Thiosulphate Dropped--Testing for PM?

[Ferrell]

Does anyone know what the ORP should be reading for thiosulphate leach?

 

[Ferrell]

We've been doing a lot of research on thiosulphate leach and it appears the ORP needs to be in the 150-200 range for it to work. The problem we're finding is that thiosulphate leach (when mixed according to the patent or what has been recommended on this forum) ends up in an ORP range of about 45-65....and adding ammonia to get the pH up to at least 8 (recommended it be from 8-10) drops the ORP lower, it doesn't raise it.

Any suggestions on this? Have any of you using this leach been checking the ORP value or just the pH? Any ideas how to get the ORP value up where it should be without dropping the pH to the basement? It seems they go the opposite direction from the experimenting we're doing.

 

[butcher]

Ferrell, this is beyond my understanding, so what I say here is speculation and just a guess.

Being unfamiliar with the caustic leach, I will speak of an acidic leach here.

from what I understand the ORP oxidation reduction potential is jut a millivolt reading using a circuit with reference probes to get an idea of the oxidation or reduction potential of the solution (basically how well the electrons can oxidize or reduce in solution), depending on the type of solution.

from my understanding (I will use chlorine here I have a little more familiarity with), chlorine in solution is somewhat basic, when we get it in an acidic solution we form gas of chlorine in solution, this is what dissolved the gold the chlorine oxidizing the gold and forming a metal chloride from reaction of the oxidized gold with the HCl acid.

So the bleach Chlorine (a base about pH 13), and an acid Hydrochloric acid (an acid about pH 0 to 1), would by themselves neutralize the solution to form a salt. not to mention the gold and the acid forming a gold salt in solution, at first addition of the small amount of chlorine we would in probability see a high ORP reading, but it would soon go down as the chlorine was used up or the chlorine gassed off, also as we added chlorine to this solution we raised the pH of the acid, just a tad closer towards the neutral on the scale. And as the chlorine is exhausted the ORP reading would come back down (not much potential for gold to loose many more electrons in this solution).

As pH goes up the millivolt reading of the ORP meter will go down, this is indicating the chlorine or oxidizer is not as effective. (I am thinking of chlorine in solution as an oxidizer here, not the thiosulfate leach you are working with), so in this case I can bring the pH down, or add more oxidizer chlorine to raise the ORP reading.

Although I may have this all messed up in my head, and if I do hopefully someone who understands this can straighten me out and help you also.

 

[butcher]

Will this help?


https://circle.ubc.ca/bitstream/handle/2429/40336/ubc_2012_spring_deutsch_jared.pdf?sequence=3

 

[Ferrell]

Thank you, butcher. I apologize, I thought I had my settings so I'd be notified if there was a reply but didn't get one, so assumed no one had replied. I just stopped by and saw both of your notes. I'll point them out to my husband when he gets home this evening.

I thought this might be of interest. We had some old black precip from our last thiosulphate drop. We haven't had much luck putting it in a crucible with flux and pouring any gold. We were reading Action Mining's instructions with the leach they sell, saying it would give a black precip 'sludge' and it should be put directly into a cupel with lead or bismuth. So, I did just that yesterday. Took about 4-5 Tablespoons of the precip spread across a filter paper, folded to a small square and placed in a cupel with bismuth. I'm posting a pic of what I got. Looks like the thiosulphate hasn't been the problem, but the way we've tried to process the precip. I'm taking this little BB to a local jeweler tomorrow that specializes in determining gold content to see what we've got. Hoping it's decent.

 

[Ferrell]

This is a picture of what we got from the few tablespoons of thiosulphate precip that I mentioned in my last post. Couldn't get the photo to load last time. Hopefully it will now.

 

[butcher]

Ferrell,
That is great, I know you and your husband have worked hard for that button of gold, maybe if you plant it back in the ground so it will grow more of them beauties, It will be nice to see you guys get the process to where things are working well for you, also please keep us informed we all learn from sharing.

 

[Ferrell]

Thanks, butcher. Now to figure out exactly what we did to arrive at this point. That was a very old batch we hadn't treated and unfortunately, wasn't labeled. We've really been struggling with the entire process from leaching to refining and still have tons of questions and things we need to learn. I'm afraid it's been one step forward, three steps back most of the time. :roll:

 

[butcher]

One step forward and two backwards, that sounds like a dance, mining on small scale could be a very hard way to get a few pennies if your lucky, and can do it and not to mention the work involved.

I wish you and your Husband good luck, I know learning can be hard, and learning to work ore is really a challenge, also you could move mountains for very little or no gain, good luck.

