Cementing with Zinc didn't go as planned.

[Yggdrasil]

Yes, if you have any questions, please let me know. I don't hide any answers. I do the work outdoors. Hydrogen sulfide gas, which is created from the combination of sodium metabisulfite and zinc powder, does not harm me.

You really need to study.
Hydrogen Sulfide is one of the deadliest gases out there.
But I don't think it is formed by Zinc and SMB.
But Pyrite and HCl on the other side can be used to generate it.

And you have not answered these questions:
Do you have an assay?
What do you do with your waste?

 

[jakson]

You really need to study.
Hydrogen Sulfide is one of the deadliest gases out there.
But I don't think it is formed by Zinc and SMB.
But Pyrite and HCl on the other side can be used to generate it.

And you have not answered these questions:
Do you have an assay?
What do you do with your waste?

I don't have a lab analysis of the rock, but the metallization in the rock is well done.We throw our garbage in the plain and the uninhabited area

 

[Yggdrasil]

I don't have a lab analysis of the rock, but the metallization in the rock is well done.We throw our garbage in the plain and the uninhabited area

And polluting the water for the future generations, right.

I have said this many times you need to study how to treat ores, and that is not done with acids.

Go get an assay or do one yourself.
At least cupel some concentrate to get a bead to test.
Where in the world are you working?
Generally speaking?
Siberia, South America , Asia or other?

 

[jakson]

و آلودگی آب برای نسل های آینده، درست است.

من این را بارها گفته ام که شما باید نحوه تصفیه سنگ معدن را مطالعه کنید و این کار با اسیدها انجام نمی شود.

برو آزمایش بده یا خودت انجام بده
حداقل مقداری کنسانتره بریزید تا یک مهره برای آزمایش بگیرید.
کجای دنیا کار می کنی؟
به طور کلی؟
سیبری، آمریک

I am from asia(middle east)The heavy metals that are naturally present in the soil have always polluted the water. I don't think that Aqua Regia's waste has more pollution. Anyway, thank you for your attention.There is no reliable laboratory in my country. The operators of the laboratories in my country are liars and frauds who deliberately declare the gold and platinum group test results to be much lower than the truth.

 

[FrugalRefiner]

I am from asia(middle east)The heavy metals that are naturally present in the soil have always polluted the water. I don't think that Aqua Regia's waste has more pollution.

Unfortunately, that's not true. The heavy metals that are naturally present in your soils are generally locked up as metallics, or bound with other elements and/or compounds, like sulfides, etc. Once you dissolve them in AR, you free them from those bonds, and they do, in fact, become more pollution.

Consider copper. You can put a piece of copper metal in your mouth and you won't have any reaction because the copper is in its metallic state. But if you dissolve that copper in AR, the copper ions become highly toxic to virtually every plant and animal on the planet.

Dave

 

[Aidin61]

We have noticed when we have very fine precipitate that do not settle well, boiling in dilute Sulfuric will let it agglomerate better.

The theory is that it aquire a coating that hinders it to agglomerate.
By using weak hot Sulfuric this coating is removed and the particles get cleaner and settles well.

hey there!
I have a pregnant AR solution and I use Copperas to precipitate gold from the solution. As I add the precipitant, the gold particles start to form but they are very fine (like dust) and most of them are suspended in the solution (which make the solution cloudy) and it takes long time to settle down and I have to wait over night to collect all gold particles.

The question is: which chemicals, as coagulant, fit to my solution (solution pH=2 and temp=23 celsius degree) that makes the particles to stick together and settle down faster?
you suggest "weak hot Sulfuric acid solution" to my case as well?
Thanks.

 

[Yggdrasil]

hey there!
I have a pregnant AR solution and I use Copperas to precipitate gold from the solution. As I add the precipitant, the gold particles start to form but they are very fine (like dust) and most of them are suspended in the solution (which make the solution cloudy) and it takes long time to settle down and I have to wait over night to collect all gold particles.

