Anyone try potassium monopersulfate as an oxidizer?

[jsargent]

I have not seen mention of using potassium monopersulfate here and was curious. It is a common non-chlorine oxidizer readily available at swimming pool supply shops. Basically it is a dry formulation of Caro's Acid, which is a combination of sulfuric acid and 30%+ hydrogen peroxide. Caro's acid is unstable and not something I would want to mess with but monopersulfate is easy and fairly safe to handle and let me tell you... it's aggressive. One interesting oddity about it is if you combine it with salt water it produces copious amounts of free chlorine so along with HCL it makes for an effective HCL halide leach for gold. Here is a patent:
http://www.patentstorm.us/patents/5401296/description.html

 

[butcher]

I am not familiar with that product, but have done a little study on caro's acid.
sulfuric and HCl would make a chlorine gas,and there are plenty of hydrogens,and oxides,
I believe your end products would be metal acidic solution & salts of sulfates,
not much doubt in my mind it would disolve the metals,and would most likely be very reactive, foaming over if not careful,
lots of things will disolve or leach metals,
but a selective recovery process, needs to be established to make it effective.
and safety of operator and the enviroment also needs to considered.
I did not read patent, most of the times with ore we want to eliminate the sulfides by roasting them prior to chloride leach with an oxidizer, there are uses for sulfuric leachs but normally for base metals,
ore leaching although similar, is quit different than from recovering metals from electronics or jewelry ect.

 

[fixinator]

:shock: I tried something similar to this. It seemed all was well until I tried to precipitate the gold. Now I have a smelly mess. I used the potassium monopersulfate to regenerate the acid peroxide solution.

It was working so well I just kept stripping and dissolving parts. I even threw in a couple pellets of pool chlorine. It dissolved all the metals. There was no black powder left on the bottom of the pail.

Now the dilemma. I had a busy summer and didn't have much time to work the lab in my shed. Now it's cold. I brought this bucket and a couple others in to the garage to work. After testing with SnCl I diluted this solution approx 1.5x. I then started adding smb. I could see the gold precip in a thick cloud. I walked away for awhile and when I came back there was no gold powder to be seen. :twisted: I added more smb, then more. I read on this forum that excess oxidizers can be wiped out with smb. I added alot (about 3.5 pounds altogether) at regular intervals. I added smb in solution, powder and chunk. each time it precipitated gold heavily. Later it was gone.

The solution still has a rapid stain when tested.

I tried pushing it out with copper then iron. NO LUCK!!

After reading that patent I think the problem is that it made a water soluble form of gold chloride. Or gold halide perhaps. Now I don't have any sodium borohydride or the facilities to follow this part of the patent. I hesitate to boil because I have already seen values condensing on the bucket lid.

Incidentally The addition of the iron caused strong odor of hydrogen sulfide in the sample I added it to.

This stuff works too well!!! It also takes a different method to precipitate.

If any of you knowledgeable people have an idea how to recover my values......I would gladly buy you dinner!!!


Fix

 

[jsargent]

:shock: I tried something similar to this. It seemed all was well until I tried to precipitate the gold. Now I have a smelly mess. I used the potassium monopersulfate to regenerate the acid peroxide solution.

It was working so well I just kept stripping and dissolving parts. I even threw in a couple pellets of pool chlorine. It dissolved all the metals. There was no black powder left on the bottom of the pail.

Now the dilemma. I had a busy summer and didn't have much time to work the lab in my shed. Now it's cold. I brought this bucket and a couple others in to the garage to work. After testing with SnCl I diluted this solution approx 1.5x. I then started adding smb. I could see the gold precip in a thick cloud. I walked away for awhile and when I came back there was no gold powder to be seen. :twisted: I added more smb, then more. I read on this forum that excess oxidizers can be wiped out with smb. I added alot (about 3.5 pounds altogether) at regular intervals. I added smb in solution, powder and chunk. each time it precipitated gold heavily. Later it was gone.

The solution still has a rapid stain when tested.

I tried pushing it out with copper then iron. NO LUCK!!

After reading that patent I think the problem is that it made a water soluble form of gold chloride. Or gold halide perhaps. Now I don't have any sodium borohydride or the facilities to follow this part of the patent. I hesitate to boil because I have already seen values condensing on the bucket lid.

Incidentally The addition of the iron caused strong odor of hydrogen sulfide in the sample I added it to.

This stuff works too well!!! It also takes a different method to precipitate.

If any of you knowledgeable people have an idea how to recover my values......I would gladly buy you dinner!!!


Fix

Have you tried cementing out the gold with zinc powder? Or, can you quickly filter the SMB precip out before it re-dissolves? Probably need a vacuum buchner funnel if you don't have one already. Another approach would be to use a more powerful reducing agent, precip everything, and then chelate out the iron with citric acid. Then dry the remaining precip and do a lead fusion and cuppel it. Good luck :!:

 

[fixinator]

The smb dissolves too fast to filter it before it redissolves. I think I really over did it with the oxidizers
The iron didn't work. the solution started to show a layer on top that tested negative but it soon remixed never to appear again. I haven't tried zinc yet. Last time I mixed zinc and smb it stunk me out of the shed. This time I'm in the garage.

I tried an experiment with 150 ml and a teaspoon of sodium hydroxide.
I think I may be on to something. I'm going to let it settle all night and test it in the morning.

 

[butcher]

keeep us posted this sound interesting. maybe move this outside for your saftey.

 

[qst42know]

From the patent sodium hydroxide is a major part of the precipitant, but not the complete answer.

"The sodium borohydride solution consists of 6 weight percent sodium borohydride, 20 weight percent sodium hydroxide, and 74 weight percent water. Sodium borohydride is a reducing agent which converts the soluble metal cations to the insoluble elemental metals."

 

[Platdigger]

This may also be a good place for hydrazine sulfate with sodium hydroxide.

The hydrazine I believe, is an even better reducer than the boro.

I must add that the extra oxygen should first be removed by boiling
or some other method. Also the hydrazine being used sparingly.

Randy

 

[Lou]

Hydrazine is a better reducer because one of the reduction products is nitrogen gas.

Borohydride is more stable in basic medium--acid rapidly decomposes it.


Lou

 

[fixinator]

I feel like I have hijacked this thread. Perhaps I have even gotten off topic. I am starting a new thread in the help section. It will have the results of my experiment with lye and keep a running documentation of this. But first I have an errand to run. bbl.

Fix