Zirconia powder and method for processing the same

Abstract

The application belongs to the field of ceramic powder processing, and discloses a processing method of zirconium oxide powder, which comprises the following steps: adding deionized water, a first dispersing agent and zirconium oxide powder into a vertical ball mill to mix and grind once to obtain slurry one; adding the slurry one, deionized water and a second dispersing agent into a sand mill to mix and grind twice to obtain slurry two; and then filtering and spray granulating the slurry two to obtain the processed zirconium oxide powder; by controlling the particle size of the zirconium oxide powder, the diameter of zirconium beads during grinding, the adding amount of the dispersing agent and the concentration of the zirconium oxide in the slurry, the zirconium oxide powder with a D90 particle size of 0.6-0.7 microns and a specific surface area of 10.5-11.5 m 2 / g can be obtained; in addition, the application further discloses a zirconium oxide powder prepared by the processing method of the zirconium oxide powder.

Description

TECHNICAL FIELD

[0001] The application relates to the field of ceramic powder processing, in particular to a zirconium oxide powder and a processing method thereof. BACKGROUND

[0002] Zirconium oxide has the properties of high melting point, high hardness and excellent wear resistance, and is widely used in various fields, especially in high-temperature ceramics. When high-temperature ceramic materials are prepared, the particle size and specific surface area of the zirconium oxide powder will affect the performance of the high-temperature ceramic materials, so the particle size and specific surface area of the zirconium oxide are strictly controlled during the production of the zirconium oxide.

[0003] There are a large number of existing technologies for controlling the particle size and specific surface area of the zirconium oxide powder, such as:

[0004] Chinese patent application 202010112534.9 discloses a zirconium oxide powder and a superfine grinding method thereof, and Chinese patent application 201910767179.6 discloses a composite zirconium oxide powder method, a preparation method and an application thereof.

[0005] The above-mentioned existing technologies can control the particle size of the prepared zirconium oxide powder within a certain range.

[0006] The present application finds that by adjusting the concentration of the glue and matching different particle sizes of the zirconium beads during the multiple grinding process, the particle size and specific surface area of the ground zirconium oxide powder can be controlled within a certain range.

[0007] The problem to be solved by the present application is how to control the particle size and specific surface area of the ground zirconium oxide powder. SUMMARY

[0008] The purpose of the present application is to provide a zirconium oxide powder and a processing method thereof, by adding zirconium oxide powder with an initial particle size of 30-50 mu m and controlling the concentration of zirconium oxide in the slurry of the first grinding and the second grinding, a zirconium oxide powder with a D90 particle size of 0.6-0.7 mu m and a specific surface area BET of 10.5-11.5 m 2 / g can be obtained.

[0009] To achieve the above-mentioned purpose, the present application discloses a processing method of a zirconium oxide powder, comprising the following steps:

[0010] Step 1: weigh the zirconium oxide powder, deionized water and first dispersant, mix them in a vertical ball mill, add zirconium beads for the first grinding, and obtain slurry one;

[0011] Step 2: the slurry one, deionized water and the second dispersant are mixed in a sand mill, zirconium beads are added for secondary grinding, and the slurry two is obtained;

[0012] Step 3: the slurry two is filtered and spray granulated, and the processed zirconia powder is obtained;

[0013] The particle size of the zirconia powder is 30-50 μm.

[0014] In the primary grinding, the diameter of the zirconium beads is 4-6 mm, the grinding speed is 500-600 rpm, and the grinding time is 1.5-2 h.

[0015] In the secondary grinding, the diameter of the zirconium beads is 0.3-0.5 mm, the grinding speed is 400-700 rpm, and the grinding time is 70-110 min.

[0016] The mass ratio of the zirconia powder to the deionized water in the slurry one is 50-55:45-50, and the mass ratio of the zirconia powder to the deionized water in the slurry two is 30-35:65-70.

[0017] The total mass of the first dispersant and the second dispersant is 0.2-0.3% of the mass of the zirconia powder, and the mass ratio of the first dispersant to the second dispersant is 1.8-2.2:2.8-3.2.

[0018] When the zirconia powder with an initial particle size of 30-50 μm is ground, different zirconium beads are used for grinding in the primary grinding and the secondary grinding. If the concentration of the slurry does not change, the particle size of the zirconium beads is directly changed to a smaller one. Due to the poor flowability of the slurry during grinding, the grinding effect of the powder is reduced. Changing the concentration of the slurry will inevitably lead to instability of the slurry system and easy occurrence of grain agglomeration. Therefore, the dispersant needs to be supplemented synchronously during the water supplementing process to stabilize the dispersion system, so as to effectively improve the uniformity of the zirconia powder and reduce the particle size of the powder.

[0019] Preferably, the specific operation of the secondary grinding is as follows: first, grinding at a speed of 400-500 rpm for 20-40 min, and then grinding at a speed of 500-700 rpm for 50-70 min.

