Trouble reading stannous
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I think there would be no gold in solution with the use of too much SMB, so you would not see these two reactions in the same test.
This is not saying that if you had colloids from a dirty solution that held gold colloids (tin in solution can be a problem here) and you also had too much SMB in solution at the same time, but the stannous test would not detect this reduced gold here either anyway as the gold would already be reduced, and would not show positive in the test.
This is not saying that if you had colloids from a dirty solution that held gold colloids (tin in solution can be a problem here) and you also had too much SMB in solution at the same time, but the stannous test would not detect this reduced gold here either anyway as the gold would already be reduced, and would not show positive in the test.
This may sound stupid but I'm just trying to understand
Butcher, are you saying that the gold dropped as sub-particles? Particles so fine that they don't settle on the bottom. The stannous doesn't detect this type of gold and that is the reason for The missing color. If I do understand right then is there something that can be done to make the gold drop as bigger particle size?
Butcher, are you saying that the gold dropped as sub-particles? Particles so fine that they don't settle on the bottom. The stannous doesn't detect this type of gold and that is the reason for The missing color. If I do understand right then is there something that can be done to make the gold drop as bigger particle size?
Say I have dissolved some gold and did not remove the base metals in pretreatment, let us use electronic scrap in our example. tin and lead from solder not removed well, copper and several other base metals all in solution, Oh without pretreatments we did not incinerate either, so we have oils, maybe some glues plastic or other trash in solution, you know the regular mess.
The gold can be reduced to metal in solution by the base metals, the oil can make some float, the dirty solution can keep our gold from settling.
Tin will reduce the dissolved gold back to elemental metal (giving the dissolved gold electrons), the tin really does not dissolve well in solution when oxidized in the HCl solution, so filtering the solution becomes a big problem, also the gold in this solution even though it has changed back to a metal will not settle, it form colloids of gold particles of gold with polarity repelling each other keeping each other in solution.
For our stannous chloride solution to work, the gold must be oxidized in solution (missing electrons), in our test the stannous chloride reduces the gold to elemental metal, and making gold colloids in solution that reflect light the violet color we see, (purple of cassius).
In our example of gold colloids in solution the gold is already reduced to elemental metal, circulating colloids of metal gold in solution that will not precipitate, and if we add stannous chloride to this elemental gold in solution we will see no reaction, no purple of cassius, because the gold is already reduced to metal, we can easily throw away gold in our waste stream because we do not know it is there.
Now add the copper laden dirty solution and other base metals and oils to this mess and we have some problem on our hands, we cannot filter, if we dilute things get worse (more of a gummy mess), if we lower acid content (adjust pH less acidic it also gets worse), we can try and add strong acid HCl, or better yet H2SO4, and boil and concentrate to try and break the colloids so our gold will settle, sometimes this works (depending how bad the solution is), other times just concentrating evaporating to salt (adjust pH neutral rinse salts) dry an incinerate and the boil powders in HCl, with hot rinses to help remove tin that we oxidized in the incineration process,
Basically stating over to clean up our mess removing dirt oils tin and base metals before we dissolve the gold into a nice clean clear yellow solution that our stannous chloride can detect the gold in solution and we can precipitate without troubles.
Now can you see why incineration, removing solder and other base metals, before dissolving our gold can save you time and trouble, not to mention you will not be throwing away most of your gold.
The gold can be reduced to metal in solution by the base metals, the oil can make some float, the dirty solution can keep our gold from settling.
Tin will reduce the dissolved gold back to elemental metal (giving the dissolved gold electrons), the tin really does not dissolve well in solution when oxidized in the HCl solution, so filtering the solution becomes a big problem, also the gold in this solution even though it has changed back to a metal will not settle, it form colloids of gold particles of gold with polarity repelling each other keeping each other in solution.
For our stannous chloride solution to work, the gold must be oxidized in solution (missing electrons), in our test the stannous chloride reduces the gold to elemental metal, and making gold colloids in solution that reflect light the violet color we see, (purple of cassius).
In our example of gold colloids in solution the gold is already reduced to elemental metal, circulating colloids of metal gold in solution that will not precipitate, and if we add stannous chloride to this elemental gold in solution we will see no reaction, no purple of cassius, because the gold is already reduced to metal, we can easily throw away gold in our waste stream because we do not know it is there.
