# Saturation point of HCL / Bleach



## Gold Trail (Sep 13, 2009)

I was wondering what the saturation Point of HCL / Bleach is?

IE how many milliliters per troy ounce of gold powder?

I just disolved about 4.3 Troy ouces of gold powder and it took about 1 gallon HCL and 1/3 gallon bleach

just seemed like a lot

I know Aqua Regia can hold quite a bit, but it seems the HCL / Bleach doesnt seem to match up.

ive had AR almost candy apple red with gold saturation before, but i could not seem to get the HCL / bleach 
much more than dark yellow bordering but not quite orange in color

Thanks in advance

Ryan


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## markqf1 (Sep 13, 2009)

Good question Ryan.
I think it would be a matter of how much the hcl will hold, as all of the free chlorine is eventually expelled.

I usually can boil an hcl/cl solution down by about a third before nacl crystals start to form.
Maybe this means I could have reactivated it with more(bleach)chlorine, and gotten it to absorb one third more pm's.
Reuseing and reactivating leach solutions until they are fully loaded, has to be cost effective.


Steve, Lou?

Mark


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## lazersteve (Sep 13, 2009)

The saturation level depends on temperature and water content mainly.

If you want to get it really saturated use a higher concentration bleach -- household is only 2-5% bleach, industrial bleach is 5-12% hypochlorite or better. Dry bleaching powder (calcium hypochlorite) is very near 100% dry bleach by weight.

Steve


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## markqf1 (Sep 14, 2009)

Thanks for the tip Steve.
I make my own "super clorox" :lol: 

Any idea as to how much the solution will hold?

Mark


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## lazersteve (Sep 14, 2009)

Gold III Chloride (AuCl3) is soluble to 68 g/100 ml in cold water according to wiki. 

Since Gold III Chloride is about 65% metallic gold by weight that equates to about 44.2 grams of gold in 100mL of cold water.

Gold Chloride forms a dimer with HCl to yield chloroauric acid (H[AuCl4]) in a one to one molar ratio. This means that in the presence of HCl and water even more gold chloride would be dissolved. 

Since HCl is soluble in water up to 38% by weight you could roughly calculate the maximum amount of gold a concentrated solution of HCl would hold as:

38% HCl =12.39 Molarity

12.39 x ~197 g/mol (molar mass of Au) = 2440.83 grams Au per liter as chloroauric acid dimer;

now we need to add the mass of Gold III Chloride that will be dissolved by the water content of the acid:

Density of 38% HCl = 1.189 g/mL x 1000 mL/L = 1189 g/L (grams per liter of 38% HCl)

Mass of 1L 38% HCl - mass of HCl gas = mass of water :
1189 g - (12.39 moles x 36.46 g/mole) = mass of water
1189 - 451.74 = 737.26 grams of water =~737 mL of water
737ml / 100 mL = 7.37
7.37 x 44.2 g/100 mL = 325.75 g Au

Finally, ignoring any gold complexes with the free chlorine in the solution, the maximum amount of gold that a 38% cold solution of HCl can hold is roughly:

2440.83 g (as chloroauric acid dimer) + 325.75 g ( as gold III chloride in water) = 

3011.41 g Au per liter or approximately 96.83 Toz per liter. :shock: :shock: 

or about 3 grams per mL in a 'cold' solution.

This sounds like an awful lot of dissolved gold to me, can anyone else verify this figure or tell me where I'm going wrong? If other salts (NaCl, NaOCl, KCl, etc) are present the solution would obviously hold less. Even if you ignore the gold III chloride in the water you have 78.5 Toz of gold per liter of 38% HCl as the dimer chloroauric acid. 

Interesting....


Steve


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## markqf1 (Sep 15, 2009)

Thanks Steve,
Talk about heavy! 
Imagine what a two liter bottle of it would weigh.

