CN112409823A - Hydrothermal preparation method of mullite coated particles - Google Patents

Hydrothermal preparation method of mullite coated particles Download PDF

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CN112409823A
CN112409823A CN202011313540.7A CN202011313540A CN112409823A CN 112409823 A CN112409823 A CN 112409823A CN 202011313540 A CN202011313540 A CN 202011313540A CN 112409823 A CN112409823 A CN 112409823A
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hydrothermal reaction
coated
hydrothermal
mullite
particles
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程科恺
秦伍
张翼
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Guangdong Dowstone Technology Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
    • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
    • C09C1/10—Compounds of cadmium
    • C09C1/12—Cadmium sulfoselenide
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
    • C09C3/00—Treatment in general of inorganic materials, other than fibrous fillers, to enhance their pigmenting or filling properties
    • C09C3/06—Treatment with inorganic compounds
    • C09C3/063—Coating
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/04—Particle morphology depicted by an image obtained by TEM, STEM, STM or AFM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/60—Optical properties, e.g. expressed in CIELAB-values

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  • Organic Chemistry (AREA)
  • Pigments, Carbon Blacks, Or Wood Stains (AREA)
  • Silicates, Zeolites, And Molecular Sieves (AREA)

Abstract

The invention discloses a hydrothermal preparation method of mullite coated particles. The mullite-coated particle is obtained by mixing a precursor component of the particle to be coated with an aluminum source or a silicon source, carrying out hydrothermal reaction to generate a precipitate, and then sequentially adding the precursor component and the silicon source or the aluminum source, and carrying out hydrothermal reaction. According to the implementation of the method, the hydrothermal synthesis of the mullite coated particles is realized for the first time, and the preparation of the coated particles with low cost is facilitated. Particularly, in the prepared mullite-coated cadmium sulfoselenide pigment, the color development core of the cadmium sulfoselenide is uniformly dispersed in an inclusion, no cadmium is left outside, the whole synthesis environment is carried out in a sealed hydrothermal kettle, and no waste gas or sewage is discharged.

