# Gold not precipitating after showing with stannous chloride



## M Usmani (Mar 9, 2022)

Dear Respected Members I have gold ore sand in Aqua regia and it shows very good gold by testing with tin chloride, then I have tried many times after making different aqua regia to precipitate by SMB or by ferrous sulfate after using Urea, but gold is not precipitating the solution become dark reddish or sometime dark black but after 30 minute the solution become yellow again with nill precipitation, please help me in this matter, Thanks and regards usmani


----------



## Yggdrasil (Mar 9, 2022)

M Usmani said:


> Dear Respected Members I have gold ore sand in Aqua regia and it shows very good gold by testing with tin chloride, then I have tried many times after making different aqua regia to precipitate by SMB or by ferrous sulfate after using Urea, but gold is not precipitating the solution become dark reddish or sometime dark black but after 30 minute the solution become yellow again with nill precipitation, please help me in this matter, Thanks and regards usmani


Do not use Urea, use Sulfamic acid.
You have used way too much Nitric.
How do you make your AR?


----------



## M Usmani (Mar 9, 2022)

Dear I have made Aqua regia 3hcl +1hno3, but yes I have used urea


----------



## Yggdrasil (Mar 9, 2022)

Never premix AR. Add sufficient HCl to cover your item. Then add Nitric in increments until no more reaction. Then add some more HCl and repeat a couple steps, if no reaction, it is finished.
I trust you have done a proper assay.
Ore can have many deadly elements released by acids.
The best leach is determined by assay.


----------



## M Usmani (Mar 9, 2022)

Thanks a lot for your response, sure I will try this method now not to premix AR


----------



## M Usmani (Mar 9, 2022)

Dear Assay Edxrf reports attached , thanks and regards


----------



## M Usmani (Mar 9, 2022)

video of Aqua regia, putting too much stannous chloride to check


----------



## Jimdeveney (Mar 9, 2022)

M Usmani said:


> Dear Assay Edxrf reports attached , thanks and regards


How much does it cost for an analysis of materials?


----------



## M Usmani (Mar 9, 2022)

$30 for one lab report


----------



## Martijn (Mar 9, 2022)

M Usmani said:


> video of Aqua regia, putting too much stannous chloride to check


After watching your video; 
*You really need to stop everything you're doing! *
Put that solution aside in a safe place, in a safe container and keep it loosly covered. 
Go see a doctor and get a blood test.

Study how to handle chemicals, reactions and the toxic metals in solution!! 

You just ruined your pregnant solution by adding stannous like that! 
It is done with a drop of solution with a drop of stannous on a filter paper or in a spot plate. 








Safety


Maybe the most important part. Your health has more value than gold.




goldrefiningforum.com












When In Doubt, Cement It Out


When In Doubt, Cement It Out This is advice I often give to new members who find they've created a bit of a mess, and they're wondering how to recover their values (gold, silver, PGMs, etc.). Perhaps they've followed a process they've seen on YouTube that left out some important details...




goldrefiningforum.com













Dealing with Waste


I have been roaming this site for a few weeks, and with Hoke's book on it's way (fyi Harold) and Steve's DVD's I should be ready to start recovering pm's here pretty soon. I do have concerns about how to correctly deal with wastes. I am looking for some insight into how you guys deal with this...




goldrefiningforum.com




*Use gloves!! Don't breathe those fumes!!*

Use proper chemical beakers and a fume hood! 

That gold is not worth your life and the medical bill can easily be far bigger than your gold! 

Martijn.


----------



## Martijn (Mar 9, 2022)




----------



## M Usmani (Mar 10, 2022)

Martijn said:


> After watching your video;
> *You really need to stop everything you're doing! *
> Put that solution aside in a safe place, in a safe container and keep it loosly covered.
> Go see a doctor and get a blood test.
> ...