The question is: which chemicals, as coagulant, fit to my solution (solution pH=2 and temp=23 celsius degree) that makes the particles to stick together and settle down faster?
you suggest "weak hot Sulfuric acid solution" to my case as well?
Thanks.

Welcome.
We need much more information.
What was dissolved, how was the AR made, how was it deNOxed and so on.
How was it tested?

Here are something for your studies:

We ask our new members to do 3 things.
1. Read C.M. Hokes book on refining jewelers scrap, it gives an easy introduction to the most important chemistry regarding refining.
It is free here on the forum: https://goldrefiningforum.com/phpBB3/viewtopic.php?f=54&t=19798
2. Then read the safety section of the forum: https://goldrefiningforum.com/forums/safety.47/
3. And then read about "Dealing with waste" in the forum: https://goldrefiningforum.com/threads/dealing-with-waste.10539/

Suggested reading:
https://goldrefiningforum.com/forums/the-library.101/
https://goldrefiningforum.com/threads/when-in-doubt-cement-it-out.30236/
https://goldrefiningforum.com/threa...le-read-this-before-you-post-about-ore.33333/


Forum rules is here.
https://goldrefiningforum.com/threads/gold-refining-forum-rules.31182/


Edit to add information

 

[nickvc]

hey there!
I have a pregnant AR solution and I use Copperas to precipitate gold from the solution. As I add the precipitant, the gold particles start to form but they are very fine (like dust) and most of them are suspended in the solution (which make the solution cloudy) and it takes long time to settle down and I have to wait over night to collect all gold particles.

The question is: which chemicals, as coagulant, fit to my solution (solution pH=2 and temp=23 celsius degree) that makes the particles to stick together and settle down faster?
you suggest "weak hot Sulfuric acid solution" to my case as well?
Thanks.

If you bring your solution to a low boil it should help to settle the gold faster but be sure you have no free oxidizer or your gold will redissolve..

 

[Aidin61]

Welcome.
We need much more information.
What was dissolved, how was the AR made, how was it deNOxed and so on.
How was it tested?

Here are something for your studies:

We ask our new members to do 3 things.
1. Read C.M. Hokes book on refining jewelers scrap, it gives an easy introduction to the most important chemistry regarding refining.
It is free here on the forum: https://goldrefiningforum.com/phpBB3/viewtopic.php?f=54&t=19798
2. Then read the safety section of the forum: https://goldrefiningforum.com/forums/safety.47/
3. And then read about "Dealing with waste" in the forum: https://goldrefiningforum.com/threads/dealing-with-waste.10539/

Suggested reading:
https://goldrefiningforum.com/forums/the-library.101/
https://goldrefiningforum.com/threads/when-in-doubt-cement-it-out.30236/
https://goldrefiningforum.com/threa...le-read-this-before-you-post-about-ore.33333/


Forum rules is here.
https://goldrefiningforum.com/threads/gold-refining-forum-rules.31182/


Thanks for your reply;

I already have read C.M. Hokes's book but unfortunately there is no information about my question.
I'm refining "polishing bags" and i successfully have been refining them for several times with high efficiency as follow:
incineration of bags, digestion in AR (1 part nitric acid and 4 part chloridric acid as in Hokes's book), deNOxing with heat to kill excess acid, giving time to the solution to cooling down, filtration (to get clear AR pregnant solution), precipitating gold from pregnant AR with Copperas (ferrous sulfate), testing of the post-precipitated solution with stannous chloride.
My problem is: I have to wait over night to collect gold particles from the bottom of vessel because they are very fine when they are formed in precipitating step.
best regards

 

[Yggdrasil]

I already have read C.M. Hokes's book but unfortunately there is no information about my question.
I'm refining "polishing bags" and i successfully have been refining them for several times with high efficiency as follow:
incineration of bags, digestion in AR (1 part nitric acid and 4 part chloridric acid as in Hokes's book), deNOxing with heat to kill excess acid, giving time to the solution to cooling down, filtration (to get clear AR pregnant solution), precipitating gold from pregnant AR with Copperas (ferrous sulfate), testing of the post-precipitated solution with stannous chloride.
My problem is: I have to wait over night to collect gold particles from the bottom of vessel because they are very fine when they are formed in precipitating step.
best regards

Two things.
Are they incinerated to a level where you can guarantee it is completely free from Carbon?
It may be wise to leach the powder with HCl to get rid of as much base metal as possible before adding the Nitric.
How do you deNOx with heat?
Just boiling or going all the way to syrup?
Answer this and we can give further advise.
Hokes book will keep giving so read it at least 3 times.

