PRECURSOR WITH TRANSFORMED CRYSTAL FORM AND PREPARATION METHOD THEREOF

Abstract

The disclosure discloses a precursor with a transformed crystal form and a preparation method thereof. The preparation method includes: (1) heating a carbonate solution, a cobalt salt to allow a reaction, and spray adding a carbonate solution to allow a reaction to obtain a cobalt carbonate slurry; (2) allowing the slurry to stand, spray adding a cobalt salt and a carbonate solution, and spray adding a cobalt salt using a single spray head at a flow rate of 1 m.sup.3/h to 3 m.sup.3/h and a carbonate solution using no less than three spray heads each at a flow rate of 0.2 m.sup.3/h to 5 m.sup.3/h to obtain cobalt carbonate with a transformed crystal form; and (3) further spray adding a cobalt salt and a carbonate solution to the cobalt carbonate with a transformed crystal form, heating to allow a constant-temperature reaction, and washing and calcining a product.

Claims

1. A preparation method of cobaltosic oxide, comprising the following steps: (1) heating a 0.8 mol/L to 1.8 mol/L carbonate solution, spray adding a cobalt salt and reacting, and spray adding a 2.5 mol/L to 3.5 mol/L carbonate solution and reacting to obtain a cobalt carbonate slurry with a particle size of 3 μm to 5 μm; (2) allowing the cobalt carbonate slurry to stand, and spray adding a cobalt salt and a 2.5 mol/L to 3.5 mol/L carbonate solution separately to allow a reaction to obtain a cobalt carbonate slurry with a particle size of 9 μm to 13 μm; and spray adding a cobalt salt using a single spray head at a flow rate of 1 m.sup.3/h to 3 m.sup.3/h and spray adding a 2.5 mol/L to 3.5 mol/L carbonate solution using no less than three spray heads each at a flow rate of 0.2 m.sup.3/h to 5 m.sup.3/h to obtain cobalt carbonate with a transformed crystal form; and (3) further spray adding a cobalt salt and a 2.5 mol/L to 3.5 mol/L carbonate solution to the cobalt carbonate with a transformed crystal form, performing a constant-temperature reaction under heating, and washing and calcining a resulting product to obtain the cobaltosic oxide, wherein in steps (1) and (2), the cobalt salt is spray added at a flow rate of 1 m.sup.3/h to 3 m.sup.3/h, and the 2.5 mol/L to 3.5 mol/L carbonate solution is spray added at a flow rate of 0.2 m.sup.3/h to 5 m.sup.3/h.

2. The preparation method according to claim 1, wherein in step (1), the carbonate solution is at least one selected from the group consisting of an ammonium bicarbonate solution, a sodium carbonate solution, a sodium bicarbonate solution, and a potassium bicarbonate solution.

3. The preparation method according to claim 1, wherein in step (1), the cobalt salt is one selected from the group consisting of cobalt sulfate and cobalt chloride.

4. The preparation method according to claim 1, wherein in step (1), a pH is controlled at 7.45 to 7.65 during the reaction.

5. The preparation method according to claim 1, wherein step (2) further comprises: allowing the cobalt carbonate slurry obtained after the reaction to stand, removing a resulting supernatant, and spray adding the cobalt salt and the 2.5 mol/L to 3.5 mol/L carbonate solution to allow a reaction; and repeating the above process multiple times until the cobalt carbonate slurry with a particle size of 9 μm to 13 μm is obtained.

6. The preparation method according to claim 1, wherein step (3) further comprises: allowing a cobalt carbonate slurry obtained after the constant-temperature reaction to stand, removing a resulting supernatant, and spray adding the cobalt salt and the 2.5 mol/L to 3.5 mol/L carbonate solution; repeating the above process multiple times until a solid content in the cobalt carbonate slurry reaches 400 g/L to 580 g/L; and dispensing the cobalt carbonate slurry, and further spray adding the cobalt salt and the 2.5 mol/L to 3.5 mol/L carbonate solution to obtain spherical cobalt carbonate with a particle size of 14.5 μm to 22 μm.

7. The preparation method according to claim 1, wherein in step (3), the calcining is conducted at 700° C. to 770° C. for 5 h to 10 h.

