HTS code 3804.00.10.00 covers "Residual lyes from the manufacture of wood pulp, whether or not concentrated, desugared or chemically treated, including lignin sulfonates, but excluding tall oil of heading 3803 › Lignin sulfonic acid and its salts" under the US Harmonized Tariff Schedule. This is the official duty rate charged by US Customs when this product is imported into the United States, sourced directly from the U.S. International Trade Commission and refreshed daily.