Method for producing lithium hexafluorophosphate
View Patent ↗In order to provide a method for producing lithium hexafluorophosphate capable of producing lithium hexafluorophosphate of a higher purity than in the related art without the necessity for after-treatment for removal of impurities, a method is characterized by filtering lithium hexafluorophosphate coexisting with a solvent and then carrying out after-filtering drying in a gas atmosphere containing PF 5 .
1. A method for producing lithium hexafluorophosphate, said method comprising the steps of:
providing lithium hexafluorophosphate in a solvent;
providing a treatment gas atmosphere, said treatment gas atmosphere containing PF 5 ;
filtering said lithium hexafluorophosphate in the presence of said treatment gas atmosphere; and
carrying out post-filtering drying of said lithium hexafluorophosphate in the presence of said treatment gas atmosphere;
wherein a concentration of PF 5 in said gas is in the range of 1 mol % to 50 mol %.
2. The method of claim 1 , wherein PF 5 is present in a ratio of 0.003 KG to 0.3 KG per 1 KG of lithium hexafluorophosphate.
3. The method of claim 2 , wherein the ratio is 0.003 KG to 0.03 KG per 1 KG of lithium hexafluorophosphate.
4. The method of claim 1 , wherein a maximum concentration of impurities contained in said treatment gas atmosphere is 100 parts per billion (ppb).
5. The method of claim 4 , wherein the maximum concentration of impurities is 10 ppb.
6. The method of claim 4 , wherein the impurities include moisture.
7. The method of claim 1 , wherein said treatment gas atmosphere is selected from the group consisting of HF gas, HCl gas, nitrogen gas, argon gas, helium gas, xenon gas, dried air, a gas that does not react with PF 5 and lithium hexafluorophosphate, and any combination thereof.
8. The method of claim 1 , further comprising a step of heating said lithium hexafluorophosphate to 105° C. for a period of 6 hours to 8 hours after carrying out said post-filtering drying.
9. The method of claim 8 , wherein said lithium hexafluorophosphate is heated to 105° C. for a period of 6 hours to 8 hours.
10. A method for producing lithium hexafluorophosphate, said method comprising the steps of:
providing lithium hexafluorophosphate in a solvent;
providing a treatment gas atmosphere, said treatment gas atmosphere containing PF 5 ;
filtering said lithium hexafluorophosphate in the presence of said treatment gas atmosphere; and
carrying out post-filtering drying of said lithium hexafluorophosphate in the presence of said treatment gas atmosphere;
wherein a concentration of PF 5 in said gas atmosphere is in the range of 1 mol % to 10 mol %.