8. Cobaltosic oxide prepared by the preparation method according to claim 1.

9. Cobaltosic oxide prepared by the preparation method according to claim 2.

10. Cobaltosic oxide prepared by the preparation method according to claim 3.

11. Cobaltosic oxide prepared by the preparation method according to claim 4.

12. Cobaltosic oxide prepared by the preparation method according to claim 5.

13. Cobaltosic oxide prepared by the preparation method according to claim 6.

14. Cobaltosic oxide prepared by the preparation method according to claim 7.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG. 1 is a scanning electron microscopy (SEM) image of the cobalt carbonate with a transformed crystal form prepared in Example 1;

[0045] FIG. 2 is a cross-sectional view of the cobaltosic oxide prepared by calcining cobalt carbonate with a transformed crystal form in Example 1;

[0046] FIG. 3 is a cross-sectional view of the cobaltosic oxide prepared by calcining cobalt carbonate with a transformed crystal form in Example 2;

[0047] FIG. 4 is an SEM image of the cobalt carbonate with a non-transformed crystal form in Comparative Example 1; and

[0048] FIG. 5 is an SEM image of the cobaltosic oxide prepared by calcining cobalt carbonate with a non-transformed crystal form in Comparative Example 1.

DETAILED DESCRIPTION OF ILLUSTRATED EXAMPLES

[0049] The concepts and technical effects of the present disclosure are clearly and completely described below in conjunction with examples, so as to allow the objectives, features and effects of the present disclosure to be fully understood. Apparently, the described examples are merely some rather than all of the examples of the present disclosure. All other examples obtained by those skilled in the art based on the examples of the present disclosure without creative efforts should fall within the protection scope of the present disclosure.

Example 1

[0050] A preparation method of cobaltosic oxide was provided in this example, including the following steps: [0051] (1) Preparation of raw materials: Cobalt sulfate was dissolved in deionized water to prepare a cobalt salt solution with a cobalt ion concentration of 120 g/L; ammonium bicarbonate was dissolved in deionized water to prepare a carbonate solution with a concentration of 220 g/L; and ammonium bicarbonate was dissolved in deionized water to prepare a solution C with a concentration of 120 g/L. [0052] (2) Nucleation: 2 m.sup.3 of the solution C was added as a base solution to a reactor, heated to 40° C. and kept at the temperature by a circulating water bath, and continuously stirred at 150 rpm; a single spray head was used to spray the cobalt salt solution into the reactor at a flow rate of 1.5 m.sup.3/h until a pH in the reactor was reduced to 7.5, and then a single spray head was used to spray the 220 g/L carbonate solution at a flow rate of 2 m.sup.3/h, where a pH was stably controlled at 7.5 by adjusting the flow rate of the 220 g/L carbonate solution; and when a particle size of cobalt carbonate reached 3.5 μm, the feeding and the stirring were stopped to obtain a dispersive sample slurry. [0053] (3) Crystal transformation process: The dispersive sample slurry was subjected to static settlement for the first time, and a resulting supernatant was removed; the cobalt salt solution was sprayed with a single spray head at a flow rate of 1.5 m.sup.3/h and the 220 g/L carbonate solution was sprayed with a single spray head at a flow rate of 2 m.sup.3/h, and after the reactor (10 m.sup.3) was filled up with a slurry, the feeding was stopped; then a cycle of “static settlement-supernatant removal-spraying the cobalt salt solution and 3 mol/L carbonate solution with a single spray head-stopping feeding when the reactor was filled up” was repeated until a particle size of a seed crystal reached 10 μm; a seed crystal slurry was dispensed for the first time into two parts; and to one part of the seed crystal slurry, the cobalt salt solution was sprayed with a single spray head at a flow rate of 1.5 m.sup.3/h and the 220 g/L carbonate solution was sprayed with three spray heads each at a flow rate of 2 m.sup.3/h until a particle size reached 11 μm to complete the crystal transformation for cobalt carbonate, where a pH was stably controlled at 7.3. [0054] (4) Growth: The cobalt salt solution was sprayed with a single spray head at a flow rate of 1.5 m.sup.3/h and the 220 g/L carbonate solution was sprayed with three spray heads each at a flow rate of 2 m.sup.3/h, where a temperature was controlled at 50° C. and a pH was stably controlled at 7.3; 3 h later, the feeding and the stirring were stopped, a resulting slurry was allowed to stand, and a resulting supernatant was removed; the stirring was started, and the next round of feeding continued; the above feeding was repeated until a solid content in a cobalt carbonate slurry in the reactor reached 450 g/L; the cobalt carbonate slurry was dispensed for the second time, and then the feeding continued with the reaction conditions unchanged; and the above operation was repeated until cobalt carbonate had a target particle size to obtain a slurry of spherical cobalt carbonate with a transformed crystal form. [0055] (5) The slurry of spherical cobalt carbonate with a transformed crystal form was washed for 50 min, dewatered for 20 min, and dried for 6 h to obtain a spherical cobalt carbonate powder with a transformed crystal form, which had a median particle size Dv50 of 18.5 μm and a TD of 1.96 g/cm.sup.3. [0056] (6) The dried spherical cobalt carbonate powder with a transformed crystal form was subjected to one-step calcination at 700° C. for 6 h in an air atmosphere to obtain spherical cobaltosic oxide with a median particle size Dv50 of 16.5 μm.

