Purification of Nickel Sulfate by Batch Cooling Crystallization

Abstract

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 Á6H 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.

The Effect of Reaction Conditions and Presence of Magnesium on the Crystallization of Nickel Sulfate

“…Nickel is an important component in a wide range of materials such as stainless steel, nickel-or copper-based alloys and catalysts, crystal UV-filters, and the cathode of ion batteries [1][2][3][4]. Among these, nickel containing electric vehicle batteries (EVBs) has seen a dramatic increase in production over the last decade as a result of the environmental targets set by, amongst others, the EU [5,6].…”

“…Nickel can be recycled from various sources such as spent batteries, spent catalysts, or from process streams in the hydrometallurgical industry [4,[9][10][11]. In industrial hydrometallurgical production by electrowinning, nickel metal is produced from an electrolyte solution of nickel sulfate.…”

“…For this purpose, crystallization exper seeded with α-NSH6 are employed as a strategy to control the precipitation pr Among the nickel sulfate phases shown in Figure 1 that can be precipitated in the mined experimental range, α-NSH6 is preferred due to its lower water content a higher stability in storage conditions. The effects of magnesium on the crystallizatio stability of nickel sulfate is investigated due to earlier work showing high levels of u and possible incorporation of magnesium in the crystal bulk [4,26]. Finally, stab precipitated crystals both in solution and in dry state is followed, which can have pr implications on the recovery and storage of nickel salts.…”

Crystallization of nickel sulfate and its purification process: towards efficient production of nickel-rich cathode materials for lithium-ion batteries

“…11 Thus, several alternative approaches for nickel sulfate crystallization have been proposed, which include eutectic freeze crystallization, cooling crystallization, and antisolvent crystallization. 5,12 However, none of them have been applied in the industry due to their limited empirical data to ensure efficient production of NiSO 4 ·6H 2 O and their requirement for additional solvents/reactions. Despite the drawbacks of the conventional evaporative crystallization method, it has the advantage of a relatively high crystal growth rate, well-established procedures, and no requirement for additional solvents/reactions.…”

High Purity Nickel Recovery from an Industrial Sidestream Using Concentration and Liquid–Liquid Extraction Techniques

“…It has been previously reported that nickel recovery from industrial sidestreams can be achieved by a number of hydrometallurgical-based routes such as chemical precipitation, 4,5 ion exchange, 6,7 membrane technology, 8 solvent extraction, 9,10 cooling crystallization 11,12 and electrowinning. 13,14 Of these, solvent extraction (SX) has become established as a commercially viable industrial-scale unit process that allows nickel capture.…”