99.5%? Is it possible?

[Irons]

Digestion must be very fast too. They are going to call you the flash refiner!. 8)

I bet the atomizer is not too easy to build.

I wonder how a modified power sprayer would work.

:shock:

Why am I getting the drift that you have been joking with me for a while Irons?. :lol:

I'm being perfectly serious. I bought a power washer a while back and the manual says it will generate over 2000 psi, depending on which nozzle you use. I bet it would break up the Gold quite well. There would probably have to be more than one nozzle. I don't know how many nozzles one power washer would handle, but they are not that expensive and two or more would be a reasonable expense.

 

[4metals]

If you get the particles small enough, and that is what the atomizer is there for, the acid penetrates and the digestion is complete. Yes there are silver chlorides but the coating over undissolved metal to trap values is minimal if it exists at all due to the fine particle size. The ability of the acid to penetrate a silver chloride coating is apparently greater than the size of the particles.

And Fournines is right, seeing a bar one minute, molten metal the next and then fine mud is a sight to see.

 

[HAuCl4]

If you can wash the AgCl very well of me (HAuCl₄ :lol: ) and there are no other nasty PGMs at all present, then I agree with you 100%. 8)

I perfectly believe fournines. I understand he runs a large operation in NYC. I was just joking, because I have only seen 5,000 OZ in pictures and films, like mostly everybody else.

 

[HAuCl4]

Digestion must be very fast too. They are going to call you the flash refiner!. 8)

I bet the atomizer is not too easy to build.

I wonder how a modified power sprayer would work.

:shock:

Why am I getting the drift that you have been joking with me for a while Irons?. :lol:

I'm being perfectly serious. I bought a power washer a while back and the manual says it will generate over 2000 psi, depending on which nozzle you use. I bet it would break up the Gold quite well. There would probably have to be more than one nozzle. I don't know how many nozzles one power washer would handle, but they are not that expensive and two or more would be a reasonable expense.

OK...so we got the pressure source, water nozzles, hydraulic capacitor, anyone got a picture of the heated metal nozzle, melter?.

 

[Barren Realms 007]

You don't use a heated metal nozzle to inject the gold to be atomized. You can take a crucible drill 1/8" holes in the bottom. This is the crucible you are going to pour your molten gold into. You heat the crucible with the holes in it and then you pour your gold into that and it run out the holes thru the atomizer and you are complete.

 

[HAuCl4]

Cool. Simpler than I thought.

What angle, pressure and volume per second of water through the nozzles (3 nozzles?) to produce sub 100 mesh powder?.

At what temperature do you pour the metal?.

 

[HAuCl4]

I was thinking that inquarting and then atomizing would be even better. Even with a less than perfect atomizer, and a less than perfect 1:3 inquart.

Get the best of both worlds: Flash digestion, no values at all trapped in the AgCl, and 9999 Ag possible in 1 pass without re-processing AgCl. Insolubles like Rh, etc. available immediately. Still would probably need to re-cycle the nitric. :shock:

 

[HAuCl4]

Think again dude, it works..........well.

I take your word for it 4metals!. Cheaper than $150 K too!. :lol:

 

[HAuCl4]

So using one of these atomizers, the "new standard" is something like:

400 Lb of 4 metals refined in 4 hours to 4 nines?. :lol:

I can see gold could be done in 1-2 hours, silver 2-3 hours, Pd 2-3 hours, and a stretch to do 9999 Pt in 4 hours, but perhaps possible?.

Less than 1 per 1000 in "losses" too.

Unthinkable stuff 20 years ago!. 8)

edit: Probably not cost effective to refine small amounts of Pt, Pd on a daily basis, yet technically possible.

 

[Irons]

I have a question about settling time and any losses from colloidal gold suspended in the water. One time bottleneck I see, is the Gold settling time. If it takes a day or more for the fines to settle out, that would be a significant bottleneck in the process. You can filter the water with a sub-micron filter but if you do it too soon, the filter will clog and the process will slow to a crawl again. It could take weeks or months for the finest particles to settle out. I've found that a few drops of acid in 4 liters of water speeds things up a lot, but it still takes time, and time is money.

 

[HAuCl4]

Hi Irons: I thought about that and the best solution I could come up with was using a COARSE filter and passing the liquid twice, the second time through, the larger particles acting like a filter for the small particles.

Like a bed of rocks on the bottom, then of pebbles, then of sand, then of mud.

