Specificationscaustic soda, sodium hydroxide (flakes/solid/pearls) water treatment, paper making, soap making, textiles, printing & dyeing, etccaustic soda flakessodium hydroxide flakes usemainly used in water treatment, paper making, soap making, textiles, printing & dyeing, chemical fiber, pesticides, petro-chemical, medical and food industries. items super grade standard grade. sodium hydroxide % 99.5 99.0sodium carbonate% 0.5 0.8sodium chloride % 0.045 0.050ferroso-ferric oxide % 0.004 0.004silicon dioxide % 0.004 0.006sodium sulfate % 0.050 0.060copper % 0.0002 0.0003calcium % 0.005 0.008