Hydrochloric acid is a significant side-stream generated in various chemical processes - the so-called condensation reactions.  Only a very small quantity is derived from the direct reaction between chlorine and hydrogen.

The most important source is the MDI/TDI production which finally produces polyurethanes.  This acid has a high purity which makes it suitable for the production of coagulants.  Other production processes, such as MCA, LAB or Sodium Bisulphate are also used as sources of hydrochloric acid.

Hydrochloric acid dissolves the aluminium and iron containing raw materials without leaving significant volumes of insoluable residues.  The chlorides of either aluminium or iron have an excellent solubility in water, making the application of these kinds of coagulants easy and very efficient.