Lithium hexafluorophosphate process for - Lithium - Ion Battery Equipment

Lithium hexafluorophosphate process for lithium battery -Lithium - Ion Battery Equipment

At present, domestic mainstream LiPF6 manufacturers mainly use HF solvent method, but they have their own characteristics in the specific process.

1. Dofluoro Chemical Co., Ltd

Dofluoropoly Chemical Co., Ltd. has invented a double kettle HF solvent method to prepare LiPF6, and the process is shown in Figure 4. First, PCl5 reacts with anhydrous HF to obtain the mixed solution of PF5 and anhydrous HF, then prepare the anhydrous HF solution of LiF, add it to the mixed solution, and obtain high-purity LiPF6 crystals through reaction, crystallization, separation and drying.

Anhydrous HF slowly reacts with PCl5 at – 20~– 30 ℃ to generate PF5 and HCl gas, which is cooled to – 40 ℃ and then enters the surge tank. PF5 gas reacts with LiF – HF solution in 1 # reactor to obtain LiPF6. The generated by-product HCl gas, excess PF5 and a small amount of nitrogen enter 2 # reactor, and PF5 continues to react with LiF to generate LiPF6. After the reaction, HCl gas is discharged from the top of 2 # reactor. A small amount of HF gas mixed with it can be removed by deep condensation, and industrial hydrochloric acid solution is obtained through the two-stage absorption system of double reactors. The residual liquid mixture in the reactor is transported to the crystallization tank, and the LiPF6 product is obtained after crystallization, washing and drying. The dried HF is refined by the recovery tower and then enters the LiF preparation kettle for recycling.(Lithium - Ion Battery Equipment)

Advantages of this preparation process: using the principle of chemical balance, a double kettle series circulation operation is introduced in the preparation process of LiPF6, so that the liquid lithium hydrogen fluoride can fully react with the gas PF5, and the gas and liquid can react homogeneously. At the same time, the addition of lithium hydrogen fluoride can also play the role of air flow stirring, accelerate the reaction rate, and improve the element conversion rate.

2. LiPF6 preparation process of Tianci High tech Materials Co., Ltd

Tianci High tech Materials Co., Ltd. has developed a process for preparing alkali metal hexafluorophosphate. The process can be simply summarized as follows: PF5 gas and LiF solution are metered, mixed and reacted in a microchannel reactor, and the reaction solution is crystallized and dried to produce LiPF6. Firstly, LiF with a mass ratio of 1:4 and anhydrous HF are introduced to generate HF solution of LiF, and then PF5 gas and LiF solution are respectively pumped into the microchannel mixer module with a metering pump for mixing (molar ratio of 1:1). The reaction time is 30s and the reaction temperature is – 10 ℃. The reaction product is filtered out of the reaction equipment, evaporated, crystallized, filtered, heated and dried at 50 ℃ to obtain LiPF6 product, and the yield can reach 96.2%.

The advantages of this preparation process: the microchannel reactor is used for mixing, the reaction time is shortened, the efficiency is significantly improved, and the need for additional devices in conventional batch reaction and leakage in transfer are avoided, so the safety is improved.

3. Jiujiujiu Technology Co., Ltd. LiPF6 preparation process

Jiujiujiu Technology Co., Ltd. has developed a closed loop reaction equipment, and the LiPF6 produced is subject to atomization drying treatment. Solvents and solutes are easy to be separated effectively, with high separation efficiency and low energy consumption. Continuous and automatic production can be realized. The specific process is shown in Figure 5.

LiPF6 and other reaction products are pumped to the dryer for atomization, and flow from top to bottom along the spraying direction from the top of the dryer. The temperature in the dryer increases gradually from top to bottom. During the solution flow, anhydrous HF gas is continuously separated from the solution until there is no HF gas in the solution. The anhydrous HF gas flows out through the top of the dryer, part of it flows into PF5 reactor I, and the other part flows into anhydrous HF condenser I to form anhydrous HF liquid, which is returned to reaction equipment III as reaction solvent after metering. The anhydrous HF gas flowing into PF5 reaction equipment II reacts with PCl5 to obtain PF5 and HCl gas. The reaction products in reaction equipment II slowly flow into reaction equipment III to ensure excessive PF5. HCl gas is collected in the tail gas absorption device to prepare hydrochloric acid. The utilization efficiency of each reaction product is high.

The traditional production process of LiPF6 is complex, and the synthesis, crystallization and other links are dangerous, so it is difficult to achieve continuous and automatic production. This process provides a high-quality, safe and environment-friendly production method of LiPF6.



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