Aqua Regia vs. Acid Peroxide.

[Irons]

peroxide +hcl dissolves gold, pt and pd ---i do it almost daily

I agree. Pd will dissolve in H2S04, HCl and Nitric. If there's enough Pd, it will generate Cl on its own by stripping the Hydrogen from HCl and that will dissolve almost anything in time.


Every source of material is different and each case has to be examined on an individual basis. Working with ores is totally different than working with the metals in refined form.

 

[arthur kierski]

instead of using h202 at 3% i use at 30%(100volumes -)
example 100cc of hcl , put the metals or powder to dissolve and then 50cc h2o2 (100volumes) slowly ---the reaction does not needs heat because it is quite violent---when fizzing stops , heat the solution to eliminate exceess o2----i repeat, i do it almost every day

 

[NuggetHuntingFool]

I find it's the strangest thing. The method you use to get rid of base metals that doesn't dissolve gold. Then a little heat, or higher concentrations and it suddenly dissolves the gold and not the base metals...


So many different ways of attacking so many different combinations of materials.


It's like this takes a lifetime to learn because of all of the different variables. I can see why you guys like it. It's like a new mystery with each new material you process.

 

[Harold_V]

I find it's the strangest thing. The method you use to get rid of base metals that doesn't dissolve gold. Then a little heat, or higher concentrations and it suddenly dissolves the gold and not the base metals...

That may not be what's happening. Don't lose sight of the fact that precious metals in solution are easily cemented (precipitated) by replacing them with the base metals that have not been dissolved. It may not happen initially, but as the solution loses its ability to dissolve the values, the conversion will take place. Armed with this idea, there are times when you can use the process to advantage.

You'll have to rely on one of the chemists to word this so it makes chemical sense ------I have no idea exactly how it works---I just know it does.

Harold

 

[Irons]

I find it's the strangest thing. The method you use to get rid of base metals that doesn't dissolve gold. Then a little heat, or higher concentrations and it suddenly dissolves the gold and not the base metals...


So many different ways of attacking so many different combinations of materials.


It's like this takes a lifetime to learn because of all of the different variables. I can see why you guys like it. It's like a new mystery with each new material you process.

PGMs have a strong affinity for Hydrogen, they act as catalysts, sometimes to your disadvantage and concentration, temperature and pressure all play a factor.

Learn the electrochemical series. It plays a very important role.

 

[arthur kierski]

both ar and ap dissolve pms and base metals---both forms silver chloride as a white curdy powder---the difference is the various concentrations of the reagents and heat---for instance,cold ar does not dissolve pt--but dissolves au and pd----ap with 3%peroxide does not dissolve gold----
pdo +rho will be dissolved only if you reduce these oxides to metal---etc, etc---for instance in hokes book she reduces pdo to pd by leaving the pdo in hcl---others reduce with sodium formate in a carbonated solution
black sand (i never done anything with it) might have iron which must be eliminated before an ar or ap attack or it will consume all the hcl first by dissolving this iron---might have silicates which might need naoh or hf to dissolve ---etc

 

[NuggetHuntingFool]

After hearing the stories and dangers I don't even want to go near Hydrofluoric Acid.

I like my bones and want to keep them where they are.

 

[arthur kierski]

after all my explanation--you take a small item out of it and says that you do not use or is afraid of using it---i did not tell you to use hf or naoh in black sand---i told you that i do not have experience with black sands---i just wanted to tell you that you can extract precious metals with ap or ar --depending on heat and concentrations of the various reagents

 

[Anonymous]

@ Harold/Kumar(A.K) Even though I somewhat hijacked this thread you guys were a big help and super informitive.

@Nugs I hope I didn't derail the answers you were seaking.


Thanks again.

 

[NuggetHuntingFool]

The thread has been very helpful.

I appreciate the help for sure.

I was just making a joke about the HF Acid, and still wouldn't want to go near it!

I should have some black sands by the end of Fall. Hopefully they'll have PM's for me to chase.

Thanks