Perrhenic acid solution (PRA)

Appearance
Colourless to straw coloured liquid

Rhenium content
20.0 - 60.0 %

Sulphate content
200 ppm maximum

Nitrate content
0.2 % maximum

Impurities as detected with respect to solution
Au, Ag, Pd, - 25 ppm maximum each
Pt, Ru, Ir, Rh - 500 ppm maximum each
As, Pb, Cu, Ni - 25 ppm maximum each
Ba, Fe - 50 ppm maximum each
K, Si, Ca, Na, Mg - 250 ppm maximum each