Pins in AP

Hi,First time posting.I am just finishing my first batch of fingers in the crockpot.Everything is working great so far.I want to try pins and the contacts from the memory cards on the motherboards.My question is will the gold plating from the pins and contacts release like the fingers or will it dissolve in the solution?And if so can you put the SMB in the solution without filtering first?Thanks for the information so far,cant wait to melt my first button.

Welcome to the forum Kevin

Hello kevin,
You better filter it if don't want some dirt, plastic or other particules to contaminate your gold...

And Welcome !

Kevin,

AP will usually dissolve some gold at first. As the base metals go into the solution most of the gold gets precipitated out as a dark mud. If any gold remains in the solution, filter the solution and add SMB to get the gold out.

AP works on all types of plated scrap. With loose pins you should make sure the pins fully dissolve before filtering out the gold mash. Plenty of HCl washes will clean up any very small pieces of pins mixed in the foils.

Steve

I have tried on two separate occassions to see if the AP method would work for pins. It does and it does not. It does attack the base metals but uses a lot of the solution to absorb the copper and other base metals and it does take a long time for all the base metals to completely dissappear.

I personally recommend the cell method as it is quick, controlled, and efficient. There is a bit of set up needed but when you have all the parts it does work very well. The major dangers being the sulfuric acid used and electricity. Steve has a video tutorial about how the cell works and I use it quite frequently for pins.

Hi, I just finished deplating a lot of pins. I followed the instructions that steve posted. I filered the solution thru 3 coffee filters and collected a heavy coat of black paste. The solution still looked very black so I ran it thru 3 more filters and got about the same amount of black paste. However the solution still looked black.

I put the solution in a vision ware pot and boiled it down till about one third was left. It was very thick and the sides of the pot were covered with the black paste (gold I hope).

How many times do you have to filter the solution to get all the gold out? Is it all right to boil away all the liquid and the process the filters and paste from the pot in AR?

Bob Noble

Bob,

When your cell is full you should:

• Let all the black powder settle
• Pour off the bulk of the concentrated sulfuric acid. Don't worry about the small amount of residual black powder that is in the acid that is poured off as you can get it on the next batch.
• The remaining acid with the bulk of the black powder in it should be slowly added (let it cool before adding more) to five or six times it's volume of water.
• Stir this very well and allow to settle again.
• Siphon off the colored solution. Repeat this process until the wash is no longer colored.
• Test a few drops of the rinse water with a drop or two of 3% unscented clear household ammonia, if the rinse water turns blue when the ammonium hydroxide is added, copper is still present and more rinsing is required.
  
  
• Combine the washes and boil this down for reuse.
• Filter the rinsed black powder.
• A short boil in HCl followed by several water rinses will further clean the gold powder.
• Incinerate the black powder to a red heat. DO NOT MELT.
• Dissolve the black powder with AR or HCl-Cl and proceed as typical for these processes.

The concentrated acid that was poured off is used in your next cell run as is. Hot concentrated acid is very dangerous, so exercise extreme caution when handling it. Never add water to concentrated sulfuric acid/powder mixture, add the acid/powder slowly to the water instead.

If you do not rinse the powder throughly before filtering the acid in the liquid will dissolve the filters. This may be why so much of your powder is passing through the filters.

Incineration is a critical step to ensure the highest purity product.

Steve