JP2009215124A - Method for producing transition metal compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a transition metal compound, by which a large amount of a transition metal compound can be stably produced, a transition metal compound having a sharp grain size distribution can be obtained, and metallic foreign matter can be prevented from mixing in the production process. <P>SOLUTION: The method for producing a transition metal compound is characterized by using a diaphragm pump in the production process. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a transition metal compound.

2. Description of the Related Art In recent years, with the reduction in size and weight of portable electronic devices and communication devices, lithium secondary batteries having high output and high energy density have attracted attention as power sources thereof and as power sources for automobiles.
As positive electrode active materials for lithium secondary batteries, transition metal compounds are known. Among them, it is known that a lithium transition metal composite oxide such as LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ having a standard composition is preferable. Further, from the viewpoint of safety and raw material cost, LiNi _1-X Mn _X O _{2 in} which a part of the transition metal of these lithium transition metal composite oxides is substituted with another transition metal (where 0 ≦ X ≦ 1) , LiNi _{1-x′-y ′} Mn _{x ′} Co _{y ′} O ₂ (where
Lithium transition metal composite oxides having the same layered structure as LiCoO ₂ and LiNiO ₂ such as 0 ≦ X ′ ≦ 1, 0 ≦ Y ′ ≦ 1, 0 ≦ X ′ + Y ′ ≦ 1) have attracted attention.

  As a method for producing these transition metal compounds, for example, a lithium raw material, a nickel raw material, a cobalt raw material, a manganese raw material, etc. are mixed in a dry process, and then fired, crushed, classified, a nickel raw material, a cobalt raw material, a manganese raw material, etc. If necessary, a slurry containing a small amount of lithium raw material is spray-dried to form a granular material, and then dry mixed with the lithium raw material so that the desired composition ratio is obtained, followed by firing, crushing, and classification, or A method in which a composite carbonate obtained by co-precipitation of nickel, cobalt, manganese, etc., for example, as carbonate is calcined and decarboxylated, and the resulting granulate and lithium raw material are dry mixed and then calcined, crushed and classified Etc. are used.

  As the application of lithium secondary batteries to portable devices and automobiles rapidly expands, it has been required to supply lithium secondary batteries stably. In order to stably supply a lithium secondary battery, it is necessary to stably produce a transition metal compound used for the electrode. That is, among the above-described methods for producing transition metal compounds, there is a demand for a production method that can stably produce a large amount of transition metal compounds.

  In addition, lithium secondary batteries are required to have high performance such as high capacity and high output. In particular, in order to realize a high capacity, studies for thinning the electrode of the lithium secondary battery are being actively conducted. For this reason, the transition metal compound used for the electrode needs to have a sharp particle size distribution. That is, among the above-described methods for producing a lithium transition metal composite oxide, there is a demand for a production method that can obtain a sharp particle size distribution when a transition metal compound is used.

  Furthermore, it is known that the inclusion of metallic foreign matter in the materials constituting lithium secondary batteries, especially the positive electrode active material, may lead to battery failure and further risk of battery ignition, etc. In the manufacturing process of the transition metal compound which is a positive electrode active material, there is a demand for a manufacturing method in which no metallic foreign matter is mixed.

In the above-described method for producing a transition metal compound, in a method for producing a positive electrode material for a lithium secondary battery, comprising a step of preparing a slurry by pulverizing a raw metal compound with water and a step of spray drying the prepared slurry Conventionally, tube type pumps, screw pumps and the like have been used for transporting slurry.
However, in the process of preparing the slurry and the process of spray drying, when a tube-type pump is used, in addition to not being able to secure a sufficient amount of slurry transport for mass production, the pulsation during transport is large. There has been a problem that the flow rate of transportation changes due to deterioration of the tube and the load on the production equipment increases. Moreover, since the tube may be damaged by pulsation, there is a problem that a long time is required for maintenance. Further, due to the large pulsation during transportation, there is a problem that a stable particle size cannot be obtained when the slurry is sprayed or the particle size becomes broad.

When a screw pump is used, a sufficient amount of slurry can be secured for mass production, but the flow rate may decrease due to wear of parts due to continuous use. Therefore, there has been a problem that it takes a long time to maintain the parts. Furthermore, there is a problem that a worn metal foreign matter is mixed and there is a risk of eventually leading to ignition of the battery.
The present invention has been made in view of the above problems. That is, the object of the present invention is to produce a transition metal compound having a sharp particle size distribution, in which a large amount of the transition metal compound can be stably produced in the method for producing a transition metal compound, and the production process. Is to provide a production method capable of preventing the mixing of metallic foreign matters.

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using a diaphragm pump in the method for producing a transition metal compound, thereby completing the present invention.
That is, the gist of the present invention is as follows.
(I) A method for producing a transition metal compound, wherein a diaphragm pump is used in the production process.
(II) The method for producing a transition metal compound is a production method comprising a step of preparing a slurry by pulverizing a raw metal compound together with water, and a step of spray drying the prepared slurry, the step of preparing the slurry In the step of spray drying, a diaphragm pump is used during the transportation of the slurry, and the production method as described in (I) above.
(III) The method according to (I) or (II), wherein the diaphragm pump is a diaphragm pump having a pulsation rate of less than 3%.
(IV) The production method according to any one of (I) to (III) above, wherein the transition metal compound is a lithium transition metal composite oxide.

  In the method for producing a transition metal compound, by using a diaphragm pump, a large amount of the transition metal compound can be stably produced, and a transition metal compound having a sharp particle size distribution can be obtained. In addition, it is possible to prevent the mixing of metallic foreign matters.

Hereinafter, embodiments of the present invention will be described in detail. However, the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention is specified by these contents. is not.
<Transition metal compounds>
The use of the transition metal compound produced by the method for producing the transition metal compound of the present invention (hereinafter referred to as “the production method of the present invention” as appropriate) is not particularly limited, but according to the production method of the present invention, According to this manufacturing method, since metal impurities are not mixed, it is preferably used for electronic materials such as a display material, a dielectric material, a magnetic material, a semiconductor material, a superconducting material, and a battery material. Among these, it is more preferable to use for battery materials. Examples of the battery material include a fuel cell material, a lithium primary battery material, and a lithium secondary battery material. Among these, it is more preferable to use for the negative electrode material or positive electrode material of a lithium secondary battery, and it is especially preferable to use for the positive electrode material of a lithium secondary battery.