Maybe a mistake at wiki. :lol: 

Mark


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## DNIndustry (Sep 18, 2009)

No, lazersteves math is correct.
Your chemistry logic is kicking some ass


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## markqf1 (Sep 18, 2009)

Rule # 1- Never doubt Steve!
Rule # 2- Never doubt Steve!
I'll let you guess what rule # 3 is. :lol: 

Mark


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## Gold (Sep 18, 2009)

That's just to much math for me.  
I was waiting on someone to verify it, It was interesting. I assume that the numbers reflect at or near 100 % conditions ?
And to think i thought battery acid was dense. :shock: 

Great job steve :!: 

I wonder :idea: 
Could that be made into a spread sheet for other metals like say copper ? Silver ?


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## Gold (Sep 18, 2009)

Gold said:


> I wonder :idea:
> Could that be made into a spread sheet for other metals like say copper ? Silver ?



Yeah, before someone say's something about the silver hcl thing, I meant for each acid. Like Hcl, Nitric, AR. 
The maxium amout of metals each would hold at a certain acid concentration. Is that possible ? 

Who's the spread sheet guy ?


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## Gold Trail (Sep 18, 2009)

Wow, Steve, thats quite the equation there. It does seem like alot.

I was asking the question more less to balance my mixing ratios. I had recently disolved a little over 3 tr oz and ended up with close to three gallons of Auric cloride due to little knowledge of its saturation point (and my impaitiantness) 

I guess the question i intended to ask, is how many ml household bleach and how many ml HCL per tr oz of gold powder. 

I have no doubts to your math and chemisrty skills (I have 0 chemistry experiance ) But, i just dont see 78.5 Toz in 1 liter of household bleach and HCL

I have had close to 3 Toz in a less than 1/2 full coffee pot of AR with it pushing blood red. i just couldnt seem to the the bleach / HCl much more than canary yellow

Thanks for your indepth research into this matter, had i known it went that deep, i would have asked the question differently. 

. i assumed it was one of those things you just knew. 

but that what I get for assuming things. 

Ryan


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## lazersteve (Sep 18, 2009)

Goldtrail,

The bleach plus HCl limits are lower due to the formation of sodium chloride. The use of HCl and chlorine gas at around 90C will get you closer to the theoretical maximums. 

With the HCl and bleach you'll have to evaporate out the water and remove the sodium chloride that precipitates to get better concentrations.

Ralph, 

A while back I started a spread sheet with various base metals and acid combination to determine solubility limits, but I never finished it 100%.

Steve


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## teabone (Sep 20, 2009)

Three grams per ml. Talk about a pregnant solution. I would still have to see it to believe it.


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## DNIndustry (Oct 11, 2009)

Back to the top with this one...

May be I missed something but. NaClO is actually a weak base .

Clorine is not the by product but clorine dioxide (ClO2)

The problem you are running into is not the saturation of the solution... 
But you are actually neutralizing 

NaOH is a intermediary product.


I believe I found some equations to back this up.


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## Palladium (Oct 11, 2009)

DNI, did you get my last post in response to your P.M. about resin beads.
Anyone who p.m.'s me on my Aflac account, I can't receive p.m.'s from Aflac.

:arrow: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=48&t=2269&p=49325#p49325


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## DNIndustry (Oct 12, 2009)

Wow. You made my day. To be honest I thought you were just being ..a poop. 
Thanks for going out of your way!

It is really great to see they recommend XAD-7.
I attached a document I found helpful
Thats what I have been considering.
I bought a sample.
Not enough to fill my columns though. Do you have a good source for volume? Sigma is the cheapest I have found but it takes a lot of hoops to get registered.
any suggesttions

I have 7 columns that I plan on running in an array. 5 cm diameter 60 cm length. ( I also have some 6"x5ft units, cant afford to fill them )
I have some peristaltic metering pumps that control multivalve rotary solenoids to change solvents and outputs.
By stagering them in procession (load,rinse,wash,rinse,elute,regenerate,wash) I would be able to create fine gold every few hours automatically.
I am pumped!


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## Palladium (Oct 12, 2009)

Your welcome D.N.I.
I have been busy putting together my next chapter in my life. Sorry it took so long. Give me some time to do some more research and i'll get back to your on the resin's and beads.

