Industrial processes are procedures involving chemical, physical, electrical, or mechanical steps to aid in the manufacturing of an item or items, usually carried out on a very large scale. Industrial processes are the key components of heavy industry.
Certain chemical process yield important basic materials for society, e.g., (cement, steel, aluminum, and fertilizer). However, these chemical reactions contribute to climate change by emitting carbon dioxide, a greenhouse gas, through chemical reactions, as well as through the combustion of fossil fuels to generate the high temperatures needed to reach the activation energies of the chemical reactions.
Cement (the paste within concrete)
Calcination – Limestone, which is largely composed of fossilized calcium carbonate (CaCO3), breaks down at high temperatures into useable calcium oxide (CaO) and carbon dioxide gas (CO 2), which gets released as a by-product. This chemical reaction, called calcination, figures most prominently in creating cement (the paste within concrete). The reaction is also important in providing calcium oxide to act as a chemical flux (removal of impurities) within a blast furnace.
CaCO 3(s) → CaO(s) + CO 2(g)
Steel
Smelting – Inside a blast furnace, carbon monoxide (CO) is released by combusting coke (a high-carbon derivative of coal) and removes the undesired oxygen (O) within ores. CO 2 is released as a by-product, carrying away the oxygen and leaving behind the desired pure metal. Most prominently, iron smelting is how steel (largely iron with small amounts of carbon) is created from mined iron ore and coal.
Hall–Héroult process – Aluminium oxide (Al 2O 3) is smelted with coke (C) in a high-temperature electrolysis reaction, yielding the desired pure aluminium (Al) and a mixture of CO and CO 2.
Al 2O 3(s) + 3 C(s) → 2 Al(s) + 3 CO(g)
2 Al 2O 3(s) + 3 C(s) → 4 Al(s) + 3 CO 2(g)
Fertilizer
Haber process – Atmospheric nitrogen (N2) is separated, yielding ammonia (NH3), which is used to make all synthetic fertilizer. The Haber process uses a fossil carbon source, generally natural gas, to provide the CO for the water–gas shift reaction, yielding hydrogen (H2) and releasing CO 2. The H2 is used to break the strong triple bond in N2, yielding industrial ammonia.
CH 4(g) + H 2O(g) → CO(g) + 3 H 2(g)
CO(g) + H 2O(g) → H 2(g) + CO 2(g)
N 2(g) + 3 H 2(g) → 2 NH 3(g)
Other chemical processes
Disinfection – chemical treatment to kill bacteria and viruses
Pyroprocessing – using heat to chemically combine materials, such as in cement
Pidgeon process – produces magnesium, reducing the oxide using silicon
Steam reforming, water gas shift reaction – produce hydrogen and carbon monoxide from methane or hydrogen and carbon dioxide from water and carbon monoxide
Vacuum metalising – a finishing process
Van Arkel–de Boer process – for producing titanium, zirconium, hafnium, vanadium, thorium, or protactinium