of my concerns was determining if there were thresholds (which were discussed) surrounding either chemical reactions (fumes, heat) and/or production costs such as the escalation of chemicals used in the process.

Another concern would be the process itself. Do you stage your processes to maximize the efficiencies? for example: Let's say you process 5-8 lbs of fingers at a time. When you harvest the gold foils from that batch, do you combine this output with the output from other batches until you have a specific amount of foils (in grams) to dissolve - or do you maintain a process integrity by processing the batch from start to finish is a single lot?

I can see where the process integrity is important for the first-timers just so that there is a grasp of the entire process, but after there is a clear understanding of the process, hazards, and waste issues - I would think that moving from a linear process to a demand flow process would maximize the time involved per the gold output.

You guys have been doing this for a long time, and I want to lean on your expertise as much as I can.

Thanks.

 

[goldsilverpro]

If I understand your question, I think you're putting the cart before the horse. In my opinion, you first need to come to an full understanding of the processes. The best way to do this is by experimenting with very small lots. Only then, should you try to maximize the processes. This maximization is dependent on your particular situation - How much fumes can your setup tolerate? - What equipment do you have? - What type parts are you running? - What process(es) are you using?, Etc., etc. If you start small and gear up progressively, you'll soon be able to answer your own questions.

In reading the posts on this forum, you have surely realized that there are very few absolutes. There are just too many variables, especially with electronic materials. The closest thing to an absolute are Harold's excellent instructions for running karat gold scrap.

 

[skyline27]

Does anyone have any actual examples of processing multiple batches of foils from when they are stripped until melting. How many grams did you dissolve in Acid-Clorox? Are there benefits to concentrating your foils into one big batch rather than going A-Z with a single batch?

Any advice would be great!

 

[lazersteve]

Personally I work in a linear fashion with very few exceptions.

I will start a new batch of fingers immeadiately after the filtering of the foils to keep the 'gold flowing' if you will. This also helps me determine how much volume of the AP solution will need to be disposed of after each batch. I fill the new bucket with enough of the used AP soltuion to cover the fingers in the second batch and process the remaining AP solution for disposal.

As for how many grams of foils to process using the HCl-Cl it's a matter of effort verses scale. You don't want to process such small batches that you spend a lot of time for a gram or two of gold, and conversely you don't want to have such a large batch of foils to digest that it takes gallons of bleach unless your operation is properly scaled up for handling a reaction of this size.

I find gold drops better from solutions if there is more of it as opposed to less. A solution with very little gold will barely make a thin layer of brown mud on the bottom of a liter beaker, whereas processing 5-20 grams in a liter beaker makes for a sizable precipitation which is much easier to handle and further process.

The question of how much gold will HCl-Cl dissolve per mL is purely academic. It can be calculated if desired, but the calculated number is not necessary.

Cover your gold foils with HCl in a container that will hold two to three times the volume of HCl used and slowly add small amounts of Clorox with stirring until no foils remain. With each addition stir the reaction constantly until no more gold will absorb into the solution , then add another small dose of Clorox.

Adding the Clorox all at once or too fast just produces large volumes of Cl2 gas which will be wasted and cause you more grief in the long run. When properly performed this reaction produces very little residual chlorine gas. The gas should all work towards converting the gold into auric chloride and therefore ideally should not escape into the air.

Steve

 

[Fragum]

Awesome responses....Thanks!

 

[aflacglobal]

I just notice your avatar. That dude is running with scissors in his hand.
:lol: :lol: :lol:

 

[goldsilverpro]

Steve, have you ever tried a drip system for the bleach?

 

[lazersteve]

Not yet, but I think Steve Spevak had mentioned that previously. It sounds like an excellent idea. It may even eliminate the Cl2 fumes completely.

Steve

 

[aflacglobal]

What about that acid, Which one i can't remember. They use it in swimming pools to control the release of free chlorine in the water.
Would that help any ?

 

[skippy]

Screw top mustard bottles make pretty good drippers.