2528.00.00
Natural borates and concentrates thereof (whether or not calcined), but not including borates separated from natural brine; natural boric acid containing not more than 85 percent of H3BO3 calculated on the dry weight
HTS code 2528.00.00 covers natural borates and concentrates, including boric acid with specific purity levels. Use this code for classifying these mineral products, noting they generally enter the U.S. with free duty, as defined within Chapter 25's mineral product classifications.

Detailed information for HTS Code 2528.00.00
This code falls within Chapter 25 of the Harmonized Tariff Schedule, which covers mineral products. Specifically, 2528.00.00 covers natural borates and concentrates, whether or not calcined, excluding those separated from natural brine and boric acid exceeding 85% H3BO3. Subdivisions further categorize these materials into natural sodium borates, natural calcium borates, and all other natural borates, so choose the suffix that best reflects the specific type of borate being reported. Reporting is done in kilograms, and the correct statistical suffix should be selected to indicate the precise composition of the natural borate material.
| Chapter | Chapter 25 - Salt; sulfur; earths and stone; plastering materials, lime and cement |
| Section | Section V - Mineral Products |
Duty snapshot
Quick reference for the duty outcomes tied to this HTS line.
Free
Standard trade partners (NTR)
N/A
Eligible FTA or preference programs
The general duty rate for HTS code 2528.00.00 and its subdivisions (2528.00.00.05, 2528.00.00.10, and 2528.00.00.50) is free, meaning no duty is assessed on imports meeting the code's description. A special rate is not specified, but eligibility for preferential trade programs, such as Free Trade Agreements (FTAs), may apply, potentially reducing or eliminating duties further, contingent on meeting the rules of origin and other FTA requirements. All reported quantities must be in kilograms (kg).
Rate of Duty (Column 2): Free
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Code subdivisions
2528.00.00.05
Natural borates and concentrates thereof (whether or not calcined), but not including borates separated from natural brine; natural boric acid containing not more than 85 percent of H3BO3 calculated on the dry weight > Natural sodium borates and concentrates thereof (whether or not calcined)
2528.00.00.10
Natural borates and concentrates thereof (whether or not calcined), but not including borates separated from natural brine; natural boric acid containing not more than 85 percent of H3BO3 calculated on the dry weight > Natural calcium borates
2528.00.00.50
Natural borates and concentrates thereof (whether or not calcined), but not including borates separated from natural brine; natural boric acid containing not more than 85 percent of H3BO3 calculated on the dry weight > Other
Chapter & section notes
Chapter notes
Section notes
Latest update
Last updated
November 15, 2025
Revised every January & July
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