# Trouble with 3-1 ratio making AR using nitric substitutes



## cableman (Jan 1, 2013)

Sorry for posting such a dumb question but in my defense I searched around and found a lot of info but not the conversion chart or precise measurements for what I am doing. After reading Hoke, I see that I can use substitutes for the Nitric Acid When making Aqua Regia (like Potassium Nitrate [KN03], Sodium Nitrate [NaN03], or Ammonium Nitrate [NH4N03] ) therefore keeping the cost down considerably because Nitric Acid can be expensive. I prefer to use the Sodium Nitrate and Hydrochloric Acid but I am unsure as how to correctly maintain a 3 to 1 ratio of the chemicals because Hydrochloric is in liquid form while the other substitutes I mentioned are in powder or granular form.

I know that there is a lot of difference of opinion when mixing Aqua Regia and just how much water to add but the ratio of 1 part Nitric Acid to 3 parts Hydrochloric Acid stays the same. My problem is if I mix; per say, 500 ml of Hydrochloric then how do I know what 1/3 of that would be if I weighed or measured the Sodium Nitrate? Sorry for bothering you with such simple question but I do not want to have chemical accident because of ignorance.

Any advice on adding water in this situation would be greatly appreciated. From my reading it seems that the addition of water will help the chemical reaction but that was when I was reading about a straight mix of hydrochloric and Nitric both in liquid form lab grade. It seems that I also read somewhere that when using water (H2O) in this situation it needs to have chlorine present if you are to add it. I can't remember where I read this, I just made a notation to look into it because I have well water and otherwise I would be using distilled water.

Thank you in advance for any advice. I have been studying the processes for recovering and refining gold (I will be recovering from computer parts and regular electronics) and I see several different ways of recovering the gold depending upon the condition of the material you are starting with. For example recovering from CPU's, fingers from computer boards, or from different plated surfaces. I have figured it out on my own which process to use in each instance for my own purposes anyway without posting questions every time I look for an answer but in this case I must put safety first because I do not want to mess up when mixing acids where there is a potential danger of accident.

If someone could help me with this process of mixing the liquid and granular knowing how to figure my ratio I would be so grateful. I can measure in any way I need to, from weight to volume. I have very sensitive scales as well as a set that weighs up to 80 lbs.


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## ericrm (Jan 1, 2013)

its true that it would be nice to know how much hcl is loss for each gram addition of different nitrate


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## cableman (Jan 1, 2013)

So sorry about this post. I got to this forum in a round about way and put this is the wrong place. I would move it but I don't know how to once it has been posted. Possibly the moderator will move it or delete it. Again I am so sorry. I found the main forum and this site rocks. I think the answer to my question is that for 1 ml of 70% Nitric Acid the equal amount of Sodium Nitrate is 1.34 grams. I am just a beginner so do not blindly take that conversion to be correct without confirming it. I just mainly wanted to apologize for posting in the wrong place and let the moderator know that he can move it or delete it. I will not be making the same mistake again.


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## gold4mike (Jan 3, 2013)

Cableman,

It's a good practice to estimate the amount of chemicals you'll need and to proceed accordingly. This will at least get you close to knowing what to expect.

As you browse the board you'll find some posts by GSP that mention the fact that he recommends adding the chemicals separately. In the case of AR, start by adding slightly more than the projected amount of HCl and, perhaps one fourth of the Nitric (or Nitrate in the case of Poorman's AR). Slowly add heat and let the reaction run until you see no more red/brown fumes evolve.

Add more Nitric or Nitrate in small increments until nearly all of the metal is dissolved. Once you get near the endpoint use an eyedropper or something similar for the last few additions, stopping when the metal is dissolved.

This will ensure that you don't use too much Nitric and have issues with precipitation. As you gain experience you'll get a feel for how much to add when.


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## butcher (Jan 4, 2013)

HCl + NaNO3 --> HNO3 + NaCl

From this balanced equation of our reactants and our products, we see we can make nitric acid, notice that table salt NaCl sodium chloride is also made, notice also (after the arrow) we have only nitric acid and no hydrochloric acid, only nitric acid and NaCl, we can use this formula to tell how much of each chemical in grams is needed to make the nitric and table salt.

(Note to make poor mans aqua regia we will need extra HCl see below).

To do this we need to look at the periodic chart or table of elements.
http://www.ptable.com/

Now we can use the molecular weight of the elements to get the weight of each element, add these together to get the molecular weight of each compound in our recipe in grams or moles, and the molecular weight of our products, in moles.

The balanced equation gives us the mole proportion of the reactants and the products.

Here we see in our equation one mole of hydrochloric acid HCl mixed with one mole of sodium nitrate NaNO3, gives us one mole of nitric acid HNO3 and one mole of sodium chloride NaCl.

From the periodic chart we will look at the atomic weight of each atom in the hydrochloric acid, Hydrogen in the acid (from our periodic table) H=1, and chlorine gas in the acid from our chart Cl=35.4 so adding these up we get a weight for a mole of hydrochloric acid of 36.4grams per mole.