Moreover, the transition metal compound produced by the production method of the present invention is not particularly limited, but is a compound having a structure capable of desorbing and inserting Li ions, such as phosphate compounds, lithium transition metals. Examples include composite oxides and sulfides.
In particular,
(1) Phosphorus having an olivine structure and generally represented by LiMePO ₄ (Me is at least one or more transition metals), specifically, LiFePO ₄ , LiCoPO ₄ , LiNiPO ₄ , LiMnPO _4, etc. Acid salt compounds,
(2) It has a spinel structure capable of three-dimensional diffusion of lithium ions and is generally expressed as LiMe ₂ O ₄ (Me is at least one transition metal), specifically, LiMn ₂ O ₄ , A lithium transition metal composite oxide having a spinel structure, such as LiCoMnO ₄ , LiNi _0.5 Mn _1.5 O ₄ , CoLiVO ₄ ,
(3) It has a layered structure that enables two-dimensional diffusion of lithium ions and is generally expressed as LiMeO ₂ (Me is at least one transition metal), specifically, LiCoO ₂ , LiNiO ₂ , _{LiNi 1-X Co X O 2} ( however, 0 ≦ X ≦ 1), LiNi 1-X'-Y 'Mn X' Co Y 'O 2 ( however, 0 ≦ X' ≦ 1,0 ≦ Y '≦ 1 , 0 ≦ X ′ + Y ′ ≦ 1), L
A layered structure including iNi _0.5 Mn _0.5 O ₂ , Li _1.2 Cr _0.4 Mn _0.4 O ₂ , Li _1.2 Cr _0.4 Ti _0.4 O ₂ , LiMnO _{2 and the} like. Lithium transition metal composite oxide having,
(4) Sulfides, for example, TiS ₂ or MoS ₂ having a two-dimensional layered structure, or a strong three-dimensional skeleton structure, and a general formula Me _{X ″} Mo ₆ S ₈ (where Me is Pb, Ag, Examples thereof include various transition metals including Cu, and a chevrel compound represented by 0 ≦ X ″ ≦ 1).

Among them, a lithium transition metal composite oxide having a spinel structure or a layered structure is preferable, and a lithium transition metal having a layered structure is preferable in that good battery characteristics can be obtained when used as a positive electrode active material for a lithium secondary battery. A composite oxide is particularly preferred.
As a specific example of the lithium transition metal composite oxide having a layered structure, it is preferable to have a composition represented by the following formula (1).

_{Li x Ni a Mn b Co c} M d O 2-δ (1)
In the formula (1), M represents a metal element that substitutes a part of Ni and Mn sites. Specific examples of M include elements such as Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn, Nb, Zr, Mo, W, Sn, and B.
In the formula (1), a, b, c and d are 0 ≦ a ≦ 0.9, 0 ≦ b ≦ 0.9, 0 ≦ c ≦ 0.9, 0 ≦ d ≦ 0.4 and a + b + c + d. Represents a number satisfying = 1. Further, x represents a number satisfying 0.7 ≦ x ≦ 1.3, and δ represents a number satisfying −0.1 <δ <0.1.

Among these, a lithium transition metal composite oxide containing nickel, manganese and cobalt represented by the following formula (2), a lithium transition metal composite oxide containing nickel, cobalt and aluminum represented by the formula (3), etc. preferable. Especially, what is represented by Formula (2) is preferable.
Li _{1 + y} (Ni _g Mn _h Co _i ) O _2-δ (2)
In the formula (2), y represents a molar excess amount of Li of the stoichiometric ratio or more, and is usually 0 or more, preferably 0.02 or more, and usually 0.2 or less, preferably 0.15 or less, More preferably, the number is 0.10 or less. If y is outside this range, the crystal structure of the lithium transition metal composite oxide of the present invention may become unstable, or the performance of a lithium secondary battery using this may be reduced.

In the formula (2), g is usually larger than 0, preferably 0.1 or more, more preferably 0.2 or more, and usually 0.8 or less, preferably 0.7 or less, more preferably Is a number of 0.5 or less.
Further, in the formula (2), h is usually larger than 0, preferably 0.1 or more, more preferably 0.2 or more, and usually 0.6 or less, preferably 0.5 or less, more preferably Is a number of 0.4 or less.

In the formula (2), i is usually 0 or more, preferably 0.1 or more, more preferably 0.2 or more, and usually 0.5 or less, preferably 0.4 or less, more preferably The number is 0.35 or less.
Further, g, h, and i are numbers satisfying g + h + i = 1.
When g, h, and i are out of the above ranges, the capacity of the lithium secondary battery using the lithium transition metal composite oxide obtained by the production method of the present invention may be reduced.

Further, in the equation (2), δ represents a number which is usually larger than −0.1 and usually smaller than 0.1 as in the equation (1).
Li _{1 + z} Ni _1-ef Co _e Al _f O _2-δ (3)
In the formula (3), z represents a molar excess amount of Li at a stoichiometric ratio or more, and is usually 0.01 or more, preferably 0.02 or more, and usually 0.2 or less, preferably 0.15 or less, More preferably, the number is 0.10 or less. If z is out of this range, the crystal structure of the lithium transition metal composite oxide may become unstable, or the performance of a lithium secondary battery using the same may be deteriorated.

In the formula (3), e is usually larger than 0, preferably 0.05 or more, more preferably 0.1 or more, and usually 0.4 or less, preferably 0.3 or less, more preferably Is a number of 0.2 or less.
Further, in the formula (3), f is usually 0 or more, preferably 0.02 or more, more preferably 0.04 or more, and usually 0.3 or less, preferably 0.25 or less, more preferably The number is 0.2 or less.

If e and f are too small, the chemical stability of the lithium transition metal composite oxide may be insufficient. If e is too large, the cost will increase. If f is too large, the lithium transition metal composite of the present invention will be increased. There is a possibility that the capacity of the lithium secondary battery using the oxide is lowered.
Further, in Expression (3), δ represents a value similar to that in Expression (2).
<Raw metal compound>
Although it does not specifically limit as a raw material metal compound used for the manufacturing method of this invention, For example, it selects from the group which consists of lithium raw material, nickel raw material, cobalt raw material, manganese raw material, iron raw material, vanadium raw material, chromium raw material, and titanium raw material At least one starting metal compound is used. Among these, at least one raw material metal compound selected from the group consisting of a lithium raw material, a nickel raw material, a cobalt raw material, and a manganese raw material is preferably used from the viewpoint of battery characteristics.

<Diaphragm pump>
Diaphragm pump is a positive displacement pump that pressurizes or sucks liquid or gas by expansion and contraction of the diaphragm, has no rotating part in contact with fluid, has a simple structure and is excellent in sealing properties, and is toxic It is used for various purposes including transportation of gas or liquid.

