Regarding the recycling of scrap metal, iron, aluminum and copper are used.

Copper: With good conductivity, it can be used as wires and daily necessities, and form alloys with other metals, such as brass and bronze.

Aluminum: Because it is protected by oxide film, it is not easy to be corroded. Its alloy is light and strong, and it is used to make doors and windows of automobiles, airplanes and household cookers.

Iron: hard, low cost, used in construction, machinery, transportation, etc.

I hope it helps you.

Iron is a widely used metal. There is a lot of iron ore in the earth's crust. People dig out these iron ores, remove impurities, and then put them into a smelting furnace with a temperature of more than 2,000 degrees to make iron. Because there is a lot of iron on the earth, iron is not very expensive. Iron is widely used in industry and life. In life, you need a lot of steel bars to build a floor (steel is made of iron, which I will talk about below). The water pipes at home are also made of iron, a gas bottle is made of steel, a bicycle rack is made of iron, and the iron pot in the kitchen is also made of iron. Industry can be used as bridges, machines, pipes and so on. Our human body also contains a lot of iron. The iron content of normal adult males is 50mg/kg, and that of normal adult females is 35mg/kg. If a person lacks iron, it will cause iron deficiency anemia, and the harm of anemia need not be said by me. Therefore, iron is an essential trace element for human body.

Copper is also a widely used metal. You can buy copper core wires in hardware stores, that is, wires with copper as conductor. Because the resistivity of silver is the smallest among metals that people can extract in large quantities, but because silver is expensive, copper and aluminum with the second highest resistivity are used as wires. Why do some thieves repeatedly commit crimes and sell wires to the acquisition booth? It's because the acquisition booth recycles copper from wires, and copper is more expensive than iron. Pure copper is very soft and golden yellow, so people mix copper with other metals to make alloys, which brings other characteristics to copper. For example, four bronze alloys of tin 1 were weapons of the Warring States period, and the bronze sword of Gou Jian, the king of Yue, is still extremely sharp. There is also white copper, which is also an alloy of copper and tin. Copper is also a trace element in human body, but its content is far less than that of iron. The copper content of the whole human body is only 100 to 150mg, which is not good for the liver.

Aluminum can replace metals in other oxides (aluminothermic method). Its alloy is light and tough, and it is a structural material for making airplanes, rockets and automobiles. Pure aluminum is widely used in cables. Widely used in making daily utensils.