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Metallic materials are an important material basis for the development of human society, and most metallic elements exist in minerals in the form of compounds in nature. As a result, millions of tons of metal are extracted from metal minerals each year for industrial and agricultural purposes, the largest of which is iron.

The process of obtaining metal elements from metal minerals is called metal smelting. Different metal smelting methods are different, the more active the metal, the more difficult the smelting process. According to the metal activity sequence table, we can know that it is most difficult to smelt active metal potassium, calcium, sodium, magnesium, and aluminum. For these metals, electrolysis is used in the production in practice, and only when a metal compound is fused by electrolysis can a metal be obtained. The less active metals such as iron, molybdenum, tungsten, and copper are usually obtained by CO reductants and mineral reactions; mercury and silver metals are usually obtained by heating and decomposing their minerals; the most stable platinum and gold are found in nature in the form of a single substance, which can be obtained directly from the ore. This may explain why the history of human use of metals began in the Bronze Age, followed by the Iron Age, followed by aluminum products.

However, the reserves of metal minerals are limited and cannot be recycled, so how to protect the metal resources has become an urgent problem. After analysis, we can solve the problem from the following aspects. First of all, control the centralized development of resources in the development process to avoid the waste of symbiotic metals due to limited development conditions. Secondly, it is important to do a good job in the use of metal corrosion prevention. It is reported that the world's annual corrosion of metal equipment and materials is equivalent to 20-40% of the annual output. Common anticorrosion methods include coating metal with plastic, painting, painting oil, enamel, plating more corrosion-resistant metals (such as copper, chrome, etc.), adding metal chromium and nickel to make stainless steel, etc. Finally, we should actively develop new materials to replace the original metal materials.

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