长期的可利用性国民经济各部门中使用的大多数材料,如从矿石冶炼出的铜、镍、钛等等,在地球上越来越难找到它们的富矿,这对它们的生产经济效益带来了更多的困难。然而,铝是地壳中的含量比铁还多,在地壳中含量最多的第三个元素。当今已知的富铝铝矾土的蕴藏量至少够200年使 Long-term Availability Most materials used in various sectors of the national economy, such as copper, nickel, titanium, etc., smelted from ores have made it increasingly difficult to find their rich ore on the Earth, which has brought about their economic benefits in production More difficulties. However, aluminum is the third element in the earth’s crust that contains more iron than the iron and is the most abundant in the crust. The amount of alum bauxite known today is at least 200 years old