A pump forces the spent hydrochloric acid through a pre-filter and into the evaporator loop, comprised of the Evaporator exchanger and the Separator.

In the evaporator loop, the spent acid begins to vaporize at approximately 102°C. As the solution increases in concentration, the temperature increases in the loop. When the proper solution temperature/concentration is reached, a ferrous chloride concentrate is withdrawn slowly from the loop and transferred to a storage tank for sale as a solution or for conversion into a solid crystal.

Forced by expansion, the acid and water vapors are driven from the Separator and into the Rectifier. The concentration of acid is controlled in this step to return excellent quality acid to the pickling process.

The remaining water vapor, stripped of acid, continues its journey into the Condenser where it is sub-cooled and condensed to nearly pure water. This water is reused as rinse water in the pickling process or is returned to the pickling tank with the concentrated acid.

last updated April, 2003