Example 2

[0057] A preparation method of cobaltosic oxide was provided in this example, including the following steps: [0058] (1) Preparation of raw materials: Cobalt sulfate was dissolved in deionized water to prepare a cobalt salt solution with a cobalt ion concentration of 150 g/L; ammonium bicarbonate was dissolved in deionized water to prepare a carbonate solution with a concentration of 210 g/L; and ammonium bicarbonate was dissolved in deionized water to prepare a solution C with a concentration of 100 g/L. [0059] (2) Nucleation: 2.5 m.sup.3 of the solution C was added as a base solution to a reactor, heated to 40° C. and kept at the temperature by a circulating water bath, and continuously stirred at 150 rpm; a single spray head was used to spray the cobalt salt solution into the reactor at a flow rate of 1.5 m.sup.3/h until a pH in the reactor was reduced to 7.5, and then a single spray head was used to spray the 210 g/L carbonate solution at a flow rate of 2 m.sup.3/h, where a pH was stably controlled at 7.5 by adjusting the flow rate of the 210 g/L carbonate solution; and when a particle size of cobalt carbonate reached 3.5 μm, the feeding and the stirring were stopped to obtain a dispersive sample slurry. [0060] (3) The dispersive sample slurry in the reactor was subjected to static settlement for the first time, and a resulting supernatant was removed; the cobalt salt solution was sprayed with a single spray head at a flow rate of 1.5 m.sup.3/h and the 210 g/L carbonate solution was sprayed with a single spray head at a flow rate of 2 m.sup.3/h, and after the reactor (10 m.sup.3) was filled up with a slurry, the feeding was stopped; then a cycle of “static settlement-supernatant removal-spraying the cobalt salt solution and 3 mol/L carbonate solution with a single spray head-stopping feeding when the reactor was filled up” was repeated until a particle size of a seed crystal reached 11.5 μm; a seed crystal slurry was dispensed for the first time into two parts; and to one part of the seed crystal slurry, the cobalt salt solution was sprayed with a single spray head at a flow rate of 1.5 m.sup.3/h and the 210 g/L carbonate solution was sprayed with four spray heads each at a flow rate of 2 m.sup.3/h until a particle size reached 12.5 μm to complete the crystal transformation for cobalt carbonate, where a pH was stably controlled at 7.5. [0061] (4) The cobalt salt solution was sprayed with a single spray head at a flow rate of 1.5 m.sup.3/h and the 210 g/L carbonate solution was sprayed with four spray heads each at a flow rate of 2 m.sup.3/h, where citric acid (a molar ratio of the 210 g/L carbonate to the citric acid was 100:1.0) was added, a temperature was controlled at 55° C., and a pH was stably controlled at 7.5; 3.5 h later, the feeding and the stirring were stopped, a resulting slurry was allowed to stand, and a resulting supernatant was removed; the stirring was started, and the next round of feeding continued; the above feeding was repeated until a solid content in a cobalt carbonate slurry in the reactor reached 480 g/L; the cobalt carbonate slurry was dispensed for the second time, and then the feeding continued with the reaction conditions unchanged; and the above operation was repeated until cobalt carbonate had a target particle size to obtain a spherical cobalt carbonate slurry. [0062] (5) The spherical cobalt carbonate slurry was washed for 50 min, dewatered for 20 min, and dried for 6 h to obtain a spherical cobalt carbonate powder with a transformed crystal form, which had a median particle size Dv50 of 18.8 μm and a TD of 2.01 g/cm.sup.3. [0063] (6) The dried spherical cobalt carbonate powder with a transformed crystal form was subjected to one-step calcination at 750° C. for 6 h in an air atmosphere to obtain spherical cobaltosic oxide with a median particle size Dv50 of 16.8 μm.

