Description

Project Background 

Nickel sulfate is commercially available in three hydration forms: anhydrous nickel sulfate, nickel sulfate hexahydrate (NiSO₄·6H₂O), and nickel sulfate heptahydrate. Among these, nickel sulfate hexahydrate is the preferred product for lithium-ion battery manufacturing due to its high purity and excellent chemical stability.

Based on application requirements, nickel sulfate products are generally classified into electroplating grade and battery grade. With the rapid expansion of the electric vehicle (EV) and energy storage industries, demand for battery-grade nickel sulfate has grown significantly, as it serves as a key raw material for manufacturing ternary cathode precursor materials such as NCM (Nickel-Cobalt-Manganese) and NCA (Nickel-Cobalt-Aluminum).

Different cathode formulations require varying nickel contents, placing increasingly stringent requirements on product purity, trace impurity control, crystal morphology, particle size distribution, and batch-to-batch consistency.

To satisfy these demanding specifications, we provide a dedicated Battery-Grade Nickel Sulfate Hexahydrate Evaporation & Crystallization Plant. The system integrates evaporation, concentration, crystallization, solid-liquid separation, and drying into a complete process solution. Through precise control of supersaturation, temperature profile, residence time, and crystal growth conditions, the plant consistently produces high-purity nickel sulfate hexahydrate crystals with uniform particle size and excellent product quality.

Process Flow Description 

Since the solubility of nickel sulfate increases significantly with temperature, the crystallization process is designed to maximize crystal yield while maintaining excellent crystal quality.

The process consists of the following steps:

Concentration Evaporation

Low-concentration nickel sulfate solution is first concentrated using an energy-efficient evaporator until the required supersaturation level is achieved.

Vacuum Flash Crystallization

The concentrated solution is introduced into a vacuum flash crystallizer, where rapid pressure reduction causes partial evaporation and cooling, inducing controlled crystallization of nickel sulfate hexahydrate.

Slurry Thickening

The crystal slurry is transferred to a thickener to increase solids concentration and recover additional crystals, thereby improving overall product yield.

Centrifugal Separation

The concentrated slurry is fed to a centrifuge for efficient solid-liquid separation, producing wet nickel sulfate hexahydrate crystals while recovering saturated mother liquor for recycling.

Drying

The wet crystals are dried in a vibrating fluidized bed dryer to achieve the specified final moisture content while preserving crystal integrity and minimizing particle breakage.

This optimized process delivers high crystal recovery, excellent product purity, uniform crystal morphology, and stable, energy-efficient operation.

System Configuration 

The complete crystallization plant typically consists of the following equipment:

Energy-Efficient Evaporation System

A Multi-Effect Evaporator (MEE) or Mechanical Vapor Recompression (MVR) Evaporator is selected according to plant capacity, utility availability, and operating cost requirements, ensuring optimum energy efficiency.

Crystallization System

Depending on product specifications, the plant can be equipped with:

• Vacuum flash crystallization

• Cooling crystallization (batch or continuous)

Both configurations provide precise crystal growth control and excellent product quality.

Thickener

Recovers additional crystals from the slurry, increases solids concentration, and maximizes overall nickel recovery.

Centrifuge

Provides high-efficiency solid-liquid separation while minimizing crystal loss and maintaining product quality.

Vibrating Fluidized Bed Dryer

Uniformly dries the wet crystals to the specified moisture content with high thermal efficiency and gentle product handling.

Automated Control System

An advanced PLC/DCS control system continuously monitors and regulates key process parameters, including temperature, pressure, concentration, liquid level, vacuum, and flow rate, to ensure safe, stable, and fully automated plant operation.

System Advantages  

• High-purity battery-grade nickel sulfate hexahydrate production

• Optimized crystal morphology and narrow particle size distribution

• High nickel recovery through efficient mother liquor recycling

• Low energy consumption with MEE or MVR technology

• Fully automated operation with real-time process monitoring

• Stable continuous production with excellent product consistency

• Flexible plant configuration to accommodate different production capacities and process requirements

• Compact layout with low operating and maintenance costs

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