[0020] Preferably, the addition amount of the zirconium beads in the primary grinding is 430-470 kg, and the addition amount of the zirconium beads in the secondary grinding is 65-75 kg.

[0021] Preferably, the first dispersant and the second dispersant are both polycarboxylate D305 or polycarboxylate AD8098.

[0022] Preferably, the filter screen mesh number in step 3 is 1200 meshes.

[0023] The inlet temperature is 240 DEG C, the outlet temperature is 100 DEG C, the atomizer rotating speed is 14000 rpm, and the pump speed is 0.2 MPa.

[0024] Further, the application discloses a zirconium oxide powder prepared by the processing method.

[0025] Preferably, the D90 particle size of the zirconium oxide powder is 0.6-0.7 μm, and the specific surface area BET is 10.5-11.5 m 2 / g.

[0026] The application has the following beneficial effects:

[0027] The application provides a zirconium oxide powder and a processing method thereof, wherein the zirconium oxide powder with a particle size of 30-50 μm is ground in two steps, the slurry concentration of the first grinding and the second grinding is controlled, and a dispersing agent is added to stabilize the dispersion system while the slurry is controlled, so that the zirconium oxide powder with a D90 particle size of 0.6-0.7 μm and a specific surface area BET of 10.5-11.5 m 2 / g can be obtained after the zirconium beads with different particle sizes are used for grinding. DETAILED DESCRIPTION

[0028] In the description of the application, it should be noted that, in the examples, the specific conditions not mentioned are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not marked with the manufacturer, and are all conventional products that can be purchased on the market.

[0029] Example 1

[0030] Step 1: 100 kg of zirconium oxide powder with a particle size of 40 μm is weighed with deionized water according to a mass ratio of 52.5:47.5, and then added into a vertical ball mill together with a first dispersing agent, mixed, and 450 kg of zirconium beads with a diameter of 5 mm is added and ground at a rotating speed of 550 rpm for 1.8 h to obtain slurry one;

[0031] Step 2: the slurry one, deionized water and a second dispersing agent are added into a sand mill and mixed, and 70 kg of zirconium beads with a diameter of 0.4 mm is added and ground at a rotating speed of 450 rpm for 30 min, and then ground at a rotating speed of 600 rpm for 60 min to obtain slurry two with a mass ratio of zirconium oxide powder to deionized water of 32.5:67.5;

[0032] Step 3: the slurry two is filtered through a 1200 mesh filter screen, and then spray granulation is carried out under the conditions of an inlet temperature of 240 DEG C, an outlet temperature of 100 DEG C, an atomizer rotating speed of 14000 rpm and a pump speed of 0.2 MPa to obtain the processed zirconium oxide powder.

[0033] The first dispersant and the second dispersant are both polycarboxylate D305, and the total mass of the polycarboxylate D305 is 0.25% of the mass of the zirconium oxide powder.

[0034] The mass ratio of the first dispersant to the second dispersant is 2:3.

[0035] Example 2

[0036] Step 1: 100 kg of zirconium oxide powder with a particle size of 30 μm and deionized water were weighed according to a mass ratio of 52.5:47.5, and then were added into a vertical ball mill together with the first dispersant, and 450 kg of zirconium beads with a diameter of 5 mm were added to grind for 2 h at a speed of 500 rpm to obtain slurry one;

[0037] Step 2: The slurry one, deionized water and the second dispersant were added into a sand mill to mix, and 70 kg of zirconium beads with a diameter of 0.4 mm were added to grind for 40 min at a speed of 400 rpm, and then were ground for 70 min at a speed of 500 rpm to obtain slurry two with a mass ratio of 32.5:67.5 of the zirconium oxide powder to the deionized water;

[0038] Step 3: The slurry two was filtered through a 1200 mesh filter screen, and then was spray granulated under the conditions of an inlet temperature of 240 ℃, an outlet temperature of 100 ℃, a speed of an atomizer of 14000 rpm and a pump speed of 0.2 MPa to obtain the processed zirconium oxide powder.

[0039] The first dispersant and the second dispersant are both polycarboxylate D305, and the total mass of the polycarboxylate D305 is 0.25% of the mass of the zirconium oxide powder.

[0040] The mass ratio of the first dispersant to the second dispersant is 2:3.