Dear Martin Thanks a lot for advise really I have to careful in future, I just want to show the stannous reaction that is why I have put too many stannous, still a good ratio of gold it is not precipitating. Anyway really thanks


----------



## Martijn (Mar 10, 2022)

Reasons for gold not precipitating are usually:
1: toooo much nitric, 
2: no gold in solution or 
3: too little free HCl for the SMB to react with. 
4: other mysterious things that can be in the mix by following bad youtube advice like urinating in your chemical cocktail or not perfoming the chemistry steps like filtering properly. 

You get the best clearly readable stannous test results with a solution that's not concentrated, but diluted and letting it spread out on a paper filter tip. 
Dark spots can be anything. 

Now your soup looked like purplish, so i suspect some gold. 

But study safety first *and ask us before *you go and copy another you tube disaster recipe. 
*Study the links I gave you and you will (should) know how to proceed*. 

*But really: use gloves!! *

To understand and help you with your specific issue a bit better: post a picture of your 'sand' please. 

Stay safe.

Martijn


----------



## M Usmani (Mar 10, 2022)

I highly appreciate your response.
pictures of sand attached. I have done aqua regia too many times but always the same result, now sure I will do with steps and precautions.
thanks and regards


----------



## Martijn (Mar 10, 2022)

Great! But first desribe the steps you intend before making another toxic mess.

Looks just like a bag of 'mount baker mining machines' shaker table tailings. 
What is the source? 
Is it (maybe even chemical) waste in some way that was donated to you to process? 

Have you tried (if you have access to it) milling, gravity separation and assaying the different fractions?
Or have you tried classifying and using a gold pan? 

This will tell you if there is anything worth going after in the first place and where the most values are concentrated and how to recover it most cost efficiently. 

If not, then processing ore or sand tailings like you have, maybe is not a profitable option for you. 

Honestly, repeating AR, or anything else for that matter, many times expecting a different result is the definition of something I would not want to be accused of. 

Assay about 100 or 200 grams of the concentrates and make a plan from there. 

Martijn.


----------



## Barstool miner (Mar 10, 2022)

M Usmani said:


> Dear Respected Members I have gold ore sand in Aqua regia and it shows very good gold by testing with tin chloride, then I have tried many times after making different aqua regia to precipitate by SMB or by ferrous sulfate after using Urea, but gold is not precipitating the solution become dark reddish or sometime dark black but after 30 minute the solution become yellow again with nill precipitation, please help me in this matter, Thanks and regards usmani


Hi, pool acid has an ingredient that keeps the Chlorine in solution so Aqua Regia made with Muriatic acid just redesolves the gold so it will not precipitate properly. Use Sodium thiosulfate to neutralise the excess Chlorine Gas still in solution . use very little as to much will redesolve the gold again .


----------



## Martijn (Mar 11, 2022)

Barstool miner said:


> Hi, pool acid has an ingredient that keeps the Chlorine in solution so Aqua Regia made with Muriatic acid just redesolves the gold so it will not precipitate properly. Use Sodium thiosulfate to neutralise the excess Chlorine Gas still in solution . use very little as to much will redesolve the gold again .


That makes no sense to me at all. Please explain.


----------



## M Usmani (Mar 11, 2022)

Martijn said:


> Great! But first desribe the steps you intend before making another toxic mess.
> 
> Looks just like a bag of 'mount baker mining machines' shaker table tailings.
> What is the source?
> ...


Dear Martin Thanks for your detailed reply, the source is my friend who has a mine near river and from there I am getting sand on payments.
yes I have installed Sluice box and shaking table for making concentrate, after making concentrate the iron particles not left the gold particles because gold particles are very very small than iron particles so iron came with gold too. So after that I have tried aqua regia method to recover gold but failed. Now with all precautionary measures I would like to make aqua regia with very less Nitric acid and would try to precipitate as per your advise, I would be thankful if you spare some time and some line to guide in this matter
thanks and regards


----------



## Martijn (Mar 11, 2022)

Near a river you say. You (may) have sand containing placer gold. 
Are you paying for bags of tailings or concentrates or just sand dug up and you're concentrating it? Not quite clear to me.

