这一工业原料比稀土还宝贵，中国储量占世界九成，但只够开采七年

Core Insights - The selection of materials is a core issue in military equipment, with non-ferrous metals being crucial components, particularly rare metals like tin, which is increasingly scarce [1][3]. Group 1: Importance of Tin - Tin has historically been an essential material in weapon manufacturing due to its excellent ductility [3]. - Approximately 35 countries are major tin producers globally, but the overall tin content is relatively low, with current estimates suggesting that global tin mining can only sustain production for another 35 years [3]. - China holds the largest tin reserves in the world, but due to high consumption rates, these reserves are expected to last only another 7 years [3]. Group 2: Applications and Properties of Tin - Tin is not easily oxidized in the air, making it vital in various industrial fields, particularly for its corrosion-resistant alloys [5]. - Tin is widely used in mechanical, aerospace, and superconducting materials, earning it the nickname "the MSG of industry" [5]. - Common misconceptions exist regarding tin products, such as tin foil, which is mostly aluminum, and tin cans, which are typically steel coated with a thin layer of tin [5]. Group 3: Tin Supply and Recycling - The primary source of tin is cassiterite, with some coming from its sulfides, but as resources become scarcer, countries are increasingly focusing on tin recycling [7]. - The recycling process is becoming an important part of the market supply as demand for tin continues to rise, highlighting its precious nature [7].