JP2017178662A - Sodium transition metal group 2 metal fluorophosphate compound and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alkali transition metal group 2 metal fluorophosphate compound in which an alkali metal element, a group 2 metal element and a transition metal element are cations, and a phosphate ion and a fluoride ion are anions. It is an object to provide a manufacturing method thereof. SOLUTION: A general formula Na2 (AxBy) PO4F (where x is a numerical value in a range of 0 <x <1, y is a numerical value in a range of 0 <y <1, and y = 1-x is satisfied. A is a transition metal element selected from Mn, Fe, Co, and Ni, and includes one or more transition metal elements. B is Mg and / or Ca.) Sodium transition Group 2 metal fluorophosphate compound. And a sodium raw material, a transition metal raw material, a Group 2 metal raw material, a fluorine raw material and a reducing agent are reacted in water at 100 to 200 ° C. to produce the above alkali transition metal Group 2 metal fluorophosphate compound. Provide a way. [Selection diagram]

Description

  The present invention is useful for applications such as solid electrolytes, secondary battery positive electrode materials, negative electrode materials and catalysts, and uses alkali metal elements, transition metal elements, and group 2 metal elements as cations, and phosphate ions and fluoride ions. The present invention relates to an alkali transition metal group 2 metal fluorophosphate compound used as an ion and a method for producing the same.

  Alkali transition metal fluorophosphate compounds are expected to be used for various applications such as solid electrolytes, positive electrode active materials for secondary batteries, negative electrode materials and catalysts. In particular, large secondary batteries that are assumed to be used in automobiles and road leveling have high expectations for sodium (Na) secondary batteries that have high cost requirements and low resource limitations. However, the Na secondary battery has a problem that the voltage is lower than that of the lithium (Li) secondary battery and the energy density is inferior.

As means for solving this problem, an alkali transition in which the alkali metal (A) of the alkali transition metal phosphate compound-based positive electrode material LiFePO ₄ used in the Li secondary battery is further added to double the theoretical electric capacity. Metal fluorophosphate compounds M ¹ ₂ M ² PO ₄ F (M ¹ = Li, Na.M ² = Mn, Fe) have been reported.

However, in the conventional synthesis method, a fluorine raw material such as sodium fluoride (NaF) or ammonium fluoride (NH ₄ F) is added to the alkali transition metal phosphate compound so as to achieve a condition of hermetic firing at a high temperature of 1000 ° C. or higher. There was a problem that fluorine eroded the crucible wall and the like strongly (for example, see Patent Document 1). In order to solve the erosion of fluorine on the crucible wall or the like, a two-stage method is proposed in which the raw material is mixed and pulverized by a ball mill and then further fired at a low temperature at 300 ° C. (see, for example, Patent Document 2). There is a problem in cost because expensive raw materials such as salt are used.

  Moreover, the product manufactured by high temperature baking also has the problem that a specific surface area becomes small, and the product by which low temperature baking was carried out also had the problem that crystallinity was low and it was inferior to stability. Furthermore, the sodium manganese fluorophosphate compound has a problem that it is difficult to exchange electrons at the positive electrode, and the ability as a battery positive electrode material is low.

  Furthermore, in the firing method using solid mixing as described above, it is difficult to maintain the composition of the composite because decomposition of phosphate due to heating and heat dissipation of fluoride are likely to occur. An additive element useful for maintaining charge / discharge stability and reversibility cannot be introduced, and is not suitable for production of a fluorophosphate compound.

  As described above, although the alkali transition metal fluorophosphate compound is highly useful, in order to solve the problems in the production conditions, the alkali transition metal fluorophosphate compound having more excellent battery reactivity and stability. There is a need for a production method under low temperature conditions.

JP2012-204307 JP2013-69653A

  INDUSTRIAL APPLICABILITY The present invention is an alkaline transition metal group 2 having an electron-accepting ability useful as a battery positive electrode material and having an alkali metal element, a group 2 metal element and a transition metal element as cations and phosphate ions and fluoride ions as anions. It aims at providing a metal fluorophosphate compound and its manufacturing method.