[0041] Example 3

[0042] Step 1: 100 kg of zirconium oxide powder with a particle size of 50 μm and deionized water were weighed according to a mass ratio of 52.5:47.5, and then were added into a vertical ball mill together with the first dispersant, and 450 kg of zirconium beads with a diameter of 5 mm were added to grind for 1.5 h at a speed of 600 rpm to obtain slurry one;

[0043] Step 2: The slurry one, deionized water and the second dispersant were added into a sand mill to mix, and 70 kg of zirconium beads with a diameter of 0.4 mm were added to grind for 20 min at a speed of 500 rpm, and then were ground for 50 min at a speed of 700 rpm to obtain slurry two with a mass ratio of 32.5:67.5 of the zirconium oxide powder to the deionized water;

[0044] Step 3: The slurry two was filtered through a 1200 mesh screen, and then spray granulated at an inlet temperature of 240℃, an outlet temperature of 100℃, an atomizer rotating speed of 14000 rpm, and a pump speed of 0.2 MPa to obtain the processed zirconia powder.

[0045] The first dispersant and the second dispersant are both polycarboxylate D305, and the total mass of the polycarboxylate D305 is 0.25% of the mass of the zirconia powder.

[0046] The mass ratio of the first dispersant to the second dispersant is 2:3.

[0047] Example 4

[0048] The example 1 is basically the same, except that the diameter of the zirconium beads for the first grinding is 4 mm, and the diameter of the zirconium beads for the second grinding is 0.5 mm.

[0049] Example 5

[0050] The example 1 is basically the same, except that the diameter of the zirconium beads for the first grinding is 6 mm, and the diameter of the zirconium beads for the second grinding is 0.3 mm.

[0051] Example 6

[0052] The example 1 is basically the same, except that the mass ratio of the zirconia powder to deionized water in the slurry one is 50:50, and the mass ratio of the zirconia powder to deionized water in the slurry two is 30:70.

[0053] Example 7

[0054] The example 1 is basically the same, except that the mass ratio of the zirconia powder to deionized water in the slurry one is 55:45, and the mass ratio of the zirconia powder to deionized water in the slurry two is 35:65.

[0055] Example 8

[0056] The example 1 is basically the same, except that the total mass of the first dispersant and the second dispersant is 0.2% of the mass of the zirconia powder.

[0057] Example 9

[0058] The example 1 is basically the same, except that the total mass of the first dispersant and the second dispersant is 0.3% of the mass of the zirconia powder.

[0059] Example 10

[0060] The example 1 is basically the same, except that the amount of the zirconium beads added in the first grinding is 430 kg, and the amount of the zirconium beads added in the second grinding is 75 kg.

[0061] Example 11

[0062] The same as example 1, except that the added amount of zirconium beads in the first grinding is 470 kg and the added amount of zirconium beads in the second grinding is 65 kg.

[0063] Comparative example 1

[0064] Step 1: 100 kg of zirconia powder with a particle size of 50 μm and deionized water were weighed according to a mass ratio of 52.5:47.5, and then added into a vertical ball mill together with the first dispersant, 450 kg of zirconium beads with a diameter of 5 mm were added and ground at a speed of 550 rpm for 1.8 h to obtain slurry one;

[0065] Step 2: The slurry one was added into a sand mill, and 70 kg of zirconium beads with a diameter of 0.4 mm were added and first ground at a speed of 450 rpm for 30 min, and then ground at a speed of 600 rpm for 60 min to obtain slurry two with a mass ratio of zirconia powder to deionized water of 52.5:47.5;

[0066] Step 3: The slurry two was filtered through a 1200 mesh screen, and then spray granulated under the conditions of an inlet temperature of 240 ℃, an outlet temperature of 100 ℃, an atomizer speed of 14000 rpm, and a pump speed of 0.2 MPa to obtain the processed zirconia powder.

[0067] The first dispersant is polycarboxylate D305, and the mass of polycarboxylate D305 is 0.15% of the zirconia powder.

[0068] Comparative example 2

[0069] The same as example 1, except that the particle size of the zirconia powder in step 1 is 20 μm.

[0070] Comparative example 3

[0071] The same as example 1, except that the particle size of the zirconia powder in step 1 is 60 μm.

[0072] Comparative example 4

[0073] The same as example 1, except that the diameter of the zirconium beads in the first grinding is 7 mm and the diameter of the zirconium beads in the second grinding is 0.2 mm.

[0074] Comparative example 5

[0075] The same as example 1, except that the diameter of the zirconium beads in the first grinding is 3 mm and the diameter of the zirconium beads in the second grinding is 0.6 mm.

[0076] Comparative example 6

[0077] The same as example 1, except that the mass ratio of zirconia powder to deionized water in slurry one is 60:40, and the mass ratio of zirconia powder to deionized water in slurry two is 40:60.

[0078] Comparative example 7

[0079] The same as example 1, except that the mass ratio of zirconia powder to deionized water in slurry one is 45:55, and the mass ratio of zirconia powder to deionized water in slurry two is 25:75.

[0080] Performance test:

[0081] The specific surface area of zirconia powder is tested automatically by using a nitrogen adsorption specific surface area tester model 3020. A certain amount of sample prepared by example 1-11 or comparative example 1-7 above is placed in a sample tube, degassed in a degassing station, and then placed in the above instrument to complete the detection automatically, and the specific surface area of the powder is obtained.

