Talk:A-level Chemistry/OCR (Salters)/Elements from the Sea

Extraction of metals
Metals are vital to our everyday life. There are 4 main processes involved with extracting metals:

Mining

The metal must first be mined. This is often done on a huge scale. The world's largest mine (Kennecott Copper Mine) is located in Salt Lake City, Utah, and provides over 15% of the US's copper needs.

Concentration

The rock is first ground to a powder. Next, it undergoes a process known as froth floatation:


 * First, the powder is covered in a chemical called a collector, which binds only to the mineral grains - the useful part. This makes them water-repellent.
 * Next, Air and detergent is blown in, creating a froth. Rememeber that the mineral is covered in a water repelling chemical which means it becomes concentrated in the froth and can easily be removed.
 * Finally, these mineral grains go to the smelter which is the next step. The unwanted slurry goes to the tailings pond and hopefully, disposed of with consideration to the enviroment.

Smelting

In flash smelting, the previously concentrated minerals are passed down a reaction shaft, with a potent mixture of silica and oxygen-enriched air. A highly exothermic reaction takes place.

Sulphur dioxide is produced which is toxic and reacts with water in clouds to form acid rain. This is converted to sulphuric acid to reduce the amount of SO2 that is emitted.

Electrolytic refining (electrolysis)