Summary for nitrates from silver cyanide bath Discussion
nitrates from silver cyanide plating bath are discussed as a concern, but Ron Graf says the plating manuals he has read claim nitrates up to 100 g/liter are not usually detrimental to silver plating. He notes that in his own work with bright silver (Cookson Silverex II), he has used nitrate sparingly for several years without ill effect. Rather than trying to remove nitrate directly, he explains that he mostly uses barium hydroxide to remove carbonate; if the pH rises above 13.2, he also uses barium nitrate to precipitate barium carbonate while leaving potassium nitrate in solution. The practical takeaway is that nitrate may not need to be removed at all if the bath is otherwise performing well, and carbonate control is the more common maintenance issue in his approach.
Q. Hello ,
I think nitrogen in our silver cyanide bath is a problem. I want to remove nitrogen compound as NO3 out of the bath . How I do that?
Any help please. Thank you very much. : )
Tawan
lab s. – bangkok, Thailand
2004
A. The plating manuals I have read claim that nitrates up to 100 g/liter are not usually detrimental to silver plating. Therefore, one of the alternative methods I use for carbonate removal has been the use of Barium Nitrate to drop out Barium Carbonate, leaving Potassium Nitrate in solution. I have used Nitrate (sparingly) in bright silver (Cookson Silverex II) for several years to no ill effect. I mostly use Barium Hydroxide to drop carbonate but if the pH goes over 13.2 I also use BaN03.
Ron Graf
– Claymont, DE, USA
May 26, 2009