| Cu is widely used,mainly in the fields of electricity,power,electronics,architecture,machinery,manufacturing,and national defense.It ranks second in the consumption of non-ferrous metal materials in my country[1],and Cu is used as An important metal material that has a history of more than 5,000 years and is widely used by humans.The rapid development of industry has led to a sharp increase in the consumption of Cu and its alloys,because Cu has many characteristics and is used in many fields.China's Cu resources cannot meet the needs of the national economy,so it is necessary to develop efficient and pollution-free methods to obtain high-purity Cu,which is of great significance to the sustainable development of the world and my country's Cu resources[2].As a new type of green solvent,eutectic solvent(DESs)has the characteristics of simple preparation,good conductivity,low price and non-toxicity,so it is used as the electrolyte for electrolytic separation of Cu-Ni alloys.This article synthesized choline chloride-ethylene glycol(ChCl-EG)DES,measured the solubility of cuprous chloride(CuCl)and Ni chloride(Ni Cl2)in it,and studied its viscosity and conductivity.It is used as an electrolyte for electrolytic separation of Cu-Ni alloys.Cyclic voltammetry and linear sweep voltammetry were used to study the electrochemical behavior of Cu(I)in CuCl+ChCl-EG DES.In the electrolysis experiment,the influence of current density,electrolyte temperature,CuCl concentration and electrolysis time on the product Cu powder purity,current efficiency and specific energy consumption was studied.The main research results are as follows:(1)The physical property test of CuCl+ChCl-EG DES showed that when the temperature increased from 323 K to 363 K,the solubility of CuCl increased from 0.58mol·L-1 to 2.7 mol·L-1,and the solubility of Ni Cl2·6H2O increase from 0.16 mol·L-1 to0.44 mol·L-1 is due to the increase in the solubility of ChCl-EG DES to non-polar substances due to the increase in temperature.When the temperature increases from323 K to 363 K,the conductivity of CuCl+ChCl-EG DES increases,and its viscosity decreases.When the CuCl concentration increases,the conductivity and viscosity of CuCl+ChCl-EG DES increase accordingly.In the test range of this research,the minimum viscosity of CuCl+ChCl-EG DES is 41.63 m Pa·s,and the maximum conductivity is 27.32 m S·cm-1.(2)The electrochemical test was carried out with a three-electrode system.The cyclic voltammetry test showed that Cu(I)can be reduced to metallic Cu in CuCl+ChCl-EG DES.There is a significant difference between ECu(I)/Cu and lnc Cu(I).The good linear relationship indicates that increasing the concentration of CuCl is beneficial to the reduction of Cu(I)ions on the Ti electrode in CuCl+ChCl-EG DES.The linear sweep voltammetry test shows that the anode dissolution rate and cathode reduction rate of Cu are far greater than those of Ni in all experimental conditions,and increasing the temperature is conducive to the separation of Cu-Ni alloys.(3)In the electrolysis experiment,the influence of current density,reaction temperature,CuCl concentration and electrolysis time on the separation process of Cu and Ni was studied.The study found that when the current density increased from 2m A·cm-2 to 10 m A·cm-2,the current efficiency of electrolytic separation of Cu and Ni increased from 94.76%to 99.21%,and the specific energy consumption increased from48.21 k W·h·t-1 to 249.36 k W·h·t-1.As the reaction temperature increases,the current efficiency increases from 93.78%to 99.89%,while the specific energy consumption decreases from 608.85 k W·h·t-1 to 281.49 k W·h·t-1.When the CuCl concentration increases from 0.5 mol·L-1 to 2.5 mol·L-1,the current efficiency first increases and then decreases,and the specific energy consumption is reversed.When the electrolysis time was extended from 2 h to 6 h,the change trend of current efficiency and specific energy consumption was similar to the effect of different CuCl concentrations.Compared with the reaction temperature,CuCl concentration and electrolysis time,the current density has a more significant impact on current efficiency and specific energy consumption.The microscopic morphology analysis of the product shows that the electrolytic separation of Cu-Ni alloy can obtain irregular bulk Cu powder with a particle size of about 50?m?150?m,and its morphology is mostly dendritic,wheat ear and cauliflower,and the purity is as high as 99.97%.XRD analysis showed that the products were all elemental Cu,and the preferred crystal plane of Cu crystallites was(111),that is,the(111)crystal plane was the main growth direction. |
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