I think with good vacuum that would work. I've used that trick before in a water treatment application, but not on those very fine particles of precious metals.

Maybe the guys doing it will speak on how they actually do it.

 

[HAuCl4]

Maybe I didn't put my idea across correctly Barren:

A fiberglass cloth filter (that can be leached). Pass the liquid once, and the coarse particles stay, the fines some stay some get through. Pass it again, and the previously trapped particles act like a filter now, etc.

Maybe waiting is better. I do not know. What's the typical waiting time?.

A vibrating tank is another alternative, a centrifugal filter yet another, but trying to keep it simple.

 

[HAuCl4]

If one could manage to use little enough water for the atomization (recirculate it?), there would be no need to filter at all, just put in the reactor as is, add the hot HCl, start to stir and feed the NaClO₃ as solid. :idea:

Or just atomize into the cold HCl and heat it up at the same time!. I.e.: Use the HCl instead of water, to atomize :idea: :idea:

 

[4metals]

Most of the metal settles within 15 minutes, in a 3000 ounce pour about 2 ounce of fine are adrift in the water. For tight production schedules, process the 2998 ounces which have settled and the balance has settled within 24 hours so it can go in the next lot.

As far as letting the HCl heat up from the reaction, bad move. The sodium chlorate would gas off the Cl₂ and not do as much work as if the acid was warm. Remember the molecules are dancin' and jigglin' when they are warm so they're more reactive.

 

[Irons]

The Cl₂ may be dancin' right out of the leach if it gets too warm. :mrgreen:

 

[4metals]

There is a world of difference between being warm when the metal is being digested and being warm when it is being dropped. I always drop gold from cold acid, the colder the better, the cold acid drops all of its silver so it can be filtered out before dropping.

The only digestion I can think of that is better with cold acid is to separate gold from platinum, the gold will digest but the platinum will be much less soluble.

The settling I spoke of above is strictly due to the small size of the atomized karat material which is in water, not even digested yet.

 

[Oz]

I put my gold chloride solutions in the freezer to precipitate my silver chloride, as the double dilution with water creates so much unnecessary waste. The added benefit is that if I filter quickly the solution is still cold when I go to precipitate, greatly increasing the solubility of SO₂. This may be more important to me than some as I add my SMB dry. If you are lacking dedicated freezer space or are just in a hurry, ice cubes do wonders.

Empirically it seems that 32F or lower is every bit as effective as dilution with water X2 at room temperature. Does anyone have access to solubility charts for silver chloride that could confirm my observations?

For those that have never chilled auric chloride, when your solution is cold, dry SMB just drops to the bottom of your beaker before it reacts and gives off no wasted SO₂ bubbles for you to breathe until near the endpoint of the reaction. If you keep it cool (the reaction is exothermic) you can reach the endpoint without dispelling noxious SO₂ gas and still have complete precipitations as long as you do not add SMB/SO₂ gas too rapidly.

 

[HAuCl4]

People would be better served if they heed the words of 4metals as the guy actually DOING it, as opposed to my wild speculative ideas POSTING on how it COULD be done differently. 8)

I keep thinking that properly washing and filtering the AgCl is the lengthiest and hardest part. How long does it actually take 4metals?.

 

[4metals]

Silver chlorides from a 3000 oz batch, about 240 ounces of silver expected, do not slow things down much. The chlorides settle quickly in the acid and the liquid is siphoned into a filter with strong vacuum, the chlorides / insolubles are the last to hit the filter as they have settled to the bottom. They are soft white fluffy chlorides and rinse easily with cold water.

Later they are removed from the filter and washed / soaked in hot water to remove any lead chloride. Overall they do not slow down the procedure other than requiring filtration to remove them. But that's normal with aqua regia as well if there is no nitric pre-treat of an inquart.

 

[HAuCl4]

So, for the record:

How long does it take to get all the bars/fine shot of 9999 fine gold from the moment you put the 3,000 Oz of scrap in the induction furnace?.

Melt- 5 minutes?
Gold mud atomized - 5 minutes?
Mud settled - 15 minutes.
Digestion in hot HCl-NaClO₃ - 20 minutes ?.
AgCl filtering and washing - 20 minutes ?.
NH₄Cl drop of Pt, Pd salts and filtering- 15 minutes ?
Gold drop and wash- 35 minutes?
Melt and pour of fine gold- 15 minutes ?.