Sodium Hydroxide Flakes is used in many industries, mostly as a strong chemical base in the manufacture of pulp and paper, textiles, drinking water, soaps and detergents and as a drain cleaner. Physical Appearance White Flakes, Material shall be free from foreign matter, dirt or other visible impurities Sodium Hydroxide [as NaOH] Min. 99.50 Sodium Carbonate [as Na2CO3] Max. 00.40 Chlorides [as Cl] Max. 00.030 Sulphate [as SO4] Max. 00.030 Silicates [as SiO2] Max. 00.02 Iron [as Fe] Max. 20.00 Copper [as Cu] Max. 02.00 Nickel [as Ni] Max. 02.00 Manganese [as Mn] Max. 01.00 Chlorates & PerChlorate [as NaClO3] Max. 10.00 Matter insoluble in Water. Max. 00.050