Product classification

HS code for Fused magnesia: 2519.90

Magnesia, fused or dead-burned (sintered), whether or not containing small quantities of other oxides added before sintering, other magnesium oxide, whether or not pure, (not natural magnesium carbonate).

Classification of fused magnesia under HS 2519.90

Fused magnesia is classified under HS code 2519.90. This classification falls within Chapter 25, which covers salt, sulfur, earths, and stone, specifically heading 2519 for natural magnesium carbonate (magnesite) and magnesium oxide. Fused magnesia is produced by the fusion of magnesite or caustic calcined magnesia in electric arc furnaces at temperatures exceeding 2750 degrees Celsius. This process results in a high-density, high-purity crystalline material with superior refractory properties. The HS code 2519.90 is a residual category for magnesium oxide that is not natural magnesium carbonate. It includes both fused magnesia and dead-burned (sintered) magnesia. The classification is justified because the material remains a mineral product of Chapter 25, even though it has undergone high-heat processing to alter its physical structure, provided it has not been further processed into a finished refractory article of Chapter 68 or 69.

Covers
  • Electrically fused magnesium oxide
  • Dead-burned (sintered) magnesia
  • High-purity synthetic magnesia
  • Calcined magnesite (other than natural)
  • Fused magnesia grains for heating elements
Also under 2519.90
  • RHI Magnesita Fused Magnesia
  • Vesuvius Dead-Burned Magnesia
  • Magnezit Group Sintered Magnesia
  • Martin Marietta Magnesia Specialties

Codes often confused with 2519.90

Common mistake. Fused magnesia is often misclassified under HS code 2519.10, which is strictly reserved for natural magnesium carbonate (magnesite) in its raw or crushed state. Another common error is classifying it under HS code 2816.10, which covers magnesium hydroxide and peroxide; however, fused magnesia is an oxide, not a hydroxide. Additionally, if the magnesia is mixed with binders to form a ready-to-use refractory mortar, it should be classified under HS code 3816.00 rather than 2519.90.

2519.10Magnesium carbonate (magnesite); natural2816.10Hydroxide and peroxide of magnesium3816.00Refractory cements, mortars, concretes and similar compositions, including dolomite ramming mix, other than products of heading 38.01

Top exporters and importers of HS 251990 (the code used for fused magnesia), 2025

In 2025, the largest exporter of HS 251990 (the code used for fused magnesia) in UN Comtrade data was China, with 47% of world exports; the largest importer in UN Comtrade data was the United States, with 13% of world imports. Countries that did not report 2025 data are estimated from partner records, which can understate them.

Figures cover everything classified under HS 251990, not only fused magnesia.

Top exporters 2025 · share of world exports

  1. 1 China $860M
  2. 2 Netherlands $142M
  3. 3 Brazil $99M

World total: $1.8B Reported figures on UN Comtrade ↗

Top importers 2025 · share of world imports

  1. 1 United States $266M
  2. 2 India $193M
  3. 3 Germany $183M

World total: $2.1B Reported figures on UN Comtrade ↗

How these figures are built

109 countries reported 2025 trade to UN Comtrade in HS 2022, and their own totals are used. Countries that did not report are estimated from what other countries recorded trading with them. Those estimates miss trade with other non-reporting countries, so they can be low, and a non-reporting country can rank higher than shown or be missing from the list. World totals add both and leave out trade between two non-reporting countries. Figures are in current US dollars; reported imports are mostly valued CIF and exports FOB, and exports include re-exports. The UN Comtrade links show the underlying records; they can also list a few reporters left out here (regional groups and older HS editions).

Source: UN Comtrade (United Nations Statistics Division), 2025 annual data.

Brazil NCM codes for fused magnesia

Brazil splits HS 2519.90 into 2 NCM codes. Pick the one that matches your product:

Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.

Questions about fused magnesia

What is the HS code for Fused magnesia?

The HS code for Fused magnesia is 251990 (Magnesia, fused or dead-burned (sintered); whether or not containing small quantities of other oxides added before sintering, other magnesium oxide, whether or not pure, (not natural magnesium carbonate)). The HS code for fused magnesia is 2519.90, which also covers dead-burned and other magnesium oxides.

How do I classify Fused magnesia for customs?

Fused magnesia is classified under HS code 251990 — Magnesia, fused or dead-burned (sintered); whether or not containing small quantities of other oxides added before sintering, other magnesium oxide, whether or not pure, (not natural magnesium carbonate). This is a 6-digit subheading level code.

Is fused magnesia considered a chemical or a mineral?

For customs purposes, fused magnesia is classified as a mineral product under Chapter 25, despite the high-temperature industrial processing used to create it.

Which countries are the top exporters of fused magnesia (HS 251990)?

In 2025, the top exporters of HS 251990 (the code used for fused magnesia) in UN Comtrade data were China ($860M, 47% of world exports), the Netherlands ($142M) and Brazil ($99M). World exports came to about $1.8B, 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.

Which countries are the top importers of fused magnesia (HS 251990)?

In 2025, the top importers of HS 251990 (the code used for fused magnesia) in UN Comtrade data were the United States ($266M, 13% of world imports), India ($193M) and Germany ($183M). World imports came to about $2.1B, 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.

Is the HS code for Fused magnesia the same in all countries?

The base HS code 251990 for Fused magnesia is internationally standardized for the first 6 digits across 200+ countries. Individual countries may add additional digits for national tariff lines and specific classifications.

What is the NCM code for fused magnesia in Brazil?

Brazil splits HS 251990 into 2 NCM codes, so the right one for fused magnesia depends on the product's details: 2519.90.10 (Fused (electrofused) magnesia), 2519.90.90 (Dead-burned magnesia and other magnesium oxide).