Gold Refining with hypochlorite

[Rifkhan]

I have few doubts regarding refining with Na Hypochlorite.

1. May I know how much gram of industrial grade sodium hypochlorite powder is needed to make a 15% of sodium hypochlorite solution?
2. What proportion of sodium hypochlorite solution: HCl should be added for the refining process?

I tried with adding tiny pellets of gold with 35% Con HCl (100ml) and industrial grade sodium hypochlorite powders (5 grams)

I found a cloudy solution with a white precipitate. I felt chlorine gas is emitting. But the gold remained same without getting dissolved.

I have added three images of side, top, and bottom views.


Can anyone please guide me where I have gone wrong.

 

[Yggdrasil]

When using hypochlorite, we use the liquid version.

Have what you need to dissolve in a beaker add HCl until it is covered and drip hypochlorite into solution and stir.
It is important to not add too much, it will neutralise the HCl.
Stir until no more dissolving happens.
Add i bit more and repeat.
Again measuring the ph if possible to make sure the HCl are not neutralised.
It is not suited for lumps of gold only foils and powders.
To me it seems you have overdone the hypochlorite massively.

 

[Rifkhan]

When using hypochlorite, we use the liquid version.

Have what you need to dissolve in a beaker add HCl until it is covered and drip hypochlorite into solution and stir.
It is important to not add too much, it will neutralise the HCl.
Stir until no more dissolving happens.
Add i bit more and repeat.
Again measuring the ph if possible to make sure the HCl are not neutralised.
It is not suited for lumps of gold only foils and powders.
To me it seems you have overdone the hypochlorite massively.

Thank you @Yggdrasil for the reply. I will try with reducing the hypochlorite solution.

Regarding producing a hypochlorite solution
What I did was, I added 2 grams of Powder with 50 ml distilled water. And I checked for the PH & it indicates around 5.70.
Added few powder and water with many trials but it was in the range of 5.9- to 6.9 approximately.
My question is also how can this be acidic? hypochlorite has to be base. Right?

 

[Yggdrasil]

When you buy it ready mixed it is at least.
Reading wikipedia it shows it is not basic at its own.
But as pure powder it decomposes fast if not cooled down.
So I expect it is already decomposed.
Better use liquid or even better Sodium chlorate.

Read here:
https://en.m.wikipedia.org/wiki/Sodium_hypochlorite

 

[Rifkhan]

When you buy it ready mixed it is at least.
Reading wikipedia it shows it is not basic at its own.
But as pure powder it decomposes fast if not cooled down.
So I expect it is already decomposed.
Better use liquid or even better Sodium chlorate.

Read here:
https://en.m.wikipedia.org/wiki/Sodium_hypochlorite

As you said, I think I have added excess amount of Sodium Hypochlorite.
So I will try with adding dropwise of Sodium Hypochlorite. I am also planning to use Clorox instead of preparing a Sodium Hypochlorite solution from its powder.

 

[Yggdrasil]

I'm suspecting your powder may have gone bad, depending on when you bought it and how you stored it.

 

[MicheleM]

1- 15 % per cent concentration of a solute in a solvent : 150 g NaClO for 1000 g (1000 mL) of H20 ( 15 /100 moles proportion is different) but why ? It is a very high concentration
2- anhydrous NaOCl is potentially explosive, and the solid pentahydrate degrades quickly. usually i add small quantities of NaOCl (aq) ( bleach) to HCl (aq) in steps: 1) pour Hcl in the beaker with gold powder/foils 2) add small quantity of bleach and immediately cover your beaker and wait until all the chlorine reacts 3) check if gold /black powders are still in the beaker 4) if some gold still there then repeat from step 2)

 

[Rifkhan]

I'm suspecting your powder may have gone bad, depending on when you bought it and how you stored it.

It has time for the expiry. But never know when it comes to industrial grade.

 

[Rifkhan]

1- 15 % per cent concentration of a solute in a solvent : 150 g NaClO for 1000 g (1000 mL) of H20 ( 15 /100 moles proportion is different) but why ? It is a very high concentration
2- anhydrous NaOCl is potentially explosive, and the solid pentahydrate degrades quickly. usually i add small quantities of NaOCl (aq) ( bleach) to HCl (aq) in steps: 1) pour Hcl in the beaker with gold powder/foils 2) add small quantity of bleach and immediately cover your beaker and wait until all the chlorine reacts 3) check if gold /black powders are still in the beaker 4) if some gold still there then repeat from step 2)

Thank you for the reply @MicheleM.
Yes. I realized it is too much concentration.
And regarding covering the beaker as soon adding the bleach. I didn't do that before.
So I will try that.