(H=1) + (Cl=35.4) = HCl 36.4g/mole

Now the sodium nitrate NaNO3
Na sodium the atomic weight is 22.9
N nitrogen atom is 14
Oxygen atom is 16
Note in sodium nitrate we have three atoms of oxygen so we multiply 3 X 16 to get an atomic weight of the three oxygen atoms as 48 (3 X16 =48)
Now adding these up we get 22.9 + 14 + (3 X16) or,
22.9 + 14 + 48 = 84.9 
NaNO3 = 84.9g/mol

So one mole of HCl (38.4 grams per mole) and one mole of NaNO3 (84.9 grams per mole) will give us one mole of HNO3 (nitric acid) and one mole of NaCl (sodium chloride), You can calculate the products in weight also using this same procedure.

HNO3
H=1
N=14
O=16 
Three atoms of oxygen (3 X 16 = 48)
HNO3 = 63grams per mole

Table salt 
Sodium chloride
NaCl 
Na = 22.9
Cl = 35.4
NaCl = 58.3 g/mol

Note in the formula, we are only making HNO3 nitric acid and NaCl table salt, with no free hydrochloric acid in the products of our formula (after the arrow), so now if we wanted poor mans aqua regia we would need 3 to four times this amount of hydrochloric acid in moles.

Also with our acids these liquids are acid a certain dilution with water, so we must also look at the specific gravity of the acids in our calculations, and also consider water content to determine the strengths of our solution or products, I did not go into that here, also I may have rounded off some of the weights here for the discussion.


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## butcher (Jan 6, 2013)

Thought I would try to continue this (math as I understand it).

So if we want to make an aqua regia solution
we need to look at solutions, and we want approximately a ratio of one part nitric acid and 4 parts hydrochloric acid, for this we showed above that the HCl and NaNO3 consumed our HCl to make nitric acid, so we actually need 5 parts HCl with 1 part NaNO3.
Review:
HCl + NaNO3 --> HNO3 + NaCl
(36.4g/mol) HCl + (84.9g/mol) NaNO3 --> (63g/mol) HNO3 + (58g/mol) NaCl
This made nitric and salt.
We still need more HCl to make aqua regia:
36.4g/mol HCl X 5 (parts) = 182g

So:
5 HCl + NaNO3 --> HNO3 + NaCl + 4HCl
(182g/mol) 5 HCl + (84.9g/mol) NaNO3 --> (63g/mol) HNO3 + (58g/mol) NaCl + (145.6g/mol) 4 HCl

HCl specific gravity chart:
http://www.handymath.com/cgi-bin/hcltble3.cgi?submit=Entry


Lets use 32% hydrochloric acid in our example, which from the chart shows to have a specific gravity of 1.159.

This is 32% by wt HCl and 68% water by wt.
The percentage tells us we have 32g HCl per 100grams of concentrated solution.
The specific gravity tells us it is heavier for the same volume of water, 
Water has a specific gravity of about 1g/ml @ 4 deg C
The specific gravity gives us the density of the acid of 1.159g/ml

32% by wt HCl/100g solution
(HCl 36.4g/mol atomic weight)
Specific gravity at this concentration 1.159g/ml

From this we can determine the mass weight of HCl in each milliliter of solution:

(32g HCl / 100g conc. soln.) X (1.1593g /1 milliliter) = 0.37097g/ml mass weight of HCl/ ml of solution

So for a liter we have 0.37097g/ml X 1000ml = 370.97g mass wt of HCl per liter of solution at this concentration.

Hope to continue this post later if some chemist does not come here and help with the rest (I think I will have to do a little more home work to complete formula, also if any one finds a problem in the math, or equations let me know.

Editted in red to correct for(mistake in Sp. Gr. reading) thanks for finding my mistake.


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## butcher (Jan 7, 2013)

OK from above,
I need 182g/mol HCl (for 5 moles of HCl in my home made aqua regia), (1 part to make nitric in solution and 4 parts free HCl).

Using 32% by weight concentration HCl.
(With HCl molecular atomic weight 36.4g/mol).
Having a specific gravity of 1.159g/ml
We have determine my solution contains 0.37097g/ml mass weight HCl per milliliter of concentrated solution.

so if I am doing this right (???)
with the goof up corrected as far as I can tell

(182g/mol HCl needed) / (0.370976g/ml) (HCl mass wt / ml) = 490.5 milliliter of solution needed to get 1.82g HCl using 32% acid.

2 cups =~ 480 ml

So looks like about 2 cups of my HCl acid with about 85 grams of NaNO3 fertilizer will give me about 2 cups of homemade poor man’s aqua regia.


Hoke states 1 fl oz HNO3 and 4 fl oz HCl will dissolve a troy ounce of gold, 
That about equal to:
30ml HNO3 and 118 ml HCl per troy ounce of gold.
Or
6 teaspoons of HNO3 and 8 tablespoons of HCl per troy ounce of gold.
Or 148ml aqua regia per troy ounce of gold

With that in mind my 2 cups (480ml) of poormans aqua regia solution could come close to dissolving 2.4 troy ounces of gold.


Now where did I goof?
Goof Editted in red


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## butcher (Jan 8, 2013)

Poormans aqua regia formula how much, continued:

Of coarse the total volume of solution would end up more volume from liquids and salts in the reactants.
5 HCl + NaNO3 --> HNO3 + NaCl + 4HCl
Approximate:
Reagents:
5 HCl (480ml), (182g), (32% conc. by wt. acid, Sp.Gr 1.159g/mol), (HCl atomic wt 36.4g/mol), (5x36.4g/mol).
+
NaNO3 (84.9grams)

{If using KNO3 101g}

--- Yields --->

Products:
HNO3 (71ml of solution by proportion) (63g/mol)
+
NaCl (58g/mol)
+
4HCl (386ml of solution by proportion) (145g) (4x35.4g/mol)

This has been calculated to be able to dissolve approximately 2.4 troy ounces of gold 
Or 74.54 grams of gold.

