贵金属矿砂及其精矿。
冶金是物理、化学、工程有关,金属矿砂开采,最后的产品。
Metallurgy is the physics, chemistry, and engineering related to metals from ore extraction to the final product.
各种天然砂,不论是否着色,但第二十六章的含金属矿砂除外。
Natural sands of all kinds, whether or not coloured, other than metal-bearing sands of Chapter 26.
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