  As a result of intensive studies to achieve the above object, the present inventors have found a novel sodium transition metal group 2 metal fluorophosphate compound that solves the above problems and a method for producing the same, and complete the present invention. It came to.

That is, the present invention relates to the general formula Na ₂ (A _x B _y ) PO ₄ F (where x is a numerical value in the range of 0 <x <1 and y is a numerical value in the range of 0 <y <1. , Y = 1−x, A is a transition metal element selected from Mn, Fe, Co, and Ni, and includes a single or two or more kinds of transition metal elements, and B is Mg and / or Ca. ) Is a sodium transition metal group 2 metal fluorophosphate compound and a method for producing the same.

  The present invention will be described in detail below.

The general formula Na ₂ (A _x B _y ) PO ₄ F according to the present invention (where x is a numerical value in the range of 0 <x <1, y is a numerical value in the range of 0 <y <1, y = 1−x, A is a transition metal element selected from Mn, Fe, Co, and Ni, and includes a single or two or more kinds of transition metal elements, and B is Mg and / or Ca. The sodium transition metal group 2 metal fluorophosphate compound represented by) is a solid solution in which a part of the transition metal is replaced with a group 2 metal of the periodic table. Specifically, Na ₂ (Mn, Fe, Mg) PO ₄ F, Na ₂ (Mn, Fe, Mg, Ca) PO ₄ F, Na ₂ (Mn, Co, Ca) PO ₄ F, Na ₂ (Mn , Fe, Ca) PO ₄ F, Na ₂ (Mn, Fe, Co, Mg) PO ₄ F, Na ₂ (Mn, Fe, Co, Ni, Mg) PO ₄ F, Na ₂ (Mn, Fe, Ca) Examples thereof include solid solutions such as PO ₄ F, Na ₂ (Fe, Co, Mg, Ca) PO ₄ F, among which Na ₂ (Mn, Fe, Mg) PO ₄ F, Na ₂ (Mn, Fe, Mg, Ca) PO ₄ F, Na ₂ (Mn, Co, Ca) PO ₄ F, Na ₂ (Mn, Fe, Ca) PO ₄ F, Na ₂ (Mn, Fe, Co, Mg) PO ₄ F, Na ₂ ( _{Mn, Fe, Ca) PO 4} F, Na 2 (Fe, Co, Mg, Ca) PO F is preferred will now be described in detail a method for manufacturing the alkali transition metal Group 2 metal fluorophosphate compound.

The alkali transition metal group 2 metal fluorophosphate compound represented by the general formula Na ₂ (A _x B _y ) PO ₄ F is composed of a sodium material, a phosphoric acid material, a transition metal material, a group 2 metal material, a fluorine material, and It can manufacture by making a reducing agent react at 100-200 degreeC in water.

  Examples of the sodium raw material include sodium hydroxide, sodium sulfate, sodium nitrate, sodium carbonate and the like. Examples of the phosphoric acid raw material include phosphoric acid, pyrophosphoric acid, hexametaphosphoric acid and the like. Moreover, a sodium phosphate salt can be used as both a sodium raw material and a phosphoric acid raw material, In this case, sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, etc. are mentioned. Among sodium raw materials and phosphoric acid raw materials, trisodium phosphate and disodium hydrogen phosphate are preferable.

  Examples of transition metal materials include sulfates such as manganese sulfate, iron sulfate, cobalt sulfate and nickel sulfate, nitrates such as manganese nitrate, iron nitrate, cobalt nitrate and nickel nitrate, manganese chloride, iron chloride, cobalt chloride and nickel chloride. A chloride etc. are mentioned, Among these, manganese sulfate, iron sulfate, cobalt sulfate, and iron chloride are preferable.

