Dissolving silver braze from tungsten carbide I'm working out the best process to chemically strip silver brazing from tungsten carbide (WC) bits. My main objective is to recover the silver as a relatively pure metal. When I use $\ce{HNO3}$ at anywhere from 20-70%, it dissolves the solder and I end up with a red solution.  When I try to use cementation (putting copper metal in the solution) to precipitate the $\ce{Ag}$ as sponge, it isn't working. 

Can any one help me figure out what's going on here?  The brazing being used should be 50-60% $\ce{Ag}$ by weight. I'm not sure yet if there is $\ce{Pd}$ or not.
Most common silver brazes are 50 to 90 % silver with copper or maybe zinc.  A complication may be the WC; it is sintered with 2 to 20 % cobalt ( usually).