-----------------
We can divide these formulas and amounts down to see how much it would take to dissolve a troy ounce of gold and then see how much to dissolve a gram of gold, I have already done the math and will not post the math, but will give amounts I came up with:

We see above how much to dissolve 2.4 troy ounces of gold or 74.5 grams above formula.
-----------------
For a troy ounce of gold:
Reactants:
5HCl 32% (148.75ml), (75.8g HCl)
NaNO3 (35.3g)
{If using KNO3 42g}
---> 
Products:
HNO3 (29.58ml), (26.25g)
NaCl (24.1g)
4HCl (118.75ml),(60.6g)
-------------------
For a gram of gold:
Reactants:
5HCl (4.78ml) (2.43g HCl)
NaNO3 (1.13g)
{If using KNO3 1.35g}
--->
Products:
HNO3 (0.95ml) (o.84g)
NaCl (0.77g)
4HCl (3.81ml) (1.94g HCl)
--------------------
After doing this I looked in the general reaction list to see how close my calculation came to the one posted there, and to my surprise I found the amounts posted there the same equivalent to my formula here, so I can deduce they done this homework also to get what I have.
---------------
From general reaction list:
Reactants:
960ml HCl 32%
8 oz NaNo3 (225.7g)
480ml water

I calculated ratios of this formula compared to my formula they came out the same.
I would love to see their scratch pad of the math when this was figured.

I calculated the approximate amount of gold this would dissolve to be 200 grams of gold, or 6.43 troy ounces of gold.
(In the general reaction list it states this will dissolve about 160g pins or about 32oz of ceramic CPU's)
--------------------
Adding water, notice the water in the formula above, I did not figure water in my original formula, as the acid is 68% water already, but the added water will help when heating to under a boil, from evaporation to keep from forming salts from evaporation, consider this also when working with poor mans aqua regia, if working with cold solution the water added can dilute the solution, working with very hot solutions the water will keep from forming salts from evaporation, in both reactions the added water can help to keep fume down somewhat. 


Now we would want to not premix this solution or formula, and we would want to add the calculated amount of HCl acid and add the NaNO3 a little at a time, for several reasons, one we do not want to have excess HNO3 when we are finished dissolving gold that will need to be removed (especially here were salts form easily on evaporation of this solution, and also so that we create the gases and chemicals in solution to react with the gold and not be wasted as gas unused, and our solution stays active to dissolve the metals (see below for more discussion on this).

When aqua regia is mixed (even without metals in solution), the two acids begin to react with each other forming volatile components in the solution (that will normally react with the gold), these after a while dissipate or decompose, this is why we cannot make aqua regia and store it for later use, (besides the fact that dangerous pressure’s could develop from the decomposition of the acid in a sealed vessel which could explode a glass vessel), aqua regia decomposes (made long before using) would not be very effective at all for dissolving gold, although it would still be a very strong acid solution.

To illustrate this I will use this formula:

3HCl + HNO3 --> NOCl + CL2 +2H2O

Notice the nitrosyl chloride NOCl formed and chlorine gas in solution, both of these decompose or dissipate (or react with gold if in solution).

Nitrosyl chloride reacts with water and hydrolyses and decomposition:
NOCl + H2O --> HNO2 + Cl + H
NOCl + H2O --> HNO2 + HCl
NOCl + 2H2O --> HNO2 + HCl + H2O
When reacting gold with aqua regia the these chemicals and products react to dissolve gold when solution is fresh, chemicals we see in the formulas above NOCl and chlorine gas HNO2 chlorides HNO3 and HCl and so on.


Nitric acid is a strong oxidizer.
We normally say nitric acid does not dissolve gold by itself this is a fact.
But it can dissolve an undetectable trace of gold, oxidizing this trace of gold by removing an electron from the gold atom, 
(Some say it plates back or stays attached to the metal, if gold if chlorides or other Halide’s are not involved).

With chlorine ( which is reduce to chloride with the oxidized gold) HCl in solution these chlorides are involved (as in aqua regia), this gold atom missing electron attaches itself to 3 or four (chlorine atoms)chloride atoms (formally chlorine with an excess electron to share with the gold atom) and form gold chloride salts dissolved in solution, in highly acidic state as HAuCl4, or more dilute as AuCl3.
(I have trouble saying this to where it makes the most sense)

Some common formulas gold and aqua regia:
Au + 3NO3 + 5H --> Au3+ + 3NO2 + 3H2O
And
Au3+ + 4Cl --> AuCl4


Au + NO3 + 4H --> Au3+ + NO + 2H2O


Au + HNO3 + 4HCl --> HAuCl4 + NO + 2H2O

What no comments surely someone can add to this or find a mistake in my math or how I stated this here or how it should be stated better.


cableman< you need to be careful about asking dumb questions I might try to answer it, then you get a dumb answer. :lol:


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## tek4g63 (Jan 8, 2013)

> What no comments surely someone can add to this or find a mistake in my math or how I stated this here or how it should be stated better.



