As specialists in the areas of acid procurement and acid regeneration, it only makes sense that we begin a series along these topics in our blog. Our goal is to create a source of information for you in the internet which, through its crisp and understandable form, will keep you informed about these exciting technologies and be accessible to everyone who is interested.
Applications for Acid Regeneration or Oxide Production Plants:
The chloride in the following periodic table can be decomposed into a metal oxide and hydrochloric gas via a pyrometallurgical process (Krivanec, 1988). Depending on whether or not an acid or a metal oxide stands by the value in the foreground, you have an acid or metal oxide production plant.
Under conditions of increased temperatures, the following chemical reaction occurs:
MeCl2 + H2O => MeO + 2 HCl
4 MeCl2 + 4H2O + O2 => 2 Me2O3 + 8 HCl
2 MeCl3 + 3 H2O => Me2O3 + 6 HCl
Hydrochloric acid regeneration plants are in wide use in steel mills. This application represents that largest market for the regeneration technology. Hot rolled sheets have a scale layer caused during the production process that prevents them from being further processed in the cold roll mill. Removing the scaling produces a large volume of waste acid (up to 20.000 L/h per facility) and the most economical solution (which just so happens to increase plant independence) is to process the acid directly on site.
A generally acceptable rule of thumb is that regeneration plants become feasible after ~2500 L/h and should be considered to replace having a recycler take the waste away and sourcing a reliable supply of fresh acid. Sometimes geographical considerations mean that even smaller operations be covered by such a system. Because of this, it is important to know that pyrometallurgical systems require a minimum volume from 300L/h in order to be technically feasible.
To be continued…
Krivanec H.K., Kladnig W.F., Herstellung von Oxidrohstoffen nach dem Andritz-Ruthner-Sprühröstverfahren, Mag. f. Verfahrenst., 112/11 (1988), 762-769