Methods for recovering bis(2,4,4-trimethylpentyl) dithiophosphinic acid
AssigneeVale S.A.
InventorsMarc Detournay, Arnaud Jacques De Sainte Marie, Jean-Paul Raymond Duterque, Indje Ognianov Mihaylov
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Abstract
This invention provides a method to recover valuable DTPA from DTPA solvent extraction organic solution that avoids the need to operate at either high or very low temperatures, with extended reaction times and having to carry out solid/liquid separation on organic solution. Furthermore, the invention provides the flexibility of selecting appropriate base solution to carry out the DTPA recovery process and further provides the ability to directly treat metal-containing DTPA organic solution.
Claims21
A method for recovering bis(2,4,4-trimethylpentyl)dithiophosphinic acid (DTPA) from a DTPA-containing organic solution, comprising:
- (a) contacting the DTPA-containing organic solution with an aqueous base solution supplied in excess of a stoichiometric requirement for acid-base neutralization or in excess of a stoichiometric requirement for metal cation-exchange reactions for the amount of DTPA contained in the organic solution to produce DTPA-rich and DTPA-lean organic phases;
- (b) separating the two organic phases;
- (c) contacting the DTPA-rich organic phase with a first acidic solution to produce a base-free DTPA-rich organic solution;
- and
- (d) contacting the DTPA-lean organic phase with a second acidic solution to produce a base-free DTPA-lean organic solution.
Dependencies are inferred from the claim text.