A new approach to zinc–nickel separation using solution alkalinization method: application to a zinc plant residue

• Published in: Rare metals Vol. 39; no. 11; pp. 1341 - 1347
• Main Authors: Ghomi, Mostafa Aghazadeh, Moghaddam, Javad, Ahmadi, Naghi Parvini
• Format: Journal Article
• Language: English
• Published: Beijing Nonferrous Metals Society of China 01.11.2020; Springer Nature B.V
• Subjects: Biomaterials; Cadmium; Chemical analysis; Chemical precipitation; Chemistry and Materials Science; Energy; Leaching; Materials Engineering; Materials Science; Metallic Materials; Nanoscale Science and Technology; Nickel; Physical Chemistry; Pouring; Precipitates; Residues; Selectivity; Separation; Sodium hydroxide; Washing; Zinc; Precipitation; Nickel; Separation; Alkalinization; Zinc
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-015-0682-3

The present investigation involves the separation of zinc and nickel from a sulfate solution using the acidic leaching of zinc plant residue after cadmium removal step as precursor (42.88 wt% Zn, 8.50 wt% Cd and 2.33 wt% Ni). Separation of nickel from the solution was done by pouring it into a strong alkaline sodium hydroxide solution due to precipitation of nickel hydroxide and conversion of zinc to the soluble Zn ( OH ) 4 2 - complex. Higher degrees of separation were reached by pouring more diluted solutions into the stronger alkaline media. To clear pursue of the process, design of experimental methodology was applied for experiments. Scrutinizing different washing steps on nickel-rich precipitates shows that the washing process decreases zinc content and thereby increases overall selectivity coefficient. Outcomes show that, at the optimized condition, Ni/Zn weight ratio in the solid product becomes about 104 times higher than the initial ratio in the initial feed solution and a nickel concentrate with 29.98 wt% Ni and 5.99 wt% Zn is achieved. At the same time, the chemical analysis of filtrate shows only 4.4 mg·L −1 Ni in the alkaline zinc solution, which means that over 99 % nickel is recovered. The study on changes of zinc concentration with time shows that the process could be completed only after few minutes.