Example 3

[0064] A preparation method of cobaltosic oxide was provided in this example, including the following steps: [0065] (1) Cobalt sulfate was dissolved in deionized water to prepare a cobalt salt solution with a cobalt ion concentration of 100 g/L; sodium bicarbonate was dissolved in deionized water to prepare a carbonate solution with a concentration of 230 g/L; and sodium bicarbonate was dissolved in deionized water to prepare a solution C with a concentration of 80 g/L. [0066] (2) 1.8 m.sup.3 of the solution C was added as a base solution to a reactor, heated to 45° C. and kept at the temperature by a circulating water bath, and continuously stirred at 150 rpm; a single spray head was used to spray the cobalt salt solution into the reactor at a flow rate of 3 m.sup.3/h until a pH in the reactor was reduced to 7.5, and then a single spray head was used to spray the 230 g/L carbonate solution at a flow rate of 4 m.sup.3/h, where a pH was stably controlled at 7.5 by adjusting the flow rate of the 230 g/L carbonate solution; and when a particle size of cobalt carbonate reached 5.5 μm, the feeding and the stirring were stopped to obtain a dispersive sample slurry. [0067] (3) The dispersive sample slurry was subjected to static settlement for the first time, and a resulting supernatant was removed; the cobalt salt solution was sprayed with a single spray head at a flow rate of 3 m.sup.3/h and the 230 g/L carbonate solution was sprayed with a single spray head at a flow rate of 4 m.sup.3/h, and after the reactor was filled up with a slurry, the feeding was stopped; then a cycle of “static settlement-supernatant removal-spraying the cobalt salt solution and 230 g/L carbonate solution with a single spray head-stopping feeding when the reactor was filled up” was repeated until a particle size of a seed crystal reached 11.5 μm; a seed crystal slurry was dispensed for the first time into two parts; and to one part of the seed crystal slurry, the cobalt salt solution was sprayed with a single spray head at a flow rate of 3 m.sup.3/h and the 230 g/L carbonate solution was sprayed with four spray heads each at a flow rate of 4 m.sup.3/h until a particle size reached 12.5 μm to complete the crystal transformation for cobalt carbonate, where a pH was stably controlled at 7.5. [0068] (4) The cobalt salt solution was sprayed with a single spray head at a flow rate of 3 m.sup.3/h and the 230 g/L carbonate solution was sprayed with four spray heads each at a flow rate of 4 m.sup.3/h, where a temperature was controlled at 56° C. and a pH was stably controlled at 7.5; 4.0 h later, the feeding and the stirring were stopped, a resulting slurry was allowed to stand, and a resulting supernatant was removed; the stirring was started, and the next round of feeding continued; the above feeding was repeated until a solid content in a cobalt carbonate slurry in the reactor reached 460 g/L; the cobalt carbonate slurry was dispensed for the second time, and then the feeding continued with the reaction conditions unchanged; and the above operation was repeated until cobalt carbonate had a target particle size to obtain a spherical cobalt carbonate slurry. [0069] (5) The spherical cobalt carbonate slurry was washed for 70 min, dewatered for 25 min, and dried for 10 h to obtain a spherical cobalt carbonate powder, which had a median particle size Dv50 of 19.8 μm and a TD of 2.11 g/cm.sup.3. [0070] (6) The dried spherical cobalt carbonate powder was subjected to one-step calcination at 750° C. for 5 h in an air atmosphere to obtain spherical cobaltosic oxide with a median particle size Dv50 of 17.8 μm.

Example 4

[0071] A preparation method of cobaltosic oxide was provided in this example, including the following steps:

[0072] The preparation method was basically the same as that in Example 1 except that, before the static settlement for the first time in step (3), a particle size reached 4.5 μm; a particle size reached 13 μm after the crystal transformation was completed; citric acid was added during crystal transformation; a spherical cobalt carbonate powder obtained after the drying had a median particle size D50 of 21 μm and a TD of 2.23 g/cm.sup.3; the one-step calcination was conducted at 760° C. for 6 h; and obtained spherical cobaltosic oxide had a median particle size Dv50 of 18.5 μm.

