... 4) free sample is available Specification: ASSAY (as KNO3)99.4% minPOTASSIUM OXIDE (as K2O )46.0% minNITROGEN13.0 ... 0.03% maxIRON(as Fe)0.002% maxNITRITES0.01% maxHEAVY METAL (as Pb)0.001% maxPARTICLE SIZE100% -20 mesh, ... , Fertilizers, Metal Heat Treatment and Heat Transfer, Ceramics, Oxidizer, Petrochemicals, Toothpaste, Denitrifies, eat Curing, Cheese, rocket propellants potassium nitrate 99.7%