| Ammonia/ammonium leaching has become an effective method for recovering copper,nickel and cobalt from oxidized ores,marine manganese nodules and various secondary resources.The chemical properties of copper,nickel and cobalt are similar.These metals can be dissolved into ammonia solution simultaneously by forming metal ammonia complexes.Therefore,an efficient separation method is essential for recovering copper,nickel and cobalt from ammonia medium.Solvent extraction technology is favored for its advantages of simple operation,low energy consumption,solvent selectivity and easy large-scale application.This technology has been successfully applied to the separation and recovery of various metals and plays a key role in the field of hydrometallurgy.The physical and chemical properties of ammonia complex ions of copper,nickel and cobalt are very similar.Commonly used copper extraction reagents not only have excellent extraction performance for copper ammonia complex ions,but also have good extraction performance for nickel and cobalt ions.Therefore,the separation of copper,nickel and cobalt from ammonia solution by solvent extraction is still a recognized technical problem.In this paper,oxime extractant and phosphorus-oxygen extractant were used to form a binary synergistic extraction system.The high efficiency separation of copper,nickel and cobalt in ammonia solution was achieved by using the difference of the intensity of the anti-synergistic effect of the binary extraction system on copper,nickel and cobalt.The specific research contents and conclusions of this paper are summarized as follows:1.The effect of LIX84 extractant on the extraction of copper and nickel was studied.The effects of reaction time,LIX84 concentration,total ammonia concentration and comparison on the extraction of copper and nickel were investigated.The results showed that the extraction kinetics of copper with LIX84 extractant alone was significantly higher than that of nickel,and the extraction equilibrium time of copper was faster than that of nickel.The concentration of total ammonia in solution had little effect on the extraction rate of copper and nickel.2.Highly efficient separation of copper and nickel from ammonia/ammonium chloride media using the LIX84/TBP synergy system.The effects of LIX84 concentration,modifier TBP concentration,extraction equilibrium time,total ammonia concentration,initial concentration of copper and nickel and the extraction and separation of Cu/Ni were studied.Under the optimal extraction conditions,the synergistic system consists of 10 vol.%LIX84 and 4 vol.%TBP,kerosene as diluent,reaction time 2 min,initial copper and nickel concentrations of 2.0 g/L,total ammonia At a concentration of 4.0 mol/L,the extraction rate of copper can reach 99.95%,while the extraction rate of nickel is less than 5.7%,and the separation coefficient of copper and nickel can be as high as 32,766.At the same time,as a comparison,the copper-nickel extraction separation of the LIX84/BESO co-extraction system was studied.The results showed that the antagonism effect of TBP on LIX84 was significantly higher than that of BESO.3.The separation of three kinds of ions of copper,cobalt and nickel in ammonia solution was studied.Since the trivalent cobalt is not extracted by the ketoxime extractant,the divalent cobalt ion in the ammonia solution is oxidized to the trivalent cobalt ion,followed by extraction and separation.The results show that the LIX84 and TBP synergistic system can effectively separate copper and nickel cobalt.The raffinate in the experiment was re-extracted and separated using LEX84,nickel was extracted,and cobalt was left in the raffinate to achieve efficient separation of nickel and cobalt.4.UV(Vis),infrared(FT-IR),1H-NMR,31P-NMR,mass spectrometry,theoretical calculations,etc.The mechanism of separation and separation of copper and nickel by LIX84 and TBP was studied.The hydrogen bond between LIX84/TBP was proved by these analyses. |
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