Section 06 Products of the chemical or allied 28 Inorganic chemicals; organic or inorganic compounds of precious metals, of rare earth metals, of radioactive elements or isotopes 28 11 Other inorganic acids and other inorganic oxygen compounds of non-metals 28 11 22 Silicon dioxide Commodity Code Description 28 11 22 00 Silicon dioxide 28 11 22 10 In powder form 28 11 22 90 Other