Diaphragm pumps include pumps that reciprocate the diaphragm through a cam or the like, and pumps that reciprocate the diaphragm using a reciprocating magnet as a vibrator.
Compared to electromagnetic diaphragm pumps that use magnetic force, in the case of pumps that use external power such as motors and engines, the external power source and the pump are directly connected, or pulleys, belts, and cams are used. There is an advantage that the rotation speed can be freely selected. In the case of electromagnetic diaphragm pumps, iron loss and copper loss must be taken into account, but when external power is used, if the input of the rotary shaft is obtained from the main motor or main engine, only net input can be obtained. There is also an advantage that there is no extra loss.

  In the diaphragm pump, an organic material such as rubber or fluorine resin or a metal is used as a diaphragm material. From the viewpoint of preventing contamination of metallic foreign matter, the fluororesin diaphragm pump uses the expansion and contraction of the diaphragm, so that the diaphragm is required to have good flexibility. As a result, the thickness of the diaphragm is subject to certain limitations regardless of the material. For this reason, the pressure of the fluid which can be handled will be limited with the intensity | strength of a diaphragm.

  In general, diaphragm pumps have less pulsation. Therefore, it is useful in a method for producing a transition metal compound having a sharp particle size distribution. Moreover, as a diaphragm pump, diaphragm pumps, such as a series type and a double type, are mentioned. In order to obtain a transition metal compound having a sharper particle size distribution, it is effective to use a diaphragm pump that prevents pulsation. For example, a double diaphragm pump as shown in FIG. Is preferably set to a phase opposite to each other because the pulsation rate can be kept low. Further, the pulsation rate can be changed by appropriately selecting a cam that transmits external power. Examples of the shape of the cam include a circular eccentric cam and a special constant speed cam. In particular, if a diaphragm pump using a special constant speed cam as shown in FIG. 2 described later is used, the fluid discharge rate can be adjusted to be almost constant by superimposing a special phase, thereby further reducing the pulsation rate. Is more preferable because

The pulsation rate of the diaphragm pump is preferably less than 10%, more preferably less than 5%, and particularly preferably less than 3%.
Here, if the pulsation rate of the diaphragm pump is less than 10%, it is preferable because the particle size distribution of the transition metal compound becomes sharp.
The pulsation rate of the diaphragm pump can be obtained by the following equation.

Pulsation rate = ± [{(peak flow rate−minimum flow rate) / average flow rate} / 2] × 100
<Manufacturing method>
The production method of the present invention is not particularly limited. For example, in the method for producing a lithium transition metal composite oxide, the raw materials are mixed in a wet form to form a slurry, and the slurry is spray-dried to form a granular material. A method of pulverizing and classifying (this production method may be referred to as “spray drying method” in the present application). Among them, a lithium raw material, a nickel raw material, a cobalt raw material, a manganese raw material, etc. are mixed in a wet form to form a slurry. A method of spray drying to form granules, firing, crushing, and classification (this production method may be referred to as “lithium pre-added spray drying method” in the present application), or nickel raw material, cobalt raw material, manganese raw material, etc. If necessary, a small amount of lithium raw material is mixed in a wet manner, and the slurry is spray-dried to form a granular material, and further lithium raw material so as to have a desired composition ratio. A method of dry-mixing, firing, crushing, and classifying (this production method is sometimes referred to as “lithium post-addition spray drying method” in this application), or a nickel raw material, a cobalt raw material, a manganese raw material, etc. The composite carbonate obtained by co-precipitation as a salt is calcined and decarboxylated, and the resulting granule and lithium raw material are dry mixed, and then calcined, crushed and classified (this, the production method in this application, "It may be called" coprecipitation method "). Among these, it is preferable to use a diaphragm pump in the “spray drying method” because the effects of the present invention can be sufficiently obtained.

  In the “spray drying method”, a diaphragm pump can be used for slurry circulation in a process (wet pulverization process) in which a raw metal compound is wet pulverized into a slurry, and the slurry obtained by wet pulverization is spray dried. In addition, a diaphragm pump can be used for slurry feeding in the process of forming a powdery body (spray drying process), and it is also possible to use the diaphragm pump in both the wet pulverization process and the spray drying process. .

  When using a diaphragm pump at the time of slurry feeding in the spray drying process, it is preferable from the point that the particle size distribution of the obtained lithium transition metal compound is sharp, and at the time of slurry circulation and slurry feeding in the wet grinding process and spray drying process When a pump is used, a large amount of transition metal compounds can be produced stably. When a transition metal compound is used, a sharp particle size distribution can be obtained. It is particularly preferable because it can be prevented.

<Particle size of transition metal compound>
The particle size of the transition metal compound obtained by the production method of the present invention is arbitrary as long as the effects of the present invention are not significantly impaired.
However, the transition metal compound desirably has a median diameter of 20 μm or less, preferably 15 μm or less, when the particle size distribution is measured by a laser diffraction method on a sample that is not subjected to dispersion treatment by an ultrasonic oscillator. If the median diameter exceeds the upper limit, it is not possible to stably supply a slurry suitable for the desired particle size, or a large number of coarse particles will be generated, and a sharp particle size distribution cannot be obtained as a transition metal compound. The effects of the present invention may not be obtained.

  On the other hand, the lower limit of the median diameter is usually 1 μm or more, preferably 3 μm or more. If the median diameter is below the above lower limit, it is not possible to stably supply a slurry suitable for the desired particle size, or the fine powder increases and the particles of the transition metal compound aggregate to form a transition metal compound. A sharp particle size distribution may not be obtained, or the effects of the present invention may not be obtained.

  The median diameter of the transition metal compound may be a value measured by a known laser diffraction / scattering particle size distribution measuring device (Horiba, Ltd .: LA-920 type) based on JIS Z 8825-1. it can. Moreover, as a dispersion medium used in the measurement, a 0.1% by weight sodium hexametaphosphate aqueous solution is used. Furthermore, the application time of ultrasonic waves (output 30 W, frequency 22.5 kHz) at the time of measurement is 0 minute, and the refractive index used at the time of measurement is 1.60a010i (real part 1.60, imaginary part 0.10).

<Specific surface area of transition metal compound>
The specific surface area of the transition metal compound obtained by the production method of the present invention is arbitrary as long as the effects of the present invention are not significantly impaired.
However, the specific surface area of the transition metal compound is usually 10 m ² / g or less, preferably 5 m ² / g or less. When the median diameter exceeds the upper limit, there may occur a problem that the coating properties of the transition metal compound obtained by the present invention are deteriorated or the battery performance is deteriorated.

