Limestone flux; limestone and other calcareous stone, of a kind used for the manufacture of lime or cement
Limestone flux; limestone and other calcareous stone, of a kind used for the manufacture of lime or cement
Duty Rate (from China)
Except for products described in headings 9903.03.02–9903.03.11, articles the product of any country, as provided for in subdivision (aa) of U.S. note 2 to this subchapter
Except as provided in headings 9903.88.13, 9903.88.18, 9903.88.33, 9903.88.34, 9903.88.35, 9903.88.36, 9903.88.37, 9903.88.38, 9903.88.40, 9903.88.41, 9903.88.43, 9903.88.45, 9903.88.46, 9903.88.48, 9903.88.56, 9903.88.64, 9903.88.66, 9903.88.67, 9903.88.68, or 9903.88.69, articles the product of China, as provided for in U.S. note 20(e) to this subchapter and as provided for in the subheadings enumerated in U.S. note 20(f)
Products classified under HTS 2521.00.00.00
High-Calcium Limestone Flux
High-calcium limestone flux is a coarsely crushed calcareous stone with at least 95% calcium carbonate content, specifically used in blast furnaces to remove impurities during steel production. It falls under HTS 2521.00.00.00 because it is limestone of a kind used for lime or cement manufacture, distinguished by its chemical purity and fluxing properties. This raw material is essential for slag formation in metallurgical processes.
Cement Kiln Feed Limestone
Cement kiln feed limestone consists of medium-to-coarse crushed calcareous rock selected for its consistent calcium carbonate levels, fed directly into rotary kilns for clinker production. It qualifies for HTS 2521.00.00.00 as limestone expressly used in cement manufacturing. The material's purity ensures optimal lime reactivity during calcination.
Lime Production Quarry Limestone
Quarry-run limestone blocks or crushed stone from high-purity deposits, intended for quicklime production via calcination in lime kilns. Classified under HTS 2521.00.00.00 due to its specific suitability for lime manufacture, characterized by uniform reactivity and low contaminants. This feedstock is critical for industries like steel, chemicals, and water treatment.
Fluxing Calcareous Stone for Steel Mills
Coarse angular calcareous stone flux, sized 1-4 inches, used in steel mill basic oxygen furnaces to form slag and protect furnace linings. HTS 2521.00.00.00 covers this as limestone flux specifically for lime-related industrial processes. Its high melting point and impurity-binding properties define its metallurgical role.
Hydrated Lime Manufacturing Limestone
High-brightness limestone suitable for producing hydrated lime used in construction and chemical applications. Falls under HTS 2521.00.00.00 as raw material expressly for lime production. Its fine reactivity post-calcination defines industrial suitability.
Chemical-Grade Flux Limestone
Ultra-pure limestone flux for chemical processes requiring consistent calcium source, such as precipitated calcium carbonate production. HTS 2521.00.00.00 applies to its role in lime-based chemical manufacturing. Low silica ensures purity in end products.
Glass Manufacturing Calcareous Stone
Calcareous stone flux for soda-lime glass production, providing network stabilization. Though glass-making, classified under HTS 2521.00.00.00 as limestone used for lime manufacture (soda-lime process). Specific silica-calcia ratios required.
Portland Cement Raw Limestone
Raw limestone chunks from specific geologic formations, crushed to 3-6 inch sizes for grinding into cement raw meal. Meets HTS 2521.00.00.00 as calcareous stone used in cement production. Purity levels ensure proper clinker chemistry ratios.