adapt process according to base metal?

[lanfear]

Hi guys. I'm new to this, so bear with me =) I have looked around, and the one question I can't seem to find an answer to is just that. Do you have to adapt you chemical processing according to the base metal?
Example: I have stripped 20 motherboards and have an accumulation of gold plated metals. Is there one process that can help me strip these?

 

[lazersteve]

There is no single tool in your refiners toolbox that works for every scrap type. Each has specific strong and weak points. It's best to work with small samples of each type of scrap and determine which reagent is best for your type of scrap. Diluted nitric acid works great on high copper and silver, but is a pain (or even worthless) if tin, stainless, or certain plastics are present. Acid Peroxide works good for finely divided gold and removing copper based material, but it's relatively slow. HCl (muriatic acid) works great on iron and tin based scrap. Aqua Regia (AR) is great for quick dissolving of metallic gold. The sulfuric stripping cell works great on medium to large sized gold plated objects.

Think of the various refining methods as tools in your household tool box. Is there a single tool in that household box that works for all jobs? No.

Steve

 

[lanfear]

Thank you. Then it seems that the sulfuric stripping cell is the best method of stripping various gold plated metals. Is there any negative effects in this process?

 

[FrugalRefiner]

Thank you. Then it seems that the sulfuric stripping cell is the best method of stripping various gold plated metals. Is there any negative effects in this process?

Well,

It's not quite that simple. Fingers are gold plated, but they're better processed in AP. CPU legs are gold plated, but difficult to run in a stripping cell. The stripping cell requires an electrical contact to the item to be stripped. That can be difficult to achieve with fingers or CPUs because you have to make contact with each contact or pin.

Other negative aspects of the stripping cell are that it uses concentrated sulfuric acid. Of the common acids we use, sulfuric is the most destructive to human tissue.

The process also doesn't lend itself well to developing yield data. Cleaning the cell and processing the recovered gold is time consuming and there's usually a little gold left in the sulfuric acid. So it's difficult to take a small sample of an item, process it to completion, and calculate the yield per piece or per pound.

Sulfuric is also highly reactive with organic compounds, so it's best to keep them out.

As Steve mentioned above, there is no single tool or process that is right for everything, even if everything is gold plated.

The more you study, the more this will start to make sense.

Dave

 

[lanfear]

Thank you guys. I can see I have a lot more reading to do before I am remotely ready to start processing. In the meantime I will harvest and watch my twinkling piles grow.

 

[bswartzwelder]

Lanfear,
Many newcomers to precious metal recovery and refining make the same mistake. They are in a hurry to have beautiful gold buttons in their hands. They do not read enough and make mistakes. These mistakes can cost them the very gold they were trying to recover, or worse yet, can be harmful or even fatal to them, their relatives, friends, neighbors, or pets. You have made a wise decision to continue collecting the valuables containing precious metals and to read. In Lazersteves signature line there is a loist of excellent reading material which is all FREE. Take advantage of it. This forum has a tremendous amount of information. It's all FREE as well. Your gold will still be there for you to process once you have the knowledge to do so. The three most important thing to remember are: 1. be safe, 2. Read and study all you can, and 3. Take your time. Welcome to the forum.

 

[johnny309]

So....according to the title in question.....
I have encountered recently some plugs made in the 60'.....base metal is brass.....the "stop" layer is Ag/Pd..(70/30)...and gold platted...
So...:
1)gold cell...out of the picture
2)AP slow...
3) Nitric ...problems with tin,but it seeams the best way around it
Your comment and suggestions are welcomed.....

 

[lazersteve]

50% Sulfuric acid with heat.

Steve

 

[lanfear]

Just curious. Why would the cell be out of the question? Is it a chemical reason?

 

[johnny309]

Just curious. Why would the cell be out of the question? Is it a chemical reason?

Because will be hard to recover silver....and Pd on the other hand.

Steve...thanks...I'll have to try it....

 

[lanfear]

Ah.. Because the cell would take those too. Need to catch up on cell's.