Alums

Alums — double sulfate salts most commonly encountered as potassium alum or ammonium alum — are widely used in water treatment as coagulants, in food processing as leavening and firming agents, and in paper manufacturing and dyeing. All US imports fall under a single tariff line (2833300000). Mexico is the leading foreign supplier, with France, Spain, and Italy also among the top sources, reflecting established European chemical production capacity. Food-contact and food-additive applications may require FDA compliance review depending on the specific alum form and intended use.