Extractive Recovery of Nicke from Hazardous Waste Leaching Solution with the New Synergistic Extraction System
Selective extraction and separation of Ni2+from Mn21,Ca2+and Mg2+were found to be a bottleneck in the resource utilisation of hazardous wastes containing valuable metals.The extraction,washing,and stripping equilibrium pH isotherms of a synergistic extraction system consisting of Mextral 984H/Isononanoic acid were investigated using Aliquat 336 as a modifier.The results shows that at the temperature of 25 ℃,with a volume fraction of Aliquat 336 was 1%and the extraction equilibrium pH of 5.0,the extraction rate of Ni2+was 96.3%.Under the condition of stripping equilibrium pH of 1.0,the stripping rate of Ni2+reaches 97.5%.The modifier Aliquat 336 significantly improve the stripping kinetics of the Hydroxamic acid/carboxylic acid synergistic system for Ni2+.The nickel-loaded organic phase obtained by three-stage countercurrent extraction and two-stage scrubbing process was subjected to three-stage stripping with 150 g/L H2SO4 at O/A=10,and the Ni2+content in the nickel-rich stripping solution is about 30 g/L.The mechanism of Ni2+extraction with Mextral 984H/Isononanoic acid synergistic extraction system is a ion-exchange reaction,and the structure of the Ni-complex is probably the NiA2(HL)2.
synergistic extractionseparation and purificationhazardous wastestripping kineticsnickel extraction