Salt and Vinegar Gold Recovery - day 6

Nothing much new but here is a picture of the bare pcb fingers.  

Most of the gold is off.  Still has 2 days to go at least.  These may stay in the beaker until the 11th due to my day job.

Salt and Vinegar Gold Recovery - day 4&5

So all the exciting stuff has already happened.

We just have the seafoam blue liquid.  You can see some gold foils when stirred up.

They are there.  Tomorrow I will pull out a board or two to look at.

Salt and Vinegar Gold Recovery - day 3

So this is around 1am.  The liquid turned a dark emerald green.

It also had a lot of green bubble around the fingers.

I stirred it up and added about 20-40ml of hydrogen peroxide.  I did this for no other reason than I only had a little left and wanted to see what it would do.  Well it started foaming up pretty bad.  There was also some dark brown foam.

By the morning it turned to that seafoam blue color.  This is a thick liquid.

From this point on you cannot see much.  I will just have to wait.

Salt and Vinegar Gold Recovery - day 2

So it has been 24 hours and the liquid is now a really dark blue.

The liquid was stirred and you can see gold foils.

Hard to photograph as they move fast.

Salt and Vinegar Gold Recovery - Again, day 1

In the last series of posts I recovered quite a bit of gold foils from 200 grams of trimmed gold circuit board fingers.

I also for the fun of it dropped 0.8 Troy ounces of copper out of solution by adding some scrap aluminum to left over waste.

This time around I am using the same formulas as before.  The only exception is I have 239.4 grams of trimmed fingers.  Plus some leftovers that still had gold foils from the last batch that need to be rerun.

All set up and ready to go.  I add all the vinegar, salt and hydrogen peroxide and turn on the air.

This after just 30 minutes.

Will post updates daily on this batch.  Stay tuned.

How to recover gold with Salt and Vinegar - Part 3

Recovering dissolved metals in the waste water.

Since we are recovering gold foils from trimmed circuit board fingers we know we have fiberglass, gold and copper.  It is safe to say the blue color in the liquid comes from the dissolved copper under the gold plating.  I figured this out when funneling the liquid into 1 gallon milk jugs.  All I had was a metal funnel with a stainless steel screen in it.  It immediately produced a result by dropping copper on the screen.

So my first genius idea was to boil down the solution and concentrate it.  Then add aluminum to drop the copper.  But since my hotplate failed on me I only had one of these.  It did not work fast enough.  On to plan two.

Dump it all into a 5 gallon bucket and add a scrap of aluminum.  This is only after an hour and the liquid is close to clear in color.  Also a heavy vinegar scent coming from the liquid.

This will be filtered and the copper will be melted.

How to recover gold with Salt and Vinegar - Part 2

On to part 2 recovering the foils.  There are two ways this is accomplished, with and without Hydrochloric Acid.  In chatting with sreetips on YouTube I found that filtering the light blue liquid clogs the filters.  He suggested using some HCL to dissolve the light blue foam.  I did not get photos of this process.  I used a bit of tap water to wash down the sides of the beaker.  Then I added 100ml of HCL 25ml at a time.  It took all 100ml to dissolve the light blue foam and make it a green liquid.  Then I ran it through a strainer into a 5 gallon bucket.

What was left behind in the beaker.

Take time to wash every piece of trimmed circuit boards to make sure no gold foil remains.  A lot will fall through the strainer.

Keep cleaning the fingers and separate them into different groups.  The clean fingers are now just fiberglass boards and can be discarded.  Pieces with foil will have to be run again. Gold foils in another beaker.

Keep adding more water and wash the gold.  You want to keep all the gold you can in a bucket.  Strain into a beaker with a coffee filter or two paper towels.  Do this until the water is clear.

Once all the blue water is taken off the foils save it for part 3.  Wash the gold foils into a clean container so they can be refined later.

Next time part 3 what to do with the waste liquid.