It does look a bit like zinc chromate. My go-to for difficult to remove paint/primer is brake fluid, though I have never tried to remove zinc chromate.
As you may know, zinc chromate is highly toxic. If you intend to sand off the stuff, don't breath in the dust, and you really shouldn't get it on your skin, either. Not sure of the toxicity of the dust relative a sprayed mist, but I would definitely treat the dust as toxic. If this stuff is zinc chromate, I would wear a respirator if doing any sanding, or at the least, do any sanding wet..