Opinions on pitfalls before attempting unorthodox procedure:

[HAuCl4]

Thanks Harold. I had never heard about zone refining. It seems fascinating, but as you said, very involved with expensive equipment,etc.

I watched a Miller chlorination setup years ago. It's much simpler than people think, but it is for lots of 100 oz min.(my guess). And no matter what they tried, they said they could never get above 997-998 in fineness. They were processing up to 500 oz in a few hours.

That's pretty much my understanding as well. Speed is its one outstanding feature. I included it only because you had asked about bringing metal fine without dissolution.

I got so comfortable with the AR process that I thought nothing of dissolving 75 ounces per session, which was my normal procedure.

Harold

I think you did well Harold. A normal procedure, which was very familiar and comfortable to you, and which you made a business off, which made it even better: Profitable. Most of us here can only aspire to that as hobbyists and/or small batch processors.

On the other hand, hobbyists are free to explore and experiment and ask questions of the elders ( ). For example:

Last week I was watching Steve's fine videos on the Per-Sulphuric cell for deplating...and during today's afternoon nap, the idea hit me: What if I hang a say 990 fine gold anode on a similar cell and a copper cathode on same?. If I have a slightly modified cell, (hand drawn pic attached), then the gold should drop as anode "mud", and the silver, copper, etc. should go into the electrolite and perhaps plate on the cathode?.

This gold "mud" would be finer and, after several good washes, may even make the 9999 grade?.

I understand the gold in this instance actually went "into solution" for a few moments (thanks to the per-sulphuric acid created by the voltage at the anode), and then inmediately re-precipitated as it contacted the electrolite again.

Not anywhere an "invention", but a variation of an existing setup, that might produce some very fine gold, especially if properly washed afterwards. I think I may build one of these to experiment. (It sounds like a better idea than the lead sequence I started with...lol).

What do you guys think?.

 

[butcher]

HAuCl4 good idea but?
unless the gold is already fairly pure, there will be co-deposit of gold with the copper, in an electrolyte that will plate out copper.

in an electrolyte and electrode that will not plate copper, but copper is put into electrolyte solution, and gold is in mud slimes there is still contamination of your gold.

you may be able to clean up the gold some, using membranes or filter bags but it will still have contamination and need refining.

I like the idea you want to come up with better mouse traps, but first it's better to learn about all the mouse traps that have been invented, why they work and why they dont, you can be wasting your valuble time trying to build a better light bulb, but without understanding how light bulbs already invented work and why they dont you are just wasting your time.

funny how many people want to build a prepetual machine and do not understand the principles of how machines work or the laws of physics.

spend your time learning the existing methods well why they work and why they don't, then you may see some point that they can be altered or improved, but without that understanding your just shooting in the dark,
people have been working on refining for thousands of years and with that much brainpower, do you not think that you can come up with a better mouse trap without understanding the principles?

I do not mean this to discourage you, but like the miner with fools gold and gold fever,just trying to help you see its not that easy to get rich, or come up with better mouse traps untill you understand what real gold is or the mouse trap fundamentals.

 

[HAuCl4]

HAuCl4 good idea but?
unless the gold is already fairly pure, there will be co-deposit of gold with the copper, in an electrolyte that will plate out copper.

in an electrolyte and electrode that will not plate copper, but copper is put into electrolyte solution, and gold is in mud slimes there is still contamination of your gold.

you may be able to clean up the gold some, using membranes or filter bags but it will still have contamination and need refining.

I like the idea you want to come up with better mouse traps, but first it's better to learn about all the mouse traps that have been invented, why they work and why they dont, you can be wasting your valuble time trying to build a better light bulb, but without understanding how light bulbs already invented work and why they dont you are just wasting your time.

funny how many people want to build a prepetual machine and do not understand the principles of how machines work or the laws of physics.

spend your time learning the existing methods well why they work and why they don't, then you may see some point that they can be altered or improved, but without that understanding your just shooting in the dark,
people have been working on refining for thousands of years and with that much brainpower, do you not think that you can come up with a better mouse trap without understanding the principles?

I do not mean this to discourage you, but like the miner with fools gold and gold fever,just trying to help you see its not that easy to get rich, or come up with better mouse traps untill you understand what real gold is or the mouse trap fundamentals.

