2521.00.00.00/High-Calcium Limestone Flux/China

High-Calcium Limestone Flux from China

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.

Duty Rate — China → United States

35%

Rate breakdown

9903.03.0110%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
9903.88.0325%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)
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Import Tips

• Verify chemical composition certificates showing high CaO content to confirm classification under 2521.00.00.00 and avoid misclassification as general crushed stone

• Ensure documentation specifies end-use for lime/cement manufacture, as flux properties must be evidenced for duty-free entry in some cases

• Watch for particle size specs; overly processed stone may shift to heading 2522 if not raw flux material