  Group 2 metal raw materials include hydroxides such as magnesium hydroxide and calcium hydroxide, chlorides such as magnesium chloride and calcium chloride, phosphates such as magnesium hydrogen phosphate and calcium hydrogen phosphate, or magnesium sulfate and sulfuric acid. Examples thereof include sulfates such as calcium, among which calcium hydroxide, magnesium chloride, calcium chloride, magnesium hydrogen phosphate, calcium hydrogen phosphate, and magnesium sulfate are preferable, and magnesium hydrogen phosphate and calcium hydrogen phosphate are particularly preferable. preferable.

  Examples of the fluorine raw material include sodium fluoride, potassium fluoride, and ammonium fluoride. Among them, sodium fluoride and potassium fluoride are preferable.

  Examples of the reducing agent include oxalic acid, ascorbic acid, sulfurous acid, sodium sulfite, thiosulfuric acid, sodium thiosulfate, sodium monosulfide, hydrazine, and the like. Among these, oxalic acid, sodium sulfite, sodium thiosulfate, and hydrazine are preferable. These may be used singly or in combination of two or more.

  In the method for producing an alkali transition metal group 2 metal fluorophosphate compound of the present invention, it is particularly preferable to use a production method according to the reaction formula represented by the formula (1).

Contains two or more transition metal elements. B is Mg and / or Ca. x is a category of 0 <x <1 (wherein A is a transition metal element selected from Mn, Fe, Co and Ni, and is a single or surrounding numerical value, and y is 0 <y <1 (The numerical value of the range, y = 1−x.)
In the production method of the present invention, sodium ions, group 2 metal ions, phosphate ions, transition metal ions, and fluoride ions when the sodium material, phosphate material, transition metal material, group 2 metal material and fluorine material are mixed. There is no particular limitation on the molar ratio. More preferably, it is more preferably 1 to 2 mol of phosphate ions, 2 to 5 mol of sodium ions, 0 to 1 mol of group 2 metal ions, and 1 to 4 mol or more of fluoride ions with respect to 1 mol of transition metal ions. The battery reactivity and stability can be improved by appropriately adjusting the charging ratio of each raw material so as to be 1 to 1.25 mol of phosphate ions, 1 to 2 mol of fluoride ions and 2 to 2.5 mol of sodium ions. An excellent alkali transition metal group 2 metal fluorophosphate (1) can be produced. The reducing agent is charged so that the reduction equivalent is preferably in the range of 0.5 mol to 1.5 mol, more preferably in the range of 0.8 mol to 1.2 mol, with respect to 1 mol of the transition metal ion. By adjusting the ratio, the alkali transition metal fluorophosphate (1) having excellent battery reactivity and stability can be produced. .

  These raw materials are dissolved or dispersed in water for production. The weight of water to be used is preferably 0.5 to 5 times, particularly preferably 1 to 3 times the weight of sodium raw material, phosphoric acid raw material, transition metal raw material, group 2 metal raw material, fluorine raw material and reducing agent.

  The production method of the present invention is preferably carried out at a pH of 7 or more, particularly preferably 7-12.

  The reaction temperature in the manufacturing method of this invention is 100-200 degreeC, Preferably it is 120-180 degreeC. The reaction time is preferably 5 hours or more, more preferably 5 to 20 hours, and particularly preferably 8 to 16 hours.

  The metal element in the transition metal raw material may contain a single or a plurality of metal elements. Moreover, the group 2 metal raw material may contain a single or a plurality of metal elements. These can be produced by simultaneously dissolving and using a water-soluble salt, and can be produced as a solid solution containing two or more transition metal elements and group 2 metal elements.

  The reaction is preferably carried out in a closed pressure vessel whose inner surface is coated with a fluororesin or the like in order to avoid a reaction between the transition metal raw material or the fluorine raw material and the container raw material.

  Since the alkali transition metal group 2 metal fluorophosphate compound of the present invention contains almost no impurity phase and is excellent in crystallinity, it is excellent in stability in an electrolytic solution of a Na secondary battery. Furthermore, since it is a synthesis condition at a low temperature of 100 to 200 ° C., it is composed of fine particles in which crystal growth is suppressed, has a large specific surface area, and is excellent in the reactivity of insertion and desorption of Na ions. For these reasons, the alkali transition metal group 2 metal fluorophosphate compound of the present invention is suitable as a positive electrode material for a Na secondary battery.