Example 5

[0073] A preparation method of cobaltosic oxide was provided in this example, including the following steps:

[0074] The preparation method was basically the same as that in Example 2 except that, before the static settlement for the first time in step (3), a particle size reached 4.2 μm; a particle size reached 11 μm after the crystal transformation was completed; citric acid was not added during crystal transformation; a spherical cobalt carbonate powder obtained after the drying had a median particle size D50 of 16 μm and a TD of 1.89 g/cm.sup.3; the one-step calcination was conducted at 680° C. for 6 h; and obtained spherical cobaltosic oxide had a median particle size Dv50 of 14.7 μm.

Comparative Example 1

[0075] A preparation method of cobaltosic oxide was provided in this comparative example, including the following steps: [0076] (1) Cobalt sulfate was dissolved in deionized water to prepare a cobalt salt solution with a cobalt ion concentration of 120 g/L; ammonium bicarbonate was dissolved in deionized water to prepare a carbonate solution with a concentration of 220 g/L; and ammonium bicarbonate was dissolved in deionized water to prepare a solution C with a concentration of 120 g/L. [0077] (2) 2 m.sup.3 of the solution C was added as a base solution to a reactor, heated to 40° C. and kept at the temperature by a circulating water bath, and continuously stirred at 150 rpm; a single spray head was used to spray the cobalt salt solution into the reactor at a flow rate of 1.5 m.sup.3/h until a pH in the reactor was reduced to 7.5, and then a single spray head was used to spray the 220 g/L carbonate solution at a flow rate of 2 m.sup.3/h, where a pH was stably controlled at 7.5 by adjusting the flow rate of the 220 g/L carbonate solution; and when a particle size of cobalt carbonate reached 3.5 μm, the feeding and the stirring were stopped to obtain a dispersive sample slurry. [0078] (3) The dispersive sample slurry in the reactor was subjected to static settlement for the first time, and a resulting supernatant was removed; the cobalt salt solution was sprayed with a single spray head at a flow rate of 1.5 m.sup.3/h and the 220 g/L carbonate solution was sprayed with a single spray head at a flow rate of 2 m.sup.3/h, and after the reactor was filled up with a slurry, the feeding was stopped; then a cycle of “static settlement-supernatant removal-spraying the cobalt salt solution and 220 g/L carbonate solution with a single spray head-stopping feeding when the reactor was filled up” was repeated until a particle size of a seed crystal reached 10 μm; a seed crystal slurry was dispensed for the first time, the cobalt salt solution was sprayed with a single spray head at a flow rate of 1.5 m.sup.3/h and the 220 g/L carbonate solution was sprayed with a single spray head at a flow rate of 2 m.sup.3/h until a particle size reached 11 μm, where a pH was stably controlled at 7.3. [0079] (4) The cobalt salt solution was sprayed with a single spray head at a flow rate of 1.5 m.sup.3/h and the 220 g/L carbonate solution was sprayed with a single spray head at a flow rate of 2 m.sup.3/h, where a temperature was controlled at 50° C. and a pH was stably controlled at 7.3; 3 h later, the feeding and the stirring were stopped, a resulting slurry was allowed to stand, and a resulting supernatant was removed; the stirring was started, and the next round of feeding continued; the above feeding was repeated until a solid content in a cobalt carbonate slurry in the reactor reached 450 g/L; the cobalt carbonate slurry was dispensed for the second time, and then the feeding continued with the reaction conditions unchanged; and the above operation was repeated until cobalt carbonate had a target particle size to obtain a spherical cobalt carbonate slurry. [0080] (5) The spherical cobalt carbonate slurry was washed for 50 min, dewatered for 20 min, and dried for 6 h to obtain a spherical cobalt carbonate powder, which had a median particle size D50 of 18.2 μm and a TD of 1.98 g/cm.sup.3. [0081] (6) The dried spherical cobalt carbonate powder was subjected to one-step calcination at 700° C. for 6 h in an air atmosphere to obtain spherical cobaltosic oxide, where the cobalt tetraoxide partially cracked and had a median particle size Dv50 of 16.2 μm.

