sodium thiosulphate And hypochloride leaching

[labalkeny]

Hi all.
i am new to the forum, and dont seem to find any info on thipsulphate leaching / hypochloride leaching of a sulphide gold ore.
could someone point me in the correct direction!
i need to choose one of 2methods above based on its simplicitu.

 

[g_axelsson]

a sulphate gold ore.

I can't help you with the leach, but I'm curious, I've never heard about a sulphate gold ore before. Sure it isn't a sulphide gold ore?

Göran

 

[Barren Realms 007]

Hi all.
i am new to the forum, and dont seem to find any info on thipsulphate leaching / hypochloride leaching of a sulphate gold ore.
could someone point me in the correct direction!
i need to choose one of 2methods above based on its simplicitu.

This thread should help you out. Read the posts by Deano.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=85&t=22668

 

[labalkeny]

Thank u very much Goran,for that correction. i wil check the link.
thanks

 

[labalkeny]

Barren R, am checking out the thread! big up(thanks)

 

[labalkeny]

Hello, this place is surely a sea of vital chemistry information. I managed to go through threads given, but would still need asistance with the following.
1-i bought a 500g sodium thiosulphate marked 99%, how many grams of this 99%thio do i mix in how much water, to make what concentration to be able to leach economically and succesfully?
what is the recomended concentration of thiosulphate needed to do leaching?

2-rapid fixer(photo fixing ammonium thiosulphate) ,how much water is mixed to have it do gold ore leaching.
Can some one throw more light on the numbers as regards concentration in thio leach, together with time taken for the process to completely leach .
I thank u all.
labalkeny

 

[Barren Realms 007]

Hello, this place is surely a sea of vital chemistry information. I managed to go through threads given, but would still need asistance with the following.
1-i bought a 500g sodium thiosulphate marked 99%, how many grams of this 99%thio do i mix in how much water, to make what concentration to be able to leach economically and succesfully?
what is the recomended concentration of thiosulphate needed to do leaching?

2-rapid fixer(photo fixing ammonium thiosulphate) ,how much water is mixed to have it do gold ore leaching.
Can some one throw more light on the numbers as regards concentration in thio leach, together with time taken for the process to completely leach .
I thank u all.
labalkeny

The thread I listed a couple of posts above this one gives all of that information. All you have to do is read closely and put the information together.

 

[labalkeny]

"My preference is for pH 7, 200 grams per litre plain salt, calcium hypochlorite starting at 1 gram per litre.
The lower you can keep the hypochlorite levels the less attack on metals apart from gold.
This also makes a good silver leach if the solution is circulated through a cannister of activated carbon so that the silver level in solution is always kept low.
The silver will load on the carbon to the point where it can actually be burnished, similarly to gold.
Recover the precious metals by ashing "
This i picked.from Deano's explanation of chlorine leach method.
May U direct me to information showing me details about thiosulphate leach like the.one above for chlorine leach.
what thiosulphate concentration in moles per liter is recomended for the thio leach?
awaiting a responce.
Labalkeny

 

[labalkeny]

Barren R thanks,.but it looks like i there only is a detailled info on the chlorine leach, like theone written by Deano.
I cant seem to find a page stating the concentration of the thiosulphate needed to leach may u pliz quote one!
Bigup.

 

[Barren Realms 007]

Barren R thanks,.but it looks like i there only is a detailled info on the chlorine leach, like theone written by Deano.
I cant seem to find a page stating the concentration of the thiosulphate needed to leach may u pliz quote one!
Bigup.

I was thinking it was in that thread but I didn't find it. That thread has been condensed from it's original version but I don't think that information was left out of the original thread.

Do a search on Deano's posts and see what you can find out. I'm pretty sure he has a written more on the subject you are asking about.

http://goldrefiningforum.com/phpBB3/search.php?author_id=40539&sr=posts

 

[Deano]

Thiosulfate leaching is not a preferred method for several reasons.

The leach solutions are generally in the range 5 to 30 grams per litre ammonium thiosulfate, around 7 grams per litre blue copper sulfate with ammonium hydroxide added to pH 9.5 to 10.

This is a fairly narrow pH slot in which to operate.

This is a relatively expensive leach solution which will consume high levels of thiosulfate during leaching.

The gold/silver thiosulfate complexes load very poorly onto carbon and resin.

