Preparation method of zirconium-iron red pigment for ceramic inkjet and application thereof

Abstract

The application provides a preparation method of a zirconium-iron red pigment for ceramic inkjet printing, and comprises the following steps: S1: a first dispersant solution is mixed with a zirconium-containing powder to perform first ball milling, to obtain a first mixed slurry; S2: the first mixed slurry is mixed with an iron-containing powder to perform second ball milling, to obtain a second mixed slurry; S3: the second mixed slurry is subjected to third ball milling, to obtain a third mixed slurry; the third mixed slurry is subjected to solid-liquid separation, and the solid phase material is taken out, dried, mixed with a silica sol and a second dispersant solution, and subjected to fourth ball milling, to obtain a fourth mixed slurry; and S4: the fourth mixed slurry is dried, mixed with a fluoride mineralizer, and calcined, to obtain the zirconium-iron red pigment for ceramic inkjet printing. The application selects raw materials, combines physical grinding and chemical decomposition reaction, reduces the particle size of reactants, reduces the reaction temperature, and finally obtains the zirconium-iron red pigment with a particle size of less than 1 microns, which is applied to ceramic inkjet printing.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of ceramic ink, and particularly relates to a preparation method of zirconium-iron red pigment for ceramic inkjet and application thereof. BACKGROUND

[0002] The traditional decoration process of ceramic is mainly screen printing, and the zirconium-iron red pigment has bright color and strong color development under the decoration process. The process for manufacturing the zirconium-iron red pigment adopts a solid phase method, that is, zirconia, iron red and quartz powder are ball milled for ten hours, then a mineralizer is added and loaded into a sagger, and then firing is performed at about 1100 DEG C. The average particle size of the zirconium-iron red after firing is about 20 microns. The manufacturing process of the pigment is simple, has little environmental pollution and low manufacturing cost, and is the only red pigment with good color development and high cost performance on the market.

[0003] Nowadays, the decoration process of ceramic is mainly inkjet printing. The most basic requirement of the inkjet printing on the pigment is that the average particle size of the particles is less than 1 micron. The particle size of the zirconium-iron red pigment prepared by the traditional solid phase method reaches 20 microns, which is much larger than 1 micron. If the zirconium-iron red pigment with a particle size larger than 20 microns is applied to the inkjet printing process, the color development is weak. If the zirconium-iron red pigment is directly crushed to below 1 micron in the traditional way, the surface structure will be damaged, resulting in poor color development. Therefore, it is urgent to find a new preparation method to control the particle size of the zirconium-iron red pigment to below 1 micron. SUMMARY

[0004] The present application is directed to at least one of the problems existing in the prior art. To this end, the present application provides a preparation method of zirconium-iron red pigment for ceramic inkjet and application thereof. The zirconium-iron red pigment can be applied to the inkjet printing process and has good color development effect.

[0005] According to a first aspect of the present application, a preparation method of zirconium-iron red pigment for ceramic inkjet is provided, comprising the following steps:

[0006] S1: a first dispersant solution is mixed with zirconium-containing powder to perform first ball milling, to obtain a first mixed slurry;

[0007] S2: the first mixed slurry is mixed with iron-containing powder to perform second ball milling, to obtain a second mixed slurry;

[0008] S3: the second mixed slurry is subjected to third ball milling to obtain a third mixed slurry; the third mixed slurry is subjected to solid-liquid separation, and the solid phase material is dried and mixed with silica sol and a second dispersant solution to perform fourth ball milling, to obtain a fourth mixed slurry;

[0009] S4: the fourth mixed slurry is dried and mixed with a fluoride mineralizer to perform calcination, to obtain the zirconium-iron red pigment for ceramic inkjet.

[0010] Preferably, the particle size of the ball milling beads used in the first, second and third ball milling processes is 0.3-0.4 mm.

[0011] Preferably, the size grading of the ball milling beads used in the fourth ball milling process is 2:3:5 for large, medium and small ball milling beads, respectively, and the particle size of the large, medium and small ball milling beads is 1.5 cm, 0.8 cm and 0.4 cm, respectively.

[0012] Preferably, the rotation speed of the first, second and third ball milling processes is 1200 rpm.

[0013] Preferably, the rotation speed of the fourth ball milling process is 250 rpm.

