A continuous crystallization system and method for large particle nickel sulfate

Abstract

The invention discloses a large-grain nickel sulfate continuous crystallization system and method. The continuous crystallization system includes a main crystallizer, a classifier, a cooling unit, a dissolving unit and circulation equipment. The system reduces the number density of crystals in the main crystallizer by setting a fine-grain elimination cycle, and at the same time, the overflow magma is dissolved by the dissolving unit and returned to the crystal bed of the main crystallizer to provide supersaturation for the secondary growth of the remaining crystals. The nickel sulfate crystal obtained by adopting the continuous crystallization method of the present invention has a large particle size, the average particle size can reach more than 1500 μm, the particle size distribution is uniform, and the diameter distance is less than 0.6. Compared with the traditional batch process, it has high production efficiency, low labor intensity, stable product quality, and unit Advantages of low energy consumption.

Description

technical field [0001] The invention belongs to the technical field of industrial crystallization, and in particular relates to a continuous crystallization system and method of large-grain nickel sulfate. Background technique [0002] Nickel sulfate is an important inorganic salt chemical raw material, which is widely used in electroplating, battery materials, semiconductor materials, catalysts, metal coloring and other fields. Nickel sulfate products mainly exist in the form of hydrates, mainly including nickel sulfate hexahydrate and nickel sulfate heptahydrate. Studies have shown that when the temperature is lower than 31.5°C, the obtained crystal is nickel sulfate heptahydrate, and the nickel sulfate obtained above 53°C is β-type nickel sulfate hexahydrate. The performance of β-type nickel sulfate hexahydrate is unstable, and when the temperature is lower than 53°C, it will undergo crystal transformation to the more stable α-type nickel sulfate hexahydrate. The crysta...

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Problems solved by technology

Not only the production efficiency is very low, but also the operation is complicated and the labor intensity of the workers is high

At the same time, the intermittent operation mode also has the disadvantages of wide particle size distribution range, large product differences between batches, and unstable product performance indicators.

[0005] In recent years, some related companies have also directed their research to the continuous crystallization process of nickel sulfate. For example, the invention patent application CN202110167094.1 recently proposed by Huayou Cobalt Co., Ltd. is the latest patent on the continuous crystallization process of nickel sulfate, which records a continuous method of production The crystallization system and crystallization process of nickel sulfate, which introduces the fine-grain elimination cycle to improve the crystal size to a certain extent, realizes continuous production, but due to the relatively simple system structure, it lacks the recovery ratio of fine crystals in the fine-grain elimination cycle and The adjustment method of cutting particle size, and the relationship between dissolution rate and particle size are not considered, resulting in unsatisfactory effects. The average particle size of the product is only 800 μm, and from its attached Figure 4 According to the particle size distribution curve provided, the distribution curve has a trailing peak around 100 μm, and a certain proportion of fine particles are still mixed in the crystal product

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