Recovery is by precipitation onto either zinc, copper or iron filings.

No de-aeration is required prior to the precipitation step.

The recovered precious metals will always contain copper from the leach solution which is co-precipitated with the precious metals.

The major problems with commercial use apart from cost are the ammonia fumes and corrosion of any steel in the plant.

The leach system has been heavily researched over the years, best of luck in finding a better way to run it.


Deano

 

[labalkeny]

Very vital info,thanks Deano.
1-what about precipitating the gold ans silver using sodium sulfide, and regenerating the thiosulphate to reuse in the leaching process.
2-how much time does it take the thiosulphate to leach an ore?
3-is there away to go around a ph meter? i dont seen to see one around !
labalkeny

 

[anachronism]

I may be incorrect however I think what Deano was trying to say politely was "reasons not to use it."

From your reply you seem to have discounted the parts of the post that you didn't want to hear. Why ask for advice if you're not prepared to listen to the advice given?

Edit for three words missing.

 

[nickvc]

I will echo anachronisms last post, if Deano advises for or against a process listen very carefully he really is the expert at this type of processing.

 

[labalkeny]

No,no,no. gentle men, i do not dispute anachronism,ruther iam.saying, can sodium sulfite drop both gold and silver so the leachant can be regenersted for reuse!
look at my situation, plenty of ore, extremly complicated hypochloride process , cynide is highly restricted not even seen anyway.
only option left is probably thio.
if sodium sulfite generates leach and drops Ag& Au, under what consitions some texts say under acidic thio conditions & others say just drops. how does one proceed from here?
I am an rf(radio frehency) technician , not a chemist. just suggested so we can share and if am wrong be corrected!
if it were u (by u i mean every person who cares) what would be the best method to employ?
thnks

 

[goldsilverpro]

http://goldrefiningforum.com/phpBB3/search.php?keywords=thiosulfate&terms=all&author=deano&sc=1&sf=all&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

 

[Deano]

Gold can be precipitated from a thiosulfate leach at slightly acid pH by many precipitants.

Why does the mining industry not use this form of recovery ?

The chemical costs associated with the pH shifts, you have to both lower and then raise the pH back into the leaching slot make it totally not viable.

You also have the problem of the copper precipitating out and thus needing to be redissolved with the ammonia.

This redissolving only occurs in the presence of aqueous ammonia so you now have to cope with the high level of ammonia fumes.

Recovery from this type of leach has always been by metal displacement with no pH shift and even this method has too many costs , filtration being the major one, for commercial practice.


Deano

 

[Deano]

If you are looking to run a commercial leach plant you really have only two options.

One is to use a chloride leach, the other is to use a cyanide leach.

The pH 7 saline hypochlorite leach will work well but it will attack any metal parts of the plant it comes in contact with.

It can be run as CIL or as a vat leach with separate carbon canister.

This leach type is difficult to use with an ore having appreciable levels of sulfides. These sulfides will consume hypochlorite and lower the pH, this means needing more care with process control.

Especially if run as a vat leach it is a commercial contender for leaching of ores, depending on the ore.

For cyanide leaches you have two options, you can use commercial sodium or calcium cyanide at pH11 in CIL or vat leach.

Recovery is by carbon or, after filtration, zincing.

The second option is to use potassium ferrocyanide to generate potassium cyanide.

The only reason you use this method is that the potassium ferrocyanide has virtually no restrictions on transport or storage.

The conditions for use are virtually the same as for sodium cyanide, the only qualifier is that the formation of the cyanide complex is catalysed by UV and thus either sunlight or UV lights at night are required.


Deano

 

[labalkeny]

Goldsilver pro and Deano thanks alot i appreciate the positive effort !
Let me get down to those links and check them out . Also the chlorine /hypochloride method i shal check once again.
thanks

 

[labalkeny]

goldsilver pro i have gone through the links and i think like Deano sugested, chloride leaching looks good.
With the battle lines drown,lets begin!
Deano, within the hypochlorous acid leach 'zone', confirm;
1- a 200litre air tight highdensity plastic tank can be openned for regular ph checks.
2- silt fine ore/ concentrate particle size is no problem with leac.
Now the survivalist way, stuck kilometers away in gold desert with a dead ph meter. how can a litmus paper with all its colour chart coresponding to ph 1 to 14 be used to save the leach thats already in water?