gold in solution..
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NobleMetalWorks
Well-known member
Interesting question you ask...
Instead of arguing about gold being dissolved in HCl alone, lets assume that this is not possible. Gold under normal conditions should not really dissolve in HCl.
I think the question you are asking is how much gold can Aqua Regia hold in solution.
The question was recently asked and answered, all you need to do is use the search function. I cannot remember off the top of my head what it is exactly, however, I do know I can dissolve a kilo of scrap in about 5,000 ml of Ar. It depends on the compensation of the scrap material, and how much of that other material will go into solution, gold goes after other metals higher on the reactivity scale, or rather those higher on the reactivity scale would displace or cement out gold out of solution.
If you are starting with pure gold, then I really am at a loss. But then again if you are starting with 24k gold why would you be dissolving it into any solution?
Scott
Instead of arguing about gold being dissolved in HCl alone, lets assume that this is not possible. Gold under normal conditions should not really dissolve in HCl.
I think the question you are asking is how much gold can Aqua Regia hold in solution.
The question was recently asked and answered, all you need to do is use the search function. I cannot remember off the top of my head what it is exactly, however, I do know I can dissolve a kilo of scrap in about 5,000 ml of Ar. It depends on the compensation of the scrap material, and how much of that other material will go into solution, gold goes after other metals higher on the reactivity scale, or rather those higher on the reactivity scale would displace or cement out gold out of solution.
If you are starting with pure gold, then I really am at a loss. But then again if you are starting with 24k gold why would you be dissolving it into any solution?
Scott
I cannot answer your questions,of how much gold each of these will hold.
But it is my belief that the HCl/NClO (bleach) would dissolve and hold and very little gold compared to aqua regia, HCl/NaClO is not as strong as aqua regia, it is much more diluted with water, the bleach lowers the acidity of the HCl, it cannot be concentrated like aqua regia can.
But it is my belief that the HCl/NClO (bleach) would dissolve and hold and very little gold compared to aqua regia, HCl/NaClO is not as strong as aqua regia, it is much more diluted with water, the bleach lowers the acidity of the HCl, it cannot be concentrated like aqua regia can.
hi butcher, il try to explain myself better,...concerning a second refinement, lets just say i have 100 oz of once refined precipitated Au i have two choices, what would be an efficientl amount of either solution should be used to refine a given amount of Au ? isnt there some kind of standard table one can go by regarding ratio?
How much aqua regia to dissolve gold, how much nitric needed:
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=15880
As far as the HCl/bleach I have no figures, I just know I normally have a larger volume of solution with less dissolved gold, bleach is over 90% water and the HCl also is over 60% water, this gives a very dilute solution, but HCl has its advantage when dissolving fine gold powders, gold flakes, gold off of ceramic or glass, it is much easier to deal with as far as removing the oxidizer for the precipitating process, as with the aqua regia process excess HCl does no harm and helps to keep the solution acidic (as bleach is a base solution, with sodium hydroxide added to the bleach to keep the hypochlorous acid in solution.
Using a dry form of bleach can make a more concentrated solution, but can also cause problems as it is very easy to add too much oxidizer, I will use it for ore but not for dissolving metallic gold or gold powders.
If I really wanted to know how much gold it would take into solution I would find out, take 1 gram of fairly pure dry gold powders, or clean dry foils, add 4ml of HCl and with a pipette puts drops of bleach in the lightly heated solution, adding drops and waiting for the reaction to complete before adding more bleach, also keeping the solution acidic so you may have to watch pH, also HCl or bleach can be added as needed to dissolve the powders, keeping record of how much you used to dissolve the gram of gold, this would give you a base line idea, posting your results would be interesting.
If you are not very familiar with using aqua regia, I suggest using HCl/NaClO, where you can.
I find the HCl/concentrated peroxide seems to hold more gold in solution.
Remember gases leaving the solution of any of these oxidizers are usually gases not working to dissolve metals, normally the better you can keep them in solution longer the more work they will do, it may take a little longer to complete the reaction, just a few things to help keep them in solution refluxing condensing these gases on cooler surfaces and dripping back into solution, watch glass, reflux condenser, and so on, dilution of solution can also help as most of the gases are water soluble and most will stay in solution longer than the water vapors, controlling the temperature, a little dilute peroxide added to nitric acid.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=15880
As far as the HCl/bleach I have no figures, I just know I normally have a larger volume of solution with less dissolved gold, bleach is over 90% water and the HCl also is over 60% water, this gives a very dilute solution, but HCl has its advantage when dissolving fine gold powders, gold flakes, gold off of ceramic or glass, it is much easier to deal with as far as removing the oxidizer for the precipitating process, as with the aqua regia process excess HCl does no harm and helps to keep the solution acidic (as bleach is a base solution, with sodium hydroxide added to the bleach to keep the hypochlorous acid in solution.
Using a dry form of bleach can make a more concentrated solution, but can also cause problems as it is very easy to add too much oxidizer, I will use it for ore but not for dissolving metallic gold or gold powders.
If I really wanted to know how much gold it would take into solution I would find out, take 1 gram of fairly pure dry gold powders, or clean dry foils, add 4ml of HCl and with a pipette puts drops of bleach in the lightly heated solution, adding drops and waiting for the reaction to complete before adding more bleach, also keeping the solution acidic so you may have to watch pH, also HCl or bleach can be added as needed to dissolve the powders, keeping record of how much you used to dissolve the gram of gold, this would give you a base line idea, posting your results would be interesting.
If you are not very familiar with using aqua regia, I suggest using HCl/NaClO, where you can.
I find the HCl/concentrated peroxide seems to hold more gold in solution.
Remember gases leaving the solution of any of these oxidizers are usually gases not working to dissolve metals, normally the better you can keep them in solution longer the more work they will do, it may take a little longer to complete the reaction, just a few things to help keep them in solution refluxing condensing these gases on cooler surfaces and dripping back into solution, watch glass, reflux condenser, and so on, dilution of solution can also help as most of the gases are water soluble and most will stay in solution longer than the water vapors, controlling the temperature, a little dilute peroxide added to nitric acid.
goldenchild
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- Aug 14, 2009
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wood4lif said:
For our intents and purposes... no. You'll find all kinds of ratios and numbers on this subject but in practice will come to realize that the best course of action is to add your reagents incrementally. For gold you would add enough HCl to cover your material and small amounts of nitric. There are too many factors that come into play i.e. heat, surface area, vessel used, reagent concentration, that calculating exactly how much AR is needed is futile. Premixing your reagents tends to be wasteful. If you find any numbers on this subject they were probably produced from a highly controlled experiment in a lab somewhere. Or maybe not. Use the CREDIBLE numbers as rough guidelines.
