5. .Specification of Caustic soda Caustic soda flakes: 96% 98% 99% Caustic soda solid: 96% 98% 99% Caustic soda peals: 99% PURITY Na2CO3 Nacl Fe2O3 96% 1.4% max 2.8% max 0.01% max 98% 1.1% max 0.6% max 0.01% max 99% 0.9% max 0.15% max 0.0