Kinetic study of the dissolution of metallic nickel in sulphuric acid solutions in the presence of different oxidants

Abstract

The dissolution of metallic nickel particles in sulphuric acid solutions has been studied in this work. The effect of temperature, sulphuric acid concentration, and oxidant type has been assessed. In the presence of hydrogen peroxide or dissolved oxygen the dissolution of nickel was fast. A shrinking particle model was used to fit the experimental data and estimate kinetic parameters. The apparent reaction rate constants calculated at 55 °C when dissolved oxygen, ferric sulphate, and hydrogen peroxide were used as oxidants were, respectively, 0.17, 0.02, and 7.13 ms−1. The dissolution of Ni in the presence of ferric sulphate occurred under surface chemical control, with an activation energy of 82.3 kJ/mol, while in the presence of hydrogen peroxide and dissolved oxygen the reaction seemed to have been mass transfer controlled. The dissolution of Ni in ferric sulphate solutions was also pH sensitive, possibly due to the formation of NiFe2O4 or NiO that was prevented when sulphuric acid concentration was 1 mol/L. The dissolution rate in ferric sulphate‐free solutions was affected negatively by temperature due to a decrease in O2 solubility.

Electrochemical deposition of nickel from aqueous electrolytic baths prepared by dissolution of metallic powder

“…1.1 which is similar to 1.2-1.3 reported in [44,46] but less than 3.5 described in [47]. Concentration of the nickel cations in the raw solution prepared by us varies from 1.4 to 1.6 M and is comparable to 1.73 M from [5] but significantly higher than 0.017-0.17 M obtained in [44,46,47]. It is important to note that we did not observe significant differences between electroplating from baths prepared from raw solutions when concentrations of Ni 2+ , H 2 SO 4 and H 2 O 2 were varied within the limits reported above.…”

“…Peroxide-to-nickel molar ratio used in the present work is ca. 1.1 which is similar to 1.2-1.3 reported in [44,46] but less than 3.5 described in [47]. Concentration of the nickel cations in the raw solution prepared by us varies from 1.4 to 1.6 M and is comparable to 1.73 M from [5] but significantly higher than 0.017-0.17 M obtained in [44,46,47].…”

“…Application of a mixture containing H 2 O 2 and a mineral acid (H 2 SO 4 [44,[46][47][48] or HCl [5]) to dissolve metallic Ni has been reported in the earlier literature. Such approach was used for dissolution of powders [5,44,47,48] and crushed electrical circuit boards [46]. This is the first step in preparation of electrolytic baths used for deposition of accelerator targets described in [5,44,48].…”

“…In contrast to [44], we add only a single portion of H 2 O 2 instead of gradual addition of several batches of the peroxide during the dissolution process. We also use a higher concentration of both H 2 SO 4 (2.50 M) and H 2 O 2 (1.63 M) as compared to [44,46,47], where the respective concentrations varies from 0.1 to 2 M for the acid and from 0.06 to 0.22 M for the peroxide. Peroxide-to-nickel molar ratio used in the present work is ca.…”

Design for Recycling Principles Applicable to Selected Clean Energy Technologies: Crystalline-Silicon Photovoltaic Modules, Electric Vehicle Batteries, and Wind Turbine Blades

“…Partial substitution with Cu/Ni is less favorable than total substitution in recycling processes that use leaching, such as FRELP, owing to the additional complexity of handling both Ag and Ni in the leach solution. The presence of Ag makes the mixture unsuitable to alternative and less expensive leaching chemistries [51]. Costs for recycling processes without leaching, such as the hot-knife/Cu smelter process, likely would be less affected by partial or total substitution of Ag with Cu/Ni.…”