On the other hand, the lower limit of the median diameter is usually 0.1 m ² / g or more, preferably 0.5 m ² / g or more. When the specific surface area is less than the lower limit, problems such as deterioration of battery performance may occur as a transition metal compound obtained by the present invention.
The BET specific surface area can be measured by a known BET type powder specific surface area measuring device. In the present invention, a BET one-point method measurement by a continuous flow method was performed using Shimadzu Corporation: Flowsorb II 2300 type specific surface area measuring apparatus, using nitrogen as an adsorption gas and helium as a carrier gas. Specifically, the powder sample is heated and deaerated with a mixed gas at a temperature of 350 ° C., then cooled to liquid nitrogen temperature to adsorb the nitrogen / helium mixed gas, and then heated to room temperature with water. The adsorbed nitrogen gas was desorbed, the amount was detected by a heat conduction detector, and the specific surface area of the sample was calculated from this.

Next, taking the lithium nickel manganese cobalt composite oxide powder as an example of the transition metal compound, the raw materials and the production method thereof will be described in more detail.
<Li raw material>
Among the raw material compounds used for the preparation of the slurry in producing the lithium nickel manganese cobalt based composite oxide by the method of the present invention, the lithium compounds include Li ₂ CO ₃ , LiNO ₃ , LiNO ₂ , LiOH, LiOH · H. ₂ O, LiH, LiF, LiCl, LiBr, LiI, CH ₃ OOLi, Li ₂ O, Li ₂ SO ₄ , dicarboxylic acid Li, citric acid Li, fatty acid Li, alkyllithium and the like can be mentioned.

Among these lithium compounds, lithium compounds that do not contain nitrogen atoms, sulfur atoms, or halogen atoms are preferable in that no harmful substances such as SO _x and NO _x are generated during the firing treatment. Further, a compound that easily forms voids by generating decomposition gas in the secondary particles of the spray-dried powder, for example, by generating decomposition gas during firing is preferable. Taking these points into consideration, Li ₂ CO ₃ , LiOH, and LiOH.H ₂ O are particularly preferable. These lithium compounds may be used individually by 1 type, and may use 2 or more types together.

<Ni raw material>
The nickel compounds include Ni (OH) ₂ , NiO, NiOOH, NiCO ₃ , 2NiCO ₃ .3Ni (OH) ₂ .4H ₂ O, NiC ₂ O ₄ .2H ₂ O, Ni (NO ₃ ) ₂ · 6H. ₂ O, NiSO ₄ , NiSO ₄ .6H ₂ O, fatty acid nickel, nickel halide and the like.

Of these nickel compounds, in that upon firing process does not generate toxic substances such as _{SO x, NO X, Ni (} OH) 2, NiO, N iOOH, NiCO 3, 2NiCO 3 · 3Ni
Nickel compounds such as (OH) ₂ .4H ₂ O and NiC ₂ O ₄ .2H ₂ O are preferred. Also,
Ni (OH) ₂ , NiO, NiOOH, and NiCO ₃ are more preferable from the viewpoint of being inexpensively available as an industrial raw material and high reactivity. In addition, Ni (OH) ₂ , NiO, and NiCO ₃ are particularly preferable from the viewpoint of easily forming voids in the secondary particles of the spray-dried powder by generating decomposition gas during firing. These nickel compounds may be used individually by 1 type, and may use 2 or more types together.

<Mn raw material>
Further, as the manganese compound, manganese oxides such as Mn ₂ O ₃ , MnO ₂ , Mn ₃ O ₄ , M
Examples thereof include manganese salts such as nCO ₃ , Mn (NO ₃ ) ₂ , MnSO ₄ , manganese acetate, manganese dicarboxylate, manganese citrate and fatty acid manganese, halides such as oxyhydroxide and manganese chloride.

Among these manganese compounds, MnO ₂ , Mn ₂ O ₃ , Mn ₃ O ₄ , MnCO are used because they do not generate gases such as SO _x , NO _x, etc., and can be obtained at low cost as industrial raw materials. ₃ is preferred. These manganese compounds may be used individually by 1 type, and may use 2 or more types together.
<Co raw material>
Cobalt compounds include Co (OH) ₂ , CoOOH, CoO, Co ₂ O ₃ , C
o ₃ O ₄ , Co (OCOCH ₃ ) ₂ .4H ₂ O, CoCl ₂ , Co (NO ₃ ) ₂ .6H ₂ O, Co (SO ₄ ) ₂ · 7H ₂ O, CoCO _{3 and the} like.

Among these cobalt compounds, _SO x during the firing process, in that it does not generate harmful substances such as _{NO X, Co (OH) 2} , CoOOH, CoO, is _{Co 2 O 3, Co 3 O} 4, CoCO 3 preferably Co (OH) ₂ , CoOO in terms of industrial availability at low cost and high reactivity
H is more preferable. In addition, Co (OH) ₂ , CoOOH, and CoCO ₃ are particularly preferable from the viewpoint of easily forming voids in the secondary particles of the spray-dried powder by generating decomposition gas during firing. These cobalt compounds may be used individually by 1 type, and may use 2 or more types together.

<Other element substitution and additives>
Further, in order to appropriately adjust the battery characteristics, other element substitution is performed in the structure of the lithium transition metal composite oxide in addition to the above Li, Ni, Mn, and Co raw material compounds to introduce a different element group, which will be described later. By adding the different element group by spray drying, it is possible to adjust the powder physical properties in the formed secondary particles. As used herein, the step of adding the foreign element added for the purpose of efficiently forming the voids of the secondary particles can be selected either before or after mixing the raw materials, depending on the nature. Is possible. In particular, it is preferable to add a compound that is easily decomposed due to mechanical shear stress applied by the mixing step after the mixing step.

Examples of the different element group introduced by performing substitution of other elements, or Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn, Nb, Zr, Mo, W, It is selected from one or more of Sn and B.
<Raw material mixing>
The method for mixing the raw materials is not particularly limited, and may be wet or dry. For example, a method using an apparatus such as a ball mill, a vibration mill, or a bead mill can be used. Wet mixing in which the raw material compound is mixed in a liquid medium such as water or alcohol is preferable because more uniform mixing is possible and the reactivity of the mixture can be increased in the firing step.

The mixing time varies depending on the mixing method, but it is sufficient that the raw materials are uniformly mixed at the particle level. For example, in a ball mill (wet or dry type), usually about 1 to 2 days, and in a bead mill (wet continuous method), a residence time. Is usually about 0.1 to 6 hours.
Lithium raw materials may be mixed simultaneously with other raw materials from the initial stage of raw material mixing, or only lithium raw materials are mixed with other raw materials in a small amount with the initial stage of raw material mixing, which is insufficient for the desired composition. The minutes may later be dry mixed with the spray-dried powder described below. Furthermore, the lithium raw material alone may not be mixed with other raw materials in the initial stage of raw material mixing, and may be dry-mixed with the spray-dried powder later so as to obtain a desired composition.

