Double or Complex Silicates (Including Aluminosilicates)

Double and complex silicates, including aluminosilicates such as synthetic zeolites, are widely used as molecular sieves, ion-exchange media, and functional fillers in detergents, catalysts, and specialty ceramics. The entire heading consolidates into a single 10-digit line (2842100000), simplifying entry filing but placing the classification burden on distinguishing these materials from simpler silicates classified elsewhere in Chapter 28. Germany leads US import supply, with China and Canada also among the top sources. Buyers sourcing from China should assess Section 301 exposure at the time of entry.