There is little copper contamination.
This might give problems with ammonium compounds like AP, for the rest it shouldn?t give problems as far as I know.
K2O isn't really in your fertilyser, it's just for farmers and such to know whats in it.
In the NPK numberthe N is for nitrogen but the P is for P2O5 and the K is for K2O.
Your fertyliser is KNO3, calculate the purity your self.