JP7256950B2 - Hardness measuring method and hardness measuring device for fired material, and method for judging whether crushing is possible - Google Patents

Description

The present invention relates to a method and apparatus for measuring the hardness of a fired product and a method for determining whether the fired product can be crushed based on the hardness of the fired product.

Lithium ion secondary battery positive electrode active material is prepared by mixing a lithium compound and a transition metal hydroxide such as nickel hydroxide in the raw material mixing process to prepare a raw material mixture, and in the firing process, the raw material mixture is placed in a ceramic container. It is obtained by filling and sintering at about 800° C. to 950° C. to obtain a sintered product, and crushing the sintered product in a crushing step (Patent Document 1).

The sintered product obtained from this sintering process is sintered as hard as ceramics. However, in order to use it as a positive electrode active material for lithium ion secondary batteries, it is necessary to pulverize it into fine powder with a particle size of about 10 μm. be.
Therefore, as a crushing method in the crushing process, for example, a method of roughly crushing the fired product with a roll crusher and then finely pulverizing it with a pin mill is implemented.
This roll crusher is used when the sintered material is continuously fed into the hopper. The level of the fired material inside exceeds the standard value and a level abnormality occurs. At this time, the continuous charging of the fired material to the charging hopper is stopped, and after the level abnormality is resolved, the continuous charging of the fired material to the charging hopper is resumed.
There is also a problem that the coarsely pulverized fired product damages the pins of the pin mill, causing the pin mill to malfunction. Furthermore, as a result of the breakage of the pins, the fired material is not pulverized to the desired particle size.

As a countermeasure against such problems, first, measure the hardness of the fired material to be crushed, set a reference value (threshold value) in advance so that an abnormality does not occur in the crushing process, and set the reference value There is a method of sorting and excluding from the crushing line so as not to process the baked products harder than the crushing process.
Therefore, Vickers hardness (HV) measurement, Brinell hardness (HBS) measurement, and the like are known as hardness measurement methods for determining the hardness of the fired material for determining the reference value. For example, in Patent Document 2, a positive electrode active material powder is pressed to obtain a molded body, and the obtained molded body is sintered to obtain a sintered body having a hardness of 100 to 600 HV. The hardness of the sintered body is measured using a Vickers hardness tester.

When the hardness measurement method proposed in Patent Document 2 is applied to the measurement of the fired product obtained in the firing process, a measurement sample of the fired product is cut out from the sagger, shaped, and measured with a hardness meter. It was necessary, and a total of about 3 hours of measurement time was required for each sagger. However, when the raw material mixture is processed using a continuous furnace in the firing process, it is necessary to measure the hardness of the fired product within a few minutes. There was no choice but to put the product into the crushing process, and as described above, there were cases where the roll crusher level was abnormal, the pin mill was damaged, and the fired product was not crushed to the desired particle size.
As described above, since there is no simple method for measuring the hardness of the fired product in a short time and determining whether or not the fired product can be put into the subsequent crushing step, there is a problem that the process control does not progress.

JP 2017-16753 A JP 2010-123396 A

In view of the above problems, a method for quickly and simply determining whether or not the fired product obtained in the firing step can be subjected to the crushing step in the next step, and the hardness of the fired product for making the determination. Provide a measuring instrument and a measuring method.

A first aspect of the present invention is a hardness measurement method using a powder fired product as an object to be measured, wherein the object to be measured is placed on the upper surface of a stage portion installed so that the upper surface is a horizontal surface. A straight rod-shaped indenter whose tip forms a pressing portion is lowered from above toward the surface of the object to be measured, and after the pressing portion contacts the surface of the object to be measured. Further, the indenter is lowered until immediately after the pressing part penetrates the baked product, and the force received by the indenter from the object to be measured during the operation is measured by a load measuring instrument. It is a hardness measurement method that

A second aspect of the present invention is a hardness measuring method according to the first aspect, wherein the object to be measured is housed in a sagger with an open top.

A third invention of the present invention is a hardness measuring method characterized in that the load measuring instrument according to the first and second inventions comprises the indenter and a load measuring section.

