Electrochemical Extraction of Nickel from Methanesulfonate Solution in the Presence of Sodium Cumenesulfonate

The work is devoted to solving an urgent scientific and practical problem involving the processing of nickel-containing heat-resistant alloys, with the extraction of nickel via electroextraction from leaching solutions. Nickel is one of the strategically important metals that are widely used in the defense-industrial complex, and its secondary use is of priority importance due to the limited natural resources and the high cost of primary production. The high purity of the nickel obtained from the processing of heat-resistant alloy waste is achieved through the use of electrochemical methods to extract the metal from leaching solutions. In the work, a new methanesulfonate solution was used as the leaching medium. Electrochemically deposited nickel is characterized by significant internal tensile stresses, which can cause its delamination from the cathode surface. The work established that the formation of nickel deposits with a reduced level of internal stresses requires the use of sulfur-containing organic modifiers. During their electrochemical decomposition on the surface of the nickel electrode, sulfur is incorporated into the deposit in concentrations close to the maximum permissible, which ensures an effective reduction in internal stresses due to the formation of a solid solution of sulfur in nickel. At the same time, the content of hydrocarbon decomposition products of additives in the coating should be minimized. It has been shown that the addition of sodium cumenesulfonate to a methanesulfonate solution in an amount of 10 mmol/l reduces the internal stresses of nickel to almost zero. It was found that in the methanesulfonate solution there is a wider range of current densities in which nickel can be deposited with constant internal stress values compared to the sulfate solution.