Comparative Example 2

[0082] A preparation method of cobaltosic oxide was provided in this comparative example, including the following steps: [0083] (1) Cobalt sulfate was dissolved in deionized water to prepare a cobalt salt solution with a cobalt ion concentration of 120 g/L; ammonium bicarbonate was dissolved in deionized water to prepare a carbonate solution with a concentration of 220 g/L; and ammonium bicarbonate was dissolved in deionized water to prepare a solution C with a concentration of 120 g/L. [0084] (2) 2 m.sup.3 of the solution C was added as a base solution to a reactor, heated to 40° C. and kept at the temperature by a circulating water bath, and continuously stirred at 150 rpm; a single spray head was used to spray the cobalt salt solution into the reactor at a flow rate of 1.5 m.sup.3/h until a pH in the reactor was reduced to 7.6, and then a single spray head was used to spray the 220 g/L carbonate solution at a flow rate of 2 m.sup.3/h, where a pH was stably controlled at 7.6 by adjusting the flow rate of the 220 g/L carbonate solution; and when a particle size of cobalt carbonate reached 3.5 μm, the feeding and the stirring were stopped to obtain a dispersive sample slurry. [0085] (3) The dispersive sample slurry in the reactor was subjected to static settlement for the first time, and a resulting supernatant was removed; the cobalt salt solution was sprayed with a single spray head at a flow rate of 1.5 m.sup.3/h and the 220 g/L carbonate solution was sprayed with a single spray head at a flow rate of 2 m.sup.3/h, and after the reactor (10 m.sup.3) was filled up with a slurry, the feeding was stopped; then a cycle of “static settlement-supernatant removal-spraying the cobalt salt solution and 220 g/L carbonate solution with a single spray head-stopping feeding when the reactor was filled up” was repeated until a particle size of a seed crystal reached 10 μm; a seed crystal slurry was dispensed for the first time, the cobalt salt solution was sprayed with a single spray head at a flow rate of 1.5 m.sup.3/h and the 220 g/L carbonate solution was sprayed with a single spray head at a flow rate of 2 m.sup.3/h until a particle size reached 11 μm, where a pH was stably controlled at 7.0. [0086] (4) The cobalt salt solution was further sprayed with a single spray head and the 3 mol/L carbonate solution was further sprayed with a single spray head, where a temperature was controlled at 50° C. and a pH was stably controlled at 7.0; 3 h later, the feeding and the stirring were stopped, a resulting slurry was allowed to stand, and a resulting supernatant was removed; the stirring was started, and the next round of feeding continued; the above feeding was repeated until a solid content in a cobalt carbonate slurry in the reactor reached 450 g/L; the cobalt carbonate slurry was dispensed for the second time, and then the feeding continued with the reaction conditions unchanged; and the above operation was repeated until cobalt carbonate had a target particle size to obtain a spherical cobalt carbonate slurry. [0087] (5) The spherical cobalt carbonate slurry was washed for 50 min, dewatered for 20 min, and dried for 6 h to obtain a spherical cobalt carbonate powder with small particles, which had a median particle size Dv50 of 17.6 μm and a TD of 1.90 g/cm.sup.3. [0088] (6) The dried spherical cobalt carbonate powder was subjected to one-step calcination at 700° C. for 6 h in an air atmosphere to obtain spherical cobaltosic oxide, where the cobalt tetraoxide partially cracked, included small particles, and had a median particle size Dv50 of 15.1 μm.

[0089] There is a sheet-like morphology on the surface of cobalt carbonate particles of Example 1 (FIG. 1). It can be seen from the cross-sectional view (FIG. 2) of the cobaltosic oxide obtained after calcination that there are significant differences between the internal and the external of a particle, with an obvious boundary line, which is caused by crystal transformation. A calcination temperature for preparing the cobaltosic oxide can be adjusted to make the boundary line disappear, as shown in FIG. 3. FIG. 4 is an SEM image of the cobalt carbonate with a non-transformed crystal form in Comparative Example 1, and it can be seen that there are bulges on the surface and there is no sheet-like morphology. As shown in FIG. 5, the cobaltosic oxide obtained by calcining the cobalt carbonate with a non-transformed crystal form has obvious cracks due to stress accumulation, resulting in poor product consistency.

[0090] The present disclosure is described in detail with reference to the accompanying drawings and examples, but the present disclosure is not limited to the above examples. Within the scope of knowledge possessed by those of ordinary skill in the technical field, various changes can also be made without departing from the purpose of the present disclosure. In addition, the examples in the present disclosure or features in the examples may be combined with each other in a non-conflicting situation.