Uranium and Rare Earth Recovery from Phosphate Fertilizer Industry by Solvent Extraction

Abstract

The paper presents a comprehensive review of the fundamental and applied aspects of the recovery of uranium and rare earths from phosphoric acid used for fertiliser production, by solvent extraction, with emphasis on the data from the pilot plant operated in Romania. The occurrence of uranium and rare earths in various phosphatic deposits is described and variations discussed. The radioactivity of the phosphatic rock is shown to be a cause for concern for control over pollution. History of the commercial recovery operations is decribed and the role of economic factor highlighted. The acidulation of phosphate rock, behavior of uranium and rare earths, influence of iron and effect of humic matter in the sulphuric acid process and the nitric acid process is discussed- Uranium extraction from the phosphoric acid by acidic organophosphorus esters is discussed in detail. The industrial flowsheets are described. Details are presented for the single cycle extraction process developed in Romania. Cost estimates are given which show the superiority of the single cycle process and its capability to produce uranium at a competitive price, while also producing rare earths as a by-product. Process flowsheet with stream data is also given for treatment of the solution obtained by nitric acid attack of the phosphate rock. Analysis of the uranium green cake (UF4) and the rare earth concentrate is given.