# Dissolving Gold Sands/Stannous Chloride



## TheeLionSupreme (Jul 25, 2013)

Ok, now I have to write this all over again. There should be a correction agumentation to the HTML for this email program. To any email that is written and then having the system tell you. You have to apply other types of info and go forward and then return to the page and Wha La.... all that you written is gone !!

Oh, OK here we go again. Today I decided I wanted to test some refined sands that I ran through a gravity shaker table. So I decided try to dissolve the sands using a 1000 ml beaker and placing 3 tablespoons of cons into the beaker then applying 275 ml of Hydrochloric Acid 32.2 % Then adding Sodium Hypochloride to the first solution. Upon doing so the solution began fizzing and then started turning a olive green color and then began turning a rich deep yellow orange color. The size of the cons placed in the beaker was pin head size what is left after 30 mesh classification. Maybe too big. After the first does of Sodium Hypochloride we stirred and added more then repeated the process 3-4 times and let set for about 2 hours noticing that the pin head size pieces of gold where not dissolving. So, I placed the beaker in a corning casserole dish and slowly brought up the heat until it was boiling. The solution after about 10 minutes of boiling became even richer in deep yellow orange color. Then stirring I noticed that the concentrates seemed to be lessened in volume. So, at this point I was thinking OK the first stage of testing these cons was successful. There are still pieces of what looks like lighter colored gold flakes in the beaker. Probably mica or pyrite??? 
Now the next step was to make so Aquous Stannous Chloride to test the first solution. I took a 1000ml beaker and placed 2.75 ml of Hydrochloric Acid 32.2% into the beaker. Then taking Soldering Wire that is 60/40. And taking approx. an inch of this wire and placing inside the solution. Then bringing the solution to boil for about 8 minutes. Then letting it cool off. Noticing very small bits of Tin/Lead floating on top and at the bottom of the solution.

After this I took a clean piece of paper towel and dipped it into the Stannous Chloride to test for gold. I took a clean Q-Tip and dipped it into the Aruic Chloride and pressed it and rolled it on to the paper towel and it stayed a rich yellow color with out any discoloration occurring. I know this could mean no gold in the sands. 

But, why did the solution turn so deep yellow orange?? (Aruic Chloride) 

I am concerned that maybe there was too much Hydrochloric Acid or maybe the Soldering Wire that is over 16 years of age would have no effect or was too little in content (tin wise) in ratio of the 275ml of Hydrochloric Acid. Could use some expert advice.
Help Erik.


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## Geo (Jul 25, 2013)

you have a lot to learn. leaching in this way seldom works, and for a couple of good reasons. did you use a strong magnet to remove the iron from the black sands. iron dissolves yellow in hcl. did you pre-treat the cons in any other way than just gravity separation? did you roast the cons to remove the sulfur? move to the prospecting section http://goldrefiningforum.com/phpBB3/viewforum.php?f=44 and you may get better answers.

by the way, how do you know there was gold in the cons to begin with?


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## butcher (Jul 26, 2013)

TheeLionSupreme,
I also see several problems, not only with the process but the thinking behind it...

Black sands are mostly compounds of iron oxide, and sulfides could also be common in sands as well as a wide variety of compounds.

Black sand usually consists of Hematite Fe2O3 (not magnetic), Iron III oxide.
Black sand also normally consist of magnetite Fe3O4 (very magnetic, loadstone sometimes itself a magnet) Iron (II, III) oxide,

Black sands or even ore can be many different compounds of metal-acid or metal bases, or metal oxides as well as other compounds, black sands are heavy but no where near as heavy as gold for this reason gold can be separated from the black sand using gravity separation, also in panning the black sand is normally heavier than the other compounds of ore so the other compounds (rocks gravel and sands) are normally panned off way before the black sand or gold.

Fools gold or pyrite FeS2 (iron sulfide) is easy to distinguish from gold, pyrite it is terribly light, brittle will crush to powder under the pressure of a knife, where gold can be smashed flat, pyrite floats out of a gold pan early in the panning stages, gold is the last to leave the pan, pyrite roasted red hot burns the sulfides into sulfur dioxide gases easily distinguished by the smell, and changes the iron to different forms of oxides of iron or iron sulfate depending on temperature and oxygen content of the roast.

