u s pat no 4 412 866 and types wherein flow rates may follow time variable functions or steps are not identical with respect to function examples are u s pat no 4 332 623 u s pat no 5 064 539 and u s pat no 5 102 553 smb methods may also include semi continuous and sequential types such as generally described in u s pat no 5 127 957 in a preferred embodiment of this invention a solution containing the acid metal salts is fed to a simulated moving bed which is filled with anion resin examples of anion resin are dowex xur 1525 msa 1 mitsubishi pa306s ma01ss ma03ss bayer m500 and or bayer m600 the number of columns or beds preferably is 1 to 8 preferably a column comprises one or several separating sections beds containing chromatographic media for example resin those feed tanks filters piping connecting flow between columns beds and or separating sections where so connected pumps valving pressure regulators metering equipment flow control and microprocessor equipment utilized in a preferred embodiment are well known in construction and function to those skilled in the art preferably the operating steps for example of an 8 column system are as shown in fig1 these steps preferably are managed by a microprocessor which controls the appropriate valve opening closing flow rates and pressures.