Studies on di-nonyl phenyl phosphoric acid (DNPPA): a potential extractant for uranium recovery from merchant grade phosphoric acid (MGA)

Solubility behaviour of DNPPA in various aqueous solutions such as MGA, WPA, 30% H2SO4, 30% H3PO4, 7.5% oxalic acid, 12% Na2CO3 etc. has been examined. Its recovery from acidic as well as alkaline solutions employing various diluents has been tested. The effects of process variables such as phase ratio (O/A), equilibration time, DNPPA concentration in aqueous solution on recovery have also been studied. A four-stage counter current extraction at a recycle ratio of 20, yielded ∼92% recovery of DNPPA from MGA employing petrofin as the diluent. Analytical methods based on potentiometry, HPLC and spectrophotometry have been standardized to determine the solubilized DNPPA in aqueous solution. (author)