Nickel sulfate crystallizer

Nickel sulfate is an inorganic substance that can be classified into three types: anhydrous (NiSO4), hexahydrate, and heptahydrate. The products are mostly hexahydrate, with two variants: alpha type and beta type. The former is a blue tetragonal crystal, while the latter is a green monoclinic crystal. Six crystal water were lost when heated to 103 ° C. Easy to dissolve in water, slightly soluble in ethanol and methanol, its aqueous solution is acidic, slightly soluble in acid and ammonia water, and toxic. Mainly used in the electroplating industry, it is the main nickel salt for electroplating nickel and chemical nickel, and also the source of metal nickel ions. It can dissociate nickel ions and sulfate ions during the electroplating process.

Working Principle:

The saturated solution of hot nickel sulfate sent from the evaporation and concentration section enters the Oslo vacuum flash evaporator, and is pumped by the circulation pump to the flash chamber. Through vacuum flash evaporation, a portion of the water is evaporated, taking away heat and reducing the temperature of the solution, resulting in supersaturation. It then flows along the downcomer to the bottom of the crystallizer and flows upward through the crystal suspension zone. The crystals in the suspension zone absorb the supersaturation and grow. The supersaturated solution passing through the suspension zone eliminates the supersaturation and continues to flow upward to the clarification zone. The clear liquid is pumped out by the circulation pump and mixed with the incoming solution before being flash evaporated in the flash evaporation chamber. A portion of the clear liquid is discharged through the overflow port to the mother liquor tank.

The nickel sulfate crystals that have grown to the required crystalline particles are discharged from the crystallizer through the discharge pump. Then centrifuge, filter, dry, and package.

The design of the nickel sulfate continuous crystallizer body is in the form of OSLO, without stirring, and belongs to the clear liquid circulation type crystallizer. The nickel sulfate crystallizer is divided into a suspended bed zone and a clarification zone. The supersaturated solution is sent into a suspended bed to promote crystal growth, and the supersaturation of the solution is eliminated. The supernatant is pumped into the heat removal unit by a circulation pump for cooling and temperature reduction. Due to the special structure of the OSLO crystallizer, larger nickel sulfate crystal particles first come into contact with supersaturated solution and preferentially grow and are discharged from the crystallizer. Therefore, the crystals produced by the nickel sulfate crystallizer have the characteristics of large particle size and uniform particle size.