[0014] More preferably, the ball milling beads are zirconium beads.

[0015] Preferably, the first and second dispersant solutions are independently prepared by dissolving a dispersant in water, and the mass concentration of the first and second dispersant solutions is independently 0.1-0.15%. The present application can reduce the particle size of the raw materials without agglomeration in the presence of the dispersant system.

[0016] More preferably, the dispersant is a mixture of polyacrylic acid sodium salt and polyphosphate, and / or the mass ratio of the polyacrylic acid sodium salt and polyphosphate is about 4:1. The use of the dispersant composition can improve the grinding efficiency.

[0017] Preferably, in step S1, the mass ratio of the ball milling beads to the first dispersant solution is 2-3:1.

[0018] Preferably, in step S1, the zirconium-containing powder is at least one of zirconium hydroxide and zirconium carbonate.

[0019] Preferably, in step S1, the amount of the zirconium-containing powder is 0.4-0.5 mol per 200 g of the first dispersant solution, calculated based on the molar amount of zirconium.

[0020] Preferably, in step S2, the iron-containing powder is iron hydroxide.

[0021] Preferably, in step S2, the amount of the iron-containing powder is 0.25-0.35 mol per 200 g of the first dispersant solution, calculated based on the molar amount of iron.

[0022] The present application uses zirconium hydroxide or zirconium carbonate and iron hydroxide as raw materials, rather than directly using traditional zirconium oxide and iron oxide, because zirconium hydroxide or zirconium carbonate and iron hydroxide can decompose in the calcination process, thereby reducing the particle size of the reactants. The reaction equation is as follows:

[0023] Zr(OH)4 = ZrO2 + H2O

[0024] ZrCO3 = ZrO2 + CO2↑

[0025] Fe(OH)3 = Fe2O3 + H2O

[0026] Preferably, the time of the first ball milling is 20-30 min; and / or, the time of the second ball milling is 40-60 min.

[0027] Preferably, the D50 of the first mixed slurry is 0.3-0.4 μm, and the D100 is 0.5-0.6 μm; and / or, the D50 of the second mixed slurry is 0.2-0.3 μm, and the D100 is 0.4-0.5 μm.

[0028] The zirconium-containing powder and the iron-containing powder are ground in a proper dispersant for a long time, and the particle size is changed from large to small. When the particle size D50 is less than or equal to 0.5 μm, the contact between the materials is most sufficient, and the quality of the synthesized zirconium-iron red pigment is optimal.

[0029] Preferably, the time of the third ball milling is 180-360 min.

[0030] Preferably, the D50 of the third mixed slurry is 0.6-0.7 μm, and the D100 is 1.3-1.4 μm.

[0031] The time of the third ball milling is greatly increased relative to the first and second ball milling, and the particle size of the slurry is not only not reduced but also increased. This phenomenon is not caused by the increase of the particle size of the monomer powder, but is caused by the repeated grinding and extrusion of the zirconium-containing powder and the iron-containing powder, and the particles are stacked and compacted layer by layer, so that the mixing effect is sufficient, the contact distance between the raw materials is reduced, the subsequent sintering temperature is reduced, the reaction can occur at a lower temperature, the growth rate of the zirconium silicate crystal is slowed down, and the product with smaller particle size is generated.

[0032] Preferably, in step S3, the process of solid-liquid separation is that the third mixed slurry is left to stand and precipitate for more than 12 h, and the supernatant is discarded.

[0033] Preferably, in step S3, the temperature of the drying is about 120 ℃; and the time of the drying is greater than 24 h.

[0034] Preferably, in step S3, the moisture content of the solid-phase material after drying is less than 0.4%.

[0035] Preferably, in step S3, the silica content of the silica sol is 29%-31%.

[0036] Preferably, in step S3, the silica particle size of the silica sol is 5-120 nm.

[0037] The present application uses silica sol instead of ordinary quartz powder or nano fumed silica, because the particle size of ordinary quartz powder is usually about 10 μm, which cannot meet the requirement of small particle size, and although the particle size of fumed silica is very small, its specific surface area is too large, which cannot contact with other reactants, that is, the space distance between raw materials is too far, which is not conducive to the reaction. The silica sol itself is a solution of nano-sized silica formed in water, after sufficient ball milling mixing, the silica is uniformly precipitated on the surface of the zirconium-iron powder by subsequent low-temperature drying, which meets the requirement of reaction.

