Reasons for Controlling Nickel Ion Concentration in Catholyte

The concentration of nickel ions in the solution has a great influence on the precipitation potential of nickel at the cathode. In order to obtain products with higher purity, there are very high requirements for the concentration in production. The following editor will briefly talk about the control of nickel ions in the catholyte. because of the concentration.

If the nickel ion concentration is too low, it will promote the precipitation of hydrogen at the cathode, which will lead to the local pH increase in the cathode area, resulting in the formation of Ni(OH)2 precipitation, which will affect the quality of the product; if the nickel ion concentration is too high, the grains of the nickel plate will be rough and the surface The formation of pimples, of course, the high concentration of nickel ions is also uneconomical.

In order to ensure product quality during production, the electrowinning production current will be flexibly adjusted according to the different nickel ion concentration to achieve a reasonable balance point, avoiding high current control, low nickel ion or low current, and high nickel ion. The surface of the electrodeposited nickel has long pores or granules, which will affect the quality of the product.

The production process must be operated in strict accordance with the requirements, the concentration can be slightly deviated but not too different, to prevent the product quality from being affected due to the mismatch between the current and the main metal concentration.

Although the harmful impurity ions in the nickel salt aqueous electrolyte can be removed as much as possible by chemical methods, the hydrogen ions in it will always exist, and it is precisely because of this that the cathode process of nickel electrolysis becomes more complicated. During the solution, hydrogen ions will be desorbed from the catholyte earlier than nickel, and a large number of pores will be formed on the surface of the electrodeposited nickel. When the pH is high, Ni(OH)2 will be precipitated, resulting in insufficient cathode nickel. Dense. Therefore, the pH value of the catholyte must be strictly controlled according to the relevant operating requirements, and the pH value during production is generally controlled at around pH 3.03.8.