<Wet grinding>
In the raw material mixing stage, it is preferable that the raw material is pulverized in parallel. As the degree of pulverization, the particle diameter of the raw material particles after pulverization is an index, but the average particle diameter (median diameter) is usually 1.0 μm or less, preferably 0.6 μm or less, and most preferably 0.4 μm or less. . If the average particle size of the pulverized raw material particles is too large, the reactivity in the firing process is lowered, and the composition is difficult to homogenize. However, making particles smaller than necessary leads to an increase in the cost of pulverization, so that the average particle size is usually 0.01 μm or more, preferably 0.02 μm or more, more preferably 0.05 μm or more. It ’s fine. A means for realizing such a degree of pulverization is not particularly limited, but a wet pulverization method is preferable. Specific examples include a dyno mill and a star mill.

  The median diameter of the pulverized particles in the slurry should be a value measured by a known laser diffraction / scattering particle size distribution measuring device (manufactured by Horiba, Ltd .: LA-920 type) based on JIS Z 8825-1. Can do. Moreover, as a dispersion medium used in the measurement, a 0.1% by weight sodium hexametaphosphate aqueous solution is used. Furthermore, the application time of ultrasonic waves (output 30 W, frequency 22.5 kHz) during measurement is 5 minutes, and the refractive index used during measurement is 1.24a000i (real part 1.24, imaginary part 0.00).

<Spray drying>
After the wet mixing, it is then usually subjected to a drying process. The method is not particularly limited, but spray drying is preferable from the viewpoints of uniformity of the generated particulate matter, powder flowability, powder handling performance, and efficient production of dry particles.
The concentration of the slurry to be subjected to spray drying is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired, but usually 1% by weight or more, preferably 5% by weight or more, more preferably 10% by weight or more, particularly Preferably it is 15 weight% or more. This is because if the slurry concentration is too low, productivity is significantly impaired. The upper limit of the slurry concentration is usually 50% by weight or less, preferably 45% by weight or less, more preferably 40% by weight or less. If the slurry concentration is too high, the viscosity of the slurry becomes high, and there is a possibility that it cannot be sprayed with a nozzle in the spraying process described later.

  Further, the viscosity of the slurry is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. Usually, it is 100 mPs · s or more, preferably 200 mPs · s or more, and usually 3000 mPs · s or less, preferably 2000 mPs. -S or less. If the viscosity of the slurry is too low, it becomes difficult to form clean spherical particles when sprayed in the spraying process described later, and if it is too high, there is a possibility that the nozzle cannot be sprayed.

Spray drying may be performed by a known method. For example, it is possible to use a method in which a gas flow and slurry are caused to flow into the tip of the nozzle so that the slurry is ejected as droplets from the nozzle and brought into contact with a drying gas to quickly dry the droplets.
When producing granulated particles by spray drying, the particle size of the obtained granulated particles can be controlled by appropriately selecting the spray format, pressurized gas flow supply rate, slurry supply rate, drying temperature, etc. it can.

Moreover, there is no restriction | limiting in the conditions at the time of spray-drying, as long as the effect of this invention is not impaired remarkably. For example, the dry atmosphere is usually air, but may be an inert atmosphere such as nitrogen. Moreover, although the temperature of the drying gas is also arbitrary, it is usually preferable to introduce into the spraying device at 80 to 300 ° C and to discharge from the device at 45 to 250 ° C.
The median diameter of the powder obtained by spray drying is usually 18 μm or less, more preferably 15 μm or less, still more preferably 12 μm or less, and most preferably 9 μm or less. However, since it tends to be difficult to obtain a too small particle size, it is usually 3 μm or more, preferably 4 μm or more, more preferably 5 μm or more.

  As the median diameter of the spray-dried particles, a value measured by a known laser diffraction / scattering particle size distribution measuring device (Horiba, Ltd .: LA-920 type) based on JIS Z 8825-1 can be adopted. . Moreover, as a dispersion medium used in the measurement, a 0.1% by weight sodium hexametaphosphate aqueous solution is used. Furthermore, the application time of ultrasonic waves (output 30 W, frequency 22.5 kHz) during measurement is 5 minutes, and the refractive index used during measurement is 1.24a000i (real part 1.24, imaginary part 0.00). The spray-dried particles used were pre-baked at 800 ° C. for 30 minutes as pretreatment for measuring the particle size distribution.

<Dry mixing>
As described above, as in the “lithium post-addition spray drying method”, only a lithium raw material is mixed with other raw materials in a small amount at the initial stage of raw material mixing, and a shortage is later sprayed to the desired composition. When dry-mixing with dry powder, or when only lithium raw material is mixed with other raw materials at the initial stage of raw material mixing, and then dry-mixed with spray-dried powder in a total amount to achieve the desired composition, lithium It is desirable to mix the raw materials in a pulverized state.

  The median diameter of the pulverized lithium raw material powder is usually 100 μm or less, more preferably 50 μm or less, still more preferably 30 μm or less, and most preferably 20 μm or less. However, if it is pulverized too small, it may react with the carbonic acid component in the air and carbonate, or absorb moisture in the air and change the quality, so it is usually 0.5 μm or more, preferably It is 1 μm or more, more preferably 5 μm or more.

The median diameter of the pulverized lithium raw material powder can be confirmed by SEM observation or the like.

<Baking precursor>
In the present invention, the “firing precursor” means a spray-dried powder itself or a lithium transition metal compound precursor before firing obtained by treating the spray-dried powder.

<Baking>
The fired precursor thus obtained is then fired. This firing condition depends on the composition and the lithium compound raw material used, but as a tendency, if the firing temperature is too high, the primary particles grow too much. Conversely, if the firing temperature is too low, the crystal structure becomes undeveloped, and the specific surface area is low. Too big. The firing temperature is usually 800 ° C. or higher, preferably 850 ° C. or higher, more preferably 900 ° C. or higher, most preferably 925 ° C. or higher, and usually 1100 ° C. or lower, preferably 1075 ° C. or lower, more preferably 1050 ° C. or lower, Most preferably, it is 1025 degrees C or less.

  For firing, for example, a box furnace, a tubular furnace, a tunnel furnace, a rotary kiln or the like can be used. The firing process is usually divided into three parts: temperature increase, maximum temperature retention, and temperature decrease. The second maximum temperature holding portion is not necessarily limited to one time, and may include two or more stages depending on the purpose, which means that aggregation is eliminated to the extent that secondary particles are not destroyed. The temperature raising, maximum temperature holding, and temperature lowering steps may be repeated twice or more with a crushing step or a pulverization step which means crushing to primary particles or even fine powder.