  In addition, the production method of the present invention can use a transition metal sulfate which is easily dissolved in water and is advantageous in terms of cost as a transition metal raw material, and has a large industrial effect since it is a one-pot synthesis.

Sealed reaction vessel used in Examples and Comparative Examples

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these Examples.

Example 1
Manganese sulfate pentahydrate _{(MnSO 4 · 5H 2 O)} 10.3wt%, iron sulfate heptahydrate _{(FeSO 4 · 7H 2 O)} 2.4wt%, magnesium sulfate heptahydrate (MgSO ₄ · 7H ₂ O) 0.7 wt%, trisodium phosphate dodecahydrate (Na ₃ PO ₄ · 12H ₂ O) 21.7 wt%, sodium fluoride (NaF) 3.7 wt% and sodium sulfite (Na ₂ SO ₃ ) The mixture was weighed at a ratio of 7.1 wt% and pulverized and mixed in a mortar. This mixed powder was put into a container with a lid made of Teflon (registered trademark) resin, and further 54.2 wt% pure water was added to adjust the whole to 100 wt%. The pH of the solution at this time was 12. This container was further sealed in an iron metal container. This container was heated for 24 hours in a thermostatic chamber heated to 120 ° C. After 24 hours, this was taken out, cooled to room temperature, the sealed container was opened, and dispersed and stirred in pure water corresponding to 8 times the amount of the sample to perform washing. This solution was filtered through filter paper. The filtrate was dried in a 120 ° C. drying cabinet for 6 hours, and further pulverized with a mortar.

The structure of the product thus obtained was evaluated using an X-ray diffractometer (SmartLab manufactured by Rigaku) and a thermogravimetric analyzer (ThermoPlus manufactured by Rigaku). As a result, it was confirmed that it was a single phase containing no impurity phase. In order to determine the composition ratio between the transition metal and the group 2 metal, the powder ground after filtration and drying was dissolved in a 1 mol / L hydrochloric acid aqueous solution, and then an excess amount of sodium carbonate was added to the transition metal and the group 2 metal. Precipitation was performed as carbonate. This was dried at 80 ° C., further oxidized and fired in a crucible at 400 ° C. for 4 hours, cooled and pulverized, and X-ray diffraction was measured with an X-ray diffractometer (SmartLab manufactured by Rigaku). Using the attached data processing software PDXL-2, the oxide phase formed by oxidation was calculated and the composition ratio was calculated, and the ratio of the transition metal to the group 2 metal was evaluated to determine the composition of the product. As a result, the product was a sodium manganese iron magnesium fluorophosphate compound (Na ₂ Mn _0.76 Fe _0.13 Mg _0.11 PO ₄ F).

  In addition, evaluation of the product of Example 2 or later and the comparative example was carried out by the method of Example 1.

(Example 2)
Manganese sulfate pentahydrate (MnSO ₄ .5H ₂ O) 11.6 wt%, ferrous chloride hexahydrate (FeSO ₄ .6H ₂ O) 2.4 wt%, magnesium chloride hexahydrate (MgCl ₂ 6H ₂ O) 0.8 wt%, calcium hydroxide (Ca (OH) ₂ ) 1.2 wt%, trisodium phosphate dodecahydrate (Na ₃ PO ₄ · 12H ₂ O) 30.5 wt%, sodium fluoride were weighed at a ratio of (NaF) 5.2wt%, sodium sulfite _(Na 2 SO ₃₎ were weighed 10.0 wt%, was ground and mixed in a mortar. This mixed powder was put into a container with a lid made of Teflon (registered trademark) resin, and further 38.2 wt% pure water was added to adjust the whole to 100 wt%. The pH of the solution at this time was 10. This container was further sealed in an iron metal container. The container was heated for 16 hours in a thermostatic chamber heated to a temperature of 160 ° C. After 16 hours, this was taken out, cooled to room temperature, the sealed container was opened, and the mixture was dispersed and stirred in pure water corresponding to 8 times the amount of the sample and washed. This solution was filtered through 5C filter paper. The filtrate was stored in a 120 ° C. drying cabinet for 6 hours, dried, and then pulverized with a mortar. Thereafter, the product was a sodium manganese iron magnesium calcium fluorophosphate compound (Na ₂ Mn _0.62 Fe _0.14 Mg _0.06 Ca _0.18 PO ₄ F) by the same method and treatment as in Example 1. It was.

