HYDROMETALLURGICAL ZINC RECOVERY PROCESS AND APPARATUS

摘要

There is provided a process for recovering a desired product from a residue and apparatus therefor. The process includes the step of recirculating either a residue formed in one stage of the process to an earlier stage of the process or the solid-waste residue to a later stage of the process. The invention uses these residues as a reagent in the step to which the residue is recirculated and thus reduces the amount of reagents which have to be added to the overall process thus reducing the cost of running the process. The earlier stage of the process is prior to a treatment step where acid is added to lower the pH of the waste being treated. The recirculation of the residue has the advantage for example of reducing the amount of acid required.