The Depth Of The Nickel Anode Liquid Copper And Other Impurities Removal

Removing copper from nickel electrolyte solution is a chronic problem in nickel metallurgical field. And it has been listed as national key scientific and technological projects continuously. Researchers have tried a variety of methods, some of which were even carried out in industrial tests. But the problem has not been effectively solved yet. In recent years Jinchuan Group are open to the community for efficiently removing copper. Due to its difficulty, the requirements of copper removal degree has been released from 2×10-3g·L-1 to 3 mg·L-1 and the mass ration of copper to nickel in copper removal residue has also been decreased from 20 to 15.In this paper, the deep separation of nickel and copper has been studied from theoretical and technological aspects with the new reagent of copper removal, NAS,which is synthesized by our research group. The specific contents are as follows:(1) According to the known thermodynamic data, the thermodynamic equilibrium of Cu-Ni-Pb-Zn-Cl-H2O system of nickel anodic electrolyte was calculated. And the c-c[CI]T and c-pH diagrams for Cu-Ni-Pb-Zn-Cl-H2O system were drawn at 298.15K. The results showed that the occurrence states of copper and nickel were free ions and complex cation at pH 4.5 in nickel anodic electrolyte, while lead and zinc existed as complex anions which can be removed by anion exchange resin. In addition, the amount of complex anions of lead and zinc increased with the Cl- concentration, which was beneficial to removing lead and zinc.(2) The thermodynamic equilibrium of removing copper from nickel anodic electrolyte by sulfide precipitation method was calculated according to the known thermodynamic data. And the logc-logc[S] and c-pH diagrams for nickel anodic electrolyte system were plotted at 298.15K. The results showed that copper, as well as part of lead and zinc can be removed from nickel anodic electrolyte by sulfidation method. Additionally, increasing copper concentration, reducing nickel concentration and controlling the adequate pH value were good to copper removal and get a higher Cu/Ni in the precipitation. (3) Results of NAS synthesizing process revealed that pH has little effect on copper removal, and stirring 30 minutes at room temperature was the optimum synthesizing condition.(4) Effects on copper removal with NAS were studied and the influences of NAS on the concentration of trace lead and zinc were investigated. Results showed that the nickel solution after removing iron was the most optimized raw material for preparing NAS, and the concentration of copper in the treated aqueous solution was less than 3 mg·L-1, and the mass ratio of copper to nickel was up to 20 under the following conditions. The dosage of NAS was 1.2 times of the theoretical value, the reaction temperature was 60℃, and the reaction time was 30 minutes. Moreover, the activity of NAS can last for 10 days.(5) Results of the quality of the electronic nickel made from copper removed solution by NAS revealed that there was no bad influence of NAS on the electrolytic nickel.(6) In addition, anion-exchange resins'abilities for absorbing trace lead and zinc from nickel anodic electrolyte were investigated. Results showed that D201 and D363 were beneficial to absorption of micro zinc and lead from nickel anodic electrolyte respectively, but absorption capacities were small. Besides, it was harmful to the removing process at a higher temperature.