 

[Yggdrasil]

I already have read C.M. Hokes's book but unfortunately there is no information about my question.
I'm refining "polishing bags" and i successfully have been refining them for several times with high efficiency as follow:
incineration of bags, digestion in AR (1 part nitric acid and 4 part chloridric acid as in Hokes's book), deNOxing with heat to kill excess acid, giving time to the solution to cooling down, filtration (to get clear AR pregnant solution), precipitating gold from pregnant AR with Copperas (ferrous sulfate), testing of the post-precipitated solution with stannous chloride.
My problem is: I have to wait over night to collect gold particles from the bottom of vessel because they are very fine when they are formed in precipitating step.
best regards

Aah, and when the precipitating metal is very fine, it hints that it is either very dirty (much base metals), very dilute or a combination of both.

 

[Återpenning]

hey there!
I have a pregnant AR solution and I use Copperas to precipitate gold from the solution. As I add the precipitant, the gold particles start to form but they are very fine (like dust) and most of them are suspended in the solution (which make the solution cloudy) and it takes long time to settle down and I have to wait over night to collect all gold particles.

The question is: which chemicals, as coagulant, fit to my solution (solution pH=2 and temp=23 celsius degree) that makes the particles to stick together and settle down faster?
you suggest "weak hot Sulfuric acid solution" to my case as well?
Thanks.

If you sleep at night , the nights will go faster.

 

[tmj883]

Copperas, Iron II sulfate, ferrous sulfate...degrades with time, temperature and humidity. It degrades into Iron III sulfate and Iron III oxide-hydroxide. Degradation is noted by a color change from pale green cristals to whiteish, yellowish, to brownish appearance. It should not be used. Get fresh greenish crystals. Prepare a solution by adding 50 grams of fresh Iron II sulfate in 100 ml distilled water for every 7.5 grams of expected gold. The solution will be pale green but cloudy. Heat gently, do not boil. Titrate the cloudy solution with hydochloric acid, drop by drop, until it clears. Filter the solution through a medium filter paper to remove anything insoluble such as free iron contaminants. It is now ready to use.

 

[anachronism]

Copperas, Iron II sulfate, ferrous sulfate...degrades with time, temperature and humidity. It degrades into Iron III sulfate and Iron III oxide-hydroxide. Degradation is noted by a color change from pale green cristals to whiteish, yellowish, to brownish appearance. It should not be used. Get fresh greenish crystals. Prepare a solution by adding 50 grams of fresh Iron II sulfate in 100 ml distilled water for every 7.5 grams of expected gold. The solution will be pale green but cloudy. Heat gently, do not boil. Titrate the cloudy solution with hydochloric acid, drop by drop, until it clears. Filter the solution through a medium filter paper to remove anything insoluble such as free iron contaminants. It is now ready to use.

Per your words in bold- no.
Please stop with this xxx grammes of Iron sulphate per gramme of expected gold. I really don't mean to sound harsh but it's utter nonsense mate, the same as it is with SMB. You add precipitant in until you reach a negative stannous test, and that's it pure and simple.

I'm not sure if this all originated from people not testing properly but it's a myth that needs busting. Can we do that? Pretty please.

Jon

 

[galenrog]

Per your words in bold- no.
Please stop with this xxx grammes of Iron sulphate per gramme of expected gold. I really don't mean to sound harsh but it's utter nonsense mate, the same as it is with SMB. You add precipitant in until you reach a negative stannous test, and that's it pure and simple.

I'm not sure if this all originated from people not testing properly but it's a myth that needs busting. Can we do that? Pretty please.