That assay report is from sept. 2019, describing crushed ore... now is it sand or crushed ore? Ore comes from hard rock mining, placer gold sand is classified, washed and concentrated. 
Did you pay for this assay, and why wait three years before processing this ore? 

Are you sure he's your friend? Friends are not always the best buisiness partners. 

Sounds to me he once got a good assay and now uses that to sell river sand with magnetic black sands. 

Anyway, i believe your possible gold containing sand was concentrated in the ground by river gravity separation in stead of hard rock, so It can be washed back out again.

No need for chemistry imo.

Classify better to comparable particle size and you can separate it all better. 
Separate iron from gold with a magnet under water, preferably where the gold line on the shaker table starts and repeat several times on both concentrate and magnetic tailings to get a better separation each time. You will drag some gold out with the iron. So redo that a couple of times to purify the gold. Put the magnet in a bag to get the iron off easily.

Once you have clean gold concentrate, just melt into a ingot and sell it with a bit of impurities. The buyer will scan the purity and pay you accordingly.

Do you have a picture of the concentrates you processed with AR? 

Why do you want to refine it further?

*Assuming you've at least watched the safety lesson and have improved your safety standard:*

To test for pm's with AR, dissolve a bit of the concentrate from the bottom in a test tube. 
Add a bit of concentrate to a test tube, cover it in HCl and add one drop of nitric. 

To speed the reaction up safely, you could au-bain-marie the test tube in hot water. 
Add HNO3 _one drop at a time_ until no more reaction is happening, so there are no more tiny bubbles forming upon addition of *one drop of *HNO3. 
If you had to add relatively much HNO3, the reaction could be stopping because of low HCl level, adding two drops of HCL will show that. 
When the reaction is done, all metals exept for silver will have dissolved, you can pick up one drop of the hopefully pregnant solution with a glass stirring rod and let it fall off in a spotplate or on a filter paper. Or dip a filter tip in the solution with a pincet, wetting only milimeters is enough. 

Add one or two drops of stannous and watch if there is any purple discoloring. If its too dark to see, add a drop of water until its dilute enough to see. Only purple is gold! Brown is not. 
Oh, and iron dissolved in HCl looks just like gold chloride! Nice and deep yellow color. 

To make things clear: the only thing i've ever panned was gold bonding wires from 50 grams of IC chips...and made a fortune..., not! LOL
8 years GRF membership and my curiosity got me this far.
So my help regarding placer gold is purely theoretical. 
But I will get corrected by other members if talk nonsense. 

I'm really curious what your replies and results are. 

Good luck!


----------



## M Usmani (Mar 11, 2022)

Martijn said:


> Near a river you say. You (may) have sand containing placer gold.
> Are you paying for bags of tailings or concentrates or just sand dug up and you're concentrating it? Not quite clear to me.
> 
> That assay report is from sept. 2019, describing crushed ore... now is it sand or crushed ore? Ore comes from hard rock mining, placer gold sand is classified, washed and concentrated.
> ...


Dear Martin thanks a lot for your so much detailed teaching. Actually the report is of 2019 is in detail, now we are using another lab for testing because it is cheap, I may share it too. we have given crushed sand of 200 mesh to lab so they have mentioned it ore, whereas in natural the sand size is approx 30 to 40 mesh. I am sharing concentrate lab report from other local lab.
thanks again for your reply and surely I will give you good news very soon after experiment 
regards


----------



## M Usmani (Mar 11, 2022)

sand concentrate picture without magnet use


----------



## Barstool miner (Mar 18, 2022)

Martijn said:


> That makes no sense to me at all. Please explain.


Hi Martijn , thank you for your interest. Hydrometallurgy has been my hobby since I was 10 years old ,I am now 75 . I have never had a bored day in my life.
Sodium thiosulphate is used to take Chlorine out of Tap water that is used for fish Aquariums . AuCl minus Cl gives you Au . Pardon my chemistry but I am a meat and potatoes type of Chemist. 
From my observations of swimming pools in the old days HCl was used to treat pool water , but when I swam my nose and eyes always burned from the Chlorine gas on the surface of the water. When Mueric acid does not let off Chlorine gas come off pool water
but the Pool has to be drained 2 times a year to get rid of rezidual acid in the pool .
So excess Chlorine gas in your leach will redesolve your precipitated gold .