 

[Geo]

Sodium hypochlorite does not work well with gold solids. It is best used for foils and powders. When NaOCl is added to HCl, three major things happens. Chlorine gas is produced and NaCl is produced and HCl is neutralized. Chlorine gas in solution is very short lived unless it's under pressure. The chlorine gasses off too quickly to dissolve anything more solid than foils and powders. Chlorine gas is lost to the atmosphere as soon as the two chemicals are mixed. Much like nitric acid, it takes roughly 1.2 grams of trichloro to dissolve 1 gram of gold. An excess of HCl is recommended as the hypochlorite is basic and will neutralize some of the acid when the two are combined. It is recommended that an excess of hypochlorite is used. The excess, after dissolution of the gold is complete, can be removed by gently boiling the solution. Hypochlorite is destroyed at temps above 112°F. The solution should be brought to a low boil for a couple of hours and allowed to cool. Expect a white precipitate of sodium chloride to form when cooled. If the solution is evaporated to concentrate gold in solution, more salt will form in the solution.

 

[Geo]

Commercial bleach that is 8% sodium hypochlorite is 8% hypochlorite by weight and not volume. 100 grams of 8% bleach will contain 8 grams of hypochlorite. In theory, 100 grams of 8% sodium hypochlorite should dissolve 8 grams of gold foils or powders.

 

[Rifkhan]

Sodium hypochlorite does not work well with gold solids. It is best used for foils and powders. When NaOCl is added to HCl, three major things happens. Chlorine gas is produced and NaCl is produced and HCl is neutralized. Chlorine gas in solution is very short lived unless it's under pressure. The chlorine gasses off too quickly to dissolve anything more solid than foils and powders. Chlorine gas is lost to the atmosphere as soon as the two chemicals are mixed. Much like nitric acid, it takes roughly 1.2 grams of trichloro to dissolve 1 gram of gold. An excess of HCl is recommended as the hypochlorite is basic and will neutralize some of the acid when the two are combined. It is recommended that an excess of hypochlorite is used. The excess, after dissolution of the gold is complete, can be removed by gently boiling the solution. Hypochlorite is destroyed at temps above 112°F. The solution should be brought to a low boil for a couple of hours and allowed to cool. Expect a white precipitate of sodium chloride to form when cooled. If the solution is evaporated to concentrate gold in solution, more salt will form in the solution.

Thank you @Geo for the reply.

This gives a good explanation of the steps.
How long will it take to dissolve around 1 gram of gold using this method?

 

[Rifkhan]

Commercial bleach that is 8% sodium hypochlorite is 8% hypochlorite by weight and not volume. 100 grams of 8% bleach will contain 8 grams of hypochlorite. In theory, 100 grams of 8% sodium hypochlorite should dissolve 8 grams of gold foils or powders.

Therefore if I take 10 grams of bleach powder, that means it is 0.8 grams of hypochlorite.
Anyhow I need 12.5 grams of commercial bleach to dissolve 1 gram of gold

 

[dkbinco]

I have few doubts regarding refining with Na Hypochlorite.

1. May I know how much gram of industrial grade sodium hypochlorite powder is needed to make a 15% of sodium hypochlorite solution?
2. What proportion of sodium hypochlorite solution: HCl should be added for the refining process?

I tried with adding tiny pellets of gold with 35% Con HCl (100ml) and industrial grade sodium hypochlorite powders (5 grams)

I found a cloudy solution with a white precipitate. I felt chlorine gas is emitting. But the gold remained same without getting dissolved.

I have added three images of side, top, and bottom views.


Can anyone please guide me where I have gone wrong.

View attachment 47614View attachment 47615View attachment 47616

Good luck dude, I am working with same stuff except with ore that people here are telling me is not smart because I don't know without an assay what all is in the ore, so Probably good I joined. I will check on your progress later, but I have read a lot about what I am trying to do, I use a 2 to 1 mix with HCI and one thing I found interesting is I have been told to use a ORP meter while oxidizeing is happening to keep above 400 and at 1000 was the best to get the most, by adding HCI a little at a time to keep it, then when the meter quits reacting when you add to it ...its done oxidizeing, no more left in solution, then adding some sodium metebisetate a little at a time to seperate it. Just FYI, and please tell me if I am out of line and or wrong, I am not a chemist and am learning so, best way to learn is ask.