 

[solar_plasma]

If you remember that to become an ion the element must become either a proton donor or an electron donor. The gold in solution is a proton donor, the metallic iron is an electron donor. Electricity is not a flow of protons but of electrons. ....................
Dr. Poe

Pardon me, but I feel like someone tells me the sky is not blue:

I do know only one kind of proton donor, an acid. That is quite the definition of an acid.

A metal cation like Na⁺ is not an acid and it is not an electron donator, but it is an ion.

Gold in solution CAN be a proton donor, an acid, IF it is in the form of an acid like chloroauric acid, H[AuCl₄]

Electricity is a flow of charges,which CAN be electrons.

This is how I understand it. Please correct me, if I am wrong, it's quite important to me.

 

[solar_plasma]

I guess the polarization of gold is too much to grasp for some. It's their insistence that gold must be reduced to a metallic in all cases. Their insistence that gold salts cannot be anionic and react like sulfur. Such stubbornness cannot be changed by reason and I don't intend to try anymore. I don't care if this thread is locked or not. I visit the forum to teach those that need my help, not to argue. Dr. Poe

Another thing that is contradicting, what I have been taught, what is written in school books and what I am teaching (maybe not incorrectly?) - Only metalloids and nonmetals can be cations or anions. Metals are always cations in ionic form.

Gold is a metal.

Please correct me.

Nevertheless this is a very informative and exciting thread and I will read it some more times.

 

[Lou]

Metals are not always cations, but for the purposes of most refining processes, they are.

Most metals form complexes in complexing acids; for instance [PtCl6]2- is an anionic complex.

 

[solar_plasma]

Metals are not always cations, but for the purposes of most refining processes, they are.

Most metals form complexes in complexing acids; for instance PtCl62- is an anionic complex.

Yes ofcourse, but the Pt's themselves are still positive....just embedded in some negative ligands(right term?), the sum of all charges is negative, so it forms a molekyle which is negative outside. :?:

edit: Tonight I will read a lot in my Inorganic Chemistry by Holleman/Wiberg - got some learning-vectors

 

[solar_plasma]

If you remember that to become an ion the element must become either a proton donor or an electron donor. The gold in solution is a proton donor, the metallic iron is an electron donor. Electricity is not a flow of protons but of electrons. ....................
Dr. Poe

Pardon me, but I feel like someone tells me the sky is not blue:

I do know only one kind of proton donor, an acid. That is quite the definition of an acid.

A metal cation like Na⁺ is not an acid and it is not an electron donator, but it is an ion.

Gold in solution CAN be a proton donor, an acid, IF it is in the form of an acid like chloroauric acid, H[AuCl₄]

Electricity is a flow of charges,which CAN be electrons.

This is how I understand it. Please correct me, if I am wrong, it's quite important to me.

Okay, I thought of so called Brönsted acids, which are defined as molekyles which can provide protons to H₂O and form H₃O^-

while Poe obviously uses the definition of so called Lewis acids, examples are even metal cations. Then you can rightly say ions are proton donors or electron donors. Still I don't like the excluding, absolute wording, since it is only one model and can be seen in several ways.

 

[Geo]

Poe was antagonistic to everyone. if he had the chance to talk down to someone or take a jab at somebody, he would. he used convoluted arguments like he expected everyone to understand what he was talking about without having to explain to us "peons".

 

[solar_plasma]

I wonder how anyone can write his dissertation without being able to shift between paradigms, at least if someone has written it on his own. Obviously this is possible in the studies of geology. In any social science this is not possible, - you wouldn't even get your bachelor. :lol:

 

[sasa123]

Can someone please help me?
I used 100 g / l natrium thiosulfate, 8g / l natrium sulfate to black sand and electronic waste. It fantastic dissolves gold! With the help of electrolysis has the results but certainly not enough, and by dipping the steel wool does nothing, so please for your advice, is this a good solution for the refining of gold? And why is gold does not stick to the steel wire? I would like to avoid ammonia and ammonium thiosulfate. I did not touch Ph.

Thanks in advance and greetings!

 

[bswartzwelder]

You joined 2 day ago and already you're trying what many would consider an advanced methodology. Have you read Hoke? Most any question you can come up with have already been answered on the forum. Use the search engine.

You will find out soon enough that the members here will not spoon feed you the answers. You must show a willingness to at least try to get the sandwers on your own.

Good luck and welcome to the forum.

 

[Mud Dobber]

I am new to this forum. I have been studying the thio leaches for a few years and have learned a lot on this forum. I found a lab study done on this subject.. You may have seen this before, but I think you guys might should check this out....
http://www.ejmpep.com/rath_et.al.pdf

 

[Geo]

I am new to this forum. I have been studying the thio leaches for a few years and have learned a lot on this forum. I found a lab study done on this subject.. You may have seen this before, but I think you guys might should check this out....
http://www.ejmpep.com-rath_et.al

The link is broken.