A fourth invention of the present invention is a hardness measuring method characterized in that the load measuring instrument according to the third invention is a force gauge.

A fifth invention of the present invention is a hardness measurement method according to the third invention, wherein the load measuring instrument comprises the indenter and a load cell of the load measuring unit, and the indenter is attached to the load cell. is.

In a sixth invention of the present invention, the indenter in the first invention converts the magnitude of the force applied to the pressing portion into at least one of current, voltage, and resistance. It is a hardness measuring method characterized in that it is connected to a measuring unit.

A seventh invention of the present invention is a hardness measuring device for measuring the hardness of a powder fired product as an object to be measured, wherein the upper part for accommodating the object to be measured is open. with a sagger,
A load measuring unit having a stage portion in which the sagger containing the object to be measured is placed, and a head portion above the stage portion that is movable in the direction of the upper surface of the stage portion, and is supported and fixed by the head portion. and a load measuring instrument comprising an indenter having a pressing portion at its tip connected to the load measuring portion, and the indenter pushes through the inside of the object to be measured by moving the head portion, and the surface of the sagger It is a hardness measuring device characterized by reaching

An eighth aspect of the present invention is the hardness measuring device according to the seventh aspect, wherein the load measuring device is a force gauge.

A ninth aspect of the present invention is a hardness measuring device according to the seventh aspect, wherein the load measuring instrument comprises the indenter and a load cell of the load measuring section, and the indenter is attached to the load cell. is.

According to a tenth aspect of the present invention, in the seventh aspect, a predetermined reference value and a hardness measurement value measured by the hardness measurement method according to any one of the first to sixth aspects If the difference f is in the relationship of "the reference value - the measured value = f> 0", the hardness of the object to be measured is accepted, and an instruction to subject the object to be measured to the crushing process is issued The hardness measuring device is characterized by having a pass/fail judgment function.

An eleventh invention of the present invention is a method for determining whether or not a fired product can be crushed, wherein the fired product is an object to be measured, a predetermined reference value, and any one of claims 1 to 6. Calculate the difference f from the hardness measurement value of the object to be measured measured by the hardness measurement method, and if there is a relationship of "the reference value - the measured value = f> 0", the object to be measured The hardness of the object to be measured is regarded as acceptable, and judgment is made as to whether or not the object to be measured is to be subjected to the crushing step.

According to the present invention, it is possible to greatly shorten the time for measuring the hardness of the fired material, and by enabling the inspection of the entire amount, it is possible to determine in advance the fired material that is hard enough to cause an abnormality in the crushing process, It is possible to eliminate the need to put it into the crushing process, reduce the frequency of occurrence of abnormalities in the crushing process, and improve productivity.
In addition, since it is possible to measure the hardness of the fired material by a simple method and determine whether or not it can be put into the crushing process, it is possible to select firing conditions that do not generate hard fired material.
Furthermore, the acceptance/rejection determination device according to the present invention enables easy acceptance/rejection determination, and by incorporating the determination device into the production line, it is possible to automatically introduce only acceptable products into the crushing process, which is a remarkable industrial effect.

It is a flowchart of pass/fail judgment. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic explanatory drawing which shows an example of the hardness acceptance/rejection determination apparatus which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic explanatory drawing of the hardness measuring device A used in the Example, (a) is a schematic external view, (b) to (d) are diagrams showing the progress of hardness measurement, and (b) is an object to be measured. When the indenter comes into contact with the indenter, (c) shows when it travels inside the object to be measured, (d) shows when it reaches the surface of the sagger, and (e) shows an example of the shape of the pressing part of the tip of the indenter (tip: double-edged shape). It is a figure which shows the hardness measurement location in an Example.

The present invention is an invention for quickly and simply determining whether or not a fired product obtained in a firing step can be subjected to a crushing step in the next step, and a powder fired product is an object to be measured. A straight rod-shaped indenter whose tip forms a pressing portion is lowered from above the object to be measured placed on the upper surface of the stage, and pressure is applied to the surface of the object to be measured. A hardness measurement method in which the indenter is lowered until immediately after the pressing part penetrates the fired object after the contact between the parts, and the force received by the indenter from the object to be measured during this operation is measured by a load measuring instrument. , a hardness measuring device using the hardness measuring method, and a method for judging whether or not a fired product can be crushed.

