Chlorine: Overview
Pipes, foam, paint pigment and clean water from salt
What this tab covers What the chemical is, how big its market is, what it is used for (with shares, volumes, why it wins and what could replace it), and its chain from raw material to end user. Ends with three things to remember.Chlorine is made by electrolysing salt brine. Each tonne comes with about 1.13 t of caustic soda and a little hydrogen, so the two products are sold as one 'electrochemical unit' (ECU). World output is roughly 80 Mt a year, about 47% of it in China. Electricity is the largest cost so chlorine is as much a power story as a chemical one. About a third goes into PVC, and much of the rest into polyurethanes, solvents, titanium dioxide and water treatment. Chlorine is hard to store or ship, so it is used close to where it is made.
Volume about 80 Mt of chlorine a year (2025, indicative, derived); Euro Chlor and the World Chlorine Council publish no world total, and commercial figures of about 92-97 Mt (P Plus 2024; Statista 2022) appear to be capacity-type estimates Market value not published as a merchant market; most chlorine is used captively. Value is usually expressed per ECU: about $400-500 per ECU in Asia and the US Gulf in late 2025 (indicative, basis: Argus caustic prices plus near-zero or negative merchant chlorine) Growth about 2-3% a year, tracking PVC and polyurethane demand in Asia; Europe is shrinking (indicative) Mysteel Nov 2025 (China caustic output 42.62 Mt); Euro Chlor monthly production 2024; Argus Chlor-Alkali Outlook Nov 2025; world total derived (indicative, basis: China at about 47% of world output)Key uses
| Use | Share | Annual volume | Why this commodity | Alternatives |
|---|---|---|---|---|
| PVC (via EDC and VCM) | 35% | about 28 Mtbasis | PVC is 57% chlorine by weight, so it locks salt-derived chlorine into a cheap, durable plastic and cuts the ethylene needed per tonne. Pipes, window profiles and cable insulation take most of it. Chlor-alkali producers integrate into vinyls to use their chlorine rather than ship it. Euro Chlor and industry splits (indicative) | Polyethylene and polypropylene pipes Aluminium and timber window frames |
| Isocyanates (MDI, TDI) and oxygenates (propylene oxide, epichlorohydrin) | 20% | about 16 Mtbasis | Chlorine makes phosgene for MDI and TDI, the building blocks of polyurethane foams, and is used in the chlorohydrin routes to propylene oxide and epichlorohydrin (for epoxy). The chlorine leaves as HCl or salt, so it is a reagent, not part of the product. Euro Chlor and industry splits (indicative) | Non-phosgene isocyanate routes (pilot scale) HPPO and PO/SM routes for propylene oxide Glycerine-to-epichlorohydrin |
| Inorganic chemicals (titanium dioxide chloride route, hydrochloric acid, hypochlorite, metal chlorides) | 15% | about 12 Mtbasis | The chloride route to titanium dioxide gives the brightest pigment and recycles most of the chlorine. Sodium hypochlorite and ferric and aluminium chlorides serve bleach and water treatment. Synthesis of HCl from chlorine and hydrogen also balances chlorine at plants with no outlet. Euro Chlor and industry splits (indicative) | Sulphate-route titanium dioxide Ozone and UV for disinfection |
| Chloromethanes and chlorinated solvents | 8% | about 6.4 Mtbasis | Methyl chloride feeds silicones, and chloroform feeds the HCFC-22 used for fluoropolymers and refrigerants. Methylene chloride and perchloroethylene are solvents under tightening regulation. Euro Chlor and industry splits (indicative) | Non-chlorinated solvents Direct process substitutes for silicone feedstock (none at scale) |
| Other organic intermediates (agrochemicals, pharmaceuticals, chlorobenzenes, chlorinated paraffins, polycarbonate via phosgene) | 17% | about 13.6 Mtbasis | Chlorine is a reactive handle that lets chemists build complex molecules; many active ingredients pass through chlorinated steps. This is the main chlorine outlet for India, where agrochemical and pharma intermediates drive demand. Euro Chlor and industry splits (indicative); DCM Shriram interview, Indian Chemical News, June 2024 | Bromine chemistry in some reactions Non-phosgene melt process for polycarbonate |
| Water treatment, disinfection and pulp | 5% | about 4 Mtbasis | Small in tonnes, large in value to society. Chlorination keeps a residual disinfectant in water networks that ozone and UV cannot. Conway notes one UK plant supplies chlorine for most of Britain's tap water. Euro Chlor (indicative); Conway, Material World (2023) | Ozone, UV, chlorine dioxide Oxygen and peroxide bleaching for pulp |
From raw material to user
- Salt and brine About 1.65-1.75 t of salt per t of chlorine, mostly solution-mined brine or solar salt (USGS MCS 2026 notes chlor-alkali is the main chemical use of salt).
- Brine purification Calcium and magnesium must be cut to parts per billion for membrane cells, using precipitation and ion-exchange resins.
- Electrolysis Membrane cells use about 2.5-2.8 MWh per t of chlorine; each t comes with 1.13 t caustic soda and 0.028 t hydrogen (EU BREF 2014, indicative).
- Drying, compression and liquefaction Wet chlorine is dried with sulphuric acid and compressed; most is piped straight into EDC, phosgene or HCl units on the same site.
- Derivatives About 35% goes to EDC/VCM/PVC; liquid chlorine in tonners and rail cars serves water works and smaller users.
Made from (commodity table)
NaCl SaltThree things to know
- Chlorine and caustic soda are made together in a fixed ratio of 1 to 1.13, so a plant must sell both, and one product often subsidises the other.
- Electricity is about half the cash cost; in 2022 Argus put the NW Europe ECU cash cost at $1,300-1,640, more than twice the Americas at about $590.
- China makes about 47% of the world's chlorine, and its merchant chlorine traded at negative prices (minus Yn100-200/t in Shandong) in October 2025.