[0082] The performance test results are shown in Table 1:

[0083] Table 1

[0084]

[0085]

[0086] Result analysis:

[0087] 1. It can be seen from examples 1-11 that when the initial particle size of zirconia powder, the grinding speed and time of zirconia powder, the diameter and amount of zirconium beads for primary or secondary grinding, the concentration of zirconia powder in slurry one and slurry two, and the amount of the first and second dispersants are changed within a certain range, the D90 particle size of the zirconia powder obtained after processing is within 0.6-0.7 μm, and the specific surface area is within 10.5-11.5 m 2 / g.

[0088] 2. It can be seen from example 1 and comparative example 1 that when the zirconia powder slurry is ground once, the concentration of zirconia in the slurry is not changed, and smaller zirconium beads are used for secondary grinding. The flowability of the slurry is poor during grinding of small particle size zirconium beads, and the grinding effect of the slurry is poor, resulting in an increase in the D90 particle size of the obtained zirconia powder and a decrease in the specific surface area of the powder.

[0089] 3. As can be seen from Example 1 and Comparative Examples 2-3, when using zirconia powder with smaller or larger particle size as raw material for grinding, due to the change of powder particle size, under the same grinding process parameters, the interaction force between particles of the powder with larger particle size is weaker during grinding, leading to insufficient grinding; while the interaction force between particles of the powder with smaller particle size is stronger, and agglomeration phenomenon is prone to occur, which in turn affects further reduction of particle size.

[0090] 4. As can be seen from Example 1 and Comparative Examples 4-5, during grinding, when the initial particle size of the zirconia powder being ground is the same, the zirconia beads with larger or smaller particle size are used for grinding in the process of primary grinding and secondary grinding, due to the different number of times of collision between the zirconia beads with different particle sizes and the zirconia powder within the same time, the D90 particle size of the obtained zirconia powder is affected, and although the zirconia beads with larger particle size in primary grinding and the zirconia beads with smaller particle size in secondary grinding are used in combination, the zirconia powder with the expected particle size and specific surface area cannot be obtained.

[0091] 5. As can be seen from Example 1 and Comparative Examples 6-7, when the concentration of the zirconia powder in the slurry during primary grinding or secondary grinding is further increased or decreased, due to the increase in the number of particles in unit volume when the slurry concentration is high, the collision frequency between particles will increase, leading to the increase in the grinding probability between particles, thereby reducing the particle size of the powder. On the contrary, when the slurry concentration is low, the collision frequency between particles decreases, and the grinding effect of the powder weakens, leading to the increase in particle size.

[0092] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application should be equivalent replacement methods, and are all included in the protection scope of the present application.

Claims

1. A method for processing zirconia powder, characterized in that, Includes the following steps: Step 1: Weigh zirconium oxide powder, deionized water, and the first dispersant, add them to a vertical ball mill and mix. Add zirconium beads and grind once to obtain slurry one. Step 2: Add slurry one, deionized water, and the second dispersant to a sand mill and mix. Add zirconium beads and grind again to obtain slurry two. Step 3: Filter and spray granulate the slurry to obtain the processed zirconium oxide powder; The zirconium oxide powder has a particle size of 30–50 μm. In the first grinding process, the zirconium bead diameter is 4-6 mm, the grinding speed is 500-600 rpm, and the grinding time is 1.5-2 hours. In the secondary grinding process, the zirconium bead diameter is 0.3–0.5 mm, the grinding speed is 400–700 rpm, and the grinding time is 70–110 min. The mass ratio of zirconium oxide powder to deionized water in slurry one is 50-55:45-50, and the mass ratio of zirconium oxide powder to deionized water in slurry two is 30-35:65-70. The total mass of the first dispersant and the second dispersant is 0.2-0.3% of the mass of the zirconium oxide powder, and the mass ratio of the first dispersant to the second dispersant is 1.8-2.2:2.8-3.

2. Both the first dispersant and the second dispersant are polycarboxylate D305 or polycarboxylate AD8098.

2. The method for processing zirconia powder according to claim 1, characterized in that, The specific operation of the secondary grinding is as follows: first grind at a speed of 400-500 rpm for 20-40 minutes, and then grind at a speed of 500-700 rpm for 50-70 minutes.

3. The method for processing zirconia powder according to claim 1, characterized in that, The amount of zirconium beads added in the first grinding is 430-470 kg, and the amount of zirconium beads added in the second grinding is 65-75 kg.

4. The method for processing zirconia powder according to claim 1, characterized in that, In step 3, the filter mesh size is 1200 mesh; During spray granulation, the inlet temperature is 240℃, the outlet temperature is 100℃, the atomizer speed is 14000rpm, and the pump feed rate is 0.2MPa.

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