help high Pd/Au

[WIZZARD]

I'm a new member. When reading posts I've looked at as many as possible to resolve my questions, however I have not found a direct answer to my problem. The normal Au reagents, FeSo4, SmB, Oxalic, SO2, drop brown mud, however Pd is suspected to confound the brown drop, because there is lot of it. The starting matrix is not secondary reduced metal scrap.

My solution of Pt/Pd/Ir/Rh/Ru/Au ( little Fe trace Ni Cu,trace Sn, Pb, Ag, Zr, lots of si ) placed into solution with AR using H2O2 as oxidizer, no nitric. Most of these NM are not reduced metal, is the reason they go into solution with modified AR. I use NaOH and sometimes NH3 to raise the pH to 4.5-5.5 to get a brown drop. I know 15% of the starting matrix is NM; 3.3% Au, 6.15% Pt, 2.55% Pd, 3% Rh and 2.55% Ir/Ru/trace Ag. Fe and other base metals in the matrix are hit with pre acid to get rid of them and rinsed well, before using AR. HCL not used as pre treatment as the particle sizes of NM are below 1 micron and this known to place some NM in solution. Inquarting with silver works, however that is another question, another 10 steps, electrochemical Mubuis cells and a lot of time.

Question; As NaOH or NH3 is added to the filtered yellow/orange pH 1 solution a brown drop forms @ 4.5pH, darker brown color at 5.5pH, allowing this to settle over night the solution's pH is close to 6, the color now very dark amber. The brown mud filtered, rinsed with H2O dried with low heat, and when ignited 800F in a stainless steel dish, a gold metal with gray metal to reddish powder residue is visible under the scope. The brown drop is suspected to be 60% Au / 40% Pd brown powder and will not melt at 2115F. Normal reagents for Au seam not to work as the brown drop of Au/Pd may also have a conflicting element locked to their atoms?

I've use NH4Cl to drop the PM as a first stage and get test book orange, to red PM salts. When igniting the salts I notice brown fumes coming from a velvet brown ignition mass toward the end of the ignition, mixed with PM sponge. AuCl is my guess, when oxalic acid added causes a brown residue to form at 900F and the residue is very golden with whitish gray PM looking metal. Remember no nitric was use.

The reason to drop by pH first is to separate Au/Pd first as dealing with the PM solution is easier without the Au.

How to part the Au/Pd brown mud is the question. The brown mud is a hydroxide of Au/Pd, thus is very soluble in weak acid. Got suggestions? Breaking atomic bonds of inner shell electrons must a trick in someone's pocket?

I'm hoping someone has been there done this and has a answer not requiring the involvement capitol investment.

WIZZARD, FNG...FORUM NEW GUY

 

[Palladium]

I'm not the one to answer your question here, but after you did your wash can't you use nitric to part it ? 60-40 in powder form.

 

[Lou]

I could swear that somewhere someplace I've given very nice, very complete instructions for separating the mix.

Anyway:

edit: Get the silicon out of there! I presume it's silicon dioxide/sand. This can be removed by a boil with base. This will also remove any tin, zinc, and lead (with perhaps a few drops of conc. hydrogen peroxide) as their zincates/stannates/plumbates.

If I were you, I'd drop them all with zinc, rinsing well with 0.5M HCl to remove zinc and other base metals. Rinse with ammonia too, then heat it to drive it off. Once all metals are in the ground state, start with nitric acid to remove the palladium as its brown (oxy)nitrate and then go after the Pd by adding an equal volume of concentrated HCl, evaporating, and adding more HCl (several times until no more red-brown NO2 is produced), when you're left with a heavy brown syrup, you're done.

Next up is gold: add 15*C aqua regia to the residual powder, the reaction should be slight. This will dissolve most all the gold and leave the Pt, Ir, Ru, and Rh alone. Filter the solution and add fresh aqua regia (look for some colour or reaction). Boil this second portion of aqua regia down, and test with stannous chloride, looking for a positive platinum. Pt shouldn't really dissolve in that temperature of aqua regia, at least not in an economically appreciable way (you'll get the Pt out by re-refining the gold or by using oxalic acid in conjunction with SO2). Alternatively, you may dissolve the gold with a carbonate-buffered NaCN solution, (as it won't touch the other metals). That suggestion is more for people who have a fume hood and practical experience with HCN, which I'll presume you lack.

Add more aqua regia, take it to nigh on boiling and leave for several hours. This should remove the platinum. You can add another portion of aqua regia and check for Pt with stannous (after a boil down--free NOx will interfere with the test!). A small amount of Rh might have co-dissolved--this will be evidenced by a green-brown tinge to your canary yellow ammonium hexachloroplatinate.

From here on out, you should really consider leaving it to a professional--you will not accomplish the separation without capital investment and a good deal of training.


Oh, and as a word of advice--unless you know what you're doing, DO NOT ADD BASE OR AMMONIA to these acid solutions. Follow the usual methods; leave selective precipitation of hydroxides for the chemist. A lot of these hydroxides/hydrous oxides have overlapping ranges and the precipitates can co-mingle.