[Measurement of hardness of fired product]
1. Hardness of Fired Product First, the fired product whose hardness is to be measured should have a thickness of about 10 cm or less in the sagger.
When a metal rod is inserted from above into the sagger set in the sagger, the hardness gradually increases, and when it is inserted more than half the thickness of the calcined object, it suddenly becomes hard and the metal rod cannot be inserted. . When the metal rod is inserted with more force, the hard baked product cracks and the metal rod reaches the sagger.
The hardness of the fired product is particularly hard in the lower layer from the bottom surface of the fired product to about 1/3 of the thickness of the fired product, which causes the above problems.
The reason why the lower layer of the fired product is particularly hard is not clear, but the Li compound in the raw material mixture melts in the firing process, and some unreacted Li compounds precipitate in the lower layer of the fired product, and after cooling, the Li compound is concentrated. It is speculated that the lower layer becomes hard. In addition, the above-mentioned sintered material having variations in hardness in the thickness direction is mixed while being pulverized, thereby causing no problem with the performance of the positive electrode active material.

2. Measurement method 2-1. Conventional general hardness measurement methods are roughly classified into the following two methods, and the hardness measurement method is appropriately selected according to the type of the object to be measured (metal, ceramics, resin).
(Conventional 1) Pressing an indenter (a metal rod or steel ball with a sharp tip) against the object to be measured with a certain load applied, the area and depth of the trace made on the object to be measured can be used to determine the hardness of the object to be measured. to measure
(Conventional 2) The hardness of the object to be measured is measured from the rebound height of the indenter (steel ball) when the indenter (steel ball) is dropped from a predetermined height above the object to be measured.
In a general measuring method, as described in the prior art, the cutout size of the object to be measured must be adjusted, and in some cases, the hardness must be measured after polishing. Therefore, it can be said that it is difficult to apply it to the manufacturing site.

2-2. Therefore, in the present invention, a rod-shaped indenter is pressed against an object (fired product) to be measured, and the tip of the indenter is inserted while locally crushing the object (fired product). to measure The load measured at this time is taken as the hardness of the object to be measured.

A force gauge (also called a push-pull gauge) is suitable as a load measuring instrument for measuring the load when an indenter is inserted into an object to be measured.
This force gauge is a device that measures forces such as tensile force, compressive force, and peeling force, and is also used to measure the hardness of elastic bodies (rubber, etc.).
The measurement range of the force gauge is so that it can measure the specifications related to the hardness of the crushed material of the crushing equipment used in the crushing process, such as roll crushers and pin mills, and the upper limit of hardness derived from the actual use of these machines. Select.

A rod-shaped indenter (hereinafter referred to as "indenter") is attached to the force gauge. The indenter is a metal rod that is longer than the thickness of the fired product. Furthermore, if the indenter is thin, it may break while being inserted into the baked product, so it is desirable that the indenter has a strength that does not break within the measurement range of the force gauge.
A tip portion of the indenter is provided with a pressing portion.
The pressing portion at the tip of the indenter may have a double-edged shape, a planar shape, a hemispherical shape, a conical shape, or the like, and may be appropriately selected depending on the state of the fired product. In this case, the "reference value" used to determine whether the hardness is acceptable is determined from data obtained by hardness measurement using an indenter having the same shape of the pressing portion.

An indenter is attached to the force gauge, and the tip of the indenter (hereinafter referred to as the pressing part) is vertically downward above the point where the hardness of the baked product is to be measured, and the force gauge is lowered vertically.
When the tip of the indenter comes into contact with the sintered material, insert the indenter further vertically into the sintered material, and the force gauge will begin to measure the load. In the process of inserting the indenter under the sintered material, the load measurement value fluctuates according to the hardness of the sintered material. show. Insert the indenter into the fired product until the tip of the indenter reaches the sagger. The point at which the tip of the indenter reaches the sagger is taken as the end point of measurement for that measuring point.