Butcher, I have a comment. WOW! You have blown my mind. 

I have printed out everything you just posted so that I can read it over and over again, until I completely understand it. You have described so well that I know that I will be able to understand and retain it. Thank you so much for taking the time to share your working knowledge! Again I can only say WOW!


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## butcher (Jan 14, 2013)

Making Aqua regia without using Hydrochloric acid (HCL) or Nitric acid (HNO3)
Using rock salt, battery acid, and a nitrate fertilizer.

In a question one of our members who said he could not get HCl hydrochloric acid, He was trying to dissolve gold using a form of home made aqua regia, (in the thread precipitation SMB vs. NaOH)

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=14490

We discussed making HCl with NaCl salt and sulfuric acid H2SO4:
2NaCl + H2SO4 --> 2HCl + Na2SO4
(Here the HCl is normally distilled from the sodium sulphate salts).

We also discussed the saturated salt and nitric acid, SSN leach normally used on ore:
2NaCl + 2HNO3 --> HCl + HNO3 + NaNO3 + NaCl
(Notice here we really do not have enough HCl in solution, and we do have some sodium nitrate form (just not quite enough acid) (it will form somewhat of an aqua regia, but is lacking also).

Then there are a couple of more formulas I would like to add here in this discussion.

Poor mans nitric acid:
2NaNO3 + H2SO4 --> 2HNO3 + Na2SO4

Poor Mans Aqua Regia:
5HCl + NaNO3 --> 4HCl + HNO3 + NaCl

OK that sets the background for what I have been thinking about.


How can I make poor mans Aqua Regia if I do not have HCl or hydrochloric acid, or HNO3 nitric acid?

Well looking at the formulas above, we see where we can generate HCl with salt and sulphuric acid; we also see where we can generate HNO3 with sodium nitrate and sulfuric acid.

H’mm 

Thinking about it with my morning pot of coffee, I came up with this, combinations of some of the formulas above.

Taking from the reaction above:
8NaCl + 4H2SO4 --> 8HCl + 4Na2SO4 (to get HCl)
And
2NaNO3 + H2SO4 --> 2HNO3 + Na2SO4 (to get HNO3)

Combining these into a new formula to try and make Aqua Regia without having access to HCl or Nitric Acid, I came up with this formula:

8NaCl + 5H2SO4 + 2NaNO3 --> 8HCl + 2HNO3 + 5Na2SO4

Dividing this formula in half gives:

4NaCl + 2.5H2SO4 + NaNO3 --> 4HCl + HNO3 + 2.5Na2SO4

This gives us Aqua Regia with some sodium sulfate salt in solution.
(Note: if we included silver it would form silver chloride and silver sulfate in this solution).

For those who may note know:
H2O = water, or (dihydrogenmonoxide)
HCl = Hydrochloric acid
HNO3 = Nitric acid
NaCl = sodium chloride (table salt, rock salt)
NaNO3 = sodium nitrate (fertilizer)
H2SO4 = Sulfuric acid
Na2SO4 = sodium sulfate


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## TomVader (Jan 18, 2013)

As long as your in a calculating mood... would it then be possible to use HCl and KNO3 to get HNO3 and KCl ? or is there something different about potassium? I don't think I'm ready to tackle the math, but how to account for the fact that HCl is in solution with H2O (32%)? Would heat be necessary for this reaction? And then what about distilling this product to get HNO3? would the KCl boil away as well? Sorry for all the questions, I should get myself some chemistry books and start from the beginning... Thanks!


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## butcher (Jan 18, 2013)

Tom, if you re-read above You will see where I gave how much if KNO3 would be needed if it is used to make poor man’s aqua regia.

The general reaction list also has information and it is an excellent document, it was only after I almost completed the math that I looked at its recipe, and found it had to have been calculated using similar math.


Poor man’s or even regular aqua regia you would not want to distill it, the reaction occurs when the two acids are mixed, gases are formed in solution, which if distilled or let set for a period of time would volatilize or change to another state, these reactions and gases are what is needed to dissolve the gold, this is why you do not make and store aqua regia for later use, the aqua regia stored would no longer be effective, although it would still be acids, I presume distilling would also destroy aqua regia usefulness to dissolve gold as well as it does, here recently I made a post trying to explain this.

If you wished to distill for a cleaner product, leaving salts behind, I suggest you make nitric and HCl separately, and distill them separately, then mix them when you want aqua regia.


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## TomVader (Jan 19, 2013)

I was thinking of an alternate method of producing HNO3, not Aqua Regia.
So HCL and KNO3 will not result in HNO3 and KCl? Thank you for your efforts.


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## butcher (Jan 19, 2013)

Tom
H2SO4 + 2KNO3 --> 2HNO3 + K2SO4
sulfuric acid and potassium nitrate will produce nitric acid and potassium sulfate most of which can be removed by chilling solution, for clean nitric it can be distilled.

check in the general reaction list, I remember Laser Steve done a great job of calculating the quantity needed to make a very good poor mans cold recipe nitric acid.


With both HCl or chlorides and nitric in acidic solution it would not be what we normally think of nitric acid, but would be more like a variant of aqua regia.
As long as both nitric and chloride are in solution it would dissolve some gold, and would also give trouble when used with silver.


