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Purification of Nickel Sulfate by Batch Cooling Crystallization
Author(s) -
Han Bing,
Bøckman Oluf,
Wilson Benjamin P.,
Lundström Mari,
Louhi-Kultanen Marjatta
Publication year - 2019
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.201800695
Subject(s) - crystallization , nickel , sulfuric acid , chemistry , solubility , impurity , sodium sulfate , filter cake , sulfate , sodium , electrowinning , chloride , moisture , magnesium , inorganic chemistry , nuclear chemistry , chromatography , organic chemistry , electrode , electrolyte
Cooling crystallization was successfully carried out in a batch cooling crystallizer from impure acidic solutions to recover nickel as nickel sulfate salt with three different cooling rates. The compositions of the solutions included impurities of sodium, magnesium, chloride, and sulfuric acid to mimic industrial nickel electrowinning process solutions. The results show that NiSO 4 ·6H 2 O mainly crystallized, and its solubility and purity decreased with the increase in the mass ratio of chloride to sulfate. Cooling rates did not have a significant influence on crystal purity; however, it did affect the filter cake moisture; lower moisture can be obtained with a lower cooling rate. The sequence of impurity removal efficiency from high to low was Cl > Na > Mg.