Study On Synthesis And Extraction Performance Of Calix [4] Arene Containing Pyridyl As A New Extractant

With the depletion of primary Ni,Co,Mn,Li and the vigorous promotion and popularization of new energy industry,the efficient recovery and comprehensive utilization of spent lithium-ion battery is of great significance to make up for the shortage of resources and environment protection.Wet recycling is the mainstream technology due to high metal recovery rate and good quality of recycled products.In wet-process factories,there is an impurity removal process before recovering valuable metal Ni/Co,Al³⁺and Fe³⁺are completely removed by Na OH neutralization（final p H=4.5～5）,while Mn²⁺,Zn²⁺,Ca²⁺and Cu²⁺are deeply extracted by D2EHPA and then gradually stripped（for manganese recovery）.However,in the actual industrialization process,the phenomenon of co-extraction of Ni/Co by D2EHPA is serious,which leads to greater consumption of related reagents and environmental pollution.Therefore,it is urgent to develop a more economical,environmentally friendly and efficient extraction system.Based on the strong coordination between pyridine groups and sulfur atoms for transition metals,this paper introduces pyridine functional groups and S atoms into calixarene matrix to synthesize ortho-pyridyl calix[4]arene（TPC[4]）,para-pyridyl calix[4]arene,dicarboxylate calix[4]arene,p-tert-butylthiocalix[4]arene and pyridyl-containing p-tert-butylthiocalix[4]arene.The subsequent ortho-pyridyl calix[4]arene（TPC[4]）was selected as the optimum,and its extraction effect in deep impurity removal of spent lithium-ion batteries was systematically studied.To reduce the reagent consumption,wastewater discharge,and production cost of Mn²⁺recovery and impurities(Zn²⁺/Cu²⁺/Ca²⁺)removal from the acid leaching solution of spent LIBs,a mixed extractant（TPC[4]+D2EHPA）was synthesized and the extraction performance for Mn²⁺and impurities was systematically investigated.The synthesis experimental results demonstrated that TPC[4]can be synthesized in a simple and high yield way with cheap raw materials.Extraction tests indicated that the separation coefficients of Mn²⁺,Cu²⁺,and Zn²⁺to Ni²⁺and Co²⁺by D2EHPA were significantly enlarged by the addition of TPC[4],which can mainly be attributed to the enhancement in difference of binding ability for cationic complexes with different size.Furthermore,the loading capacity of Mn²⁺and impurities(Cu²⁺,Zn²⁺)was also enlarged and the stripping of these cations could easily be achieved with dilute acid.Compared with traditional Mn²⁺and impurities extraction process that with D2EHPA alone,the addition of TPC[4]saved about 10.36%of the saponification alkali（Na OH）,10.36%washing acid（H₂SO₄）,～20%washing water,and more than 4.56%of organic loss.From both the economic and environmental perspectives,the mixed solvent of D2EHPA+TPC[4]exhibited an excellent application prospect.