Research On The Removal Of Iron And The Corrosion Characteristics Of Alloy Anodes During The Treatment Of Copper-based Alloy Scraps

With the continuous development of industrial society and the exploitation and utilization of copper resources,China's copper-rich resources are gradually reduced,so it is increasingly necessary to recover copper and valuable metals from secondary copper scrap.The use of copper as a matrix,adding some alloying elements to the inside to form an alloy can significantly improve the mechanical properties and corrosion resistance of copper-based alloys and is widely used,but due to the limitation of service life,fatigue damage after a certain number of years of use Can not meet certain mechanical properties and other requirements and gradually eliminated,so in the modernized industrial development of the modern society,will inevitably continue to accumulate this copper alloy scrap.In the past,people also continued to explore ways to recover copper alloy scrap.Santos et al.studied the direct recovery of copper from the circuit board in the acid copper sulfate system by the electrodeposition industry,and achieved good experimental results.The recovery rate of copper reached 96%.Our team's Wang Fei brother studied the direct electrolysis of copper-nickel alloy,and directly electrolyzed the copper-nickel alloy,and the quality of the obtained electrolytic copper was 99.96%.Direct electrolysis has many advantages,but when the iron content in the copper-based alloy scrap is relatively high,it causes problems such as a decrease in current efficiency and an increase in acidity consumption in the electrolysis process.In view of the effective recovery of copper-based alloy scraps,two aspects have been studied in this paper: The first aspect is to discuss the iron removal effect and copper recovery rate of different process conditions when removing iron from copper-based alloy scrap by pyrolysis slag.Impact.In the second aspect,the effect of heat treatment mechanism on the electrochemical corrosion behavior of copper-nickel alloys was investigated.Firstly,the effect of slag-based slag on the iron removal effect of copper-based alloys was studied.The effects of main parameters such as aeration rate,oxidization slag temperature,aeration time and slag-forming agent SiO2 on the iron removal effect were investigated.It was found that when the oxygen permeation amount is low,the iron in the copper-based alloy scrap cannot be completely oxidized,and the effect of removing iron is general.When the oxygen is introduced too much,the oxidation loss of copper is caused.In addition,the amount of slagging agent added will also affect the iron removal effect.When the slag forming agent is added in a small amount,the remaining FeO can not achieve the purpose of oxidizing slag,and can not achieve the ideal iron removal effect.When the slag forming agent is added If the amount is too much,the slag viscosity will be too high,which is not conducive to the separation of the slag phase and the metal phase.At the same time,the increase of temperature can reduce the viscosity of the slag,which is beneficial to the separation of the slag phase and the metal phase,and the mechanical entrainment loss of copper in the slag phase is reduced.According to the experiment,the oxygen content is 40ml/min,the oxidation slag temperature is 1673 K,the oxidation time is 8min,and the slag-forming agent SiO2 is added at 2.17wt%.The metal phase iron content is reduced to 0.003wt% or less.The loss rate fell to 1.14%.The iron content in the metal phase satisfies the iron content of the anode copper.Secondly,the electrochemical corrosion behavior of copper-nickel-based alloys at different temperatures was investigated.The copper-nickel-based alloy was heat treated at four different temperatures(cast,200?,500?and 800?),mainly to study the effect of heat treatment on the microstructure of the alloy,which in turn affected the electrochemical corrosion behavior of the alloy.It can be found through experiments that as the heat treatment temperature increases,the grain size of the alloy becomes larger.It can also be found by the polarization curve and impedance test that the copper-nickel-based alloy is more susceptible to corrosion at higher heat treatment temperatures.From the acidity test results,it was found that when the sulfuric acid content in the copper sulfate solution was increased from 0g/L to 160g/L,the electrochemical dissolution rate of nickel white copper in the solution was also gradually increased.It can be seen from the calculation of Arrhenius formula that the activation energy of nickel white copper in the dissolution process of copper electrolysis system is 31kJ/mol,indicating that the dissolution process of nickel white copper alloy is a diffusion control process.