JPS61151023A - Purification of lithium fluoride complex salt - Google Patents

Abstract

PURPOSE:To improve the purity of lithium fluoride complex salt to the level enabling the use as an electrolyte of high-energy battery, catalyst for organic synthetic reaction, catalyst for polymerization reaction, etc., and to decrease the water-content of the salt, by contacting a crude lithium fluoride complex salt with fluorine gas in an inert gas. CONSTITUTION:A crude complex salt composed of a fluoride of a group III-V element and lithium fluoride is made to contact with fluorine gas at -10-+100 deg.C in an inert gas. The fluoride of the group III-V element of the periodic table is preferably one or more fluorides of B, Si, Ti, Ge, Zr, Sn, P, V, As, Nb, Sb, Ta or Bi. The inert gas is preferably one or more gases selected from hydrogen fluoride, helium, neon, argon, nitrogen, carbon tetrafluoride, sulfur hexafluoride, oxygen difluoride, boron fluoride, nitrogen trifluoride and chlorine pentafluoride.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing lithium fluoride complex salts. It is industrially important as a catalyst in polymerization reactions, a doping agent for semiconductor materials, or as a raw material for these materials.

The present inventors have conducted numerous studies on purification methods for lithium fluoride complex salts, but the biggest drawback of K used in the above-mentioned applications is that lithium fluoride complex salts are highly hygroscopic, and the manufacturing process The quality of the crude lithium fluoride complex salt is degraded due to water entering as impurities from above or during storage and handling.The amount of water varies depending on the operating conditions, but the crude lithium fluoride complex salt may be in the form of crystals, lumps, or powder. When it is a solid, it contains approximately α05 to 1α00% of water in the form of crystallization water or adhering water, and this water is an unpleasant disadvantage when used for various purposes.

Here, the present inventors have developed a novel method for producing a high purity lithium fluoride complex salt.

That is, the present inventors easily and easily reacted by contacting a crude complex salt having a structure consisting of a fluoride of a group 3 to 5 element of the periodic table and lithium fluoride with fluorine at -10 to +100°C in an inert gas. It was discovered that lithium complex salts can be economically selected.

The fluoride of elements from groups 3 to 5 of the periodic table is boron.

Individual ILs of silicon, titanium, zirconium, germanium, tin, phosphorus, vanadium, arsenic, niobium, antimono, tantalum, and bismuth are fluorides of mixtures, but the main nine are necessary components for the above-mentioned uses of the present invention. The fluorides used are boron fluoride, titanium fluoride, and zirconium fluoride.

These include tin fluoride, phosphorus fluoride, arsenic fluoride, and antimony fluoride. There are various kinds of complex salts having a structure consisting of a fluoride of a group 5 or 5 element of the periodic table and a fluorinated techum, and representative ones among them include boron and titanium.

The chemical formula of Zirkoev, tin, phosphorus, arsenic, and antimony compounds in their anhydride form is as follows ((
Become.

Boron compound; LiBF4 Titanium compound; LiTiFs, Lj-*TiFs
, 1. +1sTiFy zirconium compound; LiZr
Fs, Li5bFa, LiaZrFy tin compound;
Li5nF3. Llz5nFa, Li5nFs
.

LixSnFa l Lit 5nTh phosphorus compound;
Li5bFa, Liars arsenic compound HLiAs
F5a, LiA-sFs antimono compound; Li5
bF a # L12SbF5 e Lis 5bFs
.

Li5bsFy, Ia&5bFs, IaaSz
Fs.

Li5bFa, Li super'bF7, Li5bsFsx
.

LizSbFls, LiaSbsFo.

Li5bF! 1g On the other hand, the high purity lithium fluoride complex salt targeted by the present invention is a compound represented by the following chemical formula.

LiBFa, LixSiFs, LitTiFa,
Li5bFa.

LizGeFs, Li, 5nFs, LiPFa,
LiVFa, LiAsF5゜Li5bFas, Li
5bFa, LiTaF5. LiB1. Fs, Li
,zVFy.

