HS Code 25.28 – 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 % of H3BO3 calculated on the dry weight

HS code 2528 is a 4-digit heading in the Harmonized System that covers: 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 % of H3BO3 calculated on the dry weight. Heading 2528 in the Harmonized System (HS) encompasses natural borates and their concentrates, whether or not calcined, with a crucial exclusion: borates separated from natural brine. It also includes natural boric acid, but only if its H3BO3 content does not exceed 85% calculated on the dry weight. This classification is vital for distinguishing naturally occurring borate minerals from synthetic derivatives or those extracted from brines, which fall under different headings. Borates are essential industrial minerals used extensively in glass manufacturing (especially borosilicate glass), ceramics, detergents, agriculture (as micronutrients), and fire retardants. The scope is confined to the raw or minimally processed forms, such as crushing, grinding, or calcination, which enhances their utility without fundamentally changing their chemical identity. For trade compliance, correctly identifying the origin (natural vs. brine/synthetic) and the boric acid concentration is paramount for duty assessment, regulatory adherence, and avoiding misclassification. Historically, borate trade has been significant, with major deposits driving industrial development in various regions. This heading fits squarely within Chapter 25, "Salt; sulphur; earths and stone; plastering materials, lime and cement," as it deals with naturally occurring, non-metallic mineral substances in their unprocessed or primary forms, before they undergo significant chemical transformation into more complex compounds.

Borax ore, ulexite concentrate, colemanite concentrate, kernite, tincal, boracite, natural boric acid (<=85% H3BO3), calcined borax, crude borate minerals, boron mineral concentrates, natural sodium borate, calcium borate ore, magnesium borate ore, natural anhydrous borax, refined borax concentrate (natural origin), borax pentahydrate (natural origin), borax decahydrate (natural origin), natural borate mineral powders, raw borate rock, powdered ulexite.

A common mistake is confusing natural borates with chemically processed boron compounds. Products exceeding 85% H3BO3 or those synthetically produced should be classified under 2810.00 (Boron oxides; boric acids). Borates separated from natural brine, despite being natural in origin, are explicitly excluded from 2528 and might fall under 2501.00 (Salt) if the dominant component, or other specific chemical headings. Finally, complex mixtures or highly refined boron chemicals often belong in Chapter 28, not 2528, which is reserved for natural, minimally processed minerals.

In 2025, the top exporters of HS code 2528 in UN Comtrade data were Türkiye ($242M, 55% of world exports), Bolivia ($90M) and Argentina ($39M). World exports came to about $438M, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.

In 2025, the top importers of HS code 2528 in UN Comtrade data were China ($136M, 27% of world imports), Brazil ($118M) and India ($36M). World imports came to about $513M, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.

HS code 2528 is a 4-digit heading under Chapter 25 of the Harmonized System. The first 2 digits (25) identify the chapter, and digits 3-4 (28) specify the heading. This code contains multiple 6-digit subheadings for precise product classification.