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## TomVader (Jan 20, 2013)

Thanks. I've been using Lazersteve's formula and then distilling, good results. I guess it's one thing to follow someone else's recipe and quite another to truly understand what's happening, like you do. Like a cook that can make a delicious meal, a chef can make adjustments and make it even better. I'm going to dig out my high school chemistry texts and begin studying. Thank you again.


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## butcher (Jan 20, 2013)

Tom follow this post with your chemistry book, it will help you get the idea. 
Heck with a little study you can help me get better at this.


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## butcher (Jan 21, 2013)

It appears I made a mistake in reading the specific gravity chart for HCl.

So in the above formula for poor mans I will need another half cup of acid.
About 2 cups instead of the 1.5 cups previously stated.

I will edit the above post in RED.Recalculating for my miss reading of the specific gravity of 32% HCl (1.593g) which should have been be 1.1593 @ 20 deg.

Thank you bswartzwelder for finding this mistake, and keeping me on my toes.


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## bswartzwelder (Jan 22, 2013)

Butcher,
You and the many others (too numerous to mention) have done far more to help the people on this forum than anything I could ever expect to contribute. The thanks goes out to all of you (you know who you are) for the explanations, fixing other peoples problems, keeping people safe, and making this forum not only a pleasure to read, but one of the best places to learn without being charged an arm and a leg.


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## butcher (Feb 1, 2013)

New Poor Mans aqua regia made with sulfuric acid.
4 NaCl + NaNO3 + 2.5 H2SO4 --> 4 HCL + HNO3 + 2.5 Na2SO4

Well I have done a little more homework on this to try and get the numbers on this.
Making aqua regia, with no HCl, and with no HNO3.

Using 
NaCl sodium chloride (salt)
NaNO3 sodium nitrate (fertilizer) 
Or
KNO3 potassium nitrate (fertilizer)
And 
H2SO4 sulfuric acid (98% drain cleaner)

Some reference data: 

Atomic weights from periodic chart:
Na=22.98g/mol
Cl=35.45g/mol
N=14g/mol
O=15.99g/mol
H=1g/mol
S=32.06g/mol
K=39.09g/mol

Adding up these elements in the compounds we get their atomic weight:
NaCl=58.43g/mol
NaNO3=84.98g/mol
KNO3=101.1g/mol
H2SO4=98g/mol
HCl=36.45g/mol
HNO3=63g/mol
Na2SO4=141.96g/mol

Data for our 98% H2SO4 sulfuric acid;
98% H2SO4 specific gravity 1.843g/ml
M Molarity 18.4
N Normality 36.8
Boiling point 621 deg F

Now our formula we will be using:

4 NaCl + NaNO3 + 2.5 H2SO4 --> 4 HCL + HNO3 + 2.5 Na2SO4

This tells us 4 moles of NaCl with one mole NaNO3 and 2.5 moles of H2SO4,
Will make: 
---->
4 Moles of HCl mixed with one mole of HNO3 and 2.5 moles Na2SO4.
So here we have aqua regia with some sodium sulfate in solution.

So for:
Reactants:
4 moles of NaCl : (4 x 58.43g/mol) = 233.72g/for 4 moles
One mole NaNO3 = 84.98g/mol
Or
One mole KNO3 =101.1g/mol
2.5 moles of H2SO4 : (2.5 X 98g/mol) = 245g/for 2.5 moles
Products:
4 moles of HCl : (4 X 36.45g/mol) = 145g/ for 4 moles
One mole HNO3 = 63g/mol
2.5 moles Na2SO4 : (2.5 X 141.96) = 354.9g/for 2.5 moles

Now to figure to get our 98% H2SO4 sulfuric acid in volumes of solution (milliliters needed) instead of grams weight of H2SO4 mixed in with the water of the acid needed (for one mole H2SO4 in solution):

98% concentration by weight of H2SO4 @ density of 1.843g/ml in our acid:

98%acid / 100% solution
Or
98g / 100g = 0.98

0.98 conc. X 1.843g/ml sp.gr = 1.806g/ml (H2SO4 content by weight in our acid solution)

So to get how much H2SO4 is in one liter of our 98% acid solution :
1.806g/ml X 1000ml/Liter = 1806. g/Liter 

Now I needed 2.5 moles of H2SO4 in our recipe, So:

2.5mole X 98g/mol atomic wt. H2SO4 = 245 grams H2SO4 (needed to get 2.5 moles of H2SO4)

So:

245g H2SO4 (2.5mol) / 1.806g/ml (mass wt. H2SO4/ml) = 135.66ml of solution needed to get 2.5 mols of H2SO4


Now to conclude:

Aqua regia made with salt, fertilizer and sulfuric acid.

Reactants:
4NaCl (233.7g) + NaNO3 (85g) + 2.5H2SO4 (245g 0r 135ml of 98% acid)
(If substituting KNO3 use 101g)

---------->
Products:
4HCl 145.8g/4moles)
HNO3 (63g/1mole)
2.5Na2SO4 (354g/2.5 moles)


Note also some water will be needed to keep salts in solution, or water may also be needed when solution heated due to evaporation.

Again I can use help with any mistakes in my math or figuring this out, so please review this and critique.