[0038] Preferably, in step S3, the mass ratio of the solid phase material, the silica sol and the second dispersant solution is 75:80-100:50.

[0039] Preferably, in step S3, the fourth ball milling time is about 30 min. The fourth ball milling is to mix the zirconium-iron powder and the silica in the silica sol uniformly, and the particle size of the powder is not reduced after ball milling.

[0040] Preferably, in step S4, the drying temperature is about 60℃, and the drying time is greater than 12 h.

[0041] Preferably, in step S4, after the fourth mixed slurry is dried, the water content is less than 0.2%.

[0042] Preferably, in step S4, the fluoride mineralizer is at least one of sodium fluorosilicate, sodium fluoride or lithium fluoride; and / or, the mass of the fluoride mineralizer is 3%-8% of the mass of the third mixed slurry after drying.

[0043] Preferably, in step S4, the calcination temperature is 800-900℃, and the calcination time is 2 h.

[0044] The present application reduces the particle size of the reactants by selecting raw materials and combining physical grinding and chemical decomposition reaction, and reduces the reaction temperature, and finally obtains zirconium-iron red material with a particle size of less than 1 μm for ceramic inkjet printing.

[0045] According to the second aspect of the present application, the preparation method of the first aspect of the present application is applied in the preparation of ceramic inkjet colorant.

[0046] According to one embodiment of the present application, at least the following beneficial effects are achieved:

[0047] 1. The raw materials used to produce traditional zirconium iron red pigment have a particle size between a few micrometers and tens of micrometers. The reaction to produce zirconium silicate is a synthesis reaction, and the reaction equation is: ZrO2 + SiO2 + O2 = ZrSiO4. The particle size of the product of the synthesis reaction will be larger, so the particle size of traditional products is generally around 20μm. However, the zirconium iron red pigment used for inkjet printing requires a particle size of less than 1μm. This requires the raw material to have the smallest possible particle size in order to make the target product have an even smaller particle size.

[0048] Zirconium iron red pigment is a type of pigment in which the iron oxide that produces the color is encapsulated in zirconium silicate crystals. To achieve a particle size of less than 1 μm for zirconium iron red pigment, the particle size of the encapsulated iron oxide should be as small as possible. In addition, the encapsulated zirconium silicate should not only have the smallest particle size, but also have a slow crystal growth rate in order to prepare zirconium iron red pigment with small particle size and good color development.

[0049] This invention employs multiple ball milling processes to reduce the particle size of the raw materials, and the raw material particles do not agglomerate in the presence of the dispersant system. During the third ball milling, the milling time is significantly increased compared to the first and second ball milling, but the particle size of the slurry not only does not decrease but actually increases. This phenomenon of coarsening the particle size helps to reduce the contact distance between the raw materials, lower the firing temperature, and allow the reaction to occur at a lower temperature, thereby slowing down the growth rate of zirconium silicate crystals and facilitating the preparation of zirconium iron red material with smaller particle size and better color.

[0050] 2. This invention reduces the particle size of raw materials twice through physical grinding and chemical decomposition, resulting in a very small original particle size of the raw materials for synthesizing zirconium iron red material, thereby producing zirconium iron red material that meets the particle size requirements. Attached Figure Description

[0051] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0052] Figure 1 This is a 20,000x magnified SEM image of the zirconium iron red pigment for ceramic inkjet prepared in Example 4 of the present invention.

[0053] Figure 2 This is a particle size distribution diagram of the zirconium iron red pigment for ceramic inkjet prepared in Example 4 of the present invention. Detailed Implementation

[0054] The following will describe the concept and technical effects of the present invention clearly and completely with reference to the embodiments, so as to fully understand the purpose, features and effects of the present invention. Unless otherwise specified, the raw materials used in the following embodiments and comparative examples are all conventional products that can be purchased commercially.

[0055] Example 1

[0056] This embodiment provides a method for preparing zirconium iron red pigment for ceramic inkjet printing, including the following steps:

[0057] 1. Add 4g of sodium polyacrylate (molecular weight 20000) and 1g of sodium tripolyphosphate to 5000g of water to prepare a standard solution. Take 200g of the standard solution for later use.