Thanks


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## Palladium (Oct 12, 2009)

http://www.wipo.int/pctdb/en/wo.jsp?IA=AU1993000312&DISPLAY=DESC

The resin's are made of polystyrene divinyl. 

http://www.dow.com/PublishedLiterature/dh_0045/0901b803800455a5.pdf?filepath=specialtymonomers/pdfs/noreg/503-00002.pdf&fromPage=GetDoc

I have a background in Commercial chemical coating technology and this stuff is starting to look like several products i have researched recently. The chemistry is almost that of an Elastomeric roofing product i have been talking to them about at Rohm and Haas.

Another company who make these polymers is ICI or now known as I.C.I Dulux paint company here in the states. They also own name brands like Liquid nails. They make the scent that goes in perfumes, the dye that colors your cokes and drinks; They make dyes to color glass. They make pharmaceutical grade products. They just make it all.


http://en.wikipedia.org/wiki/Imperial_Chemical_Industries


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## Wyndham (Oct 13, 2009)

From looking at the linked PDF, it seems that if someone had a very fine silt with gold in it that this mixture , if stirred, would dissolve the micro gold in the silt, in about 4 hrs.
My question is if you let the solution settle and decant the clear solution, it should have a conservatively, 95% of the available gold in solution, correct?
Also they were using sodium hyperchlorate, I believe. Would there be any difference in the reaction using calcium hyperchlorate pool bleach(I believe this is correct)
I was just thinking about the beach placers in different places, where you could concentrate the fines down to a 5 gal bucket and finish at home.
Any thoughts, Wyndham


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## 61 silverman (Dec 14, 2009)

lazersteve said:


> The bleach plus HCl limits are lower due to the formation of sodium chloride. The use of HCl and chlorine gas at around 90C will get you closer to the theoretical maximums.
> 
> With the HCl and bleach you'll have to evaporate out the water and remove the sodium chloride that precipitates to get better concentrations.
> 
> ...


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## 61 silverman (Dec 14, 2009)

Looking at the picture I posted the solution looks GREEN, It is yellow ,here is another pic of the same solution..
Mark


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## samuel-a (Dec 14, 2009)

if you still have gold powder that is undissolved in that beaker, you can't filter the NaCl without loosing the gold that still undissolved.
what i would do, after boiling of the water is to add HCL to double the amount of the solution (some of the NaCl will go back to solution dou to the water in the HCL)
and add again bleach.

and continue the process periodically (boiling out the water to 1/3 of the volume or until salt is forming, add HCL +Cl) until all gold powder is dissolve.

you should dissolve with heat also.


steve, is this the process that you had in mind?


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## lazersteve (Dec 15, 2009)

Mark,

Salt formation when boiling down HCl-Cl mixtures is very common. Once you see salt forming add just enough water to dissolve the salt before filtering and adding SMB.

When I get some free time I'll ponder the solubility limits of gold in HCl and clorox in more detail.



Steve


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## JRH (Jan 1, 2010)

I have been doing some experimenting this week with fine placer gold and HCL/Clorox. I started with 6.6gms Au,8oz HCL and 2oz Clorox. The temperature here has been ranging from about 35degrees F at night to about 55 degrees high during the day. After 24hrs at the above conditions the solution was rich golden color with a heavy deposit of salt in the bottom of the reaction jar. I then added another 8oz HCL and 2oz clorox and allowed the solution another 48 hours. Again a thick deposit of salt had formed in the bottom. I filtered the solution, dissolved the salt through the filter with water and weighed the undissolved gold which came out to be 4.1gm remaining. It appears that it is taking about 8oz HCL/2oz Clorox per 1.25gm of gold at the given temperatures. I now have the solution precipitating and hope to prove a 2.5 gm yeild or at least close to it depending on the degree of natural impurities in the gold.


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## Harold_V (Jan 2, 2010)

JRH said:


> It appears that it is taking about 8oz HCL/2oz Clorox per 1.25gm of gold at the given temperatures. I now have the solution precipitating and hope to prove a 2.5 gm yeild or at least close to it depending on the degree of natural impurities in the gold.


Keep in mind, I am not familiar with the use of HCl and Clorox.
The numbers seem rather odd to me. If you use nitric and HCl to make AR, it requires less than 5 ounces of HCl to dissolve a troy ounce of gold. Some say as little as three ounces. Others say four ounces. Could it be that you require the addition of more Clorox, but not more HCl?