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## TomVader (Feb 2, 2013)

Math is beautiful. I don't mean your math in particular, I wouldn't presume to critique it. I mean math in general. Thank you for this post, I'll save the recipe and the calculations along with all the others. I have a question, though: Will the sodium sulfate interfere with dissolving gold or later in it's precipitation?


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## butcher (Feb 2, 2013)

The sodium sulfate should not interfere with the gold, (note: it is not sodium sulfite which would precipitate gold), now if silver was in this solution I can see where the silver could form silver chloride as well as silver sulfates, also as stated above the solution would need water to keep the salts from forming.

Note this is a poor mans solution that cannot get HCL or HNO3.


Also note, HCL and HNO3 could be made separately and the majority of the salts removed (or they can be distilled separately for a very pure product), and mixed when you needed aqua regia.

I have not tried this to verify anything yet, at this point it is just the formula and the calculations.


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## dangerousdane (Feb 3, 2013)

Hi every one. I am not exactly a newbie having been reading and absorbing this massive gold mine of information since last august. I have also done some refining and have a 12 gram button of double refined gold to show for alot of time and effort and expense. Butcher PMed me and asked for help regarding the discussion mentioned above due to the fact that I taught HS science for a few years. Butcher , however it has been 12 years since I taught. I can follow it well enough but to generate the discussion you led there let alone critique it is asking for real trouble and confusion from me. I have kept my mouth shut and read and learned for a reason. This forum has so much to give it is like mining itself. it does not come without work and effort and you don't know when or where you will find something valuable. I have not posted up to now because I feel that I need to give something back before really belonging and I haven't been able to do that yet but I will soon.
D'dane


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## butcher (Feb 4, 2013)

That pretty gold button, speaks for itself, it shows you have been doing your home work, I was hoping you could help me with my homework, which I am sure you still can with your experience, we all have different experience in life we can share, I just cannot wait until you feel like you can share yours with us.

Welcome to the forum, I will wait patiently while trying to struggle through these math problems.


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## cableman (Feb 16, 2013)

You guys are awesome. I really want to use the sodium nitrate instead of straight nitric acid due to the cost. And Butcher, I had found one of those molecular weight charts (think that's what you call them) and came up with about 1.34 grams of sodium nitrate to one ml of hydrochloric acid. But now that is a one to one mix so I would only use 1.34 grams to 3ml hydrochloric for aqua regia. Thank you all for your input and even thought I am a newbie I still know enough not to mix all at once.LOL

I probably should have started another topic for this but since it was brought up should I have a problem with silver chloride using this method. It was my understanding that I would just stir and finally let the silver chloride mud settle to the bottom and pour my solution off leaving the silver chloride behind for other uses. I then thought I used urea to lower the ph and get rid of excess nitric acid before precipitating my gold with SMB and of course rinse and rinse before melting.

I wanted to try this method on some gold plated pins I have collected before trying on my CPU's so if I have something wrong please correct me and thanks so much for all you guys helping.


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## butcher (Feb 16, 2013)

cableman said:


> You guys are awesome. I really want to use the sodium nitrate instead of straight nitric acid due to the cost. And Butcher, I had found one of those molecular weight charts (think that's what you call them) and came up with about 1.34 grams of sodium nitrate to one ml of hydrochloric acid. But now that is a one to one mix so I would only use 1.34 grams to 3ml hydrochloric for aqua regia. Thank you all for your input and even thought I am a newbie I still know enough not to mix all at once.LOL



With that ratio, you have too much unconverted sodium nitrate. You will not be converting all of the sodium nitrate salt to acid, you not only will have excess sodium nitrate but also excess sodium chloride later to deal with, as NaNO3 would be in excess, which could give you trouble later, with trying to get your gold back after you dissolve it, as you will have excess nitric in solution forming during your evaporation process to remove excess nitric acid, before you could precipitate your gold. (From the excess sodium nitrates forming nitric in the acid during the evaporation process later as the solution concentrates), and with added salts NaNO3 and NaCl, you will have to use the HCl in the end any way, if you use too much sodium nitrate, to remove the nitric (adding HCl during the evaporation process, the HCl will need to be added to convert the excess sodium nitrate in solution, then HCl will be needed to keep the solution from forming crystals, salts of NaCl and salts of NaNO3, when evaporating [excess sodium nitrate and sodium chloride]), it would be better to add that HCl in the beginning where it would do more good. Forming aqua regia to dissolve the gold, than at the end where it is just wasted trying to remove excess nitric acid (to evaporate NOx gas from solution), the added sodium will also cause some trouble normally with the evaporation process (wanting to form NaCl with evaporation easier than when we use acids to make aqua regia with the normal method).

If anything I would want excess HCl and limit the NaNO3 salts.



cableman said:


> I probably should have started another topic for this but since it was brought up should I have a problem with silver chloride using this method. It was my understanding that I would just stir and finally let the silver chloride mud settle to the bottom and pour my solution off leaving the silver chloride behind for other uses. I then thought I used urea to lower the ph and get rid of excess nitric acid before precipitating my gold with SMB and of course rinse and rinse before melting.



You would have some excess chloride, so more silver could stay in solution in the concentrate chloride solution, but after free nitric is used up, and solution is diluted the silver would precipitate as silver chloride.

