... 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 ... , flotation agent, depilatory for leather, digestion auxiliary in paper-making also widely used in pigment and rubber industry, etc ...