C1a - Metals from rocks

Ores contain enough metal to make it worthwhile extracting them.

Unreactive metals such as gold are found in the Earth as the metal itself but most metals are found as compounds that require chemical reactions to extract the metal.

Metals that are less reactive than carbon can be extracted from their oxides by reduction with carbon, for example iron oxide is reduced in the blast furnace to make iron.

Iron from the blast furnace contains about 96% iron. The impurities make it brittle and so it has limited uses.

Removing all the impurites would produce puer iron. Pure iron has a regular arrangement of atoms, with layers that can slide over each other, and so is soft and easily haped, but too soft for many uses.

Most iron is converted into steel. Steels are alloys since they are mixtures of iron with carbon and other metals. The different sized atoms added distort layers in the structure of the pure metal, making it more difficult for them to slide over each other, and so alloys are harder. Alloys can be designed to have properties for specific uses. Low carbon steels are easily shaped, high carbon steels are hard, and stainless steels are resistant to corrosion.

Many metals in everyday use are alloys. Pure copper, gold and aluminium are too soft for many uses and so are mixed with small amounts of similar metals to make them harder for everyday use.

Smart alloys can return to their original shape after bein deformed.

The elemts in the central block of the periodic table are kown as the transition metals. Like other metals they are good conductors of heat and electricity and can be bent or hammered into shape. They are useful as structural materials and for making things that must allow heat or electricity to pass through them easily.

Copper has properties that make it useful for electrical wiring and plumbing. It can be extracted by electrolysis of solutions containing copper compounds. the supply of copper-rich ores is limited. new ways of extracting copper from low-grade ores are being researched to limit the enviromental impact of traditional mining.

Low density an resitant to corrosion make aluminium and titanium useful metals. These metals cannot be extracted from their oxides by reduction with carbon. Current methods of extraction are expensive because there are many stages in the process and much energy is needed.

We should recycle metals because extracting them uses limited resources and is expensive in terms of energy and effects on the enviroment.