阅读说明：本技术 一种陶瓷喷墨打印用硅酸锆包裹氧化铁红的制备方法 (Preparation method of zirconium silicate coated iron oxide red for ceramic ink-jet printing ) 是由 刘闰源 陈静 陈仁华 李婧 戴钰 刘文明 于 2019-09-29 设计创作，主要内容包括：本发明公开了一种陶瓷喷墨打印用硅酸锆包裹氧化铁颜料的制备方法。首先将弱碱性溶液缓慢滴入铁盐溶液中形成氢氧化铁溶胶并加热形成氧化铁纳米核,加入氧氯化锆溶液后滴加1～4倍摩尔比的硫酸盐溶液,利用硫酸锆溶解度低的特点使之在氧化铁纳米核表面析出形成致密包裹层,再滴加碳酸盐溶液使硫酸锆包裹层缓慢转化为碳酸锆包裹层,最后加入水玻璃形成氢氧化硅包裹层,干燥煅烧后获得陶瓷喷墨打印用锆铁红颜料；加入分散剂进一步降低颜料粒度,加入金属离子提高颜料鲜红度。本发明使氧化铁颗粒在纳米状态下被包裹,包裹过程致密充分,合成的半成品活性极高,煅烧温度低于800℃,所得颜料粒度小于1微米,颜色鲜红,完全符合陶瓷喷墨打印要求。(The invention discloses a preparation method of a zirconium silicate coated iron oxide pigment for ceramic ink-jet printing. Firstly, slowly dropping a weak alkaline solution into an iron salt solution to form an iron hydroxide sol, heating to form an iron oxide nano core, adding a zirconium oxychloride solution, then dropping a sulfate solution with a molar ratio of 1-4 times, separating out the zirconium sulfate solution on the surface of the iron oxide nano core by utilizing the characteristic of low solubility of the zirconium sulfate to form a compact coating layer, then dropping a carbonate solution to slowly convert the zirconium sulfate coating layer into a zirconium carbonate coating layer, finally adding water glass to form a silicon hydroxide coating layer, and drying and calcining to obtain the zirconium iron red pigment for ceramic ink-jet printing; the dispersant is added to further reduce the granularity of the pigment, and the metal ions are added to improve the bright red degree of the pigment. The invention enables the iron oxide particles to be wrapped in a nano state, the wrapping process is compact and sufficient, the activity of the synthesized semi-finished product is extremely high, the calcining temperature is lower than 800 ℃, the granularity of the obtained pigment is less than 1 micron, the color is bright red, and the requirements of ceramic ink-jet printing are completely met.)

1. A preparation method of zirconium silicate coated iron oxide pigment for ceramic ink-jet printing is characterized by comprising the following steps: the average particle size of the pigment is less than 1 micron, the color is bright red, and the preparation method comprises the following steps:

(1) slowly dripping the weak alkaline solution into Fe³⁺Forming ferric hydroxide colloid solution with pH value of 5-7 in the solution, wherein the concentration of the weak alkaline solution is 0.5-1 mol/L, and Fe³⁺The concentration of the solution is 1-3 mol/L;

(2) adding into the ferric hydroxide colloidal solution obtained in the step (1)Adding a dispersing agent, and continuously stirring for 5-8 hours at 80-90 ℃ to convert the ferric hydroxide colloid into hydrated ferric oxide Fe with the particle size of 20-40 nm₂O₃·nH₂An O nano-core;

(3) adding a zirconium oxychloride solution and a dispersing agent into the hydrated nano-iron oxide nano-core suspension obtained in the step (2), stirring for 5-30 min, then slowly adding a sulfate solution, stirring for 60-120 min to separate zirconium sulfate out on the surface of an iron oxide core to form a particle structure of zirconium sulfate coated iron oxide, and controlling Zr⁴⁺、Fe³⁺、SO₄ ^2-The molar ratio of the three components is (5-8) to 1 (5-32);

(4) adding carbonate solution into the suspension obtained in the step (3), stirring for 60-120 min to convert the zirconium sulfate coating into a zirconium carbonate coating, and controlling SO₄ ^2-、CO₃ ^2-The molar ratio of (1) to (2-4);