Either you did not read my post or it is you who must do some studying...

Only an experiment will help at this point.

No offense.

 

[butcher]

no offence taken, I just read the post above and did not go back further in my reading of this thread, so maybe I do need more study about what you are trying to accomplish here. I will re-read it.

 

[butcher]

after rereading this thread I stand by my suggestion for helping you to achive your goals.

I can be wrong that would not be unusual.

 

[Barren Realms 007]

That thing sounds like a monster Harold. That is a heck of a load.

Heh! The load is large, no doubt, but so is the power supply. The motor/generator is a single unit, hung vertically. The entire power supply unit weighs 3 tons.

Harold

OHHH boy I just got a woody...........I like things like that. 8)

 

[Harold_V]

Last week I was watching Steve's fine videos on the Per-Sulphuric cell for deplating...and during today's afternoon nap, the idea hit me: What if I hang a say 990 fine gold anode on a similar cell and a copper cathode on same?. If I have a slightly modified cell, (hand drawn pic attached), then the gold should drop as anode "mud", and the silver, copper, etc. should go into the electrolite and perhaps plate on the cathode?.

Unfortunately, it doesn't work that way. Not all substances will be dissolved, so the solids that are liberated drop to the bottom, just as gold does. The cell functions for the recovery of silver as well as palladium, so they would be included in the harvest, assuming they were a part of the parent bar.

If you read the patent on the process, you find that if voltage is controlled properly, base metals are not dissolved. That was the purpose of the stripping cell, to salvage items that were good aside from defective plating. That means that any traces of anything not soluble will find themselves included in the harvest, assuming they are liberated as the gold is dissolved by the cell.

However, the one thing in your favor is that the recovered gold is very finely divided---often bordering on being colloidal. Persistent (acid) washing *may* yield a high quality product, but I'm of the opinion that that would not be the case. Even gold precipitated from relatively clean solutions is difficult to wash free of contaminants----so I expect that in this case, you'd struggle to exceed 9995. If that were not the case, gold so stripped would not require further processing.

Do keep in mind, achieving 4 n's isn't easy. I don't know that I ever achieved that level of fineness.

Harold

 

[nickvc]

Just a suggestion but if you are willing to use a cell why not make a small Wohlwill cell as GSP referred to earlier admittedly you will have to dissolve some fine Au to create the gold chloride solution but if used properly you should produce high purity gold if you have a high grade feed into the cell.

 

[HAuCl4]

Thanks guys. I'll do some experimenting when I have the chance, and I'll try to remember to report my findings here.

I did not know that gold could be dissolved in any way with sulfuric acid till I saw Steve's cell video. Therefore I do not have any hands on experience with the process. A little more investigation yielded that the gold is not dissolved by sulfuric acid, but the combination of concentrated acid AND voltage at the anode, produce per-sulfuric acid which is what dissolves gold (and other metals to a lesser degree). When this compound of gold starts to travel to the cathode it becomes in contact with the normal sulfuric acid and precipitates as gold is NOT soluble in sulfuric acid. (i.e.: The per-sulfuric environment only occurs close to the anode). The other compounds copper sulphate and silver sulphate are somewhat soluble, and either travel to the cathode or drop as crystals of sulphate along with the gold.

In short; The gold went into solution atom by atom and was precipitated shortly after. I infer that with very thorough washing and boiling in acids, etc. it will be FINER than the original anode. How much FINER is the question that can only be answered by experimentation.

Of course I could also go the traditional ways of dissolving in AR, etc, etc. But if man did not dare to experiment and try new things...we would all still be eating fruit in trees somewhere in Africa...which is not neccessarily a bad thing if one is happy doing it.

Cheers. Thanks for the opinions and ideas, and now I'll just shut up.

P.S.: By the way, on the accuracy of fire assays: Years ago I had access to a digital balance with 0.0001 gr accuracy, and by making assay proof samples of about 2 grs of fine gold (from a small SBS ingot), we determined that the accuracy of our assaying in the range from 9999 to 18 Kt jewellery was 0.0002 when using 1 gr assay beads and 0.0001 when using 2 grs assay beads. There are microgram accurate balances these days that will no doubt tell how accurate the fire assay really is, but I'm convinced that is more than enough to tell if something is 9999 or 9995. Without an ICP machine (which I've never seen but would like to! ).