[0058] 2. Add 550 grams of 0.3-0.4 mm zirconium beads to the ball mill jar, and then add the 200 grams of the prepared standard solution to the ball mill jar.

[0059] 3. Weigh 0.40 mol of zirconium hydroxide powder and add it to a ball mill jar. After milling at 1200 rpm for 25 minutes, the particle size of the powder is measured to be D50 = 0.325 μm and D100 = 0.515 μm.

[0060] 4. Weigh 0.25 mol of iron hydroxide powder and add it to the ball mill jar above. Then, ball mill it again at 1200 rpm for 50 minutes. The particle size of the mixed powder is D50 = 0.218 μm and D100 = 0.446 μm.

[0061] 5. Continue ball milling at 1200 rpm for 240 minutes, and then test the particle size of the mixed powder: D50 = 0.625 μm, D100 = 1.339 μm. Pour the above slurry into a container, let it stand and settle for 12 hours, pour off the supernatant, and then put the container into a 120℃ drying oven and dry for 24 hours. The moisture content is 0.35%.

[0062] 6. Weigh 80g of silica sol with a silica content of 29% to 31%, add it together with the above-mentioned dried material and 50g of standard solution into a ball mill jar containing matching zirconium beads of different sizes. The ball mill speed is 250 rpm. After ball milling for 30 minutes, the mixture is removed and placed in a 60-degree drying oven for 12 hours. The moisture content is tested and found to be 0.16%.

[0063] The specific matching method of the zirconium beads is as follows: a total of 1.2kg of zirconium beads, with the sizes of large, medium and small zirconium beads being 1.5cm, 0.8cm and 0.4cm respectively, in a ratio of 2:3:5.

[0064] 7. Mix the above-mentioned dried material with 5% (by weight) of lithium fluoride mineralizer powder and calcine at 850°C for 2 hours. The resulting product is zirconium iron red ceramic pigment for inkjet printing.

[0065] Example 2

[0066] This embodiment provides a method for preparing zirconium iron red pigment for ceramic inkjet printing, which differs from Embodiment 1 in that:

[0067] In step 3, the molar amount of zirconium hydroxide powder is 0.50 mol. After undergoing the same ball milling treatment, the particle size of the powder is measured to be D50 = 0.358 μm and D100 = 0.586 μm.

[0068] In step 4, the molar amount of ferric hydroxide was 0.35 mol. After the same ball milling treatment, the particle size of the powder was measured to be D50 = 0.266 μm and D100 = 0.483 μm.

[0069] In step 5, after the same ball milling process, the particle size of the mixed powder was measured to be D50 = 0.635 μm and D100 = 1.396 μm.

[0070] In step 6, the amount of silica sol used is 100g;

[0071] In step 7, the amount of lithium fluoride mineralizer used is 8% of the mass of the dried material, and the calcination temperature is 800℃.

[0072] Example 3

[0073] This embodiment provides a method for preparing zirconium iron red pigment for ceramic inkjet printing, which differs from Embodiment 2 in that:

[0074] In step 3, zirconium hydroxide powder is replaced with an equal amount of zirconium carbonate powder;

[0075] In steps 3, 4, and 5, after undergoing the same ball milling process, the particle size of the powder was found to be very similar to that in Example 2.

[0076] In step 7, the lithium fluoride mineralizer is replaced with an equal amount of lithium fluoride and sodium fluoride mixture, wherein the mass ratio of lithium fluoride to sodium fluoride is 4:1, and the calcination temperature is 850℃.

[0077] Example 4

[0078] This embodiment provides a method for preparing zirconium iron red pigment for ceramic inkjet printing, which differs from Embodiment 2 in that:

[0079] In step 7, the lithium fluoride mineralizer is replaced with an equal amount of sodium fluorosilicate and sodium fluoride mixture, wherein the mass ratio of sodium fluorosilicate to sodium fluoride is 1:4, and the calcination temperature is 900℃.

[0080] The SEM image of the zirconium iron red pigment for ceramic inkjet prepared in this embodiment is shown below. Figure 1 As shown, the particle size distribution diagram is as follows: Figure 2 As shown.