----------



## Martijn (Mar 18, 2022)

Thanks for the explanation. Makes a bit more sense now. 
So the sodium thiosulphate removes free chlorine out of solution and also reduces the gold chloride? 

But I don't think excess Chlorine gas is an issue in this case, or with AR. It's an excess of nitric he's dealing with.
And having urinated in it. 
And treating black sands with AR.


----------



## M Usmani (Mar 21, 2022)

Dear Martijn, Yggdrasil and all respected members 

Thanks a lot ai have got my gold in hand , I have done as you advised.
1. I took 45 kg of sand and make it concentrated using Sluice box and then shaking table, it becomes 4 kg approx 
2. I have added 3 litre HCl in a beaker with sand and heated it at 40C then I started using nitric acid drop by drop in the beaker and I have used 30 ml max and the reaction has stoped.
3. Then I have filtered the AR and tested for gold with stannous chloride it shows very good purple black. then I have added sulfamic acid in it till reaction stops.
4. Then I took 250ml water and added 60 gram SMB in it and pour it in AR solution slowly and stir.
5. first solution become brown, then reddish brown then black, I leave for 4 hours and found the black precipitant, I filtered it and washed it 3 times with warm water and dried.The black powder came 8.6 gram.
6.Finally gone to smelting, I have added 10 gram borax, 10 gram sodium carbonate with black powder in crucible and smelted with torch, I was mad to see that I got 3.6 gram gold button( picture attached)
Thanks a lot to all members, yggdrasil and Salute to Martijn
best regards


----------



## Yggdrasil (Mar 21, 2022)

You are welcome.
The preicipitant should have been boiled in HCl to get clean gold.
It seems like it is on the low side, I would do the whole thing again with the same concentrates.
Sometimes we have to add more HCl, but here I think you needed more nitric and heat. We mostly try to keep it as close to boiling as possible without boiling so around 90ish degrees.
For the most part at least me add the SMB as powder. Have you tested the solution after dropping the gold?
Some members prefer to drop the gold at pH 1.5
And there are no need to dilute unless to get rid of the lead and silver chlorides.


----------



## M Usmani (Mar 21, 2022)

yes dear I have tested the solution after dropping gold, it is free of gold no reaction shows.The gold I got is 96% pure, some nickel, iron, titanium still present in it 
regards


----------



## Yggdrasil (Mar 21, 2022)

M Usmani said:


> yes dear I have tested the solution after dropping gold, it is free of gold no reaction shows.The gold I got is 96% pure, some nickel, iron, titanium still present in it
> regards


Well , try to run the cons again just to see if there is more.
Still 1g a kilo is not bad.
What do the assay say pr ton of ore?


----------



## Yggdrasil (Mar 21, 2022)

One of our esteemed members introduced a techinique I liked.
He moistened the SMB and cast them as balls. Dropping them one at a time into the liquor.
Less water less waste.


----------



## M Usmani (Mar 21, 2022)

good, I should try it


----------



## M Usmani (Mar 21, 2022)

_The Assay showing minimum 2 gram/ kg and max 10/ gram per kg from different places different results_


----------



## Yggdrasil (Mar 21, 2022)

Is that for ore or concentrates?


----------



## M Usmani (Mar 21, 2022)

it is concentrate result


----------



## Yggdrasil (Mar 21, 2022)

Which means you have recovery of 10-50%.

I think you need to revise your process. 
Most likely AR is not correct for this.
How much silver do you have?
Did your initial Nitric leach go long enough?


----------



## M Usmani (Mar 21, 2022)

yes you are right I have to test another batch too, sorry I have not recovered silver yet


----------



## M Usmani (Mar 21, 2022)

silver is more than gold in ore but next time I would keep an eye on silver too. 
can I get silver by diluted nitric or concentrated ?


