The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 09, 1977
Filed:
May. 19, 1976
Jorolf Alstad, Oslo, NO;
Leif Farbu, Strommen, NO;
Forskningsgruppe for Sjeldne Jordarter, Oslo, NO;
Abstract
An improved liquid-liquid extraction process for the separation of the elements of the lanthanide series is disclosed. The process involves dissolving the lanthanides in a sulfuric acid solution to form rare earth sulfates whereafter the solution is contacted with an organic solvent immiscible with water and containing di (2-ethylhexyl) phosphoric acid whereby the lanthanides are separated from impurities and at least some of the lanthanides are extracted into the organic phase. Thereafter, the organic and aqueous phases are separated and the organic phase containing the impurities-separated lanthanides is subjected to a back extraction with an aqueous phase comprising an aqueous solution with sulfuric acid. The contact time between the aqueous and organic phases in the back extraction is regulated so that a desired or desired elements of the lanthanides are back extracted into the aqueous phase. The contact time is controlled and is less than the total extraction equilibrium time between the phases. The organic and aqueous solution concentrations are also controlled. After a predetermined contact time, the aqueous and organic phases are immediately separated.