Section 06 PRODUCTS OF THE CHEMICAL OR ALLIED INDUSTRIES 28 Inorganic chemicals; organic or inorganic compounds of precious metals , of rare 28 33 Sulphates; alums; peroxosulphates (persulphates). Commodity Code Description 28 33 11 28 33 19 28 33 21 28 33 22 28 33 24 28 33 25 28 33 27 28 33 29 28 33 30 28 33 40