(Example 3)
Manganese sulfate pentahydrate (MnSO ₄ .5H ₂ O) 12.8 wt%, ferrous chloride hexahydrate (FeSO ₄ .6H ₂ O) 1.0 wt%, calcium hydroxide (Ca (OH) ₂ ) 1.1 wt%, disodium hydrogen phosphate (Na ₂ HPO ₄ ) 10.1 wt% and ammonium fluoride (NH ₄ F) 3.3 wt% were weighed and pulverized and mixed in a mortar. This mixed powder was put into a container with a lid made of Teflon (registered trademark) resin, and 4.3 wt% of hydrazine (N ₂ H ₄ ) was weighed and added. Further, 67.4 wt% pure water was added to adjust the whole to 100 wt%. The pH of the solution at this time was 11. This container was further sealed in an iron metal container. This container was heated for 16 hours in a constant temperature bath heated to a temperature of 180 ° C. It was removed after 16 hours. Thereafter, the product was treated and analyzed in the same manner as in Example 1. As a result, the product was a sodium manganese iron calcium fluorophosphate compound (Na ₂ Mn _0.76 Fe _0.04 Ca _0.2 PO ₄ F).

Example 4
Manganese sulfate pentahydrate (MnSO ₄ .5H ₂ O) 9.2 wt%, cobalt sulfate heptahydrate (CoSO ₄ .7H ₂ O) 4.9 wt%, calcium hydrogen phosphate dihydrate (CaHPO _4. 2H ₂ O) 2.4 wt%, trisodium phosphate dodecahydrate (Na ₃ PO ₄ · 12H ₂ O) 26.4 wt%, sodium fluoride (NaF) 4.5 wt% and sodium sulfite (Na ₂ SO ₃ ) Weighed at a ratio of 8.7 wt%, and pulverized and mixed in a mortar. This mixed powder was put into a container with a lid made of Teflon (registered trademark) resin, and 44.0 wt% pure water was further added to adjust the whole to 100 wt%. The pH of the solution at this time was 12. This container was further sealed in an iron metal container. This container was heated for 8 hours in a thermostatic chamber heated to 200 ° C. This was taken out after 8 hours. Thereafter, the product was treated and analyzed in the same manner as in Example 1. As a result, the product was a sodium manganese cobalt calcium fluorophosphate compound (Na ₂ Mn _0.56 Co _0.24 Ca _0.2 PO ₄ F).

(Example 5)
Manganese chloride tetrahydrate (MnCl ₂ .4H ₂ O) 4.3 wt%, iron sulfate heptahydrate (FeSO ₄ .7H ₂ O) 3.0 wt%, nickel sulfate hexahydrate (NiSO ₄ .6H ₂₎ O) 1.1 wt%, calcium hydrogen phosphate dihydrate (CaHPO ₄ .2H ₂ O) 1.6 wt%, trisodium phosphate dodecahydrate (Na ₃ PO ₄ .12H ₂ O) 16.4 wt %, Sodium fluoride (NaF) 1.9 wt% and ascorbic acid (C ₆ O ₆ H ₈ ) 3.1 wt%, and pulverized and mixed in a mortar. This mixed powder was put into a container with a lid made of Teflon (registered trademark) resin, and 68.5 wt% pure water was further added to adjust the whole to 100 wt%. The pH of the solution at this time was 8. This container was further sealed in an iron metal container. This container was heated for 8 hours in a thermostatic chamber heated to a temperature of 160 ° C. This was taken out after 8 hours. When the same treatment and analysis were conducted as in Example 1, the product was a sodium manganese iron nickel calcium fluorophosphate compound (Na ₂ Mn _0.5 Fe _0.25 Ni _0.1 Ca _0.2 PO ₄ F )Met.