In the temperature raising step, the temperature in the furnace is usually raised at a temperature raising rate of 10 ° C./min or less. If the heating rate is too high, a large amount of sintered ingots are produced when the holding temperature is increased to shorten the holding time, and the yield of the sieve is lowered when classification is performed after sintering. The baking is performed at a temperature rising rate of preferably 8 ° C./min or less, more preferably 7 ° C./min or less, and most preferably 5 ° C. or less.
Further, the lower limit of the rate of temperature increase is not particularly limited in order to exhibit the effect of the present invention, but is preferably 0.1 ° C./min or more, more preferably 0.2 ° C./min from the viewpoint of productivity. Above, most preferably, baking is performed at 0.5 / min or more.

  Although the holding time in the maximum temperature holding step varies depending on the temperature, it is usually 30 minutes or longer, preferably 3 hours or longer, more preferably 5 hours or longer, most preferably 6 hours or longer within the above-mentioned temperature range. The time is preferably 20 hours or less, more preferably 18 hours or less, and most preferably 16 hours or less. If the holding time is too short, it is difficult to obtain a lithium nickel manganese cobalt based composite oxide powder with good crystallinity, and it is not practical to have a too long holding time. If the firing time is too long, productivity is significantly impaired, which is disadvantageous.

  In the temperature lowering step, the temperature in the furnace is normally decreased at a temperature decreasing rate of 0.1 ° C./min to 10 ° C./min. If it is too slow, it takes time and is industrially disadvantageous. However, if it is too fast, the uniformity of the target product tends to be lacking or the deterioration of the container tends to be accelerated. The temperature lowering rate is preferably 1 ° C./min or more, more preferably 3 ° C./min or more, preferably 7 ° C./min or less, more preferably 5 ° C./min or less.

As an atmosphere during firing, an oxygen-containing gas atmosphere such as air can be used. Usually, the atmosphere has an oxygen concentration of 1% by volume or more, preferably 10% by volume or more, more preferably 15% by volume or more, and 100% by volume or less, preferably 50% by volume or less, more preferably 25% by volume or less.
By performing this firing step, a lithium transition metal composite compound can be obtained.

<Disintegration / classification process>
The lithium transition metal composite compound obtained in the firing step is then subjected to a crushing / classifying step.
The crushing step is a step of breaking the lithium transition metal composite compound sintered after firing to an appropriate size. The size after crushing is usually 3 cm or less, preferably 1 cm or less, more preferably 5 mm. Hereinafter, it is more preferably 1 mm or less, usually 1 μm or more, preferably 10 μm or more, more preferably 50 μm or more, and further preferably 100 μm or more. If the size after crushing is too large, the classification efficiency in the classification step, which is the next step, may be reduced. On the other hand, if the size after pulverization is too small, the spherical shape formed in the spray drying process may collapse, or fine powders may aggregate to reduce the classification efficiency in the subsequent classification process. For crushing, a device such as a circular vibrating screen, a roll crusher, or a pin mill is used. The operating conditions of each device are determined according to the desired size after crushing. The crushing step may not be performed or may be performed a plurality of times depending on the degree of sintering of the lithium transition metal composite compound.

  The lithium transition metal composite compound having an appropriate size in the crushing step is then classified to a final desired particle size in the classification step. The median diameter after classification is usually 20 μm or less, preferably 15 μm or less, and usually 1 μm or more, preferably 3 μm or more. If the median diameter exceeds the upper limit, it is not possible to stably supply a slurry suitable for the desired particle size, or a large number of coarse particles will be generated, and a sharp particle size distribution cannot be obtained as a transition metal compound. The effects of the present invention may not be obtained. If the median diameter is below the above lower limit, it is not possible to stably supply a slurry suitable for the desired particle size, or the fine powder increases and the particles of the transition metal compound aggregate to form a transition metal compound. A sharp particle size distribution may not be obtained, or the effects of the present invention may not be obtained. For classification, an apparatus such as a circular vibrating sieve, a classifier (such as a turbo screener manufactured by Turbo Industry Co., Ltd., a puffer footer manufactured by Tsukasa Industrial Co., Ltd.), or the like, is used which presses powder against a mesh screen with a blade rotating at high speed. The operating conditions of each device are determined according to the desired size after crushing. In addition, you may implement a classification process in multiple times as needed. In the classification, crushing may be performed at the same time.

[Other processes]
In the production method of the present invention, unless the effects of the present invention are significantly impaired, processes other than the classification process and the baking process described above may be performed.
For example, you may make it perform the grinding | pulverization process etc. which grind | pulverize the lithium transition metal complex oxide obtained by baking.

Further, for example, a part of the raw material may be added to or removed from the firing precursor in order to adjust the ratio of the contained elements.
Further, for example, in order to keep the median diameter and maximum particle diameter of the firing precursor within the above-described range, pulverization or the like may be performed as appropriate.

EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not limited to these Examples, unless the summary is exceeded.
<Example 1>
LiOH.H ₂ O, NiO, CoOOH, and Mn ₃ O ₄ are weighed and mixed so that the molar ratio of Li: Ni: Co: Mn is 0.05: 0.33: 0.33: 0.33. Then, water was added thereto to prepare a slurry having a solid content of 20% by weight. Using a circulating medium agitation type wet bead mill, the solid content in the slurry was wet pulverized to a median diameter of 0.37 μm. At that time, a general tube pump was used for slurry circulation. The obtained slurry was spray-dried with a spray dryer to obtain substantially spherical granulated particles having a median diameter of about 8 μm. At that time, a double circular eccentric cam type diaphragm pump was used for slurry feeding. LiOH powder having a median diameter of about 10 μm was added to the obtained granulated particles so that the molar ratio of Li to (Ni + Co + Mn) was 1.05, and dry mixing was performed to obtain a raw material mixed powder. This mixed powder was charged into a ceramic baking pot, and while circulating air, the temperature was raised to a maximum temperature of 945 ° C. at a rate of temperature increase of 5 ° C./min, held at 945 ° C. for 15 hours, and then at a rate of temperature decrease of 5 ° C./min. The temperature was lowered to obtain a fired powder having a substantially charged molar ratio composition. This fired powder was manually crushed by passing it manually through a mesh having an opening of 1 mm. Lithium transition metal composite is obtained by classifying the pre-pulverized calcined powder using a classifier (turbo screener manufactured by Turbo Industry Co., Ltd.) that presses the powder against the mesh screen with a blade that rotates at high speed. An oxide powder was obtained.

  For general tube pumps used for circulation in the wet pulverization process, the evaluation for the magnitude of pulsation is x, the evaluation for the change in flow rate with time is ○, the evaluation for the load on the equipment is x, and the maintenance frequency of the equipment is The evaluation is x, and for the double-type circular eccentric cam type diaphragm pump used for circulation in the spray drying process, the evaluation for the magnitude of pulsation is ○, the evaluation for the change with time of the flow is ◎, the sharpness of the particle size distribution of the product The evaluation for ◯ was ◯, and the evaluation for contamination with metallic foreign matters in the product was ◎.

