Process for producing nickel-cobalt salt and ammonium salt through continuous crystallization

Abstract

A process for producing nickel-cobalt salt and ammonium salt through continuous crystallization comprises the following steps: a salt-containing solution is concentrated to be close to a saturated state through a multi-effect evaporation device or an MVR evaporation device, the concentrated salt-containing solution enters a vacuum crystallization tank and then is subjected to flash evaporation cooling, salt crystals are separated out while feed liquid circulates in the vacuum crystallization tank, and slurry is obtained; then the secondary steam generated by the vacuum crystallizing tank exchanges heat with circulating cooling water or chilled water through a surface air cooler to be cooled to obtain condensate water and a small amount of non-condensable steam, and the non-condensable steam is pumped out through a vacuum pump or a steam jet pump; finally, the slurry obtained by the vacuum crystallization tank is pumped to the crystallization buffer tank and then sent to the centrifugalmachine by the crystallization buffer tank, and crystals obtained by centrifugal dehydration are dried by the drying bed to obtain crystal products with uniform granularity.

Description

technical field [0001] The invention belongs to the technical field of inorganic salt crystal production, in particular to a continuous crystallization production process for nickel sulfate, cobalt sulfate, cobalt chloride, ammonium chloride and other salts. Background technique [0002] In industrial production, it is often necessary to obtain crystal products of various inorganic salts, such as nickel sulfate hexahydrate, cobalt sulfate heptahydrate, cobalt chloride hexahydrate, ammonium chloride, etc. For example, the high-purity cobalt sulfate solution extracted by the metallurgical industry needs to go through the crystallization process to obtain the cobalt sulfate heptahydrate crystal product. In the existing production, the batch method is mainly used to obtain cobalt sulfate heptahydrate crystals. The method is mainly that the solution is intermittently cooled and crystallized in a jacketed kettle crystallizer, and then the slurry is intermittently discharged to the...

AI Technical Summary

Problems solved by technology

The existing technical process has the disadvantages of large volume and quantity of crystallizers, large investment in equipment, large floor space, intermittent operation of the system, and low degree of automation.

In addition, there are also nickel sulfate and cobalt sulfate that adopt continuous crystallization process, adopt cooling type internal circulation continuous crystallizer, and obtain magma after heat exchange and cooling with the external cooler of the crystallizer and circulating cooling water. This production method also has a crystallizer structure Complex, external cooler and crystallizer are prone to material blockage, difficult operation and maintenance, etc.

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