Resources Recycling, Korea University of Science and Technology (UST), Daejeon 34113, Republic of Korea; Mineral Resources Research Division, Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon 34132, Republic of Korea; Research & Product Development, TAE-HYUNG Recycling, Gimcheon-si, Gyoengsangbuk-do 39066, Republic of Korea.
Research & Product Development, TAE-HYUNG Recycling, Gimcheon-si, Gyoengsangbuk-do 39066, Republic of Korea.
Waste Manag. 2018 Oct;80:414-422. doi: 10.1016/j.wasman.2018.09.037. Epub 2018 Oct 3.
The ammoniacal leaching of surface-coated metals from automobile-discarded ABS plastics followed by their recovery through solvent extraction has been investigated. The leaching of ABS (typically containing 4.1% Cu, 1.3% Ni, and 0.03% Cr) could efficiently dissolve the ammine complexes of Cu and Ni, leaving Cr unleached as fine particles. The optimization studies for achieving the maximum efficiency revealed that the leaching of metal ions in different ammoniacal solutions follows the order CO > Cl > SO. The leaching carried out in a carbonate medium by maintaining the total NH concentration 5.0 M at a NHOH/(NH)CO ratio of 4:1, pulp density of 200 g/L, agitation speed of 400 rpm, temperature of 20 °C, and time of 120 min yielded the optimum efficiency of >99% Cu and Ni (i.e., 8.14 g/L and 2.57 g/L, respectively, in the leach liquor). Subsequently, the solvent extraction of metals from ammoniacal leach liquor as a function of extractant (LIX 84-I) concentration and organic-to-aqueous (O:A) phase ratio was examined. Based on the extraction data, a three-stage counter-current extraction at O:A = 1:1 was validated using 0.8 M LIX 84-I, yielding the quantitative extraction of both metals into the organic phase. Thereafter, the stripping of metals in acid solutions indicated that 0.5 M HSO could quantitatively strip Ni from the loaded organic phase; however, ∼27% Cu was also co-stripped. The rest of Cu from the Ni-depleted organic phase was separately stripped with 1.0 M HSO that can be directly sent to the electrowinning process. On the other hand, the co-stripped metals from the acidic solution can be easily separated, again using LIX 84-I as the extractant, by adopting the pH-swing method. Finally, a process has been proposed for the hydrometallurgical recovery of surface-coated metals from waste ABS plastics; that does not affect the physicochemical characteristics of the polymer substances for their reuse.
研究了从汽车报废 ABS 塑料中通过氨浸出表面涂层金属，然后通过溶剂萃取进行回收的方法。氨浸出 ABS（通常含有 4.1%Cu、1.3%Ni 和 0.03%Cr）可以有效地溶解 Cu 和 Ni 的氨络合物，而 Cr 则以细颗粒形式未浸出。为了达到最高效率，对优化研究表明，不同氨水溶液中金属离子的浸出顺序为 CO > Cl > SO。在碳酸盐介质中，通过保持总 NH 浓度为 5.0 M，NHOH/(NH)CO 比例为 4:1、浆体密度为 200 g/L、搅拌速度为 400 rpm、温度为 20°C 和时间为 120 min，Cu 和 Ni 的浸出效率最高，分别为>99%（即浸出液中分别为 8.14 g/L 和 2.57 g/L）。随后，考察了从氨浸出液中萃取金属作为萃取剂（LIX 84-I）浓度和有机相与水相（O:A）相比的函数。根据萃取数据，使用 0.8 M LIX 84-I 验证了三级逆流萃取，O:A=1:1，两种金属均定量萃取到有机相中。然后，在酸性溶液中对金属进行反萃表明，0.5 M HSO 可以定量从负载有机相中反萃 Ni；然而，约 27%的 Cu 也被共反萃。从 Ni 耗尽的有机相中用 1.0 M HSO 分别反萃剩余的 Cu，可直接送入电解过程。另一方面，用 LIX 84-I 作为萃取剂，采用 pH 摆动法，很容易从酸性溶液中分离出共萃金属。最后，提出了一种从废 ABS 塑料中回收表面涂层金属的湿法冶金工艺；该工艺不影响聚合物物质的物理化学特性，可重复使用。
