Selective extraction and separation of metal values from leach liquor of mixed spent Li-ion batteries

This work describes the extraction and separation of Mn(II), Co(II), Ni(II) and Li(l) from the leach liquor of mixed lithium ion batteries using 0.04 M Na-CYANEX272. Before the extraction step, elimination of some impurities such as Fe(III), Cu(II) and Al (III) was carried out by 20% Acorga M5640 in kerosene with agitation for 5 min at 30 degrees C at equal phase ratio of unity. The effects of the different parameters affecting the extraction rate, such as mixing time, pH, extractant concentration and temperature, were separately investigated. The obtained results indicate that the extraction behavior of the investigated metal ions depends on the pH value, where 91.2% Mn(II), 89.3% Co(II) and 95.6% Ni(II) were extracted at pH 3.5, 5.0 and 8.0, respectively, while the extraction of Li(l) was almost constant regardless of the pH value. Mn(II), Co(II) and Ni(II) were extracted in the organic phase as (MA(2)center dot 3HA)((org)) while Li(I) was extracted as (MA center dot 2HA)((org)). The thermodynamic parameters were calculated by applying Van't Hoff equations. A complete stripping and precipitation from the organic and aqueous phases could be achieved with different stripping and precipitating agents. Precipitates of Mn(II), Ni(II) and Li(l) with purity > 99% could be obtained under the investigated conditions. (C) 2015 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.