Abstract: A method and process for removal by precipitation of salts of a variety of metallic elements from aqueous solutions, including for example, copper, cadmium, chromium, zinc, nickel, lead, tin, platinum, rhodium and others with each of the metallic elements having multiple valent states. The process includes the establishment of a simultaneous oxidative-reductive cycle within the aqueous solutions, with the oxidative-reductive cycle normally being generated through the use of iodine, normally in the form of the iodide or iodate and phosphorous acid. In certain reactions, it is desirable that the pH be controlled and in such solutions, the phosphorous acid may be added in the form of a sodium salt of phosphorous acid. In the utilization of the multivalent materials, the least soluble salt generated during the oxidative-reductive cycle is removed.