Effect Of Ultrasonic Intervention On Surface Quality Of Nickel Electrolysis

Jinchuan Group Nickel Refining Plant is the largest nickel production scale and mature technology nickel refining plant in China.It adopts the soluble diaphragm electrolysis technology of nickel sulfide anode.Hydrogen produced in the electrolysis process is attached to the cathode plate,resulting in dense pores or dense agglomeration on the surface of nickel plate,which has a serious impact on the surface quality of nickel plate.Therefore,it is necessary to study the removal method and removal effect of hydrogen bubbles in nickel electrolysis process.In this paper,ultrasonic is introduced into the production process of nickel electrolysis to study the removal effect of hydrogen bubbles attached to the surface of nickel plate after ultrasonic intervention.The main contents of the study are as follows :(1)According to the principle of nickel electrolysis and the actual working conditions of industrial production,the trajectory and shape of hydrogen bubbles in the electrolyte are analyzed,and the motion model of hydrogen bubbles in nickel electrolysis is established.The Fluent software is used to simulate the motion of hydrogen bubbles in the electrolyte,and the trajectory and the change of absolute pressure during the rise process are studied.(2)According to the simulation of the movement of hydrogen bubbles in the electrolyte,the sound pressure threshold of hydrogen bubbles separating from the cathode plate or breaking is determined,and the three-dimensional model of the electrolysis device is established.The COMSOL Multiphysics simulation software is used to study the influence of the frequency,power number and installation position of the ultrasonic transducer on the hydrogen bubbles.(3)According to the actual nickel electrolysis production equipment,the ultrasonic generation system,electrolysis simulation system,bubble simulation system and image acquisition system are designed.The experimental platform is built to study the influence of the number of transducers and the installation position of transducers on the trajectory and shape of bubbles when ultrasonic intervention is carried out.n the simulation study,it is found that the frequency,power,number and installation position of the ultrasonic transducer have a great influence on the dehydrogenation effect.When the power of the transducer is the same,the effect of hydrogen removal increases with the decrease of frequency.When the transducer frequency is the same,the hydrogen removal effect increases with the increase of power.When the number of transducers reaches a certain number,the increase of the number of hydrogen removal effect is not obvious.The area of sound pressure greater than the sound pressure threshold is reduced by 68.7% when ultrasonic is installed outside the diaphragm bag,and the hydrogen removal effect is poor.In the nickel electrolysis simulation experiment,the generation of bubbles is inhibited by ultrasonic,and the bubbles appear fusion phenomenon.The fusion phenomenon of bubbles increases with the increase of the number of transducers.Since the attenuation of ultrasonic wave is large when it passes through the diaphragm bag,when the ultrasonic wave is installed outside the diaphragm bag,the shape and trajectory of the bubble are similar to those without the diaphragm bag.The simulation results and experimental results show that the ultrasonic intervention in the production process of nickel electrolysis can inhibit the generation of hydrogen bubbles,prevent the accumulation of hydrogen bubbles,and alleviate the dense pores and dense agglomeration areas caused by the accumulation of hydrogen bubbles.Therefore,the ultrasonic intervention can improve the surface quality of nickel plates caused by hydrogen bubbles.