... ,150ppm 3.purity:52%,iron:20ppm,50ppm,150ppm Appearance: Thin flakes, yellow or red, soluble water, presenting strong alkaline solution, easily ... oxidized when exposed to air, poison. Specification:1. Red flakes-purity:60%,iron:1500ppm2. Yellow flakespurity:60%,iron:30ppm,50ppm ...