----------



## Yggdrasil (Mar 21, 2022)

Silver dissolves in nitric.

But it will also passivate the gold in AR if the concentration is high enough. Even worse if the gold is too high comparing to silver it can passivate the silver too.
If silver and gold is in alloy, it has to be inquarted, that means max 25% gold then nitric leach.
It can be overcome by mechanical stirring and such.

The case is: You need to know what is in there and in what form, this will decide the type of leach you can or should do.

Cynide derivatives will dissolve both silver and gold if I understand correctly.

What you need to do now. Find out where your gold is, leach the cons. Again first dilute nitric under strong heat. Then AR again.

Even better have the leached cons assayed again, if possible to see if there are values left. If so, you know where the gold is. If not you may just have been unlucky.

A side note, the precipitaded gold needs to be boiled in HCl to clean it properly. And if it is cinnamon coloured you really do not need borax to melt gold, sometimes a significant amount of gold get locked up in the borax, specially if it is not clean.


----------



## M Usmani (Mar 21, 2022)

Thanks for detailed teaching, I should do it properly now and get silver and pure gold too after boiling in HCl.
please let me know if I not added borax then what I have to add in smelting?

regards


----------



## Yggdrasil (Mar 21, 2022)

M Usmani said:


> Thanks for detailed teaching, I should do it properly now and get silver and pure gold too after boiling in HCl.
> please let me know if I not added borax then what I have to add in smelting?
> 
> regards


If you bring a clean metal to its liquid state, it is considered melting.
If you add fluxes for reduction, oxidation or other reasons its called smelting.
If the gold is clean, you just drop it in a crucible pre glazed with borax and melt it. Of course you need to take care so you don't blow your powder out of the crucible. 
When the gold ball, solidifies just pick it up with a tweezer and drop it in water.


----------



## M Usmani (Mar 21, 2022)

Alright noted with thanks


----------



## Martijn (Mar 22, 2022)

Beatiful button! Looks like a nice pipe from what i can see. Especially from a dirty solution. Great result!

I must say again: AR is not the way to treat whole batches of placer concentrates.
Smelting is.

Now back to the beginning.

Did you improve on safety and equipment with this experiment? I sure hope so. 

Besides silver you also have platinum in the concentrates. At 40 degrees Celsius some may have dissolved.
What did you do with the waste solution?
Did you test it with stannous?

Martijn.


----------



## M Usmani (Mar 22, 2022)

Dear Martijn 
Thanks for your reply, yes I have done with complete safety precautions, I have checked waste liquid with stannous chloride it is not showing any thing.
you are right that our ore contain gold, platinum, palladium and Rhodium too, But nothing recovered yet except gold, I have to know how to recover and precipitate it.
is AR dissolve PT, Pd, Rh, Ag all ?
best regards


----------



## Yggdrasil (Mar 22, 2022)

AR will recover Gold, Platinum and Palladium. To some extent Rh if finely dispersed but minimal Silver due to pacification by AgCl.

The challenge for PGMs is to get them out of solution, cementation will take care of that, but has to be done correctly.


----------



## M Usmani (Mar 23, 2022)

Thanks for reply 
may I precipitate platinum with ammonium chloride and palladium with DEG ?
regards


----------



## Yggdrasil (Mar 23, 2022)

I guess you mean DMG.
And yes if it is done correctly.

But with low amounts, I would just drop everything with copper after SMB.
There are always losses, micrograms from grams are not too bad, worse from milligrams.
The losses will most likely be around same anyway.

Put the remaining liquids in the stock pot and save the powders from the first cementation for later refining when there are enough to warrant a new run.
When you transfer your stock pot to waste, collect the slimes and add them to the powders from cementation.


----------



## M Usmani (Mar 23, 2022)

Alright noted well with thanks


----------



## Yggdrasil (Mar 23, 2022)

M Usmani said:


> Alright noted well with thanks


Have you researched what we mean with stock pot?


----------



## M Usmani (Mar 23, 2022)

yes stock pot means remaining liquid which we store in a drum for further processing after cementation


----------