LizNbFy, LizSbFy, LizTaFy
, and LizBiFy. Comparing the chemical formula of the former and the latter, there is. Low-order fluorine compounds like nits are not compatible with higher-order fluorine compounds! I''jI!lJ is often contained in crude lithium fluoride complex salts (coarse complex salts) together with the above-mentioned water and oxyfluorine compounds. However, the total amount of these impurities in the coarse salts referred to in the present invention is If the amount of impurities is abnormally greater than 10 weight Tgb, the reaction temperature will be lower than -10 to
It is difficult to maintain a temperature of +100°C, which is not only operationally dangerous, but also causes loss of fluorine, which is not industrially advantageous.

This reaction temperature ranges from -10°C to +100°C, which is the temperature at which high-purity products can be obtained using fluorine in an inert gas without secondary decomposition of the target higher-order fluorine compound. That is, at temperatures below -10°C, the fluorination reaction becomes extremely slow, making it virtually impossible to reduce impurities, and at temperatures above 9100°C, some of the volatile components in the above-mentioned higher fluorine compounds are removed. This tends to cause side reactions such as dissipation, and to the contrary, the purity of the product decreases. Regarding the reaction between impurities in the coarse salt and fluorine, the following reactions occur collectively.

(I) The above-mentioned lower fluorine compound and fluorine cause an addition reaction to improve the content of the higher fluorine compound.

(2) Metal oxyfluorides, gold Ti4 oxides, and basic metal fluorides can be eliminated by fluorination reactions. For example, Mf: MOF is a metal element.

MOF! , Oxyfluoride such as MOF3 is MOF
n + 2 F 2-〉1vLFrl+ 2-1- O
It reacts like F2, and the vft containing 111 elements decreases.

(3) Moisture (adhered water is crystallized water) can be removed by reacting with it as follows.

HzO+ 2F! ->2HF + OF2 Oxygen fluoride is a low boiling point gas (OFg is bp, -145°0.01F
snow is bp, -57°C), which can be easily removed.

The method of the present invention involves contacting a crude complex salt with fluorine,
The reaction source must be controlled at ct''-io to +100°C.Ninth, fluorine is diluted with an inert gas to carry out the solid-gas reaction at an appropriate rate.As the inert gas, These include helium, neon, argon, fluoride ice cream, sulfur hexafluoride, carbon tetrafluoride, ethane hexafluoride, nitrogen trifluoride*, nitrogen, oxygen difluoride, boron fluoride, and chlorine pentafluoride.

In the method of the present invention, solid-gas reactions are carried out under reduced pressure, normal pressure, or increased pressure, and the method is not only a simple flow method or a filling method, but also a fluidized bed method,
The method of the present invention, which can be carried out using a fluidized reactor, a solid mechanical stirring method, or a solid rotary stirring reactor, depends on the amount and concentration of fluorine used, and the type of inert gas. Depending on the properties and reaction conditions, a batch reaction can be achieved within several seconds to several tens of hours. After the reaction is completed, unreacted fluorine can be removed by passing an inert gas through the reaction system. The method □ shown above can be carried out not only in a batch method but also in a continuous method, and the method of the present invention in which a solid and a gas are brought into contact is particularly suitable for a continuous method.

As mentioned above, the highly purified lithium fluoride complex salt purified by the method of the present invention is a highly purified lithium fluoride complex salt, which is highly fluorinated. It is in crystalline or powder form.

If this product is handled with sufficient care, the moisture in the product will be (L02- or less, especially in many cases [1
It is in the range of 00001 to α01- and has a wide range of uses as a substantially anhydrous product. Moisture in products can be quantified by mechanical analysis as well as the Karl Fuscher method.

Furthermore, if there are no impurities mixed in from containers or other handling equipment during the manufacturing process, and if the product is manufactured using a normal synthetic method and the next raw material crude complex salt is used, the purity of the target product will be 99%.
- more than 7, especially in many cases 99.5 to 100%
) lithium complex salt can be obtained.

Next, the technical content regarding the method of the present invention will be explained in more detail with reference to Examples.

It goes without saying that the method of the present invention can be carried out by arbitrarily changing its embodiments without departing from the spirit and spirit thereof.
h5. It goes without saying that the present invention should not be interpreted as being limited to the following examples.