Jon

Jon is correct. We add precipitant until stannous test is negative.

There is, however, a starting point. This is where both Jon and tmj883 may be in error. With SMB, it is roughly equal weight to expected gold, if I remember correctly, with very small additions until stannous is negative. I do not recall starting point with copperas.

The starting point is different for each precipitant, relative to amount of gold expected. Other than that, the procedure is similar for each, with very small additions until negative stannous test.

Two keys here. 1) Do not start with too much precipitant. 2) Stannous Chloride is our eyes on this.

Time for more coffee.

 

[anachronism]

Jon is correct. We add precipitant until stannous test is negative.

There is, however, a starting point. This is where both Jon and tmj883 may be in error. With SMB, it is roughly equal weight to expected gold, if I remember correctly, with very small additions until stannous is negative. I do not recall starting point with copperas.

The starting point is different for each precipitant, relative to amount of gold expected. Other than that, the procedure is similar for each, with very small additions until negative stannous test.

Two keys here. 1) Do not start with too much precipitant. 2) Stannous Chloride is our eyes on this.

Time for more coffee.

Thanks Galen

Respectfully I disagree and here's why. These "starting points" have a habit of becoming biblical rules. There are quotes all over the internet based upon these starting points and they have morphed into rules that people follow without question. To the point where I've actually seen quite a few people use these proscribed amounts and then throw the rest of the gold away. Yes, it honestly happens.

The same analogy applies to Hoke's book. At base levels Ms Hoke was (and still is) an incredible resource but a double edged sword in that she effectively and cleverly provided people with a framework whereby the layman could recover and refine gold. Where this framework goes wrong is that many people follow this by rote, without understanding the whys and wherefores of what they are doing so when something goes wrong or doesn't perform as expected, confusion occurs. Hoke's book should simply be the starting point, at which point the actual journey should begin.

To answer your specific point though- if someone understands that the actual amount of any given precipitant required (edit) to drop a gramme of gold depends upon a whole host of circumstances including temperature, contamination in solution or whether any Nitric remains (and importantly WHY and HOW those affect the process) then it's a much better starting point than a given weight.

These precipitants aren't going to cause a problem if too much is used but they will if too little is used so I think we should drop the whole weight per gramme of gold thing from our vocabulary. It makes people dependent when they could be thinking for themselves.

Excuse the long post folks. For me it's about getting people to learn and grow for themselves, and not to simply follow instructions.

Regards Jon.

 

[galenrog]

Thank you for the clarification. I sometimes do not express my thoughts as well as I should.

You are absolutely correct. “Rule of thumb”, whether it be various formulae or procedures, do frequently, and even rapidly, morph into absolutes. The reasons for this are legion. I learned this again with a new hobby I am beginning to learn.

The most important lessons from the above discussion is that it takes what it takes, and that stannous is our eyes.

Time for more coffee.

 

[anachronism]

There was absolutely nothing wrong in the way you presented your thoughts Galen.

 

[4metals]

The process detailed by @tmj883 is the textbook description. My formula is about a pound of ferrous sulfate to a quart of warm water. (which, if you do the head math is very close) The only reason I ever use ferrous is if the lot has a significant quantity of platinum group metals in it which I want to recover after the gold. It is always in a dirty solution of a dissolve awaiting a first drop.

One thing I do not like about ferrous sulfate is the fact that it does go bad, fortunately visibly so. Whenever I purchased a sack of ferrous sulfate, I immediately weighed out 1 pound portions and vacuum sealed them in a food saver pouch, this prevented the ferrous from degrading, keeping it nice and green.

The fact tmj883 pointed out about 100 ml for every 7.5 grams of gold is probably a stoichiometric reality, but in practical reality who really knows how much gold they expect from a lot of e-scrap? (assayed karat is a different story) This leaves the stannous test as the only practical real time indicator of your endpoint as Jon pointed out.

 

[galenrog]

There was absolutely nothing wrong in the way you presented your thoughts Galen.

Thank you, Jon, but a several year old stroke does still affect how I express things from time to time.

Enjoy.

Galen