The Formation Mechanism of the Third Phase in Nickel Electrolyte

Document Type

Conference Proceeding

Publication Date



Department of Materials Science and Engineering


The third phase is generated inevitably, but affects the quality of the electric nickel product in the nickel metallurgical process. This paper studies the formation and the prevention mechanism of the third phase in the raffinate. The analysis of Fe-S–Si-H O system shows that iron exists in the form of Fe at the pH value ≤ 2.17. With pH increasing, Fe begins to hydrolyze to form FeOH . FeOH continues to hydrolyze to form Fe(OH) at the pH value ≥ 4.72. Fe is reduced and hydrolyzed to FeOH when the potential ≤ 0.21 V. The precipitation of Fe SiO is reduced at the potential ≤ 0.35 V and 5 ≤ pH value ≤ 13.2 when the solution contains silicon dioxide. The analysis of the third phase shows that it is mainly iron hydroxide, iron polynuclear hydroxyl complex ions, and Fe-SO complexes. It provides theoretical guidance for the formation of the third phase in the extraction multiphase system. This also plays a positive role in the production of high-quality nickel products.

Publication Title

Minerals, Metals and Materials Series