About 50% of total coagulant production has an iron base. Iron is the second most common element in the earth's crust and can be mined in the form of iron-containing ores like magnetite or hematite. These ores are the raw materials for iron containing products.

The main raw materials are by-products from other production processes.  The most important by-product is ferrous sulphate, called 'copperas', which occurs in large quantities whilst manufacturing titanium dioxide.  The raw material here again is an ore containing titanium as well as iron. 

Other by-products are pickling liquors from the steel processing industry, both in the form of chlorides and sulphates, are produced during a surface treatment of flat steel products. 

Iron salts by-products are in a bi-valent form and can, in some cases, be directly used for sewage treatment.  When oxidized with chlorine or oxygen it wil produce a tri-valent product which is more widely applicable because of excellent performance and results when treating water.

For the production of tri-valent iron chloride, 'ferric chloride' scrap iron is also used, together with hydrochloric acid.