Description

Hydrothermal preparation method of mullite coated particles
Technical Field
The invention relates to a preparation method of a coating material, in particular to a hydrothermal preparation method of mullite coated particles.
Background
The coated particulate material generally comprises a core material and a protective layer coating the core material. In the ceramic ink-jet printing industry, the wrapping type pigment can avoid the normal color development of the pigment with high temperature instability and improve the color development effect, so that the service temperature range of the pigment is improved, and more attention is paid to people.
The existing coating particles mainly comprise classical coating particles such as silicon dioxide coating particles, zirconium silicate coating particles and the like. However, the coating materials of silicon dioxide and zirconium silicate also have certain defects, and the preparation process is relatively complex or the cost is relatively high.
Mullite (or mullite) refers to a series of minerals collectively composed of aluminosilicates. The mullite component is not fixed and has a chemical formula of 3Al2O3·2SiO2Or 2 Al2O3·SiO2Its alumina content fluctuates between 72% and 78%. Mullite is a mineral formed by aluminosilicate at high temperature, and mullite is formed when aluminosilicate is artificially heated. Natural mullite crystals are elongated needles or rods and in the form of radioactive clusters. Mullite ore is used to produce high temperature refractories. The composite material is used as a thermal barrier coating in C/C composite materials and has wide application. The mullite has the advantages of excellent thermal shock resistance, high creep resistance, high temperature stability, acid and alkali corrosion resistance and the like, the stability of the mullite is not worse than that of zirconium silicate, and the price of the basic synthesis raw material aluminum salt is far lower than that of the synthesis raw material zirconium salt of zirconium silicate. However, the mullite is easy to grow directionally into a rod shape in the growth process and cannot effectively wrap the object.
Taking ceramic ink-jet printing coating pigment as an example, most preparation methods cannot effectively coat cadmium sulfoselenide, and a mature coating method only coats zirconium silicate. If a breakthrough can be made in the mullite coating technology, the production cost of coating the scarlet pigment is greatly reduced, and the related industries make revolutionary progress.
Ceramic ink-jet printing technology is widely applied to ceramic tile surface decoration, the main color development component of the printing ink is ceramic pigment, and the maximum particle size of the pigment in the ceramic ink is required to be less than 1 micron due to the limitation of the aperture of a spray head of a ceramic ink-jet printer and the requirement of ink stability. For common ceramic pigments, the particle size can meet the requirement of ink by simple physical grinding and crushing, but cadmium selenide sulfide can be red at a high temperature of 1200 ℃ under the protection of a coating shell, and the damage of the coating shell can be caused by physical grinding, so that the red pigment fails, so that the traditional method for reducing the particle size by grinding and crushing is not suitable for coating the red pigment, and the original particle size of the coating pigment at the beginning of synthesis is required to be below 1 micron. Therefore, if the mullite-coated cadmium selenide sulfide pigment can also be used for ceramic ink-jet printing ink, the original particle size of the synthesized pigment is required to be less than 1 micron, and the technical difficulty is higher.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a hydrothermal preparation method of mullite-coated particles, in particular a hydrothermal preparation method of mullite-coated cadmium sulfoselenide pigment.
The technical scheme adopted by the invention is as follows:
in a first aspect of the present invention, there is provided:
a hydrothermal preparation method of mullite coated particles comprises the following steps:
sa-1) precursor liquid configuration: uniformly mixing aluminum salt, an auxiliary agent and part of precursor salt of the particles to be coated, and adjusting the pH value of the mixed solution;
sa-2) first hydrothermal reaction: transferring the precursor liquid into a hydrothermal kettle, and carrying out hydrothermal reaction to obtain amorphous alumina slurry;
sa-3) second hydrothermal reaction: adding the residual precursor salt solution of the particles to be coated into the amorphous alumina slurry, and carrying out a second hydrothermal reaction to obtain amorphous alumina-coated particles;
sa-4) third hydrothermal reaction: adding a silicon source into the particle slurry coated by the amorphous alumina, adjusting the pH, coating amorphous silicon hydroxide on the surface of the amorphous alumina, and carrying out a third hydrothermal reaction to obtain mullite-coated particle slurry;
s5) cleaning and drying to obtain finished mullite wrapped particles; or
Sb-1) precursor liquid configuration: uniformly mixing a silicon source, an auxiliary agent and part of precursor salt of the particles to be coated, and adjusting the pH value of the mixed solution;
sb-2) first hydrothermal reaction: transferring the precursor liquid into a hydrothermal kettle, and carrying out hydrothermal reaction to obtain amorphous silicon hydroxide slurry;
sb-3) second hydrothermal reaction: adding the residual precursor salt solution of the particles to be coated into the amorphous silicon hydroxide slurry, and carrying out a second hydrothermal reaction to obtain particles coated by amorphous silicon hydroxide;
sb-4) a third hydrothermal reaction: adding aluminum salt into the particle slurry coated by the amorphous silicon hydroxide, adjusting the pH value, coating amorphous alumina on the surface of the amorphous silicon hydroxide, and carrying out a third hydrothermal reaction to obtain mullite-coated particle slurry;
s5) cleaning and drying to obtain finished mullite wrapped particles; or