(Example 6)
Manganese sulfate pentahydrate (MnSO ₄ .5H ₂ O) 11.8 wt%, ferrous chloride hexahydrate (FeSO ₄ .6H ₂ O) 2.9 wt%, cobalt sulfate heptahydrate (CoSO _4. 7H ₂ O) 4.1wt%, magnesium hydrogen phosphate trihydrate _{(MgHPO 4 · 3H 2 O)} 1.7wt%, calcium hydrogen phosphate dihydrate _{(CaHPO 4 · 2H 2 O)} 1.7wt% Sodium dihydrogen phosphate dihydrate (NaH ₂ PO ₄ .2H ₂ O) 15.3 wt%, sodium fluoride (NaF) 1.9 wt% and sodium hydrogen monosulfide (NaSH · nH ₂ O) 9.3 wt% % And weighed and mixed in a mortar. This mixed powder was put into a container with a lid made of Teflon (registered trademark) resin, and 46.7 wt% pure water was further added to adjust the whole to 100 wt%. The pH of the solution at this time was 9. This container was further sealed in an iron metal container. This container was heated for 24 hours in a thermostatic bath heated to a temperature of 140 ° C. This was removed after 24 hours. Thereafter, the same treatment as in Example 1 was carried out and analyzed. As a result, the product was a sodium manganese iron cobalt magnesium calcium fluorophosphate compound (Na ₂ Mn _0.5 Fe _0.15 Co _0.15 Mg _0.1 Ca _{0 .1} PO ₄ F).

(Example 7)
Manganese sulfate pentahydrate _{(MnSO 4 · 5H 2 O)} 3.0wt%, ferrous hexahydrate _{(FeSO 4 · 6H 2 O)} 5.4wt% sulfuric acid, anhydrous magnesium sulfate _(MgSO 4) 1.2 wt %, Trisodium phosphate dodecahydrate (Na ₃ PO ₄ · 12H ₂ O) 18.7 wt%, sodium fluoride (NaF) 3.2 wt% and sodium sulfite (Na ₂ SO ₃ ) 6.1 wt% They were weighed in proportions and pulverized and mixed in a mortar. This mixed powder was put into a container with a lid made of Teflon (registered trademark) resin, and 62.4 wt% pure water was further added to adjust the whole to 100 wt%. The pH of the solution at this time was 10. This container was further sealed in an iron metal container. This container was heated for 12 hours in a constant temperature bath heated to a temperature of 140 ° C. This was taken out after 12 hours. Thereafter, the same treatment as in Example 1 and analysis were performed, and as a result, the product was a sodium manganese iron magnesium fluorophosphate compound (Na ₂ Mn _0.25 Fe _0.55 Mg _0.2 PO ₄ F).

(Example 8)
Manganese sulfate pentahydrate (MnSO ₄ .5H ₂ O) 3.0 wt%, Ferrous sulfate heptahydrate (FeSO ₄ .7H ₂ O) 3.0 wt%, Cobalt sulfate heptahydrate (CoSO _4. 7H ₂ O) 4.9 wt%, nickel sulfate hexahydrate (NiSO ₄ .6H ₂ O) 1.1 wt%, magnesium hydrogen phosphate trihydrate (MgHPO ₄ .3H ₂ O) 1.7 wt%, phosphorus Calcium hydrogen hydrate dihydrate (CaHPO ₄ .2H ₂ O) 1.7 wt%, trisodium phosphate dodecahydrate (Na ₃ PO ₄ .12H ₂ O) 21.5 wt%, sodium fluoride (NaF) 3.6 wt% and sodium sulfite (Na ₂ SO ₃ ) 7.1 wt% were weighed and pulverized and mixed in a mortar. This mixed powder was put into a container with a lid made of Teflon (registered trademark) resin, and further 53.8 wt% pure water was added to adjust the whole to 100 wt%. The pH of the solution at this time was 11. This container was further sealed in an iron metal container. This container was heated for 10 hours in a constant temperature bath heated to a temperature of 180 ° C. This was taken out after 10 hours. Thereafter, the same treatment as in Example 1 and analysis were conducted, and as a result, the product was a sodium manganese iron cobalt nickel magnesium calcium fluorophosphate compound (Na ₂ Mn _0.2 Fe _0.4 Co _0.1 Ni _0.1 Mg _0.1 Ca _0.1 PO ₄ F).