(5) adding water glass into the suspension obtained in the step (4), slowly dropwise adding dilute acid to adjust the pH value to be 6-7, adding polyethylene glycol, stirring for 60-120 min, precipitating a silicon hydroxide coating layer on the zirconium carbonate coating layer to form a zirconium-silicon double-coating-layer particle structure, and controlling Zr⁴⁺、SiO₃ ^2-In a molar ratio of 1: (1-1.2);

(6) and (3) obtaining a clean semi-finished product wet block from the suspension obtained in the step (5) through filter pressing and washing, drying the semi-finished product, mixing fluoride salt accounting for 1-5% of the mass of the semi-finished product, and calcining at 700-800 ℃ to obtain the zirconium silicate coated iron oxide pigment for ceramic ink-jet printing.

2. The method for preparing zirconium silicate coated iron oxide pigment for ceramic inkjet printing according to claim 1, further comprising adding Fe to the step (1)³⁺Adding metal ions into the solution, wherein the addition amount of the metal ions is Fe³⁺5-10% of molar use amount, and Ce as metal ion³⁺、Pr³⁺、Bi³⁺One or more than two of them.

3. Zirconium silicate coated iron oxide for ceramic inkjet printing according to claim 1 or 2A process for producing a pigment, characterized in that in the step (1), Fe is used³⁺The solution is one or more than two of ferric nitrate, ferric chloride or ferric sulfate solution, and the weak alkaline solution is one or more than two of ammonia water, ammonium bicarbonate solution, ammonium carbonate solution, sodium bicarbonate solution or sodium carbonate solution.

4. The method for preparing a zirconium silicate coated iron oxide pigment for ceramic inkjet printing according to claim 1 or 2, wherein in the step (2), the dispersant is an aliphatic sulfonate dispersant or a polyether carboxylate dispersant.

5. The method for preparing a zirconium silicate coated iron oxide pigment for ceramic inkjet printing according to claim 1 or 2, wherein in the step (3), the sulfate is sodium sulfate or ammonium sulfate, and the dispersant is a naphthalene-based dispersant or a lignosulfonate dispersant.

6. The method for preparing a zirconium silicate coated iron oxide pigment for ceramic inkjet printing according to claim 1 or 2, wherein in the step (4), the carbonate is sodium carbonate or ammonium carbonate.

7. The method for preparing zirconium silicate coated iron oxide pigment for ceramic inkjet printing according to claim 1 or 2, wherein in the step (5), the dilute acid is dilute hydrochloric acid or dilute sulfuric acid, and the polyethylene glycol is polyethylene glycol 500-2000.

8. The method for preparing zirconium silicate coated iron oxide pigment for ceramic inkjet printing according to claim 1 or 2, wherein in the step (6), the fluoride salt is ammonium fluorosilicate or ammonium fluoride.

Technical Field

The invention belongs to the field of ceramic pigments, and particularly relates to a preparation method of a zirconium silicate coated iron oxide pigment for ceramic ink-jet printing, which aims to reduce the particle size of the pigment and improve the bright red degree of the pigment.

Technical Field

The red ceramic pigment is inorganic mineral crystal powder with stable structure and red color for coloring ceramic blank or glaze, and has calcination temperature over 1000 deg.c and alkali metal or alkali earth metal ion with high temperature corrosion, so that the pigment has very high temperature stability and chemical stability, including zircoferrite red, coated red, cadmium sulfoselenide coated with zircosilicate, and chrome aluminum red, including Cr, and other pigment³⁺Doped aluminum corundum), manganese red (manganese aluminum spinel), chrome tin red (Cr)³⁺Doped tin sphene), and the like, while the ink-jet printing ceramic pigment is an advanced variety of the common ceramic pigment, and has more rigorous and more limited performance requirements. One of the main processes for preparing ceramic inks is to grind ceramic pigments with a sand mill for a long time to a maximum particle size of less than 1 micron. The crystal structure of the mineral can be damaged in the long-time grinding and refining process, the stability and the color development capability of the pigment are weakened, only package red and chrome tin red can be used as red pigments in the field of ink-jet printing at present, and the rest red ceramic pigments cannot develop color after being ground by a sand mill. The chrome tin red is easy to decompose in the high-temperature glaze with the temperature of more than 1100 ℃ due to the crystal structure and the components, so that the applicability is narrow, and the current main ink-jet printing red pigment is coating red. However, the price of the coated red is high, and the coated red contains heavy metal cadmium, so that the cost of the red ink of an ink manufacturer is far higher than that of the red ink of other colors, and the red ink bears the environmental protection risk, so that another new red ceramic ink-jet pigment is urgently needed by the ceramic ink market as a supplement, and more choices are provided for the ink manufacturer.

