This invention relates to an improved process and apparatus for recovering copper values from various acidic, copper bearing solutions. More particularly, this invention relates to a process and apparatus which economically recovers the copper present in such streams.
Copper is an extremely valuable metal particularly in reference to other industrial commodities such as steel or aluminum. In addition, the quality of water resources and the environment dictate the desirability of treating industrial process streams to minimize waste and degradation. Mine water or acid water resulting from the processing of copper bearing ores represents one such industrial waste in terms of being acidic due to presence of sulfuric acid and containing copper dissolved therein in the form of soluble sulfates.
To recover copper from copper bearing solutions it has been conventional to use metallic iron since it displaces any element from solution which is higher in the electromotive series. One conventional process employs a mass of scrap iron having large surface area such as detinned, shredded steel cans through which the copper bearing solution is passed. Other more sophisticated approaches are presented in U.S. Pat. Nos. 3,154,411 issued Oct. 27, 1964 and 3,333,953 issued Aug. 1, 1967, both of which employ various types of apparatus to precipitate and recover the copper from mine water. The major deficiency of the latter patent is that the mixing is accomplished within the reaction container and does not involve initially reacting powdered iron with the copper bearing solution. This is an inefficient operation and does not maximize the recovery of copper values from copper bearing solutions.