Example 1 Lithium fluoride 545 in a tetrafluoroethylene container
ft, and then 5000jFt of hydrogen fluoride to dissolve it. Boron trifluoride (BF3) gas is passed through the hemorrhoid fluid under slight pressure. Crystals of lithium borofluoride are sufficiently precipitated, and then the gold hydrogen fluoride is distilled off by heating. The obtained crude lithium fluoroborate was 1200 f and contained 0.1% linear moisture. It was placed in a rotary mixer and heated with argon-nitrogen gas at a temperature of 50 to 50°C. Diluted fluorine gas, X (F210%)'t 10
After flowing at 1/hr for 4 hours, dry nitrogen gas t-
It is circulated at 10j/hr for 50 minutes to drive out unreacted fluorine gas. The crystals are then ground in a stream of purified nitrogen and sealed in polytetrafluoroethylene bottles. The purity of the lithium holactide obtained in this way is 99.85%.
The water as an impurity was a high purity product with sp ppm.

Example 2 965- produced by reaction of phosphoric anhydride and hydrogen fluoride
525 ft of lithium hydroxide was added to 2000 ft of 70% hexafluoroline dispersion while stirring while cooling with water. After stirring for about 2 hours after the addition was complete, the reaction mixture was poured into the reactor and the furnace solution was compressed under reduced pressure to obtain a paste. This paste-like material is transferred to a platinum dish and dried under high vacuum to form a white crystal mass (crude lithium hexafluorotetraphosphate (
Li, PFa) was obtained from 1500 to 1401 N'.

This product contains LiJ'OzF 2α1 as an impurity,
HzOQ, 2nd section was included. This material was pulverized, put into a cylindrical stirring and mixing reactor, and passed through fluorine gas (F261) diluted with argon for 9 hours at 10 to 15J for 9 hours. 10! to remove unreacted F2 gas.The thus obtained lithium fluoride is a high-purity lithium hexafluorophosphate containing 96 fluoride appmt''.

Example 3 Hexafluoroarsenic acid TECUM hydrate prepared from hexafluoroarsenic acid hydrate and lithium hydroxide by a conventional method (
Li5bF@・5HzO) t When dried under reduced pressure at 50 to 70°C, a crude complex salt containing 11% of water is obtained. When this crude complex salt was placed in a stirred reactor and treated in the same manner as in Example 2 by passing fluorine gas (F2t 5%) diluted with helium while stirring, high purity lithium hexafluoroarsenate with HzO of 2 ppm was produced. Obtained ratio.

Example 4 Complex salt of antisone trifluoride and potassium fluoride (KSb
Add lithium perchlorate or Tecum water am to fluoroborate to the aqueous solution of F4) to perform double decomposition to prepare a water bath solution of lithium tetrafluoroantimonate, which is then concentrated under reduced pressure to obtain crude tetrafluoroantimony. Bring 1i of lithium oxide (Li5bF4). This product contained some basic salts and water at α2%. The kernel T-501 was put into a rotary reactor and treated in the same manner as in Example 2. Through this treatment, the anti-septane compound is converted into lithium hexafluoroantimonate, and at the same time, water is removed. The obtained lithium hexafluoroantimonate is 99.819 as Li5bF@
It had a purity of 6 Hzo 50 ppm.

As described above, the method of the present invention, which converts a lower fluoride to a higher fluoride and simultaneously removes impurities to obtain a highly purified lithium fluoride complex salt, can be conveniently applied.

Claims (3)

[Claims] (1) Fluorization characterized by contacting a crude complex salt with a structure consisting of a fluoride of a group 3 to 5 element of the periodic table and lithium fluoride with fluorine gas at -10 to +100°C in an inert gas. Purification method of lithium complex salt (2) Fluorides of elements from groups 3 to 5 of the periodic table include boron, silicon, titanium, germanium, zirconium, tin,
Claim (1) which is at least one fluoride selected from the group consisting of fluorides of phosphorus, vanadium, arsenic, niobium, antimony, tantalum, and bismuth.
Purification method of lithium fluoride complex salt described (3) The inert gas consists of hydrogen fluoride gas, helium, neon, argon, nitrogen, carbon tetrafluoride, sulfur hexafluoride, oxygen difluoride, boron fluoride, nitrogen trifluoride, and chlorine pentafluoride. A method for purifying a lithium fluoride complex salt according to claim (1), wherein at least one inert gas selected from the group