Industrial processes

The processes that turn chemistry into industry

Haber-Bosch, chlor-alkali electrolysis, nuclear fission, photovoltaics: the key processes that convert periodic-table elements into goods, energy and global commodities.

A process is more than a single reaction. It is a chain of physical and chemical transformations engineered to produce at scale, reproducibly and economically. Each process below has its history, its inventors, a key equation and specific operating conditions.

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10 processes
Chemical synthesis175 Mt/yr

Haber-Bosch process

N₂ + 3 H₂ ⇌ 2 NH₃ (ΔH = −92 kJ/mol)

Industrial synthesis of ammonia (NH₃) from atmospheric nitrogen and hydrogen under high pressure with an iron catalyst. Without it, only about 4 billion humans could be fed.

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Nuclear energy

Pressurized Water Reactor (PWR)

²³⁵U + n → ¹⁴¹Ba + ⁹²Kr + 3 n + ~200 MeV (chaîne de fission)

The most widely deployed nuclear reactor design in the world (~70 % of the fleet). Primary-loop water, pressurized to 155 bar to stay liquid at 320 °C, carries fission heat from UO₂ fuel to a steam generator that feeds the turbine.

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Metallurgy140 Mt/yr

Bayer process

Al(OH)₃ + NaOH → NaAl(OH)₄ (digestion) 2 Al(OH)₃ → Al₂O₃ + 3 H₂O (calcination)

Refining of pure alumina (Al₂O₃) from bauxite ore by selective dissolution in hot concentrated caustic soda. The mandatory step upstream of Hall-Héroult electrolysis — no Bayer, no aluminium metal.

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Electrolysis70 Mt/yr

Hall-Héroult process

2 Al₂O₃ + 3 C → 4 Al + 3 CO₂ (anode consommable, ~13 kWh/kg)

Electrolysis at 950-980 °C of alumina dissolved in molten cryolite (Na₃AlF₆) to produce aluminium metal. Universal since 1886 — it alone consumes ~3 % of world electricity.

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Chemical synthesis62 Mt/yr

Solvay process

2 NaCl + CaCO₃ → Na₂CO₃ + CaCl₂ (NH₃ recyclé en boucle)

Production of sodium carbonate (Na₂CO₃, 'Solvay soda') from brine (NaCl) and limestone (CaCO₃), with ammonia as a recycled intermediate. Has dominated soda ash production since 1865.

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Chemical synthesis270 Mt/yr

Contact process

S + O₂ → SO₂ ; 2 SO₂ + O₂ ⇌ 2 SO₃ ; SO₃ + H₂O → H₂SO₄

Production of sulfuric acid (H₂SO₄) by catalytic oxidation of SO₂ to SO₃ over a vanadium pentoxide catalyst, followed by absorption in concentrated acid. ~270 Mt/year — the world's most-produced acid.

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Chemical synthesis75 Mt/yr

Ostwald process

4 NH₃ + 5 O₂ → 4 NO + 6 H₂O ; 2 NO + O₂ → 2 NO₂ ; 3 NO₂ + H₂O → 2 HNO₃ + NO

Catalytic oxidation of ammonia (from Haber-Bosch) on a platinum-rhodium gauze to produce nitric acid. Coupled with Haber-Bosch, it's the backbone of the fertilizer and explosives industry.

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Electrolysis85 Mt/yr

Chlor-alkali process

2 NaCl + 2 H₂O → Cl₂ + 2 NaOH + H₂ (anode : 2 Cl⁻ → Cl₂ + 2 e⁻ ; cathode : 2 H₂O + 2 e⁻ → H₂ + 2 OH⁻)

Electrolysis of brine (NaCl) into chlorine (Cl₂), caustic soda (NaOH) and hydrogen (H₂) in a single process. Cornerstone of mineral chemistry — world production ~85 Mt Cl₂/year and ~80 Mt NaOH/year.

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Chemical synthesis0.2 Mt/yr

Frank-Caro process

CaO + 3 C → CaC₂ + CO ; CaC₂ + N₂ → CaCN₂ + C ; CaCN₂ + 3 H₂O → 2 NH₃ + CaCO₃

First industrial process for atmospheric nitrogen fixation (1898). Converts calcium carbide CaC₂ into calcium cyanamide CaCN₂ by direct reaction with N₂. Supplanted by Haber-Bosch from the 1920s onward but supplied Germany's agricultural nitrogen during World War I.

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Nuclear energy

Boiling Water Reactor (BWR)

²³⁵U + n → fragments + 2-3 n + ~200 MeV ; eau saturée à 285 °C / 70 bar entraîne directement la turbine

Direct-cycle nuclear reactor: core water boils at 285 °C / 70 bar to produce the steam that drives the turbine directly, without a secondary loop. ~70 reactors in service (~25 % of the world fleet), mainly in the United States, Japan and Sweden.

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