Separação hidrometalúrgica de cobre e cobalto provenientes de baterias íon-lítio empregando sistemas aquosos bifásicos

Abstract

A new green hydrometallurgical method was developed for the selective extraction of copper and cobalt from spent ion-lithium battery, using Aqueous Two-Phase System (ATPS) extraction technique. The extraction behavior of Cu(II) e Co(II) was evaluated for the optimization of the method, verifying the influence of the following parameters on the metals extraction: type and concentration of the extractants 1-(2-piridil-azo)-2- naphtol (PAN), 1-nitroso-2-naphtol (1N2N) and bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272); pH (1.00, 6.00 and 11.0); ATPS-forming electrolyte (Na2SO4 or Na3C6H5O7); tie-line length (TLL) of the system and mass ratio between top and bottom phases. The recovery efficiency was evaluated through analyzing the extraction percentage (%E) and separation factor (S) between copper and cobalt. The best conditions for selective extraction were achieved for the L64 + Na2SO4 ATPS, pH = 6.00, TLL = 50.29 % (w/w), mFS/mFI = 1, which presented SCu,Co = 321.6, using PAN as extractant agent. In the following section, the method was applied to a real ion-lithium battery sample, previously leaching with HCl and HNO3 (3:1). After 5 steps of successive extractions it was possible to obtain SCu,Co = 5.4 x 105 . Moreover, a stripping assay was carried out and after one single step, 70.5% of copper was available to a possible electrowinning step.