The zirconium iron oxide red is in a form of zirconium silicate coated iron oxide red, the coated red is in a form of zirconium silicate coated cadmium sulfoselenide, the zirconium iron oxide red and the coated red are different only in color development cores, the coated red can be applied to the field of ceramic ink-jet printing through process upgrading, and theoretically, the zirconium iron oxide red can also be used. However, the two synthetic processes are fundamentally different, the wrapping red is synthesized by adopting a liquid phase method from the beginning of birth, and the ferrozirconium red is synthesized by adopting a traditional solid phase method. The solid phase method for synthesizing the zircoferrite red is simple in process, and is mainly prepared by grinding, uniformly mixing and refining zirconium oxide, iron oxide, quartz, a fluorine-containing mineralizer and the like in a ball mill for a long time, and then calcining at about 1000 ℃. The ferrozirconium red produced by the process is low in price, but the particle size of color development core iron oxide is generally larger than 1 micron and is agglomerated together, zirconium silicate is not uniformly and sufficiently wrapped, the wrapping process is not controlled, so that the whole particles reach 10-20 microns, and the color development of the iron oxide is dark red and not bright due to the higher calcining temperature. The reason is that the currently marketed ferrozirconium red pigment cannot be applied to ceramic ink-jet printing ink.

Disclosure of Invention

In order to solve the technical problems, the invention provides a preparation method of zirconium silicate coated iron oxide pigment for ceramic ink-jet printing, which is synthesized by a salting-out coating process, further reduces the pigment granularity by matching of a dispersing agent, and can further improve the bright red degree of the zirconium iron red pigment by doping metal ions.

The technical scheme of the invention is as follows:

a preparation method of zirconium silicate coated iron oxide pigment for ceramic ink-jet printing is disclosed, wherein the average particle size of the pigment is less than 1 micron, the color is bright red, and the coloring capability is strong; the preparation method comprises the following steps:

(1) slowly dripping the weak alkaline solution into Fe³⁺Forming ferric hydroxide colloid solution with pH value of 5-7 in the solution, wherein the concentration of the weak alkaline solution is 0.5-1 mol/L, and Fe³⁺The concentration of the solution is 1-3 mol/L;

(2) adding a dispersing agent into the ferric hydroxide colloidal solution obtained in the step (1), and continuously stirring for 5-8 hours at the temperature of 80-90 ℃ to convert the ferric hydroxide colloid into hydrated ferric oxide Fe with the particle size of 20-40 nm₂O₃·nH₂An O nano-core;

(3) to the hydration obtained in step (2)Adding zirconium oxychloride solution and a dispersing agent into the iron nano-core suspension, stirring for 5-30 min, then slowly adding a sulfate solution, stirring for 60-120 min to separate zirconium sulfate out on the surface of an iron oxide core to form a particle structure of zirconium sulfate coated iron oxide, and controlling Zr⁴⁺、Fe³⁺、SO₄ ^2-The molar ratio of the three components is (5-8) to 1 (5-32);

(4) adding carbonate solution into the suspension obtained in the step (3), stirring for 60-120 min to convert the zirconium sulfate coating into a zirconium carbonate coating, and controlling SO₄ ^2-、CO₃ ^2-The molar ratio of (1) to (2-4);

(5) adding water glass into the suspension obtained in the step (4), slowly dropwise adding dilute acid to adjust the pH value to be 6-7, adding polyethylene glycol, stirring for 60-120 min, precipitating a silicon hydroxide coating layer on the zirconium carbonate coating layer to form a zirconium-silicon double-coating-layer particle structure, and controlling the molar ratio Zr⁴⁺、SiO₃ ^2-In a molar ratio of 1: (1-1.2);

(6) and (3) obtaining a clean semi-finished product wet block from the suspension obtained in the step (5) through filter pressing and washing, drying the semi-finished product, mixing fluoride salt accounting for 1-5% of the mass of the semi-finished product, and calcining at 700-800 ℃ to obtain the zirconium silicate coated iron oxide pigment for ceramic ink-jet printing.