My suggestion is, do not use excess sodium nitrate in your recipe as you suggest above.
Use gold to use up the nitric in solution, which can be done with using the ratios I stated, adding a little excess water and HCl to account for evaporation, heat your solution while dissolving your gold, leave a little gold undissolved (using up all of the nitric in solution), this way you use up the nitric in solution in the beginning.

Or you could use the gold later, as Harold suggests adding a pure gold button during the evaporation process to remove unused HNO3 from solution.

With pins you have mostly copper and very little gold, this would make recovering the gold hard to do, almost impossible especially if you are new to this, it is never a good idea to dissolve base metals with gold when you can keep from doing so. (This can be done if you know how, but it is asking for trouble, even when you know how, you are going to get higher lose of values, recovery is more difficult, and you are just asking for trouble or looking for ways to lose your gold, here you have to use acids to dissolve the copper any way, so why make taking a chance of losing your values, and giving your self more trouble to dissolve the copper, why not make and use nitric acid, (or use another method to dissolve copper without dissolving your gold).

With CPU's the base metal to gold content ratio is more suited to doing this with just minor problems.

Urea in my opinion is just a bad idea, especially here where your solution is already loaded with salts, why add another salt and contaminate the solution further, and take the chance of forming something dangerous.

Note:
UREA CAN BE DANGEROUS TO USE :!: 
Why would anyone use it where they do not need to I have no clue, and people who suggests its use should also quote the side products that can form, so the new guy will understand how he could possibly make ammonium nitrate, which could become dangerous in these metals or solutions.
My opinion Urea is just not needed or a bad idea.
Why take the chance of making an explosive substance or compound, when there is no need?
We have been taught much better methods to deal with nitric here on the forum.

Urea will not destroy HNO3 nitric acid; it can destroy nitrous acid HNO2 or NO2 in solution.


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## lazersteve (Feb 16, 2013)

Urea is not needed for refining, it's best used on the yard as a fertilizer.

If you are too heavy handed with nitric and want to chemically destroy the excess nitric, them use sulfamic acid as described in the Guided Tour--> Reaction List.

Steve


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## cableman (Feb 21, 2013)

I tell you what Butcher, you are one smart guy. I have seemed to get a lot of interest in this subject but let me tell you something about using this sodium nitrate instead of nitric acid (I guess we all want to due to the cost). I have read several posts with all different mixture levels and I have of yet found one that they were really satisfied with.

I am getting some nitric acid!! This was my first attempt at gold recovery so I am not too upset since I got some experience and got most of my equipment together and even have a little system started. The main problem with this method is the salts left behind. I broke up 4 or 5 ceramic cpu's (5.5oz) and I think I started with about 200-250ml muriatic and about 5 grams of sodium nitrate and 30 or so ml water. I got this ratio from a post somewhere. Thing is we are using weaker materials than intended for AR so I ended up adding a little nitrate even with the heat and kept it near boil for at least an hour. I ended up with some really black solution. let it cool and sit overnight, just now heating back up to add urea so I can try to precipitate with SMB. I got some real golden clear liquid with my washes and put that separate. I added urea and smb and got very little gold, which was to be expected since it was the wash. I still have the broken cpu's in original container with a lot of unknown salt. I didn't think there would be enough silver to worry about so I speculate it could be undissolved sodium nitrate. Until I figure it out it is going into slop bucket and I will crush cpu's evem more for another run.

I wonder what the main solution is so black for? I am going to add urea and smb to see what happens. I know there has to be a couple of grams or so of gold in it so I am trying to work it out without junking it up. Any ideas would be appreciated but the main thing I think about this method is the salt to deal with. It could be some kind of silver chloride but I don't know how to tell. I will update what happens with my main solution unless I get some advice first. I may let it sit overnight to do some research on it. I have already added urea but it needs a little more and I need to make two containers of it for fear of splash over. Didn't intend to make that much AR just happened in order to get it strong enough. All comments and advice welcome. You guys are the greatest. This is the best forum I have ever run across on any subject. Please give me best advice on making my waste solution safe for when I am through. Thanks to all you guys. I will add some pics. I am outside on my laptop and I don't have the camera program on this one. Will add pics when I go inside.


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## cableman (Feb 21, 2013)

Sorry Steve, didn't see your post until I started. Got that formula from reading posts where they were trying to keep costs down by using an alternative to nitric acid. I see now what you mean about the salts. I did however decide to begin with some ceramic cpu's. I thought they would be a better first try without other metals to deal with. I did make my AR a little strong just like you said I would and I now see the disadvantages of using urea. A lot of people put that in their procedure in their post without explaining alternatives. Maybe they don't know that much to begin with either. Anyway I guess you read my post above and see I made it through my first experience although I haven't precipitated the gold yet. The two yellow washes are just that. I think I got all the gold the first run. I just didn't understand the black color but I think maybe it came from the black off of the ceramic cpu's. I included the pictures of my results so far and my stannous chloride test turned out showing from left to right the two washes and on the far right my main solution which if I read it right has a good bit of gold in it. Going to do a lot more reading and do some fingers before I try the pins (they can wait). The black color in the main solution was not so dark once I poured it into another container, it just looked darker than it was.


