盐湖卤水萃取法提锂的工艺中,磷酸三丁酯-FeCl_(3)-煤油协萃体系在多次循环使用后萃取能力会下降甚至失效。将失效锂萃取剂中的Fe(Ⅲ)回收利用对盐湖提锂行业的持续发展具有重要意义。在高浓度盐酸体系中模拟失效锂萃取剂,以其中的Fe(Ⅲ...盐湖卤水萃取法提锂的工艺中,磷酸三丁酯-FeCl_(3)-煤油协萃体系在多次循环使用后萃取能力会下降甚至失效。将失效锂萃取剂中的Fe(Ⅲ)回收利用对盐湖提锂行业的持续发展具有重要意义。在高浓度盐酸体系中模拟失效锂萃取剂,以其中的Fe(Ⅲ)为铁源,NH_(4)H_(2)PO_(4)溶液为磷源,在非均相体系中制备电池级磷酸铁。研究了反应时间、氨水加入量、NH_(4)H_(2)PO_(4)溶液浓度、反应温度和搅拌速率对产品产率、粒径(D_(50))和铁磷物质的量比的影响。结果表明,在优化的工艺条件下,可制得高纯度的单斜晶系二水磷酸铁,产率为89.43%、铁磷物质的量比为0.98、D_(50)为1.81μm、比表面积为37.38 m^(2)/g、含水量为19.64%,符合电池级磷酸铁的行业标准。以自制的磷酸铁为前驱体制备的Li Fe PO_(4)/C性能良好,在0.1C倍率下的首次放电比容量为146.58 m A·h/g,首次充放电效率为94.90%,恒流充放电循环80圈后的容量保持率为91.72%。研究表明,采用NH_(4)H_(2)PO_(4)溶液反萃沉淀法可有效回收失效锂萃取剂中的Fe(Ⅲ)并制备出电池级磷酸铁。展开更多
In order to explore the effect of vacancy defects on the structural,electronic,magnetic and optical properties of CoS_(2) and FeS_(2),first-principles calculation method was used to investigate the alloys.The calculat...In order to explore the effect of vacancy defects on the structural,electronic,magnetic and optical properties of CoS_(2) and FeS_(2),first-principles calculation method was used to investigate the alloys.The calculated results of materials without vacancy are consistent with those reported in the literatures,while the results of materials with vacancy defect were different from those of literatures due to the difference vacancy concentration.The Co vacancy defect hardly changes the half-metallic characteristic of CoS_(2).The Fe vacancy defect changes FeS_(2) from semiconductor to half-metal,and the bottom of the spin-down conduction band changes from the p orbital state of S to the d(t_(2g))orbital state of Fe,while the top of the valence band remains the d orbital d(eg)state of Fe.The half-metallic Co vacancy defects of CoS_(2) and Fe vacancy defects of FeS_(2) are expected to be used in spintronic devices.S vacancy defects make both CoS_(2) and FeS_(2) metallic.Both the Co and S vacancy defects lead to the decrease of the magnetic moment of CoS_(2),while both the Fe and S vacancy defects lead to the obvious magnetic property of FeS_(2).Vacancy defects enhance the absorption coefficient of infrared band and long band of visible light obviously,and produce obvious red shift phenomenon,which is expected to be used in photoelectric devices.展开更多
文摘盐湖卤水萃取法提锂的工艺中,磷酸三丁酯-FeCl_(3)-煤油协萃体系在多次循环使用后萃取能力会下降甚至失效。将失效锂萃取剂中的Fe(Ⅲ)回收利用对盐湖提锂行业的持续发展具有重要意义。在高浓度盐酸体系中模拟失效锂萃取剂,以其中的Fe(Ⅲ)为铁源,NH_(4)H_(2)PO_(4)溶液为磷源,在非均相体系中制备电池级磷酸铁。研究了反应时间、氨水加入量、NH_(4)H_(2)PO_(4)溶液浓度、反应温度和搅拌速率对产品产率、粒径(D_(50))和铁磷物质的量比的影响。结果表明,在优化的工艺条件下,可制得高纯度的单斜晶系二水磷酸铁,产率为89.43%、铁磷物质的量比为0.98、D_(50)为1.81μm、比表面积为37.38 m^(2)/g、含水量为19.64%,符合电池级磷酸铁的行业标准。以自制的磷酸铁为前驱体制备的Li Fe PO_(4)/C性能良好,在0.1C倍率下的首次放电比容量为146.58 m A·h/g,首次充放电效率为94.90%,恒流充放电循环80圈后的容量保持率为91.72%。研究表明,采用NH_(4)H_(2)PO_(4)溶液反萃沉淀法可有效回收失效锂萃取剂中的Fe(Ⅲ)并制备出电池级磷酸铁。
基金Funded by the Scientific and Technologial Innovation Programs of Higher Education Institutions in Shanxi (No. 2020L0628)the Taiyuan Institute of Technology Scientific Research Initial Funding (No. 2022KJ072)+2 种基金the Program for the (Reserved) Discipline Leaders of Taiyuan Institute of Technologythe Fundamental Research Funds for the Central Universities (Nos. 2017TS004, 2017TS006, and GK201704005)Supported by HZWTECH for providing computational facilities
文摘In order to explore the effect of vacancy defects on the structural,electronic,magnetic and optical properties of CoS_(2) and FeS_(2),first-principles calculation method was used to investigate the alloys.The calculated results of materials without vacancy are consistent with those reported in the literatures,while the results of materials with vacancy defect were different from those of literatures due to the difference vacancy concentration.The Co vacancy defect hardly changes the half-metallic characteristic of CoS_(2).The Fe vacancy defect changes FeS_(2) from semiconductor to half-metal,and the bottom of the spin-down conduction band changes from the p orbital state of S to the d(t_(2g))orbital state of Fe,while the top of the valence band remains the d orbital d(eg)state of Fe.The half-metallic Co vacancy defects of CoS_(2) and Fe vacancy defects of FeS_(2) are expected to be used in spintronic devices.S vacancy defects make both CoS_(2) and FeS_(2) metallic.Both the Co and S vacancy defects lead to the decrease of the magnetic moment of CoS_(2),while both the Fe and S vacancy defects lead to the obvious magnetic property of FeS_(2).Vacancy defects enhance the absorption coefficient of infrared band and long band of visible light obviously,and produce obvious red shift phenomenon,which is expected to be used in photoelectric devices.
