Hydrochloric Acid

Purification

Spent Hydrochloric Acids of various origins may contain organic and inorganic impurities, which must be removed prior to being re-utilised.

Mechanical separation of undissolved components

Undissolved inorganic and solid organic impurities may be separated by using filtration. Micro-, nano-, ultra-filtration and even reverse osmosis may be used for fine purification of Hydrochloric Acid.

Thermal separation of dissolved non-volatile components

In a pre-evaporation step the dissolved inorganic and low volatile organic impurities may remain in the concentrate, whereas the recovered product, the Hydrochloric Acid, being the more volatile component, is vaporised.

 
Separation of halogens

The separation of halogen compounds from spent Hydrochloric Acid represents a frequently occurring problem. Fluorine, bromine and iodine are chemically bound and remain in the concentrate, when the acid is evaporated.

Alternatively, the acid may also be separated from bromine and iodine through chemical oxidation and the ensuing steam stripping.

Separation of volatile organic compounds

If volatile organic compounds cannot be separated by evaporation, their adsorption to specially conditioned activated carbon is mostly successful. The TOC and AOX values in the acid can be reduced to a few ppm.