Some of these iron compounds of black sands are magnetic some are not, some dissolve easily into acids some do not, As Geo stated iron can be leached into solution and will displace gold from solution if there was gold in solution, or you can also have situations with both iron and gold can both be put into solution, iron chlorides can be yellow, or green, or even look like rust red, depending on the state of the iron in solution.

Iron chlorides FeCl3 in solution looks very much like gold chloride AuCl3 in solution, and the yellow color can fool you into thinking an iron in solution is gold in solution, as both can have a yellow color, testing for iron or gold in solution is the best way to determine what the yellow colored solution actually contains, trying to leach gold from black sands you can have a situation where your mostly leaching iron and the iron is pushing the gold back out of solution, you can test for both iron and gold in solution, Hokes tells how these tests are done, see page 100 for testing for iron in solution.

I would not use the 60/40 lead tin solder to make stannous chloride with, lead free solder is very common nowadays and it is easy to find an almost pure tin solder, also making up a gold standard solution to test your stannous chloride, the stannous has to be able to reduce the gold in the test (to form metal colloidal gold metal in solution) if there is too much oxidizer in solution the gold will not reduce back to metal and will not show the purple of Cassius, or violet color of gold colloids, or fine gold metal floating around in the solution reflecting the light that purple color (even if gold is in the solution being tested if it cannot be reduced back to metal it will not show up) for this reason if the solution contains an oxidizer you should remove it before testing (this can easily be done on a very small sample before testing), there are also other tests for gold like the ferrous sulfate crystals in a spot plate or white plastic spoon looking for the brown gold being reduced by the copperas crystal.

I suggest you should do some experiments (like Hoke’s book recommends but use your gold nuggets) with your gold nuggets try to put them into solution (you may find you cannot get much of them to dissolve into solution without in-quartering and parting before trying to get them to dissolve in HCl /NaClO, but you may get enough in solution to do a test and get a reaction, after removing oxidizer, do some test on the solution (without the black sands or other compounds involved), then repeat these test by adding some black sands and your gold nuggets, doing these small scale experiments can help you get acquainted with the reactions and testing, it can also give you more of an understanding of what the reaction do by themselves or in combination, give you more of an understanding if your leach is working or if it is just a fruitless attempt, and so on, you will find that gold which normally has silver involved will not dissolve easily without being in quartered (and normally parted first) the silver can passivate the gold protecting it from the acids, HCl and bleach actually has a hard time dissolving gold any way, it will put fine flakes or powders of gold into solution but for pieces of gold of any size it has a hard time attacking it (but it will put a little of it into solution (at least enough for the stannous reaction to see , that is if the iron did not push it back out of solution by reducing the gold back to metal as a brown powder)

Hematite
http://en.wikipedia.org/wiki/Iron%28III%29_oxide
http://en.wikipedia.org/wiki/Hematite

Magnetite
http://en.wikipedia.org/wiki/Iron%28II,III%29_oxide
http://en.wikipedia.org/wiki/Magnetite

A test for gold in ore (will work on sulfide ore also), A pinch of the powdered ore, fused in a surplus mix of one part Ammonium chloride and two and a half parts of ammonium nitrate, the melted salty syrup is cooled, and dissolved in a few drops of HCl acid, drops of this solution on a Q-tip, and a drop of fresh SnCl2 stannous chloride solution, violet or red color indicates gold is involved in the ore, this test can easily be done out in the field.

If at all possible separating your gold from the black sands using gravity is normally the best method.


