6902.90 - Other:

This HTS category, 6902.90, encompasses refractory ceramic constructional goods that do not meet the specific compositional criteria outlined in the preceding subheadings (6902.10 and 6902.20). These products are designed to withstand high temperatures and thermal shock, making them suitable for use in industrial furnaces, kilns, incinerators, and other high-heat environments. Unlike the sibling categories which are defined by a high percentage of specific oxides (magnesium, calcium, chromium, alumina, or silica), this "other" category captures refractory ceramics based on their exclusion from those more narrowly defined groups, implying a broader range of compositions or a primary reliance on other refractory materials.

The distinction between 6902.90 and its siblings lies solely in the chemical composition. While all goods within heading 6902 are refractory ceramic constructional items, 6902.10 and 6902.20 are reserved for products predominantly composed of magnesium, calcium, chromium, alumina, or silica. Therefore, any refractory ceramic constructional good that does not exceed 50% by weight of these specified elements, expressed as their respective oxides, will fall under the residual category of 6902.90.

Within this category, further subdivisions exist to provide greater specificity. HTS code 6902.90.10 specifically covers "Bricks" that fit the criteria of 6902.90. This allows for a direct classification of individual refractory bricks not otherwise specified. The remaining items are captured under HTS code 6902.90.50, designated as "Other." This "Other" subheading serves as a catch-all for various refractory ceramic constructional goods such as blocks, tiles, and similar shaped items that do not qualify for the more specific "Bricks" subheading.