... uses: mainly used in the fields of metallurgy, petroleum, chemical industry, textile, papermakin, printing and dyeing pharmacy, soap, etc.Standard of identity: Caustic ... .2Fe2O3 %≤0.0040.0060.0080.010.02Standard of identity of flaky caustic soda flakes: name of specification\ grademembrance processdiaphragrn processNaOH %≥9996.0Na2CO3 ... 4. Appearance: Flakes, Pearl (white or light blue) Caustic Soda