Many industrial processes generate significant volumes of diluted acid, containing either organic or inorganic materials that cannot be neutralised and/or discharged. Evaporation is a proven process to concentrate these effluents and allow the acids to be recycled, reducing the cost of fresh acid make-up.
The main operations resulting in the production of spent acid are as follows:
- HCl thermal regeneration : HCl concentration or capacity increase
- Pigments production (for example TiO2)
- Hydrometallurgy : for copper and zinc extraction, or other non ferrous materials
- Organic synthesis, for sulphonation, nitration, alkylation, …
- Steel production : pickling baths, electrolyte from galvanisation