Here, evaluation of each effect at the time of slurry circulation in the wet pulverization step and at the time of slurry feeding in the spray drying step was performed according to the following guidelines.
[Pulse magnitude]
Evaluation ◎: Pulsation rate is less than 3% Evaluation ○: Pulsation rate is 3% or more and less than 10% Evaluation x: Pulsation rate is 10% or more [Change in flow rate over time]
Evaluation ◎: Flow rate change is less than ± 5% / year with respect to the average value ○: Flow rate change is more than ± 5% / year to less than ± 10% / year with respect to the average value Evaluation ×: Flow rate change is to the average value ± 10% or more per year [load on equipment]
Evaluation ◎: The amount of bead wear of the wet pulverizer is less than 7% / month Evaluation ○: The amount of bead wear of the wet pulverizer is 7% or more / month to less than 15% / month Evaluation x: The amount of bead wear of the wet pulverizer is 15 % / Month [equipment maintenance frequency]
Evaluation ◎: Pump disassembly inspection once / year Evaluation ○: Pump disassembly inspection twice / year to four times / year Evaluation ×: Pump disassembly inspection 5 times / year or more [Product particle size distribution sharpness]
Evaluation ◎: Frequency of (d90-d10) / median diameter is less than 1 Evaluation: Frequency of (d90-d10) / median diameter is 1 or more and less than 3 Evaluation ×: Frequency of (d90-d10) / median diameter is 3 [Mixed foreign metal in the product]
Evaluation ◎: The amount of metal magnetic deposits recovered from 1 kg of product is less than 0.1 mg. Evaluation ○: The amount of metal magnetic deposits recovered from 1 kg of product is 0.1 mg to less than 0.5 mg. Evaluation ×: recovered from 1 kg of product The amount of metal magnetic deposit is 0.5 mg or more <Example 2>
A lithium transition metal composite oxide was obtained in the same manner as in Example 1 except that a general screw pump was used for slurry circulation in the wet pulverization step.

For general screw pumps used for circulation in the wet pulverization process, evaluation for the magnitude of pulsation is ◎, evaluation for change in flow rate with time is ×, evaluation for load on equipment is ◎, and maintenance frequency of equipment is The evaluation is ○, and for the double circular eccentric cam type diaphragm pump used for circulation in the spray drying process, the evaluation for the magnitude of pulsation is ○, the evaluation for change with time of flow is ◎, the sharpness of the product particle size distribution The evaluation for ◯ was ◯, and the evaluation for contamination of metallic foreign matter into the product was ◯.
<Example 3>
A lithium transition metal composite oxide was obtained in the same manner as in Example 1 except that a double-type special constant speed cam type diaphragm pump was used for slurry feeding in the spray drying process.

For general tube pumps used for circulation in the wet pulverization process, the evaluation for the magnitude of pulsation is x, the evaluation for the change in flow rate with time is ○, the evaluation for the load on the equipment is x, and the maintenance frequency of the equipment is The evaluation is x, and for the double-type special constant speed cam type diaphragm pump used for circulation in the spray drying process, the evaluation for the magnitude of pulsation is ◎, the evaluation for change in flow rate is ◎, the sharpness of the product particle size distribution The evaluation with respect to the thickness was ◎, and the evaluation with respect to the mixing of foreign metal in the product was ◎.
<Example 4>
Example 1 except that a general screw pump was used for slurry circulation in the wet pulverization process, and a dual-type special constant speed cam type diaphragm pump was used for slurry feeding in the spray drying process. Thus, a lithium transition metal composite oxide was obtained.

For general screw pumps used for circulation in the wet pulverization process, evaluation for the magnitude of pulsation is ◎, evaluation for change in flow rate with time is ×, evaluation for load on equipment is ◎, and maintenance frequency of equipment is The evaluation is ○, and for the double special constant speed cam type diaphragm pump used for circulation in the spray drying process, the evaluation for the magnitude of the pulsation is ◎, the evaluation for the change with time of the flow is ◎, and the particle size distribution of the product is sharp The evaluation with respect to the thickness was 、, and the evaluation with respect to the mixing of foreign metal in the product was ◎.
<Example 5>
The same method as in Example 1 except that a double circular eccentric diaphragm pump was used for slurry circulation in the wet grinding process and a general tube pump was used for slurry feeding in the spray drying process. Thus, a lithium transition metal composite oxide was obtained.

In addition, for the double circular eccentric diaphragm pump used for circulation in the wet pulverization process, the evaluation for the magnitude of pulsation is ○, the evaluation for the change in flow rate over time is ◎, the evaluation for the load on the equipment is ○, Evaluation for maintenance frequency is ◎, and for general tube pumps used for circulation in the spray drying process, evaluation for the magnitude of pulsation is x, evaluation for change in flow rate over time is ○, and sharpness of product particle size distribution The evaluation was x, and the evaluation for contamination of metal foreign matter into the product was ◎.
<Example 6>
The same method as in Example 1 except that a double circular eccentric diaphragm pump was used for slurry circulation in the wet pulverization process and a general screw pump was used for slurry feeding in the spray drying process. Thus, a lithium transition metal composite oxide was obtained.

In addition, for the double circular eccentric diaphragm pump used for circulation in the wet pulverization process, the evaluation for the magnitude of pulsation is ○, the evaluation for the change in flow rate over time is ◎, the evaluation for the load on the equipment is ○, Evaluation for maintenance frequency is ◎, and for general screw pumps used for circulation in the spray drying process, evaluation for pulsation size is ◎, evaluation for change in flow rate is ×, and sharpness of product particle size distribution is The evaluation was ◎, and the evaluation with respect to the contamination of metallic foreign matters into the product was ◯.
<Example 7>
A lithium transition metal composite oxide was obtained in the same manner as in Example 1 except that a double circular eccentric diaphragm pump was used for slurry circulation in the wet pulverization step.

In addition, for the double circular eccentric diaphragm pump used for circulation in the wet pulverization process, the evaluation for the magnitude of pulsation is ○, the evaluation for the change in flow rate over time is ◎, the evaluation for the load on the equipment is ○, Evaluation for maintenance frequency is ◎, and for double-type circular eccentric diaphragm pumps used for circulation in the spray drying process, evaluation for pulsation is ○, evaluation for change in flow rate is ◎, and product particle size distribution The evaluation for sharpness was ◯, and the evaluation for metal foreign matter mixed in the product was ◎.
<Example 8>
Example, except that a double circular eccentric type diaphragm pump was used for slurry circulation in the wet grinding process, and a double special constant speed cam type diaphragm pump was used for slurry feeding in the spray drying process. 1 was used to obtain a lithium transition metal composite oxide.

