Abstract: Certain benzothiazine compounds, metal complexes thereof and solutions of said compounds in essentially water-immiscible, liquid hydrocarbon solvents are disclosed. These compounds have in their 4-keto form, the structure: ##STR1## the corresponding enol of which has the structure: ##STR2## wherein x, n, R.sup.1, R.sup.2 and R.sup.3 are as defined in the specification and claims hereof. Particular metal values are recovered from their aqueous solutions by using the benzothiazine compounds dissolved in essentially water-immiscible, liquid hydrocarbon solvents. The extraction process involves contacting the metal value containing aqueous solution with the solution of the benzothiazine in essentially water-immiscible, liquid hydrocarbon solvent and stripping the metal from the loaded organic phase.

Abstract: Certain sulfonylhydrazines, metal complexes thereof and solutions of said compounds in essentially water-immiscible, liquid hydrocarbon solvents are disclosed. The sulfonylhydrazines have the general structural formula:R--SO.sub.2 NHNH--R.sub.1wherein R and R.sub.1 are as defined in the specification and claims hereof. Particular metal values are recovered from their aqueous solutions by using sulfonylhydrazines dissolved in essentially water-immiscible, liquid hydrocarbon solvents. The extraction process involves contacting the metal value containing aqueous solution with the solution of the sulfonylhydrazines in essentially water-immiscible, liquid hydrocarbon solvent and stripping the metal from the loaded organic phase.