Example 9
Manganese sulfate pentahydrate (MnSO ₄ .5H ₂ O) 3.2 wt%, Ferrous sulfate hexahydrate (FeSO ₄ .6H ₂ O) 5.4 wt%, Calcium hydrogen phosphate dihydrate (CaHPO _{4 · 2H 2 O) 2.7wt%} , sodium phosphate thirty-two dihydrate _{(Na 3 PO 4 · 12H 2} O) 20.2wt%, sodium fluoride (NaF) 3.4 wt% and sodium sulfite (Na ₂ SO ₃ ) 6.6 wt%, and weighed and mixed in a mortar. This mixed powder was put into a container with a lid made of Teflon (registered trademark) resin, and 59.0 wt% pure water was further added to adjust the whole to 100 wt%. The pH of the solution at this time was 9. This container was further sealed in an iron metal container. This container was heated for 16 hours in a thermostatic bath heated to a temperature of 140 ° C. It was removed after 16 hours. Thereafter, the same treatment as in Example 1 and analysis were performed, and as a result, the product was a sodium manganese iron calcium fluorophosphate compound (Na ₂ Mn _0.25 Fe _0.45 Ca _0.3 PO ₄ F).

(Example 10)
Manganese chloride tetrahydrate (MnCl ₂ .4H ₂ O) 1.7 wt%, ferrous sulfate hexahydrate (FeSO ₄ .6H ₂ O) 11.9 wt%, anhydrous magnesium sulfate (MgSO ₄ ) 4.2 wt% %, Disodium hydrogen phosphate (Na ₂ HPO ₄ ) 12.3 wt%, sodium fluoride (NaF) 4.1 wt% and sodium sulfite (Na ₂ SO ₃ ) 10.8 wt%, and weighed in a mortar Grinding and mixing were performed. This mixed powder was put into a container with a lid made of Teflon (registered trademark) resin, and 54.9 wt% pure water was further added to adjust the whole to 100 wt%. The pH of the solution at this time was 8. This container was further sealed in an iron metal container. This container was heated for 48 hours in a thermostatic chamber heated to 120 ° C. This was removed after 48 hours. Thereafter, the same treatment as in Example 1 and analysis were performed, and as a result, the product was a sodium manganese iron magnesium fluorophosphate compound (Na ₂ Mn _0.1 Fe _0.5 Mg _0.4 PO ₄ F).

(Example 11)
Ferrous sulfate hexahydrate (FeSO ₄ .6H ₂ O) 7.8 wt%, Cobalt sulfate heptahydrate (CoSO ₄ .7H ₂ O) 1.6 wt%, Magnesium hydrogen phosphate trihydrate (MgHPO _{4 · 3H 2 O) 2.0wt%} , calcium hydrogen phosphate dihydrate _{(CaHPO 4 · 2H 2 O)} 1.9wt%, sodium phosphate thirty-two dihydrate _{(Na 3 PO 4 · 12H 2} O ) 21.5 wt%, sodium fluoride (NaF) 4.5 wt% and sodium sulfite (Na ₂ SO ₃ ) 7.1 wt%, and weighed and mixed in a mortar. This mixed powder was put into a container with a lid made of Teflon (registered trademark) resin, and 53.7 wt% pure water was further added to adjust the whole to 100 wt%. The pH of the solution at this time was 10. This container was further sealed in an iron metal container. This container was heated for 18 hours in a constant temperature bath heated to 160 ° C. This was removed after 18 hours. When the same treatment and analysis were conducted as in Example 1, the product was a sodium iron cobalt magnesium calcium fluorophosphate compound (Na ₂ Fe _0.5 Co _0.1 Mg _0.2 Ca _0.2 PO ₄ F). Met.

