CN105668538A - Crystallization method of lithium hexafluorophosphate - Google Patents

Abstract

The invention discloses a crystallization method of lithium hexafluorophosphate. The method comprises the following steps: 1) putting mother liquor containing lithium hexafluorophosphate into a sealed crystallization kettle; 2) pumping out the mother liquor in the crystallization kettle by a circulating pump, letting the mother liquor pass a liquid phase circulating tube and finally return to the crystallization kettle; 3) cooling the environment in the crystallization kettle within the cooling range of minus 20- minus 60 DEG C while circulating the mother liquor; and 4) carrying out liquid-solid separation in the crystallization kettle after the above steps so as to obtain a lithium hexafluorophosphate solid. The invention provides a crystallization method of lithium hexafluorophosphate. According to the method, advantages of static crystallization and agitated crystallization are combined, and crystallization efficiency is raised.

Description

A kind of method for crystallising of lithium hexafluoro phosphate

Technical field

The present invention relates to method for crystallising, especially relate to the method for crystallising of a kind of lithium hexafluoro phosphate.

Background technology

Lithium hexafluoro phosphate method for crystallising conventional at present mainly has stationary crystallization and two kinds of methods of stirred crystallization, and two kinds of methods are respectively arranged with merits and demerits. The advantage of stationary crystallization includes: 1, fluohydric acid gas remains static relatively, and stability is better, and safety is higher; 2, crystal speed of separating out is slow, and product and impurity can separate precipitation because of different dissolubility in crystal solution, are beneficial to purity and the quality of finished product. The shortcoming of stationary crystallization includes: 1, need of a sufficiently low temperature, requires higher to freezing, and crystallization time is longer, causes energy resource consumption very big, is unfavorable for cost; 2, the granule that crystallization produces is bigger, it is necessary to physical method is pulverized again, causes that product particle is irregular uniformly, and mobility is poor. The advantage of stirred crystallization includes: 1, stirred crystallization granule is uniform, and product quality is relatively stable; 2, crystallization time is short, and temperature requirement compares that stationary crystallization requirement is low, and energy consumption is less, with short production cycle can be effectively improved production efficiency; The shortcoming of stirred crystallization includes: 1, Fluohydric acid. stirred crystallization, and volatility increases, and can cause that fluohydric acid gas material loss increases; 2, stirred crystallization crystal speed of separating out is very fast, it is possible to can cause that the impurity composition in mother solution precipitates out together, causes that in product, impurity composition is higher. 3, Mixing Machine seals and easily corrodes leakage, maintenance inconvenience, causes that product quality is abnormal.

Summary of the invention

It is an object of the invention to change the defect in tradition lithium hexafluoro phosphate method for crystallising, it is provided that the method for crystallising of a kind of lithium hexafluoro phosphate, the method combines the advantage of stationary crystallization and stirred crystallization, improves crystalline rate.

To achieve these goals, the technical scheme is that the method for crystallising designing a kind of lithium hexafluoro phosphate, it is characterised in that comprise the steps:

1) mother solution containing lithium hexafluoro phosphate is loaded in the crystallization kettle sealed;

2) adopt circulating pump by liquor abstraction in crystallization kettle, and make mother solution pass through liquid phase circulation pipe, finally turn again in crystallization kettle;

3) while circulating mother liquor, crystallization kettle environment being lowered the temperature, cooling scope is at-20 ~-60 DEG C;

4) by above-mentioned steps, produce liquid-solid phase in crystallization kettle and separate, thus obtaining lithium hexafluoro phosphate solid.

Advantages of the present invention and having the beneficial effects that: provide the method for crystallising of a kind of lithium hexafluoro phosphate, the advantage that the method combines stationary crystallization and stirred crystallization, utilize the method for crystallising that liquid self circulation flows, namely equipment remains stationary as, crystal solution self-loopa is allowed by the conveying of pump, whole system is in air-proof condition, it is possible to avoid the volatilizing loss of liquid self circulation process Raw; Flowed by the self-loopa of liquid and can effectively improve heat exchange efficiency, shorten crystallization time, improve production efficiency. Adopt the method that crystal solution method of self-loopa in airtight crystallization kettle instead of tradition stirred crystallization, avoid the material loss caused because of the volatilization of Fluohydric acid. in whipping process, and a large amount of impurity caused because of stirred crystallization precipitate out jointly and the problem such as the corrosion of Mixing Machine. Meanwhile, also solve crystallization time in stationary crystallization long, the problem such as crystal solution poor fluidity.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of the present invention.

Wherein, crystallization kettle 1, crystal solution liquid phase 2, crystal solution solid phase 3, liquid phase circulation pipe 4, circulating pump 5.

Detailed description of the invention

Below in conjunction with drawings and Examples, the specific embodiment of the present invention is further described. Following example are only for clearly illustrating technical scheme, and can not limit the scope of the invention with this.

Embodiment:

The method for crystallising of a kind of lithium hexafluoro phosphate, it is characterised in that comprise the steps:

1) mother solution containing lithium hexafluoro phosphate is loaded in the crystallization kettle 1 sealed;

2) adopt circulating pump 5 by liquor abstraction in crystallization kettle 1, and make mother solution pass through liquid phase circulation pipe 4, finally turn again in crystallization kettle 1;

3) while circulating mother liquor, crystallization kettle 1 environment being lowered the temperature, cooling scope is at-30 DEG C;

4) by above-mentioned steps, producing liquid-solid phase and separate in crystallization kettle 1, respectively crystal solution liquid phase 2 and crystal solution solid phase 3, thus obtaining lithium hexafluoro phosphate solid.

The above is only the preferred embodiment of the present invention; it should be pointed out that, for those skilled in the art, under the premise without departing from the know-why of the present invention; can also making some improvements and modifications, these improvements and modifications also should be regarded as protection scope of the present invention.

Claims (1)

1. the method for crystallising of a lithium hexafluoro phosphate, it is characterised in that comprise the steps:

1) mother solution containing lithium hexafluoro phosphate is loaded in the crystallization kettle sealed;

2) adopt circulating pump by liquor abstraction in crystallization kettle, and make mother solution pass through liquid phase circulation pipe, finally turn again in crystallization kettle;

3) while circulating mother liquor, crystallization kettle environment being lowered the temperature, cooling scope is at-20 ~-60 DEG C;

4) by above-mentioned steps, produce liquid-solid phase in crystallization kettle and separate, thus obtaining lithium hexafluoro phosphate solid.