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## butcher (Feb 22, 2013)

Poor mans aqua regia is of coarse not as good as true aqua regia made with pure acids, but it will dissolve gold, and gold can be precipitated from it. If you were just dissolving gold the sodium sulfate would not interfere to much of any degree, the gold would dissolve, gold will not form a sulfate in this solution, after the gold was dissolved the solution can be filtered, if you wanted to you could even chill the solution before filtering to help remove some of the sulfate salts, the gold could then be precipitated from solution.

The poor man types of aqua regia I would normally use in a recovery process more than a final refining process,
Although you could use it in the first refining, but I would still want to do the last refining in good clean acids.

You cannot make aqua regia and store it for later use, or you cannot distill aqua regia to purify it, because it would destroy it, but you can make nitric acid and distill it, you can also make HCl and then make your aqua regia from these two acids, to get a more pure aqua regia, HCl for most all of use is cheap and easy to get, so it is just better to buy it, unless you cannot, nitric for most of us is harder to get, and can be made and distilled at home, if you use homemade nitric on silver it would need to be distilled to remove the sulfate salts from the nitric acid, just freezing the nitric will not remove all of the sulfate salts, silver will form for the most part insoluble silver sulfate salts.

Poor mans aqua regia made with HCl and NaNO3 would be better because it would not contain the sodium sulfate salts, as compared to the Poor mans aqua regia made with the NaCl + NaNO3 + H2SO4 method. Better than both of these would be aqua regia made from distilled homemade nitric acid HNO3and HCL, and of coarse best of all would be store bought nitric acid and store bought HCl acid to make your aqua regia.

Sometimes HCl and NaClO (bleach), may be preferred for it ease of dealing with when dissolving fine gold, or even the HCl + 32% H2O2.

Sometimes it may depend what acids you can get or cannot get, what type of materials your trying to recover gold from, which chemical or process you may choose, it is nice to have alternatives at times even if they would not be our first choice.


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## cableman (Feb 24, 2013)

I see the error of my ways now. I have learned a lot by the mistakes I have made in my first attempt. First off let me correct the formula I used. I don't know how I accidentally put the wrong amounts of chemicals I was going to use down in the earlier post but now I see why you were so worried about me using too much sodium nitrate. The wrong number on my amount made it an incredible ridiculous amount of sodium nitrate. It was really 1.34 grams of sodium nitrate to 250 ml of hydrochloric. I still ended up using too much just like everyone said I would it being my first time. I really messed up by using urea. I don't remember where I got that information for using urea in this process but you are right. After running a batch and reading some more and seeing what happened I realize that urea is not needed at all. I might as well throw it in the yard.

I have managed to straighten up half of my mix but I still have a problem I don't know how to deal with. I am ordering nitric acid immediately and will properly dissolve off the unwanted metals with nitric before making AR and dissolving my gold. Right now I have managed to get a great deal of PbCl2 (lead Chloride) in the half of my solution that I have not finished. I have gold flakes mixed all in it. I am unsure of which method is best to remove this. If you have any advice please tell me my options for fixing this mess. I may not be able to recover the gold but I need to at least get this solution to a safe state to dispose of if gold recovery is no longer an option. I can also make a little homemade nitric to use for now until I can get my chemically pure nitric. I don't know how long it will take to ship and I am looking for best price before I put in my order today.

I have done a lot more reading and realize where I made a lot of mistakes. I am continuing my research and feel a lot better about how I will approach my next attempt. I see the need for nitric and the trouble that using urea brings. Now that I know what I do, I can't believe that some person actually posted a formula for gold recovery the way I was told to do it and using urea. I double check my information now. If you could give me some advice on how to proceed with the removal of this lead chloride I would be most grateful. The only chemicals ever present were muriatic acid, sodium nitrate, urea, and the broken up pieces of 4 or 5 ceramic CPU's. Thanks in advance for any advice. I will not make these mistakes again. Learning the hard way like this has hammered in a couple of important things. I need nitric acid to do this with and never use urea again. Also I got straight on the correct steps in the procedure of removing the unwanted metals first before dissolving my gold.


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## butcher (Feb 24, 2013)

You can have several salts mixed with your gold at this point, luckily they are fairly easy to separate from the gold.

Most salts are water soluble (excess sodium nitrate, urea sodium chloride and so on) these would dissolve in cold water, better if hot.

Hot water not only dissolve more of the water soluble salts but can also dissolve lead chloride salts, lead chloride is not very soluble at all in cold water but in boiling hot water becomes very soluble.

silver chloride is not soluble in cold water or hot water, but it is very fluffy and will float around easily, so if we are separating lead and silver chloride salts we want the water boiling hot, and keep it that way (but not so that it circulates or stirs the salts), but very hot, and giving time for the silver chloride to settle, depending on how much of each salt we may have to use more than one wash cycle.

copper I chloride can also be an insoluble white salt in water, it will dissolve in a solution of HCl, if we have a lot of copper salts the solution will turn dark green to brown, if only a small amount it will turn green or blueish.

Lead sulfate is not soluble in water hot or cold, or silver sulfate is fairly insoluble, for these if they were with your gold I would incinerate the powders and wash with HCl and hot water to form soluble chlorides. 

A good study is the solubility rules, and then looking at charts of the solubility of these metal salts, noting solubility in water or acid, and pay attention to temperatures they may be soluble in, this will help you get a better understanding how to deal with solutions or problems when you run into them, also small experiments like Hokes book teaches can help you understand how to deal with metals how they react, what they look like and how to separate them...


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