For the hardness of the fired product at a measuring point, the maximum value of the load measured at that measuring point with a force gauge is adopted.
The hardness of the fired product shows different values not only in the depth direction, but also in the horizontal direction (=measurement points). Therefore, it is desirable to measure the hardness of the fired material in the sagger at multiple points. For example, if the size of the sagger is about 300 mm wide x 300 mm deep x 110 mm high, it is divided into two sections in the width direction and the depth direction, divided into four sections, and the hardness of the fired material near the center of each section is adjusted. Measure and calculate the average value of the maximum hardness at each measurement point.

3. Pass/Fail Judgment Method Next, a pass/fail judgment method (whether crushing is possible) will be described.
(1) Setting the reference value In advance, from the relationship between the hardness of the fired product measured by the above measurement method and the occurrence of an abnormality in the crushing process, the “hardness of the fired product” ” is defined as the judgment reference value.
At that time, the data used as the measured value of hardness is the representative value of the sample from which the measured value was obtained. Use an average value, etc.

(2) Measurement of hardness of object to be measured Using the above measurement method, the measured value of hardness is obtained. The measured value or an average value or the like is calculated based on the measured value and compared with the reference value.
The value to be compared with the reference value is usually the average value of the measured values. be.

(3) Judgment Calculate the measured value and average value of the hardness of the sintered product and compare it with the standard value. A baked product having a hardness equal to or higher than the reference value is regarded as a rejected product and is not processed in the subsequent crushing process.

4. Hardness Pass/Fail Judgment Device
The hardness pass/fail determination device consists of a "hardness measuring device" that measures the hardness of the object to be measured (baked object) to obtain a "measured value", a predetermined hardness reference value (threshold value), and It is composed of a "pass/fail judgment device" that compares the measured values obtained and judges whether the hardness of the object to be measured is pass/fail based on the magnitude of "f = reference value - measured value".
The acceptance/rejection determination by the hardness acceptance/rejection determination device is performed in the process shown in FIG.

From FIG. 1, the measured value obtained by "hardness measurement" is input to the "pass/fail judgment" section, and the difference "reference value - measured value" from the "reference value" from the reference value setting section is calculated, If the value f is f>0, i.e., when the measured value is less than the reference value, it is "passed." ', the fired product of the object to be measured is sent to the next step, the 'crushing process', and crushed. On the other hand, when it is "failed", it is removed from the production line and reprocessed separately.

Next, a "hardness pass/fail judgment device" for measuring hardness and making a pass/fail judgment will be described. FIG. 2 is a schematic explanatory view showing an example of a hardness judgment apparatus according to the present invention, which consists of a "hardness measuring apparatus A" for measuring the hardness of an object and a "pass/fail judgment apparatus B" for judging whether or not the object is suitable. It is
Taking the hardness measuring device A shown in FIG. not shown).
The force gauge 20 or the sensor portion 22 of the force gauge is equipped with an indenter 21 having a pressing portion 21a (see FIG. 3(e) for the shape etc.) at the tip. Force is transmitted to the head portion 10 (force gauge or force gauge sensor portion).

The head portion 10 is connected to a supporting column portion 12a that constitutes a part of the measurement stand 12 so as to be vertically movable. desirable. In this case, it is more desirable if the head portion 10 can move up and down at the set speed.

A sagger 2 containing a baked product 1 after baking is arranged on a stage part 11.例文帳に追加
When the head portion 10 starts to descend and the pressing portion 21a at the tip of the indenter 21 begins to come into contact with the sintered body 1, hardness measurement begins, and an electric signal indicating hardness is output to the pass/fail judgment device B. do.
In FIG. 2, the force gauge 20 or the force gauge sensor unit 22 is arranged on the head unit 10, and the head unit 10 moves up and down, thereby making it possible to measure the hardness at a fixed point of the object 1 to be measured. However, the force gauge 20 and the force gauge sensor section 22 may be single or plural as shown in the figure. Furthermore, if the hardness measuring device has a mechanism that allows the head portion 10 to move freely in XYZ, it is possible to measure the hardness of an arbitrary point for each object to be measured, and the head portion can move freely in XYZ. You may measure the hardness of the fixed point with the apparatus which can be moved.