Sc-1) amorphous alumina coating: uniformly mixing aluminum salt, an auxiliary agent and the particles to be coated, adjusting the pH of the mixed solution, and carrying out a first hydrothermal reaction to obtain amorphous alumina-coated particles;
sc-2) second hydrothermal reaction: adding a silicon source into the particle slurry coated by the amorphous alumina, adjusting the pH, coating amorphous silicon hydroxide on the surface of the amorphous alumina, and performing a second hydrothermal reaction to obtain mullite-coated particle slurry;
s3) cleaning and drying to obtain finished mullite wrapped particles; or
Sd-1) amorphous silicon hydroxide coating: uniformly mixing a silicon source, an auxiliary agent and particles to be coated, adjusting the pH of the mixed solution, and carrying out a first hydrothermal reaction to obtain amorphous silicon hydroxide coated particles;
sd-2) second hydrothermal reaction: adding aluminum salt into the particle slurry coated by the amorphous silicon hydroxide, adjusting the pH value, coating amorphous alumina on the surface of the amorphous silicon hydroxide, and carrying out a second hydrothermal reaction to obtain mullite-coated particle slurry;
s3) cleaning and drying to obtain the finished mullite wrapped particles.
In some examples, the temperature of each hydrothermal reaction is independently:
the temperature of the hydrothermal reaction in the step Sa-2) is 100-120 ℃;
the temperature of the hydrothermal reaction in the step Sa-3) is 110-130 ℃;
the temperature of the hydrothermal reaction in the step Sa-4) is 160-200 ℃;
the temperature of the hydrothermal reaction in the step Sb-2) is 100-120 ℃;
the temperature of the hydrothermal reaction in the step Sb-3) is 110-130 ℃;
the temperature of the hydrothermal reaction in the step Sb-4) is 160-200 ℃;
the temperature of the hydrothermal reaction in the step Sc-1) is 110-130 ℃;
the temperature of the hydrothermal reaction in the step Sc-2) is 160-200 ℃;
the temperature of the hydrothermal reaction in the step Sd-1) is 110-130 ℃;
the temperature of the hydrothermal reaction in the step Sd-2) is 160-200 ℃.
In some examples, the molar ratio of Si in the silicon source to Al in the aluminum salt is (2-2.5): 3.
in some examples, the aluminum salt is independently selected from at least one of sulfate, chloride, nitrate salts of aluminum; the silicon source is independently selected from water glass.
In a second aspect of the present invention, there is provided:
the hydrothermal preparation method of mullite coated cadmium sulfoselenide comprises the following steps:
s1) precursor liquid configuration: mixing aluminum salt, cadmium salt, thiourea, urea and a dispersing agent, and adjusting the pH to be 3-3.5;
s2) first hydrothermal reaction: transferring the precursor liquid into a hydrothermal kettle, preserving heat at 100-120 ℃, and carrying out a first hydrothermal reaction to form porous amorphous alumina-coated cadmium sulfide slurry;
s3) second hydrothermal reaction: dissolving selenium powder in a sulfide solution according to a molar ratio Se: S: Cd = (0.2-0.5): 1, adding the solution into amorphous alumina-coated cadmium sulfide slurry, preserving heat at 110-130 ℃, and carrying out a second hydrothermal reaction to ensure that selenium permeates into cadmium sulfide to form porous amorphous alumina-coated cadmium selenide sulfide slurry;
s4) a third hydrothermal reaction: adding water glass and a mineralizer into the amorphous alumina-coated selenium cadmium sulfide slurry, adjusting the pH to be 7-8, carrying out a third hydrothermal reaction on amorphous alumina-coated amorphous silicon hydroxide and heat preservation at 160-200 ℃ to obtain mullite-coated cadmium selenide sulfide slurry;
s5) carrying out solid-liquid separation, cleaning and drying on the mullite-coated cadmium selenide sulfide slurry to obtain the mullite-coated cadmium selenide sulfide.
In some examples, the precursor liquid has an aluminum salt concentration of 0.5 to 2mol/L in terms of Al, a cadmium salt concentration of 0.005 to 0.020mol/L in terms of Cd, a thiourea concentration of 0.005 to 0.03mol/L, and a urea concentration of 0.5 to 3 mol/L.
In some examples, the third hydrothermal reaction is carried out by adding a silicon source and a fluorine-containing mineralizer according to a molar ratio of Si: Al: F = (2-2.5) = (0.005-0.01).
In some examples, the sulfide salt is selected from at least one of ammonium sulfide, sodium sulfide.
In some examples, the aluminum salt is independently selected from at least one of a sulfate, chloride, nitrate salt of aluminum.
In some examples, the silicon source is independently selected from water glass.
In some examples, the mineralizer is selected from ammonium fluoride, lithium fluoride, sodium fluoride, potassium fluoride, sodium fluorosilicate.
In some examples, the dispersant is one or more of a naphthalene-based, sulfamic acid-based dispersant.
In some examples, the time of the first hydrothermal reaction is independently 4-24 hours;
the time of the second hydrothermal reaction is independently 4-24 h;
the time of the third hydrothermal reaction is independently 4-24 h.
The invention has the beneficial effects that:
according to the implementation of the method, the hydrothermal synthesis of the mullite coated particles is realized for the first time, and the preparation of the coated particles with low cost is facilitated.
According to some implementations of the invention, the hydrothermal preparation of the mullite-coated cadmium sulfoselenide bright red pigment is realized for the first time, the constraint of a zirconium silicate-coated pigment system is broken, and the production cost is reduced by more than 50%.
According to some implementations of the invention, ions in the initial solution form the original structure of the alumina-coated cadmium sulfide through the first hydrothermal reaction, the phenomenon that the mullite is deviated from the coated core during the later period of crystallization is avoided, the cadmium selenide sulfide is formed under the state of being isolated and coated by the alumina through the second low-temperature hydrothermal selenium infiltration, the phenomenon that the coated core is long and large in agglomeration is avoided, and finally, the mullite shell is synthesized through the third hydrothermal reaction to prepare the mullite-coated cadmium selenide sulfide scarlet pigment.
