Jewelers Polishing Wheel Waste Experiment

Gold Refining Forum

Help Support Gold Refining Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

kadriver

Well-known member
Joined
Oct 25, 2010
Messages
1,830
Location
United States
Here is 260 grams of waste removed from the hood of a jewelers polishing wheel.

It is course grit with some kind of wax as the binder for grit.

We scooped it out of the back of the hood with a plastic spatula.

I placed the material into a clean Corning ware casserole dish and put it on high heat.
 

Attachments

  • P1260262.jpg
    P1260262.jpg
    531.4 KB · Views: 1,547
  • P1260261.jpg
    P1260261.jpg
    625.4 KB · Views: 1,547
After about 30 minutes on high heat the material began to bubble and smoke.

It smelled like burning wax, this is how I concluded that wax was the binder for the grit used by the jeweler to polish gold jewelry items.
 

Attachments

  • P1260265.jpg
    P1260265.jpg
    171.7 KB · Views: 1,546
  • P1260263.jpg
    P1260263.jpg
    521.8 KB · Views: 1,546
I wanted to use a small propane torch to aid in the incineration of the material, but it immediately ignited a soon as I put the torch to it.

Not wanting things to get too hot, I covered the dish to extinguish the flames.
 

Attachments

  • P1260269.jpg
    P1260269.jpg
    619.6 KB · Views: 1,546
  • P1260268.jpg
    P1260268.jpg
    566.8 KB · Views: 1,546
  • P1260267.jpg
    P1260267.jpg
    531.3 KB · Views: 1,546
After a couple hours the material became brittle with most of the wax burned off and I began to brake it apart with a metal spatula

I then used to torch to burn the remaining wax away from the material.

It ended up as porous looking cinders that were dry and very brittle.

This process took about three hours to this point.
 

Attachments

  • P1260280.jpg
    P1260280.jpg
    897.7 KB · Views: 1,546
  • P1260279.jpg
    P1260279.jpg
    773.9 KB · Views: 1,546
  • P1260275.jpg
    P1260275.jpg
    616.4 KB · Views: 1,546
I use the shiny end of a mortar and pestle and carefully broke the pieces into as fine powder as I could being careful not to let any escape from the dish.

This was not difficult because the material was very crumbly and broke apart with little effort - a testament to the benefit of incineration in this recovery process.

This took me about 1/2 hour to get the material to this state.
 

Attachments

  • P1260284.jpg
    P1260284.jpg
    797.5 KB · Views: 1,545
  • P1260281.jpg
    P1260281.jpg
    790.6 KB · Views: 1,545
I then added about 1/2 liter (500 ml) hydrochloric acid to the now incinerated and powdered material.
 

Attachments

  • P1260286.jpg
    P1260286.jpg
    569.8 KB · Views: 1,545
  • P1260285.jpg
    P1260285.jpg
    693.1 KB · Views: 1,545
To this slurry mixture I added about 15 ml concentrated nitric acid and there was an immediate mild reaction.

I covered the dish and set it inside of a larger dish just in case it tries to boil over.

I left it this way in my fume hood to leach overnight.

More to follow on this experiment tomorrow.
 

Attachments

  • P1260290.jpg
    P1260290.jpg
    610.6 KB · Views: 1,545
  • P1260289.jpg
    P1260289.jpg
    645.7 KB · Views: 1,545
  • P1260288.jpg
    P1260288.jpg
    751.5 KB · Views: 1,545
I processed literally thousands of pounds of that material through the years.

I don't think much of your procedure. There are far better ways, and I've covered them extensively in posts on this board. I think you'd benefit by reading them.

Harold
 
Harold, I found an outline you wrote on how to process this material.

Looks like I skipped the sifting, magnet, and straight HCl treatments and went straight to AR - just like a rookie would do.

Just goes to show that I am still just an advanced beginner.

This person approached me with this material and I dived in.

We started with 75 grams of polishing sweeps and I got 3.8 grams of pure gold (I was astonished at the amount of gold)

Now that I have started with this I must finish using the process I developed myself - but I like yours better, Harold.

And I'll use it on the next batch which will probably be half a kilo.

Should the pan be made of cast iron - in your outline it just said "pan".
 
I said I was astonished at the amount of gold I got from the small sample.

But now I am flaberghasted - I completed this in just 12 hours

I will post the rest of the process I used.

I was able to recover and refine 15.9 grams of pure gold from this batch of 260 grams of polishing sweeps!

Here are some photos of the finished product.

More to follow.
 

Attachments

  • P1260367.JPG
    P1260367.JPG
    593.4 KB · Views: 1,483
  • P1260366.JPG
    P1260366.JPG
    288 KB · Views: 1,483
  • P1260364.JPG
    P1260364.JPG
    587.1 KB · Views: 1,483
Ive got a few minutes so here is the rest of the process I used

I started around 11am today by heating the mixture and letting it "cook" for about an hour
 

Attachments

  • P1260291.JPG
    P1260291.JPG
    1.7 MB · Views: 1,483
I added more HCl and nitric to the slurry to do another extraction
 

Attachments

  • P1260296.JPG
    P1260296.JPG
    693.6 KB · Views: 1,480
  • P1260295.JPG
    P1260295.JPG
    721.5 KB · Views: 1,480
After an hour or so I added the second extraction using HCl to rinse all the solids into the beaker
 

Attachments

  • P1260306.JPG
    P1260306.JPG
    706.6 KB · Views: 1,478
I kept pouring distilled water thru the solids until the filtrate ran clear of color
 

Attachments

  • P1260323.JPG
    P1260323.JPG
    790.3 KB · Views: 1,479
Back
Top