The pass/fail determination device B compares the hardness reference value predetermined for the object 1 to be measured as described above with the hardness measurement value of the object 1 measured by the hardness measuring device A, and determines the hardness of the object 1 to be measured. If the hardness of 1 is smaller than the reference value, it is judged as "accepted", and if it is equal to or higher than the reference value, it is judged as "failed".
The pass/fail determination device B is, for example, a kind of computer, and has a CPU (Central Processing Unit) and a storage device. Examples of storage devices include RAM (Random Access Memory), ROM (Read Only Memory), NVRAM (Non-Volatile RAM), HDD (Hard Disk Drive), and the like.

The pass/fail determination device B is connected by a cable C so as to exchange data with the hardness measuring device A regarding the measurement result of the hardness measuring device A of the object 1 to be measured. The connection is made through the input interface (In-Int) of the pass/fail judgment device B. FIG.
The hardness measurement result of the object 1 to be measured by the hardness measuring device A is compared with the reference value of the hardness of the object to be measured stored in advance in the storage device M by the CPU, and a pass/fail decision is made. The determination is displayed/output on a display device (Display) through an output interface (Out-Int).
In addition, the pass/fail judgment is output to another device such as a conveying device for the sagger 2 containing the object to be measured via the output interface (Out-Int), The product can also be sent to the reject processing station.

The present invention will be described in detail below using examples.

A transition metal composite hydroxide composed of nickel hydroxide, cobalt hydroxide, and manganese hydroxide was synthesized by a known method (Patent Document 1).
This transition metal composite oxide and lithium hydroxide are put into a V blender and mixed to prepare a raw material mixture, and the obtained raw material mixture is subjected to a firing process so that the dimensions in the sagger are 300 mm wide × 300 mm deep × high. A 110 mm thick sagger was filled with 6.0 kg, and the sagger filled with the raw material mixture was placed in an electric furnace and fired at 950° C. for 4 hours in an air stream. After 4 hours of firing, the prepared fired product was cooled to room temperature, the fired product was taken out from the electric furnace together with the sagger, and the hardness of the fired product was measured.

Next, the hardness was measured using a hardness measuring device A whose outline view is shown in FIG. 3(a). The hardness measuring device in FIG. 3(a) uses a force gauge 20 (manufactured by Shiro Sangyo Co., Ltd. “M123GJN-50N”) for the measurement part, and a pressing part (double-edged shape, FIG. 3(e), A 150 mm indenter 21 having a length of 150 mm was attached to the measurement part 22 to measure the hardness of the baked product 1 in the sagger 2 .
The measurement was performed at eight positions indicated by circled numbers in FIG.

In the progress of hardness measurement, as shown by the position of the indenter in the "aa'" section of FIG. 3(a) shown in FIGS. When the measurement unit 22 comes into contact with the baked product 1 of the object to be measured (the state shown in FIG. 3B) and starts to measure the "load" defined as "hardness" in the present invention. "Measurement of hardness" in a narrow sense is started. After the contact, the indenter 21 is pushed further into the baked product 2 (state shown in FIG. 3(c)). The operation of the indenter ends when it reaches the surface of the sagger 2 through the fired material 2 (state shown in FIG. 3(d)).
When observing the load by visual observation while the indenter is operating, the maximum measured value is used as data for comparison with the reference value, and extreme values indicated by the measuring unit 22 are observed during measurement. Observing whether the value exceeds the reference value, usually picking up an electric signal corresponding to the load being measured from the measuring unit 22, outputting it to the pass/fail judgment device, via the input interface (IN-Int) The measured value input to the pass/fail judgment device is stored in the storage device or the arithmetic unit (CPU) calculates the maximum value and average value of the measured value and compares it with the reference value "f = reference value - measured value" , the hardness of the fired material to be measured is determined, and the pass/fail determination signal is sent to the control system of the manufacturing process via the output interface (Out-Int)), and the subsequent crushing process Decide whether to implement or not to implement

The pass/fail index for whether or not the crushing process is implemented is to roughly crush the baked product taken out of the sagger "after measuring the hardness" of the baked product, and if the baked product is hard, coarsely crush it with the roll crusher. "Abnormal level of input hopper" occurs when the crushing speed slows down during crushing.
A total of 4 minutes was required for hardness measurement at eight measurement points.
Table 1 shows the hardness measurement results and the presence or absence of abnormalities.

