I am not a big fan of urea, especially when getting into material that may contain PGM's. So I steer clear of urea whenever possible. That said, there are many refiners out there who use urea but there are times when it causes issues.
One of the things about refining that is challenging is the amazing array of undesirable elements that can find their way into your acid. So sooner or later you will come across a mix where you need your SMB to be as selective as possible, in that case a slight increase in the pH would aid the SMB in it's intended purpose.
But when I try to teach someone the nuances of refining, I try to factor in everything possible. that includes the background of the "refiner" and the equipment they have at their disposal. Here on the forum we have refiners who use everything from coffee pots to mason jars. And despite the years of advising against it, some just put everything into aqua regia and expect wonders when the gold drops out. Should that person be told to adjust the pH? Would that person have the equipment to measure the pH? I teach people to refine using the KISS approach. If and when they come up against a problem because a method is not finely tuned to a specific scrap-type, then I will tell them what to change and why.
In this case, looking at the picture of the solution the OP posted to start this thread, selective pH for the precipitation just isn't going to help. And it is likely to cause more confusion down the line.
And as far as anyone having any doubts about my abilities, at the place I am in life that doesn't even register. I did not state how many ounces of gold I have dropped in my career to convince members that I know how to do this, I said that rather than saying "I have dropped enough of this s*** out of solution to know pH adjustment isn't a necessity." I will continue to seek the lowest common denominator and teach people to refine on a level where they can attain good results. That's where I have found people have the greatest chance of actually learning what I am trying to teach them.
One of the things about refining that is challenging is the amazing array of undesirable elements that can find their way into your acid. So sooner or later you will come across a mix where you need your SMB to be as selective as possible, in that case a slight increase in the pH would aid the SMB in it's intended purpose.
But when I try to teach someone the nuances of refining, I try to factor in everything possible. that includes the background of the "refiner" and the equipment they have at their disposal. Here on the forum we have refiners who use everything from coffee pots to mason jars. And despite the years of advising against it, some just put everything into aqua regia and expect wonders when the gold drops out. Should that person be told to adjust the pH? Would that person have the equipment to measure the pH? I teach people to refine using the KISS approach. If and when they come up against a problem because a method is not finely tuned to a specific scrap-type, then I will tell them what to change and why.
In this case, looking at the picture of the solution the OP posted to start this thread, selective pH for the precipitation just isn't going to help. And it is likely to cause more confusion down the line.
And as far as anyone having any doubts about my abilities, at the place I am in life that doesn't even register. I did not state how many ounces of gold I have dropped in my career to convince members that I know how to do this, I said that rather than saying "I have dropped enough of this s*** out of solution to know pH adjustment isn't a necessity." I will continue to seek the lowest common denominator and teach people to refine on a level where they can attain good results. That's where I have found people have the greatest chance of actually learning what I am trying to teach them.