Further, in the step (1), Fe³⁺The solution is one or more than two of ferric nitrate, ferric chloride or ferric sulfate solution, and the weak alkaline solution is one or more than two of ammonia water, ammonium bicarbonate solution, ammonium carbonate solution, sodium bicarbonate solution or sodium carbonate solution.

Further, in the step (2), the dispersant is an aliphatic sulfonate dispersant or a polyether carboxylate dispersant.

Further, in the step (3), the sulfate is sodium sulfate or ammonium sulfate, and the dispersant is a naphthalene dispersant or a lignosulfonate dispersant.

Further, in the step (4), the carbonate is sodium carbonate or ammonium carbonate.

Further, in the step (5), the dilute acid is dilute hydrochloric acid or dilute sulfuric acid, and the polyethylene glycol is 500-2000 polyethylene glycol.

Further, in the step (6), the fluoride salt is ammonium fluosilicate or ammonium fluoride.

Further, the method also comprises the step (1) of Fe³⁺Adding metal ions into the solution to improve the red degree of the iron oxide red and increase the vividness of the iron oxide, wherein the addition amount of the metal ions is Fe³⁺5-10% of molar use amount, and Ce as metal ion³⁺、Pr³⁺、Bi³⁺One or more than two of them.

The invention has the beneficial effects that:

the invention avoids the defects of uncontrollable coating process, uncontrollable color and uncontrollable granularity in the traditional solid-phase synthesis process of the zirconium iron oxide red, and uniformly precipitates the zirconium iron oxide red on the surface of particles by preparing high-dispersion nano iron oxide suspended particles and utilizing the characteristic of low solubility of zirconium sulfate to form an accurate and compact coating structure. In the process of preparing the semi-finished product, each iron oxide particle is subjected to three coating processes, which are sequentially as follows: zirconium sulfate wrapping, zirconium carbonate wrapping and silicon hydroxide wrapping, and before entering the next wrapping stage, dispersing agents are added to separate and disperse suspended particles, so that the agglomeration phenomenon is prevented. In addition, the semi-finished product synthesized by the process is an amorphous superfine compound formed under the liquid phase condition, has extremely high reaction activity, can react at the temperature of below 800 ℃ to form zirconium silicate crystals, further prevents pigment particles from growing, and finally obtains zirconium silicate coated iron oxide red pigment with the average particle size of below 1 micron, which completely meets the process requirements of ceramic ink-jet printing. In terms of color, iron oxide is easy to change into dark red tone at a high temperature of more than 1000 ℃, while in the process of the invention, the calcining temperature of the pigment is below 800 ℃, so that the iron oxide can be ensured to be still bright red, and in addition, the Ce is used for ensuring that the iron oxide is still bright red³⁺、 Pr³⁺、Bi³⁺The ion doping can further improve the bright red degree of the pigment, so that the bright red color tone of cadmium sulfoselenide is achieved.

In a word, the raw materials adopted by the invention are cheap and environment-friendly, and the pigment has the characteristics of superfine bright red, so that the zirconium iron red pigment prepared by the process of the invention becomes another red pigment which can be well applied to the field of ceramic ink-jet printing after being coated with red.

Drawings

FIG. 1 is a particle size distribution diagram of a zirconium iron red pigment synthesized by the salting-out wrapping method of the invention.

FIG. 2 is a transmission electron microscope image of a zirconium iron red pigment synthesized by salting-out wrapping method according to the present invention.

Detailed Description

The present invention will be described in further detail with reference to specific examples, but the present invention is not limited thereto.