Element 17 · Halogen
Chlorine
Chlorine — the green-yellow gas used to disinfect water supplies worldwide.
Element Facts
SYMBOL
Cl
ATOMIC NO.
17
ATOMIC WEIGHT
35.45
CATEGORY
Halogen
PERIOD
Period 3
GROUP
Group 17
Background
Chlorine was discovered in 1774 by Carl Wilhelm Scheele, who called it “dephlogisticated muriatic acid air”. Humphry Davy recognised it as an element in 1810 and named it from the Greek for its yellow-green colour. Its properties as a bleaching and disinfecting agent were quickly recognised, and it was used to bleach textiles from the 1780s. Its tragic use as a chemical weapon in the First World War (first deployed at Ypres in 1915) led to the development of gas masks.
Industrial Uses
Chlorine’s primary industrial use today is in the manufacture of PVC (polyvinyl chloride) plastic, one of the world’s most widely used materials. Other major uses include water and wastewater treatment and disinfection, paper and pulp bleaching, pharmaceuticals (many drugs contain chlorine), and as a chemical intermediate. It is produced by electrolysis of brine (the chlor-alkali process).
Scrap Viability
Why QuickStop Metals doesn’t buy Chlorine:
Chlorine is a corrosive, toxic yellow-green gas under normal conditions — not a metal, and completely unsuitable for handling at a scrap yard. It is produced industrially and consumed in chemical manufacturing processes rather than recycled from scrap.
What It's Worth
Chlorine is traded as an industrial chemical. Liquid chlorine (liquefied gas in cylinders) trades around £150–350/tonne. It is not a scrap material.