Remove Gold Plating from curved ceramic chunks

[colchis]

I've been reading and researching the info on this site for a few weeks, and I'm grateful to all of you that have provided such well-considered info. Scrapped a pile of mil-industrial oscilloscopes. Upon smashing the CRT s, I find thick gold plating on the interior surface of the ceramic chunks. (I was using the chunks as concrete filler before realizing what this stuff was!) Finding out how ceramic plating is (was in 1975) done is a research project. Anyone have ideas about how to proceed? I will experiment with HCl, but I have no idea of the base (metal, graphite, or other ?) access to HNO3 is not possible, and AR will likely dissolve the unknown base coating. Can post a picture if that is needed.

 

[etack]

Do AR and go on with your day. The base metal is likely not worth thinking about.

Eric

 

[goldsilverpro]

I once knew a guy that was processing 30,000 pounds of gold coated, broken, ceramic CRT scrap a month from Tektronix in Portland, OR, arguably the leading O'Scope manufacturer at that time. I spent months in that place as a troubleshooter for their vast gold plating facility. Unfortunately, however, I don't recall the numbers on the CRTs. I do think I recall that its thickness was approx. equal to the plating on fingers and pins. I could be totally wrong on this, however. It may be 10 micro". Whatever is there, is there. It should be relatively easy to get.

He used cyanide. Definitely the best choice if you know what you're doing and can handle it.

The CRT stuff is basically gold on ceramic and that's it. Maybe a trace of Pd that was used in between the ceramic and gold to get the gold to stick. You don't want to break that ceramic down with the acid to where it powders. It may or may not powder with strong acid. Therefore, until you know, I would start (you can always add more) with a weak aqua regia - maybe 50% (or more) water and say, 40% HCl and 10% HNO3, all by volume, of course. You may heat it although I think it should soon dissolve in the cold AR. Always stir things. Use the same acid for numerous batches of material and, ideally, use it 'til it's saturated (you'll be able to tell when by timing the stripping speed), dilute it 50%, filter it , and drop out the gold with SMB. Easy money.

Or, you could probably just dissolve the gold with HCl/peroxide or HCl/bleach. I'm an AR guy, myself.

 

[4metals]

You should also save the ceramics after you leach the gold, back in the day I processed hybrid electronic ceramics, and yes the activator for the ceramic was Palladium, but the ceramic seemed to absorb a small percentage of the acid and any metals it had in solution as well.

We crushed and sifted the ceramic into a uniform pulp so we could assay it, and shipped it as a low grade sweep, always got paid on gold and palladium.

 

[colchis]

Some very good ideas to ponder- AR-- I cannot invest in the Nitric acid. Basically, there's about 8 lbs of ceramic chunks, and (over three evenings) scrapped ALL of the gold plated ends of ALL the internal wiring in those old scopes (while daydreaming (nightdreaming?) about the price of Au skyrocketing to 2500) Here's something that I can offer about calculating the potential yield of a batch of gold-bearing FLAT surface--We know the total surface area of the batch, the expected thickness, and the density of Au(grams per cm3) ( by measuring the area of a small amount, weighing that small amount, and then doing the math on the total weight vice surface area) This way I can know before I begin buying chemicals, and assorted other tools. So--it seems that 8 lb mass of plated chunks will yield 30-45 grams of Au. (not counting the few shovelsful that I cast into the concrete job(I thought I was properly disposing gov waste!) So, Goldsilverpro-right on target. Much thanks on the Pd info- trace amount recovery is not in the cards for us- we're onto organic gardening in the spring, and I wonder whether trace Pd grows good kale? (If I have processed this stuff by Spring, it will seem like a miracle of modern technology) This is the best forum on this topic that might ever be, supported by the good minds and intentions of all (mostly). I will report the result, and any unexpected findings.

 

[necromancer]

pictures would be nice & you dont need to buy hi priced nitric acid, have you thought of "poor man's AR" (HCL / Sodium nitrate) or making your own ?

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=33&t=21242&p=219169&hilit=poor+man%27s+AR#p219169 please look through the terms & follow the links, FrugalRefiner (Dave) has done a great job laying this out for everyone.

i have the same problem as you, either it costs to much or i can't find it.

 

[etack]

Some very good ideas to ponder- AR-- I cannot invest in the Nitric acid. Basically, there's about 8 lbs of ceramic chunks, and (over three evenings) scrapped ALL of the gold plated ends of ALL the internal wiring in those old scopes (while daydreaming (nightdreaming?) about the price of Au skyrocketing to 2500) Here's something that I can offer about calculating the potential yield of a batch of gold-bearing FLAT surface--We know the total surface area of the batch, the expected thickness, and the density of Au(grams per cm3) ( by measuring the area of a small amount, weighing that small amount, and then doing the math on the total weight vice surface area) This way I can know before I begin buying chemicals, and assorted other tools. So--it seems that 8 lb mass of plated chunks will yield 30-45 grams of Au. (not counting the few shovelsful that I cast into the concrete job(I thought I was properly disposing gov waste!) So, Goldsilverpro-right on target. Much thanks on the Pd info- trace amount recovery is not in the cards for us- we're onto organic gardening in the spring, and I wonder whether trace Pd grows good kale? (If I have processed this stuff by Spring, it will seem like a miracle of modern technology) This is the best forum on this topic that might ever be, supported by the good minds and intentions of all (mostly). I will report the result, and any unexpected findings.

The best and cheapest way would be to use a sealed container of bleach and HCl. Let them soak in it until they are clean.

Eric