Specification: Rubber GradeZinc Oxide( % ): GB/T3195-92 index item Super Grade First Grade ZnO dry 99.7%min 99.5min Pb 0.037%max 0.05max Mn 0.0001max 0.0001max Cu 0.0002max 0.0002max Insoluble in hydrochloric acid 0.006max 0.008max Loss on ignition 0.2max 0.2max Screen residues(through 45 micron wet screen) 0.1max 0.1max volatile( 105 degree Celsius) 0.3max 0.4max