SPECIFICATIONS FOR PRODUCT REQUIRED SOLID CAUSTIC SODA MICROPEARLS  caustic soda micropearls are white or slightly coloured and odourless solids. ___________________________________________________________________________________ Standard specification Product characteristics  Content Unit Value Method of analysis(1) Total alkalinity ( NaOH) g/kg e 990 Titrimetry (ISO 979) Sodium carbonate (Na2CO3) g/kg d 4 Titrimetry (ISO 3196) Heavy metals* (Pb) (*) H2S Group mg/kg d 20 ICP-AES** (ISO 11885) or precipitation test (ANA-1120-0002)