In addition, for the double circular eccentric diaphragm pump used for circulation in the wet pulverization process, the evaluation for the magnitude of pulsation is ○, the evaluation for the change in flow rate over time is ◎, the evaluation for the load on the equipment is ○, Evaluation for maintenance frequency is ◎, and for double special constant speed cam type diaphragm pump used for circulation in spray drying process, evaluation for pulsation size is ◎, evaluation for change in flow rate is ◎, product particle size The evaluation for the sharpness of the distribution was ◎, and the evaluation for the metal foreign matter mixed in the product was ◎.
<Example 9>
A lithium transition metal composite oxide was obtained in the same manner as in Example 1 except that a double special constant speed cam type diaphragm pump was used for slurry circulation in the wet pulverization step.

In addition, for the double special constant speed cam type diaphragm pump used for the circulation in the wet pulverization process, the evaluation for the magnitude of the pulsation is ◎, the evaluation for the change with time of the flow is ◎, the evaluation for the load on the equipment is ◎, Evaluation for equipment maintenance frequency is ◎, and for double-type circular eccentric diaphragm pumps used for circulation in the spray drying process, evaluation for pulsation is ○, evaluation for change in flow rate is ◎, product granularity The evaluation for the sharpness of the distribution was “good”, and the evaluation for the contamination of the product with metallic foreign matters was “good”.
<Example 10>
Except that the double special constant speed cam type diaphragm pump was used for slurry circulation in the wet grinding process and the double special constant speed cam type diaphragm pump was used for slurry feeding in the spray drying process, In the same manner as in Example 1, a lithium transition metal composite oxide was obtained.

In addition, for the double special constant speed cam type diaphragm pump used for the circulation in the wet pulverization process, the evaluation for the magnitude of the pulsation is ◎, the evaluation for the change with time of the flow is ◎, the evaluation for the load on the equipment is ◎, Evaluation for equipment maintenance frequency is ◎, and for double-type special constant speed cam type diaphragm pump used for circulation in spray drying process, evaluation for pulsation magnitude is ◎, evaluation for change in flow rate over time is ◎, product The evaluation for the sharpness of the particle size distribution was ◎, and the evaluation for the mixing of metal foreign matters into the product was ◎.
<Comparative Example 1>
A lithium transition metal composite oxide was obtained by the same method as in Example 1 except that a general tube pump was used for slurry feeding in the spray drying process.

For general tube pumps used for circulation in the wet pulverization process, the evaluation for the magnitude of pulsation is x, the evaluation for the change in flow rate with time is ○, the evaluation for the load on the equipment is x, and the maintenance frequency of the equipment is The evaluation is x, and for general tube pumps used for circulation in the spray drying process, the evaluation for the magnitude of pulsation is x, the evaluation for the change in flow rate over time is ○, the evaluation for the sharpness of the particle size distribution of the product is x The evaluation of the contamination of the product with metallic foreign matters was ◎.
<Comparative Example 2>
Except that a general screw pump was used for slurry circulation in the wet pulverization process, and a general tube pump was used for slurry feeding in the spray drying process, the same method as in Example 1, A lithium transition metal composite oxide was obtained.

For general screw pumps used for circulation in the wet pulverization process, evaluation for the magnitude of pulsation is ◎, evaluation for change in flow rate with time is ×, evaluation for load on equipment is ◎, and maintenance frequency of equipment is The evaluation is ○, and for general tube pumps used for circulation in the spray drying process, the evaluation for the magnitude of pulsation is ×, the evaluation for the change in flow rate over time is ○, the evaluation for the sharpness of the particle size distribution of the product is × The evaluation for the contamination of metallic foreign matters into the product was good.
<Comparative Example 3>
A lithium transition metal composite oxide was obtained by the same method as in Example 1 except that a general screw pump was used for slurry feeding in the spray drying process.

For general tube pumps used for circulation in the wet pulverization process, the evaluation for the magnitude of pulsation is x, the evaluation for the change in flow rate with time is ○, the evaluation for the load on the equipment is x, and the maintenance frequency of the equipment is Evaluation is ×, and for general screw pumps used for circulation in the spray drying process, evaluation for the magnitude of pulsation is ◎, evaluation for change in flow rate with time is ×, evaluation for sharpness of product particle size distribution is ◎ The evaluation for the contamination of metallic foreign matters into the product was good.
<Comparative example 4>
Except that a general screw pump was used for slurry circulation in the wet pulverization process, and a general screw pump was used for slurry feeding in the spray drying process, in the same manner as in Example 1, A lithium transition metal composite oxide was obtained.

  For general screw pumps used for circulation in the wet pulverization process, evaluation for the magnitude of pulsation is ◎, evaluation for change in flow rate with time is ×, evaluation for load on equipment is ◎, and maintenance frequency of equipment is Evaluation is ○, and for general screw pumps used for circulation in the spray drying process, evaluation for the magnitude of pulsation is ◎, evaluation for change in flow rate with time is ×, evaluation for sharpness of product particle size distribution is ◎ The evaluation for the contamination of the metal foreign matter into the product was x.

  Table 1 shows the results of each test item in the above Examples and Comparative Examples.

  The field of application of the present invention is not particularly limited, and can be used for various known uses, and is particularly useful for the method of producing a transition metal composite oxide for a lithium secondary battery. Input PC, mobile PC, electronic book player, mobile phone, mobile fax, mobile copy, mobile printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, mini-disc, transceiver, electronic notebook, calculator, memory card, It is useful in a method for producing a transition metal composite oxide for a lithium secondary battery suitably used for a portable tape recorder, a radio, a backup power source, a motor, a lighting device, a toy, a game machine, a watch, a strobe, a camera and the like.

Schematic diagram of metering pump (circular eccentric cam) and suction discharge amount Schematic diagram of non-pulsating metering pump (special constant speed cam) and suction discharge amount

Claims (4)

  A method for producing a transition metal compound, wherein a diaphragm pump is used in the production process.   The method for producing a transition metal compound includes a step of preparing a slurry by pulverizing a raw metal compound with water, and a step of spray drying the prepared slurry, the step of preparing the slurry and / or The manufacturing method according to claim 1, wherein in the step of spray drying, a diaphragm pump is used when the slurry is transported.   The manufacturing method according to claim 1 or 2, wherein the diaphragm pump is a diaphragm pump having a pulsation rate of less than 3%.   The method according to any one of claims 1 to 3, wherein the transition metal compound is a lithium transition metal composite oxide.

Images