This is the 9948th most frequent Russian word.
алюминиевых
Aluminum (adjective; relating to aluminum).
In this sentence, "алюминиевых" functions as an adjective in the genitive plural form modifying the noun "кастрюли".
Эти алюминиевых кастрюли легкие и удобные.
These aluminum pots are light and handy.
Here, "алюминиевых" also acts as an adjective in its genitive plural form, describing the noun "конструкций".
Скульпторы использовали части алюминиевых конструкций.
The sculptors used parts of aluminum structures.
In this instance, the adjective "алюминиевых" describes "труб", indicating the material of the pipes.