Item Index Mercury Process Causticizing Process Diaphragm Process Superior quality First grade Acceptable part Superiorquality First grade Acceptable part Superior quality First grade Acceptable part NaOH¡Ý 99.5 99.5 99.0 97.0 97.0 96.0 96.0 96.0 95.0 Na2CO3¡Ü 0.40 0.45 0.90 1.5 1.7 2.5 1.3 1.4 1.6 NaCl¡Ü 0.06 0.08 0.15 1.1 1.2 1.4 2.7 2.8 3.2 Fe2O3¡Ü 0.003 0.004 0.005 0.008 0.01 0.01 0.008 0.01 0.02 Ca/Mg¡Ü 0.01 0.02 0.03 SiO2¡Ü 0.02 0.03 0.04 0.50 0.55 0.60 Hg¡Ü 0.005 0.005 0.0015 25/50kgs per bag.