 

[WIZZARD]

Thanks for information

The brown powder when placed in the oven at 2115F looks like red porous brick. Placing the brick in nitric leaves gold and the solution is rich in Pd.
Thanks. If I place the brown mass in nitric without bring both Au/Pd to Zero Valance goes into solution. Something said about bring it to Zero Valance

Yep, I should remove the silica, boiled in sodium hydroxide added little peroxide and much fizzing after 4 hours. Still have silicates. quartz, glass looking mater with golden bright metal flakes abundant. You think the glass beaker will dissolve or just the sand like matter?

Twenty five years ago I did some the gold recovery from golden junk, back when Fairchild Corporation was one of the leaders in chips. Got a hood, scrubber, glass, chipmunk, hot plates, and a big wooden box full of connectors when they closed down a plant. Golden box paid for everything and then some.

Cooking........ion exchange resin these days.......looks like this;

Elude or cook that is the question!

Still would like some magic on how to drop Au without the Pd.? Electricity is expensive. How about placing the brown mud back into solution, and dropping the Pd, as there is so much of it first? with ammonium chloride, No! gold, comes down too, how about...sodium chlorate? No, need to adjust pH and that would mean adding a base to the acid?????

Think I'll run some questions about this ion stuff in main forum.
WIZZARD FNG FORUM NEW GUY

 

[lazersteve]

You could put the mud into solution and use BDG to extract the gold.

Steve

 

[Palladium]

Got a hood, scrubber, glass, chipmunk, hot plates, and a big wooden box full of connectors when they closed down a plant.

Ok, i'm going to go out on a limb here and ask. What is a chipmunk ?

Irons don't you dare.

 

[Barren Realms 007]

Got a hood, scrubber, glass, chipmunk, hot plates, and a big wooden box full of connectors when they closed down a plant.

Ok, i'm going to go out on a limb here and ask. What is a chipmunk ?

Irons don't you dare.

It's a little furry animal... 8)

 

[WIZZARD]

Hey! That's a good idea, I got a quart of that around some where. Separator funnel too.

Jaw crusher. Used to crush silicon chips, glass, cpu's, boards, rocks and furry unfortunate critter just wanting to know what under one. Two plates pivot back and forth connected to shaft, connected to fly wheels to keep the inertia up. (no fly's don't have wheels). The pivot point is adjustable to allow big stuff in at the opening and by the time it reaches the smaller opening, it's crushed to 1/8 by 1/8 and smaller.

It ran away, so these days I designed two HARD FACED disks on a turntable with a opening on the top to drop stuff to be pulverized into little tinny bits. Opens the goodies up like pealing a banana. The more exposure to stuff that dissolves the stuff that dreams are made of.

WIZZARD FNG FORUM NEW GUY

 

[indecency]

Good article！From here on out, you should really consider leaving it to a professional--you will not accomplish the separation without capital investment and a good deal of training.

 

[goldenchild]

you will not accomplish the separation without capital investment and a good deal of training.

What do you mean by this?

 

[CHARLIE GREENLER]

You guys do know that there is such a thing as electrometalugical processing.If you have a 300 dollar plating unit you could come up with very pure metals.I would disolve these things in potasium cyanide,and plate each one out at a time or at the same time ,and thats one way that gets all of the gold,all of the palladium and any other metals.Wow though they sound very locked up withe eachother if it isnt as simple as heating it in as nitric solution and letting the gold atleast settle to the bottome. I would plate them out of solution(thats the most eficient way).

 

[goldsilverpro]

You guys do know that there is such a thing as electrometalugical processing.If you have a 300 dollar plating unit you could come up with very pure metals.I would disolve these things in potasium cyanide,and plate each one out at a time or at the same time ,and thats one way that gets all of the gold,all of the palladium and any other metals.Wow though they sound very locked up withe eachother if it isnt as simple as heating it in as nitric solution and letting the gold atleast settle to the bottome. I would plate them out of solution(thats the most eficient way).

Maybe you should explain this in greater detail. I know of no way you're going to separate metals by plating them individually and separately out of a cyanide solution. It might lean towards plating out certain metals but this will change constantly as the concentrations change. You'll never plate pure metals out of a mixed metals solution of cyanide. It just doesn't work that way. Sounds like an old miner's tall tale to me. However, if you can show exactly how to do it, step by step, I might change my tune.

 

[Harold_V]

You guys do know that there is such a thing as electrometalugical processing.If you have a 300 dollar plating unit you could come up with very pure metals.I would disolve these things in potasium cyanide,and plate each one out at a time or at the same time ,and thats one way that gets all of the gold,all of the palladium and any other metals.Wow though they sound very locked up withe eachother if it isnt as simple as heating it in as nitric solution and letting the gold atleast settle to the bottome. I would plate them out of solution(thats the most eficient way).

Maybe you should explain this in greater detail. I know of no way you're going to separate metals by plating them individually and separately out of a cyanide solution. It might lean towards plating out certain metals but this will change constantly as the concentrations change. You'll never plate pure metals out of a mixed metals solution of cyanide. It just doesn't work that way. Sounds like an old miner's tall tale to me. However, if you can show exactly how to do it, step by step, I might change my tune.

You won't be changing your tune, but I think Charlie needs to start doing a lot more reading and a whole lot less talking. He is so misinformed that he is not useful, endlessly posting nonsense that has nothing to do with fact. It's wasting a lot of my time, and he's leading guys down the wrong path, making it all the more difficult for them to gain a proper understanding.

How 'bout it, Charlie? Are you ready to start learning and tossing all the BS you believe?

Harold