The synthesis technique of lithium hexafluorophosphate
Technical field
The present invention relates to a kind of synthesis technique of lithium hexafluoro phosphate, more specifically to a kind of Technology of utilizing the synthetic lithium hexafluoro phosphate of non-aqueous solvent method.
Background technology
Since the eighties in 20th century, lithium ion battery came out,, big as specific energy, self-discharge is little, it is fast to have extended cycle life, discharge and recharge, memory-less effect etc., becomes first-selected high-performance secondary cell because of it possesses many high-performances.
The known electrolytical lithium salts of secondary lithium battery that can be used as comprises LiAsF
6, LiPF
6, LiBF
4, LiClO
4, LiCF
3SO
3, Li (CF
3SO
3)
2N etc., wherein lithium hexafluoro phosphate is used widely commercial because of good comprehensive performances, and output improves day by day.
Lithium hexafluoro phosphate has multiple synthetic method, comprises gas-solid reaction method, organic solvent method, ion exchange method, anhydrous hydrogen fluoride non-aqueous solvent method, have only in the above method success of anhydrous hydrogen fluoride non-aqueous solvent method realization commercially produce.
Although in the method for the synthetic lithium hexafluoro phosphate of anhydrous hydrogen fluoride non-aqueous solvent method several different technology circuits are arranged, but the core process of final synthesis technique has all utilized the reaction of the anhydrous hydrogen fluoride solution of gaseous state phosphorus pentafluoride and lithium fluoride, thus synthetic lithium hexafluoro phosphate product.Traditional gas-liquid synthesis method is utilized the hybrid reaction of liquid-gas interface in the reactor, and mixing efficiency is low, and speed of response is slow.
Summary of the invention
The purpose of this invention is to provide and a kind ofly can improve gas-liquid mixed efficient, thereby improve the synthesis technique of the lithium hexafluorophosphate of speed of response.
For achieving the above object, the present invention adopts following synthesis technique:
The gaseous state phosphorus pentafluoride feeds in the ultramicro air bubble generating unit, after the generation diameter is the microbubble of 0.1~2000 μ m, in reaction unit, react generation lithium hexafluoro phosphate crude product with the lithium fluoride that is dissolved in anhydrous hydrogen fluoride in advance, the lithium hexafluoro phosphate crude product is freezing, separate through equipment for separating liquid from solid again, separating obtained solid transfer is carried out drying treatment to drying installation, obtain the lithium hexafluoro phosphate solid;
The described weight concentration that is dissolved in the lithium fluoride of anhydrous hydrogen fluoride is controlled between 5~25%;
Described lithium hexafluoro phosphate crude product freezing temp is between-30~0 ℃;
Liquid is 50:1~1:50 with the mixed volume ratio of gas in the described reaction unit, and best mixed volume is than being 10:1~1:10.
The present invention has the following advantages:
1, gas-liquid mixed efficient height, speed of response is fast;
2, can not produce the latch up phenomenon of solid product, realize serialization production easily;
3, the solid particulate of Chan Shenging is even, the purity height.
Embodiment
Below in conjunction with embodiment the present invention is further described:
Embodiment 1
In the present embodiment ultramicro air bubble generating unit is arranged on still reaction device inside, add 50 liter weight concentration in the still reaction device in advance and be the anhydrous hydrogen fluoride solution of 15% lithium fluoride, start the ultramicro air bubble generating unit, in the ultramicro air bubble generating unit, feed phosphorus pentafluoride gas, the generation diameter is the bubble about 10 μ m, bubble enters the anhydrous hydrogen fluoride solution afterreaction of lithium fluoride, generate the lithium hexafluoro phosphate crude product, the volume ratio of liquid and gas is 9:1 in the control still reaction device in this process, crude product is cooled to-15 ℃, separates through equipment for separating liquid from solid, mother liquor can be transferred in the still reaction device, proceed the next batch reaction, solid transfer is carried out drying treatment in drying installation, obtain 15 kilograms of lithium hexafluoro phosphate solids, purity 99.8%.
Embodiment 2
The ultramicro air bubble generating unit is arranged on the outside of pipe reaction device in the present embodiment, add 80 liter weight concentration in the pipe reaction device in advance and be the anhydrous hydrogen fluoride solution of 20% lithium fluoride, start the ultramicro air bubble generating unit, and in the ultramicro air bubble generating unit, feed phosphorus pentafluoride gas, the generation diameter is the bubble about 10 μ m, bubble enters in the anhydrous hydrogen fluoride solution of the lithium fluoride in the pipe reaction device, the reaction back generates the lithium hexafluoro phosphate crude product, the volume ratio of liquid and gas is 8:3 in the control tubular type reaction unit in this engineering, crude product is cooled to-28 ℃, separates through equipment for separating liquid from solid, mother liquor can be transferred in the pipe reaction device 2, in order to the next batch reaction, solid product is transferred to and is carried out drying treatment in the drying installation, obtains 35 kilograms of lithium hexafluoro phosphate solids, purity 99.8%.
When in actual production, adopting synthesis technique of the present invention, the ultramicro air bubble generating unit both can be arranged on the outside of reaction unit, also can be arranged on the inside of reaction unit, and described reaction unit can be in pipe reaction device, still reaction device, tower-type reaction device, the tubular reactor any.