Harold


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## Oz (Jan 2, 2010)

Harold,

I do not think it is a lack of HCl but the concentration of sodium making sodium chloride solids from the bleach (sodium hypochlorite). He is diluting the salt concentration with HCl and water may be better. A stir plate would make this a non-issue as the salt would not be covering the gold. The other is the solubility of the free Cl2 in solution if he is adding too much bleach at once adding sodium but losing Cl2 gas to the atmosphere. The cool temperatures help him as Cl2 gas is more soluble in a cool solution, however the oxidizing of the gold is faster at a higher temperature, but then you have again the Cl2 gas wanting to go out of solution. Chlorine can be a fine balancing act but it eliminates de-noxing. Practicing reflux of vapors solves much.


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## JRH (Jan 2, 2010)

I should have added also that I am using a lightly sealed container for my reaction vessel. Basicly a quart container with a lightly screwed on lid. What I was trying to accomplish is allowing a controled release of the chlorine without being so tight that the top would blow off.


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## JRH (Jan 6, 2010)

After having precipitated with SMB the dried and weighed precipitate came up to be 1.7 gm. That is a good bit short of what I exspected. I am going to drop with copper in the solution to see if any other PMs come down and then try a zinc drop and weigh the results of each.


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## lucas77 (Apr 8, 2015)

I was wondering based on my own mess up if a 50/50 mix would be alright and still retain my gold and also is their a perfect color indication of when its time to precipitate your gold for a high yield I just got into this hobby recently and looking for advice


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## solar_plasma (Apr 8, 2015)

Much more information is needed to give you a satisfying answer. Here is a good point to start reading: Tips for Navigating and Posting on the Forum

The more you have read the better you will get at wording questions worth to answer, that more likely can and probably will be answered to your satisfaction.

Since you are new, those links might be of interest, too:

New to the board and want to ask questions? READ THIS FIRST

Hoke's book about refining

Hoke's book about testing

Guided Tour

Safety section

About the process using HCl and NaOCl you will find a lot of good threads if you type "HCl chlorox" in the search line. I did not understand your question, but it is probably answered on the first pages.


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## Geo (Apr 8, 2015)

JRH said:


> I should have added also that I am using a lightly sealed container for my reaction vessel. Basicly a quart container with a lightly screwed on lid. What I was trying to accomplish is allowing a controled release of the chlorine without being so tight that the top would blow off.



I understand this is an older post but I would like to reply to it now.

I would advise that you do not contain this reaction whatsoever. If the container seals due to some unforeseen reason, the HCl and sodium hypochlorite generates a huge amount of off gasses and could cause the container to explode unexpectedly. Not to mention the loss of your solutions but flying glass and chemicals is a hazard that is best to be avoided if at all possible.


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## butcher (Apr 8, 2015)

HCl and bleach (sodium hypochlorite), NaClO (which is kept basic with NaOH sodium hydroxide), mixed together basically makes salt water NaCl, some chlorine, the acid is neutralized by the basic hypochlorite.

Normally when dissolving gold we have more HCl acid and add bleach sparingly, this helps to keep solution on the acid side, and with the chlorine formed in solution, there long enough to oxidize the gold so it can form gold chloride AuCl3 with the HCl acid.

Our acid is about 68% water 32% HCl (gas), the bleach is mostly water 94%, and about 6% hypochlorite, and when these react they create some more water from the reaction as the base neutralizes the acid making salt.
So when we do dissolve our gold we have the AuCl3 and NaCl salts diluted in lots of water, if we evaporate to remove an excess of chlorine gas we saturate the solution with these salts (normally you shouldn't need to evaporate unless overuse of bleach, as a good heat alone should be enough to drive off a moderate excess of chlorine, if you do concentrate and form NaCl (and a little bit of sodium chlorate), you can just add back some water to put these water soluble salts back into solution, as too much of these salts may hold some of your soluble gold chloride in their crystals (the yellow color coloring the white salts yellowish).

You will always form salts, but with enough water you just wont see them.


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