 

[Yggdrasil]

Good luck dude, I am working with same stuff except with ore that people here are telling me is not smart because I don't know without an assay what all is in the ore, so Probably good I joined. I will check on your progress later, but I have read a lot about what I am trying to do, I use a 2 to 1 mix with HCI and one thing I found interesting is I have been told to use a ORP meter while oxidizeing is happening to keep above 400 and at 1000 was the best to get the most, by adding HCI a little at a time to keep it, then when the meter quits reacting when you add to it ...its done oxidizeing, no more left in solution, then adding some sodium metebisetate a little at a time to seperate it. Just FYI, and please tell me if I am out of line and or wrong, I am not a chemist and am learning so, best way to learn is ask.

Dkbinko:
You could start with following the advice you have been given.
Read the book of C.M Hoke, even though it is not about ore, it is about the chemistry we do here.
Search and read the forum.
Next, when dealing with chemistry it is very important to use correct denomination of chemicals.
There is nothing named:
"sodium metebisetate" at least that we use in our chemistry.
In stead of blowing frustration for not getting the answer you want.
Maybe be grateful for getting the answer you need to be still alive and healthy.

 

[Yggdrasil]

Therefore if I take 10 grams of bleach powder, that means it is 0.8 grams of hypochlorite.
Anyhow I need 12.5 grams of commercial bleach to dissolve 1 gram of gold

Can I suggest a slightly other approach.
Make a chlorine generator and bubble chlorine through the HCl.

Outside or in a fumehood of course.

Edit to add:
We expect you to do the research needed and take the neccessary precautions, so you do not injure yourself or others.

 

[Rifkhan]

That will be little risky.
But anyhow I wanted to make it happen
I don't have a chlorine generator at the moment.
And for now I have to follow the instructions you all gave me for any improvements.

 

[butcher]

If the gold in an ore is free gold in the ore (not chemically bound in the mineral makeup of the ore), visible, even if you need a loop to see it at all, then crushing and gravity is your answer.

How much gold per ton, in the rich and nonrich portion of the mine, what mechanical and chemical processes will be needed, will attempts to be profitable, or will you spend more effort or time trying to find a dime. what equipment will be needed, what outside professional help and their costs will be needed to mine and process this ore...

If the ore is chemically bound with minerals (you normally will not see the gold with a loop or less powerful microscope, then you need tons and tons of this to make recovery worth the effort.
This will normally take a lot of experiments to get a working process set up.
is the mineral ore acidic or is it basic?

How will it react to a leaching process?

What is the chemical bond, bound up with? Sulfides, arsenic, tellurides, mercury, carbonates, asbestos,, magnetites, chlorates, micas shists, silicates, hematites, bauxites, dolomite, on and on...
What preprocessing steps will be needed to prepare the material for a leaching process, like crushing grinding, roasting, floatation...

You can waste your time and put your health in danger for nothing, or you can spend a couple of dollars (to save you thousands and thousands of dollars or wasting your time for nothing ) to see what you have, assaying will be the first step to answering many of the questions we have before we even begin to look at this ore.

 

[rickbb]

I use HCL and bleach on foils from plated electronic parts. It's a very simple, cheap and easy process. It's my go to process for foils.

As several have said, use it on small batches of powdered or thin gold only. It's just not efficient to use on solid gold objects like jewelry or even placer gold. For solid gold objects like jewelry I use "poor mans" AR, an equally simple, efficient process.

Do all this in a proper fume hood.

I start with a beaker of the foils, add enough HCL to cover the foils, then slowly add small amounts of common household bleach, (5% or 8% both work). Stir and wait until it seems the process stops, then add smaller amounts of bleach. Stop adding bleach when all the gold is dissolved. This keeps you from adding too much bleach.

Put the beaker on a hot plate and set for low heat, no need to boil, just warm to the touch is enough. This will drive off any remaining chorine in an hour or so. You can then drop the gold or leave on the heat to reduce the volume and concentrate the solution, up to you. Then drop the gold using the method of your choice.

I don't know how ore was brought in to the topic, recovering gold from ore is a completely different process and you should never attempt to use any chemical digestion process on ore without knowing exactly what else is in the ore besides the gold.

Ore, (actual ore and not free gold imbedded in quartz which is not really an ore per se), can and often does contain arsenic, cadmium, various other heavy metal compounds, etc. Which is why you should get a proper assay on any ore first before doing anything to it.

 

[dkbinco]

Dkbinko:
You could start with following the advice you have been given.
Read the book of C.M Hoke, even though it is not about ore, it is about the chemistry we do here.
Search and read the forum.
Next, when dealing with chemistry it is very important to use correct denomination of chemicals.
There is nothing named:
"sodium metebisetate" at least that we use in our chemistry.
In stead of blowing frustration for not getting the answer you want.
Maybe be grateful for getting the answer you need to be still alive and healthy.

Ok thanks I will check out the book, I found a place to get an assay, and I wont do nothing until, I am reading and learning thats why I am here. I will post assay and go from there.