Process to reduce the presence of dissolved carbon dioxide in an acid water lagoon formed by mineral extraction

摘要

In a process to reduce the presence of dissolved carbon dioxide in an acid water lagoon formed by mineral extraction, the pH value is raised by injection of carbon dioxide to form an acid buffer. The carbon dioxide is introduced at a pressure of between 1 and 10 bar from an external source. The lagoon water is either pre-conditioned at less than 4.3 to 5 with e.g. CaO, MgO, NaOH, Ca(OH)(2, CaCO(3, MgCO(3. Alternatively, the lagoon is conditioned later at above 4.3 to 8.2 pH, introducing buffered water into a given geographic location at deeper layers. The pre-cleaned carbon dioxide is supplied from industrial sources. Discharge lasts from two to 30 minutes and release takes place in the lower water layers. The CO(2 and N(2/CO(2 mixture is introduced by pipes near the lagoon floor allowing the bubbles to rise and make contact with the upper layers.