Now add the copper laden dirty solution and other base metals and oils to this mess and we have some problem on our hands, we cannot filter, if we dilute things get worse (more of a gummy mess), if we lower acid content (adjust pH less acidic it also gets worse), we can try and add strong acid HCl, or better yet H2SO4, and boil and concentrate to try and break the colloids so our gold will settle, sometimes this works (depending how bad the solution is), other times just concentrating evaporating to salt (adjust pH neutral rinse salts) dry an incinerate and the boil powders in HCl, with hot rinses to help remove tin that we oxidized in the incineration process,
Basically stating over to clean up our mess removing dirt oils tin and base metals before we dissolve the gold into a nice clean clear yellow solution that our stannous chloride can detect the gold in solution and we can precipitate without troubles.
Now can you see why incineration, removing solder and other base metals, before dissolving our gold can save you time and trouble, not to mention you will not be throwing away most of your gold.
BAMGOLD
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butcher said:
Another n00b entering the equation, I've read alot, but each time I read there is 10 different paths to take from one thread, it's mind boggling really...
I haven't read this from any "tutorials" thus far, I suppose it depends on how "dirty" your product is, but could you explain in better detail this quote? :mrgreen:
Think of it this way if you had pure 0.999% gold and dissolved it you can remove contaminates, so it is only a little dirty.
Now add 0.001 part tin from solder to the above gold, and it is not only dirty but becomes a mess.
I do not know how to give you an answer, except to say the better job you do of eliminating the tin and base metals and other trash before you dissolve your gold the easier and less trouble you will have doing your recovery and refining process, and the more of your values you will get back from your processes.
The more trash in solution the more trouble you will have in trying to recover your values, and the more values you will lose in the process.
Read Hoke's book she teaches this best.
Now add 0.001 part tin from solder to the above gold, and it is not only dirty but becomes a mess.
I do not know how to give you an answer, except to say the better job you do of eliminating the tin and base metals and other trash before you dissolve your gold the easier and less trouble you will have doing your recovery and refining process, and the more of your values you will get back from your processes.
The more trash in solution the more trouble you will have in trying to recover your values, and the more values you will lose in the process.
Read Hoke's book she teaches this best.
Thanks!BAMGOLD,
You are on the right track reading Hoke's book, also do the getting acquainted experiments, doing these you can see what the reactions of various metals in acids do, and they will also help you to understand what I discussed earlier in this thread, also note how she teaches to eliminate the base metals before dissolving gold into solution, Her book is so full of small details easily missed the first time you read it, I find something new every time I re read her book.
if you just keep on the forum and absorbing the information provided here you will learn, at first it seems hard when you begin, but it does get easier, but the information and the things you will learn on the forum seem to have no ending.
may I suggest after you get acquainted with Hoke and her book, start with a simple fairly clean process to begin learning, close cut memory finger's with no solder, dissolve the copper out from under the gold foils, and then process these in HCl/ sodium hypochlorite (bleach), and precipitate with your choice of reagent like sodium metabisulfite, or ferrous sulfate, these processes are good learning tools as you do not have many of the problems you can encounter with other materials or processes, also read up on laser Steve's earlier posts on these processes, while your reading his post check out his great web site, with video's and other information, and you may need a few of the supplies he sells at extremely reasonable prices to help forum members out, Nope he does not pay me to advertise, I just like his work so much I am just doing it for free.
After working with these solutions a little while you will be able to tell when your solution is dirty and you have problems, it is just better to learn how not to get into that mess to begin withand how to avoid it if possible.
You are on the right track reading Hoke's book, also do the getting acquainted experiments, doing these you can see what the reactions of various metals in acids do, and they will also help you to understand what I discussed earlier in this thread, also note how she teaches to eliminate the base metals before dissolving gold into solution, Her book is so full of small details easily missed the first time you read it, I find something new every time I re read her book.
if you just keep on the forum and absorbing the information provided here you will learn, at first it seems hard when you begin, but it does get easier, but the information and the things you will learn on the forum seem to have no ending.
may I suggest after you get acquainted with Hoke and her book, start with a simple fairly clean process to begin learning, close cut memory finger's with no solder, dissolve the copper out from under the gold foils, and then process these in HCl/ sodium hypochlorite (bleach), and precipitate with your choice of reagent like sodium metabisulfite, or ferrous sulfate, these processes are good learning tools as you do not have many of the problems you can encounter with other materials or processes, also read up on laser Steve's earlier posts on these processes, while your reading his post check out his great web site, with video's and other information, and you may need a few of the supplies he sells at extremely reasonable prices to help forum members out, Nope he does not pay me to advertise, I just like his work so much I am just doing it for free.
After working with these solutions a little while you will be able to tell when your solution is dirty and you have problems, it is just better to learn how not to get into that mess to begin withand how to avoid it if possible.