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## Traveller11 (Jul 26, 2013)

TheeLionSupreme said:


> Ok, now I have to write this all over again. There should be a correction agumentation to the HTML for this email program. To any email that is written and then having the system tell you. You have to apply other types of info and go forward and then return to the page and Wha La.... all that you written is gone !!
> 
> Oh, OK here we go again. Today I decided I wanted to test some refined sands that I ran through a gravity shaker table. So I decided try to dissolve the sands using a 1000 ml beaker and placing 3 tablespoons of cons into the beaker then applying 275 ml of Hydrochloric Acid 32.2 % Then adding Sodium Hypochloride to the first solution. Upon doing so the solution began fizzing and then started turning a olive green color and then began turning a rich deep yellow orange color. The size of the cons placed in the beaker was pin head size what is left after 30 mesh classification. Maybe too big. After the first does of Sodium Hypochloride we stirred and added more then repeated the process 3-4 times and let set for about 2 hours noticing that the pin head size pieces of gold where not dissolving. So, I placed the beaker in a corning casserole dish and slowly brought up the heat until it was boiling. The solution after about 10 minutes of boiling became even richer in deep yellow orange color. Then stirring I noticed that the concentrates seemed to be lessened in volume. So, at this point I was thinking OK the first stage of testing these cons was successful. There are still pieces of what looks like lighter colored gold flakes in the beaker. Probably mica or pyrite???
> Now the next step was to make so Aquous Stannous Chloride to test the first solution. I took a 1000ml beaker and placed 2.75 ml of Hydrochloric Acid 32.2% into the beaker. Then taking Soldering Wire that is 60/40. And taking approx. an inch of this wire and placing inside the solution. Then bringing the solution to boil for about 8 minutes. Then letting it cool off. Noticing very small bits of Tin/Lead floating on top and at the bottom of the solution.
> ...


 Erik

Try using the hypochlorite solution at a neutral pH without adding hydrochloric acid. The bonds of the oxides are only broken when you add HCl and the pH becomes very acidic. Add salt or calcium chloride to the leach, as well.


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## Platdigger (Jul 26, 2013)

Instead of trying to maintain near neutral ph, why not try it on the Alkaline side?
Seems it would be easier to maintain an alkaline ph.
I have read about chlorine leaching being done this way but have not played with it much.


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## Traveller11 (Jul 27, 2013)

Platdigger said:


> Instead of trying to maintain near neutral ph, why not try it on the Alkaline side?
> Seems it would be easier to maintain an alkaline ph.
> I have read about chlorine leaching being done this way but have not played with it much.



The biggest problem with chlorine leaching is that cyanide leaching made it almost obsolete overnight about the year 1900 and the majority of literature I've read on it pre-dates that.

From all of the processes I've read about for making a chlorine solution, which, it stands to reason, will be a solution of hypochlorous acid, not a single one of them gives the pH of this solution as it is going into the leaching chamber.

We can do a little deducing, though, just by the process they used in the manufacture of the chlorine solution. For instance, if they are making chlorine gas by mixing calcium hypochlorite powder and sulphuric acid, and then pressurizing this into the water in the leaching chamber, the final product will be a mixture of hypochlorous and hydrochloric acids, though just how much this HCl made in this process will lower the pH of the leach solution is a topic open for debate. On the other hand, if they are making sodium hypochlorite/hypochlorous acid by the electrolysis of salt water, they will also be making sodium hydroxide, and one would expect the pH to be basic instead of acidic.

The truth of the matter is, this process may work at any pH from 5, beyond which the greater acidity may break the bonds of the oxides and put base metals such as iron into solution, to a pH of 9, beyond which the solution is so basic, all of the chlorine is tied up as hypochlorite. Neutral pH merely seems to be a handy place to begin experimenting at.

It should be remembered that all chlorine leaching processes were done in airtight, lead lined chambers with internal pressures elevated; either through the addition of pressurized air or allowing the chlorine building solution to elevate internal pressures. Some processes only required the exclusion of all air from the chamber, and it is believed that the hypochlorous molecule (HOCl) would elevate internal pressures by decomposing to HCl and releasing oxygen. Once again, this could lower pH to some degree and this is the very reason the chamber was kept airtight. Without this, all of the HOCl would decompose to HCl and no leaching, outside of iron, would take place.


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## Geo (Jul 28, 2013)

ill chime in. heap leaching used NaCl as electrolyte.


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