[0081] Comparative Example 1

[0082] This comparative example provides a traditional method for preparing common zirconium iron red pigment for screen printing processes, the solid-state process being as follows:

[0083] 1. Grind zirconium oxide and iron oxide red in a ball mill equipped with iron balls of different sizes in different proportions for 90 minutes;

[0084] 2. Add ordinary quartz powder and ball mill for another 120 minutes;

[0085] 3. Add 6% sodium fluoride by total mass, then ball mill for 30 minutes, unload and pack into a bowl;

[0086] 4. Calcine at 1100℃ for 2 hours;

[0087] This yields ordinary zirconium iron red material.

[0088] In the above steps, the molar amounts of zirconium, iron, and silicon are the same as in Example 1.

[0089] Test case

[0090] The color development properties (matte glaze at 1200℃) of the zirconium iron red pigments prepared in Examples 1-4 and Comparative Example 1 are shown in the table below:

[0091]

[0092] Analysis of the table above shows that the particle size of the zirconium iron red pigments obtained in all examples is less than 1 μm. When producing ceramic inkjet printing ink, only slight grinding for a short time is needed to meet the particle size and color development requirements of zirconium iron red ink. However, the comparative examples, due to their large particle size, require prolonged grinding to meet the particle size requirements, resulting in poor color development and failing to meet the requirements of zirconium iron red ink. Example 1 has the smallest particle size, causing the least damage to color development, thus achieving the best color. In Example 2, increasing the amount of reactants slightly increased the particle size, leading to a decrease in color strength. In Example 3, changing the type of raw materials and using mixed mineralization had some impact on both particle size and color development, but not a significant one. In Example 4, changing only the type of mineralizer had a relatively large impact on both color development and particle size. In Comparative Example 1, the larger particle size resulted in a lighter, less reddish color, leaning towards yellow, and a weakened color strength. In conclusion, the zirconium iron red pigment prepared using the method of this invention has a significantly improved quality compared to zirconium iron red pigment prepared by the traditional solid-phase method, and can fully meet the requirements of ceramic inkjet printing ink.

[0093] The embodiments of the present invention have been described in detail above with reference to the diagrams. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A method for preparing zirconium iron red pigment for ceramic inkjet printing, characterized in that, Includes the following steps: S1: The first dispersant solution is mixed with zirconium-containing powder and ball-milled for the first time to obtain a first mixed slurry, wherein the zirconium-containing powder is at least one of zirconium hydroxide or zirconium carbonate; S2: The first mixed slurry is mixed with iron-containing powder and ball-milled a second time to obtain a second mixed slurry, wherein the iron-containing powder is iron hydroxide; S3: The second mixed slurry is ball-milled for the third time to obtain a third mixed slurry; the third mixed slurry is separated into solid and liquid phases, the solid phase material is dried and then mixed with silica sol and the second dispersant solution for a fourth ball milling to obtain a fourth mixed slurry; S4: After drying the fourth mixed slurry, it is mixed with a fluoride mineralizer and calcined to obtain zirconium iron red material for ceramic inkjet printing; The first mixed slurry has a D50 of 0.3~0.4μm and a D100 of 0.5~0.6μm; the second mixed slurry has a D50 of 0.2~0.3μm and a D100 of 0.4~0.5μm; and the third mixed slurry has a D50 of 0.6~0.7μm and a D100 of 1.3~1.4μm.

2. The preparation method according to claim 1, characterized in that, The first dispersant solution and the second dispersant solution are prepared independently by dissolving the dispersant in water; the mass concentrations of the first dispersant solution and the second dispersant solution are independently 0.1~0.15%.

3. The preparation method according to claim 2, characterized in that, The dispersant is a mixture of sodium polyacrylate and polyphosphate; and / or, the mass ratio of the sodium polyacrylate to the polyphosphate is approximately 4:

1.

4. The preparation method according to claim 1, characterized in that, In step S3, the silica sol has a silica content of 29% to 31%.

5. The preparation method according to claim 1, characterized in that, In step S4, the fluoride mineralizing agent is at least one of sodium fluorosilicate, sodium fluoride, or lithium fluoride; and / or, the mass of the fluoride mineralizing agent is 3% to 8% of the mass of the third mixed slurry after drying.

6. The application of the preparation method according to any one of claims 1-5 in the preparation of ceramic inkjet pigments.

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