Example 12
Manganese sulfate pentahydrate (MnSO ₄ .5H ₂ O) 1.7 wt%, iron sulfate heptahydrate (FeSO ₄ .7H ₂ O) 14.1 wt%, calcium hydrogen phosphate dihydrate (CaHPO _4. 2H ₂ O) 1.9 wt%, trisodium phosphate dodecahydrate (Na ₃ PO ₄ · 12H ₂ O) 26.1 wt%, sodium fluoride (NaF) 4.4 wt%, and sodium sulfite (Na ₂ SO ₃ ) Weighed at a ratio of 8.6 wt%, and pulverized and mixed in a mortar. This mixed powder was put into a container with a lid made of Teflon (registered trademark) resin, and 43.4 wt% pure water was further added to adjust the whole to 100 wt%. The pH of the solution at this time was 11. This container was further sealed in an iron metal container. This container was heated for 12 hours in a constant temperature bath heated to a temperature of 180 ° C. This was taken out after 12 hours. Thereafter, the same treatment and analysis as in Example 1 were carried out. As a result, the product was a sodium manganese iron calcium fluorophosphate compound (Na ₂ Mn _0.1 Fe _0.75 Ca _0.15 PO ₄ F).

(Comparative Example 1)
Manganese sulfate pentahydrate (MnSO ₄ .5H ₂ O) 3.9 wt%, iron sulfate heptahydrate (FeSO ₄ .7H ₂ O) 3.6 wt%, calcium hydrogen phosphate dihydrate (CaHPO _4. 2H ₂ O) 6.1 wt%, trisodium phosphate dodecahydrate (Na ₃ PO ₄ · 12H ₂ O) 26.1 wt% and sodium fluoride (NaF) 4.4 wt% were weighed in a mortar. Grinding and mixing were performed. This mixed powder is put into a container with a lid made of Teflon (registered trademark) resin, 42.2 wt% of sulfurous acid (H ₂ SO ₃ ) is added, and 43.4 wt% of pure water is further added so that the whole becomes 100 wt%. Adjusted. The pH of the solution at this time was 5. This container was further sealed in an iron metal container. This container was heated for 6 hours in a thermostatic bath heated to a temperature of 100 ° C. This was taken out after 6 hours. The following treatment and analysis were conducted in the same manner as in Example 1. The product was basic calcium phosphate (Ca ₅ (PO ₄ ) ₃ (OH)), and the synthesis of the sodium transition metal group 2 metal fluorophosphate compound was could not.

1 reaction vessel (made of Teflon (registered trademark) resin)
2 Exterior can (stainless steel)

Claims (3)

General formula Na ₂ (A _x B _y ) PO ₄ F (wherein x is a numerical value in the range of 0 <x <1, y is a numerical value in the range of 0 <y <1, y = 1−x A is a transition metal element selected from Mn, Fe, Co and Ni, and includes a single or two or more kinds of transition metal elements. B is Mg and / or Ca. Transition metal group 2 metal fluorophosphate compounds.   The sodium transition metal group 2 metal fluoride according to claim 1, wherein the sodium material, phosphoric acid material, transition metal material, group 2 metal material, fluorine material and reducing agent are reacted in water at 100 to 200 ° C. A method for producing a phosphate compound. The group 2 metal raw material is at least one compound selected from the group consisting of MgCl ₂ , MgSO ₄ , MgHPO ₄ , Ca (OH) ₂ , CaCl _2, and CaHPO ₄ . A method for producing a sodium transition metal group 2 metal fluorophosphate compound.

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