Manufacturing steel
Steel is produced by reducing the carbon content of iron from the blast furnace.
This is achieved by injecting pure oxygen into molten iron at the steelworks.
Impure iron from the blast furnace typically contains around 4% carbon. When solidified, iron like this is brittle and has few uses. The carbon content is reduced to between 0.2% and 2% using the basic oxygen steelmaking (BOS) process. Oxygen gas is injected into the molten iron under pressure, oxidising carbon to gaseous carbon monoxide and carbon dioxide, which escape from the molten metal.
Cutting metals
An oxy-acetylene (ethyne) flame can be up to 3149.85 °C, which is hot enough to melt steel.
When a stream of pure oxygen is added, it reacts with the steel in an exothermic reaction. Enough heat is generated to melt the metal.
Ethyne, acetylene, is a flammable gas also known as acetylene. In an oxy-acetylene torch, ethyne is burned in oxygen to produce a very hot flame that can melt steel. When a stream of oxygen is played over the molten steel, the metal oxidises and crumbles away. This allows very thick pieces of steel to be cut, and it even works under water.
Medicine
Patients with breathing difficulties may need to breathe oxygen instead of air, as it allows their bloodstream to be more fully oxygenated.
Most living organisms need oxygen to release energy by respiration. About 21% of the air is oxygen, but people with breathing difficulties may be unable to obtain sufficient oxygen from the air. Oxygen may be administered through a face mask to help such patients obtain the oxygen their bodies need.
Oxygen is also used in breathing mixtures, such as those used by pilots at high altitudes. It is
used as a component of the breathing mixtures used by divers, pilots and astronauts. The International Space Station contains an atmosphere of 21% oxygen and 79% nitrogen at 100 kPa, which is similar to the air on Earth. Space suits contain pure oxygen under reduced pressure.
Cleaning polluted rivers
Oxygen can be pumped into polluted rivers and lakes so that they continue to support fish and other water life.
Excess nitrogenous fertiliser, washed into rivers and lakes, allows algae in the water to grow more quickly. The algae shade water plants, causing them to die. Decay bacteria feed on dead algae and the dead plants, using up dissolved oxygen as they respire. Fish and other aquatic animals die as a result. Oxygen pumped into the water replaces the oxygen used up by the decay bacteria.