The hardness was measured and the presence or absence of abnormality was confirmed by the same conditions and method as in Example 1, except that the amount of the raw material mixture filled in the sagger was 6.5 kg.
A total of 4 minutes was required for hardness measurement at eight measurement points.
Table 1 shows the hardness measurement results and the presence or absence of abnormalities.

(conventional example)
An attempt was made to measure the hardness using a Vickers hardness tester in the same manner as in the examples, but it took 3 hours for the measurement because it took time to cool the baked product and to prepare the sample.

A Hardness measuring device B Pass/fail judgment device C Connection cable M Storage device CPU Arithmetic device IN-Int Input interface OUT-Int Output interface Display Display device 1 Object to be measured (baked object)
2 Sagger 3 Measuring point 10 Head part 11 Stage part 12 Measuring stand 12a Strut part 20 Force gauge 21 Indenter 21a Pressing part (tip: double-edged)
22 Measurement unit (load cell: force gauge sensor unit)

Claims (11)

A hardness measurement method in which a fired product of powder is used as an object to be measured,
A straight rod whose tip forms a pressing portion that extends from above the object to be measured placed on the upper surface of the stage portion installed so that the upper surface is a horizontal surface toward the surface of the object to be measured. lowering the indenter, and after the pressing part contacts the surface of the object to be measured, the indenter is further lowered until immediately after the pressing part penetrates the fired object, and the operation A hardness measuring method, wherein the force received by the indenter from the object to be measured is measured by a load measuring instrument. 2. A hardness measuring method according to claim 1, wherein said object to be measured is housed in a sagger with an open top. 3. The hardness measuring method according to claim 1, wherein said load measuring device comprises said indenter and a load measuring section. 4. The hardness measuring method according to claim 3, wherein said load measuring device is a force gauge. 4. A hardness measuring method according to claim 3, wherein said load measuring device comprises said indenter and a load cell of a load measuring section, and said indenter is attached to said load cell. The indenter is connected to a load measuring section of a "force-electricity" converter that converts the magnitude of the force applied to the pressing section into at least one of current, voltage, and resistance. Item 1. The hardness measurement method according to Item 1. A hardness measuring device for measuring the hardness of a powder fired product as an object to be measured,
Equipped with a sagger with an open top that accommodates the object to be measured,
A stage portion for arranging a sagger containing the object to be measured;
having a head section above the stage section, the head section being movable in the direction of the upper surface of the stage section;
A load measuring device comprising a load measuring unit supported and fixed by the head unit and an indenter having a pressing part at the tip connected to the load measuring unit,
A hardness measuring device, wherein the indenter advances through the inside of the object to be measured and reaches the surface of the sagger by the movement of the head portion. 8. The hardness measuring device according to claim 7, wherein said load measuring device is a force gauge. 8. The hardness measuring device according to claim 7, wherein said load measuring device comprises said indenter and a load cell of a load measuring section, and said indenter is attached to said load cell. A predetermined reference value and the difference f between the hardness measurement value measured by the hardness measurement method according to any one of claims 1 to 6 is calculated, and "the reference value - the measurement value =f>0", the hardness of the object to be measured is regarded as acceptable, and a pass/fail judgment function is provided to issue a command to subject the object to be measured to a crushing process. A hardness measuring device as described. A method for determining whether or not a fired product can be crushed,
Using the fired product as an object to be measured,
A predetermined reference value and a difference f between the hardness measurement value of the object to be measured measured by the hardness measurement method according to any one of claims 1 to 6 is calculated, and "the reference value - If the measured value = f > 0”, the hardness of the object to be measured is accepted, and a pass/fail judgment is made that the object to be measured is subjected to a crushing process. Acceptance judgment method.

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