In some embodiments of the present invention, the pigment is synthesized under low temperature hydrothermal conditions of 180 ℃, so the average particle size can be less than 500nm, which fully meets the requirements of ceramic ink-jet printing.
In some embodiments of the invention, the cadmium sulfoselenide color development core is well wrapped, no cadmium remains outside, the whole synthesis environment is carried out in a sealed hydrothermal kettle, and no waste gas and sewage are discharged, so that the process is environment-friendly in both the production process and the final product.
Drawings
FIG. 1 is a graph of the particle size distribution of the mullite-coated pigment of example 1;
FIG. 2 is a graph of particle size distribution for the zirconium silicate coated pigment of comparative example 1;
FIG. 3 is an SEM image of mullite-coated pigment of example 1;
FIG. 4 is a TEM image of mullite-coated pigment of example 1;
FIG. 5 is the EDS chart of mullite wrapped pigment of example 1;
fig. 6 is an SEM image of the zirconium silicate coated pigment of comparative example 1.
Detailed Description
In a first aspect of the present invention, there is provided:
a hydrothermal preparation method of mullite coated particles comprises the following steps:
sa-1) precursor liquid configuration: uniformly mixing aluminum salt, an auxiliary agent and part of precursor salt of the particles to be coated, and adjusting the pH value of the mixed solution;
sa-2) first hydrothermal reaction: transferring the precursor liquid into a hydrothermal kettle, and carrying out hydrothermal reaction to obtain amorphous alumina slurry;
sa-3) second hydrothermal reaction: adding the residual precursor salt solution of the particles to be coated into the amorphous alumina slurry, and carrying out a second hydrothermal reaction to obtain amorphous alumina-coated particles;
sa-4) third hydrothermal reaction: adding a silicon source into the particle slurry coated by the amorphous alumina, adjusting the pH, coating amorphous silicon hydroxide on the surface of the amorphous alumina, and carrying out a third hydrothermal reaction to obtain mullite-coated particle slurry;
s5) cleaning and drying to obtain the finished mullite wrapped particles.
A hydrothermal preparation method of mullite coated particles comprises the following steps:
sb-1) precursor liquid configuration: uniformly mixing a silicon source, an auxiliary agent and part of precursor salt of the particles to be coated, and adjusting the pH value of the mixed solution;
sb-2) first hydrothermal reaction: transferring the precursor liquid into a hydrothermal kettle, and carrying out hydrothermal reaction to obtain amorphous silicon hydroxide slurry;
sb-3) second hydrothermal reaction: adding the residual precursor salt solution of the particles to be coated into the amorphous silicon hydroxide slurry, and carrying out a second hydrothermal reaction to obtain particles coated by amorphous silicon hydroxide;
sb-4) a third hydrothermal reaction: adding aluminum salt into the particle slurry coated by the amorphous silicon hydroxide, adjusting the pH value, coating amorphous alumina on the surface of the amorphous silicon hydroxide, and carrying out a third hydrothermal reaction to obtain mullite-coated particle slurry;
s5) cleaning and drying to obtain the finished mullite wrapped particles.
A hydrothermal preparation method of mullite coated particles comprises the following steps:
sc-1) amorphous alumina coating: uniformly mixing aluminum salt, an auxiliary agent and the particles to be coated, adjusting the pH of the mixed solution, and carrying out a first hydrothermal reaction to obtain amorphous alumina-coated particles;
sc-2) second hydrothermal reaction: adding a silicon source into the particle slurry coated by the amorphous alumina, adjusting the pH, coating amorphous silicon hydroxide on the surface of the amorphous alumina, and performing a second hydrothermal reaction to obtain mullite-coated particle slurry;
s3) cleaning and drying to obtain the finished mullite wrapped particles.
A hydrothermal preparation method of mullite coated particles comprises the following steps:
sd-1) amorphous silicon hydroxide coating: uniformly mixing a silicon source, an auxiliary agent and particles to be coated, adjusting the pH of the mixed solution, and carrying out a first hydrothermal reaction to obtain amorphous silicon hydroxide coated particles;
sd-2) second hydrothermal reaction: adding aluminum salt into the particle slurry coated by the amorphous silicon hydroxide, adjusting the pH value, coating amorphous alumina on the surface of the amorphous silicon hydroxide, and carrying out a second hydrothermal reaction to obtain mullite-coated particle slurry;
s3) cleaning and drying to obtain the finished mullite wrapped particles.
The particles to be coated may be various inorganic particles that can be prepared by hydrothermal reaction, or micro-materials that are stable under hydrothermal conditions, including but not limited to various ceramic pigments, inorganic nanopowders such as graphene, carbon nanotubes, metal oxides, and the like.
The temperature of the hydrothermal reaction may be adjusted according to the characteristics of the raw materials, and in some examples, the temperature of each hydrothermal reaction is independently:
the temperature of the hydrothermal reaction in the step Sa-2) is 100-120 ℃;
the temperature of the hydrothermal reaction in the step Sa-3) is 110-130 ℃;
the temperature of the hydrothermal reaction in the step Sa-4) is 160-200 ℃;
the temperature of the hydrothermal reaction in the step Sb-2) is 100-120 ℃;
the temperature of the hydrothermal reaction in the step Sb-3) is 110-130 ℃;
the temperature of the hydrothermal reaction in the step Sb-4) is 160-200 ℃;
the temperature of the hydrothermal reaction in the step Sc-1) is 110-130 ℃;
the temperature of the hydrothermal reaction in the step Sc-2) is 160-200 ℃;
the temperature of the hydrothermal reaction in the step Sd-1) is 110-130 ℃;
the temperature of the hydrothermal reaction in the step Sd-2) is 160-200 ℃.
In some examples, the molar ratio of Si in the silicon source to Al in the aluminum salt is (2-2.5): 3.
in some examples, the aluminum salt is independently selected from at least one of sulfate, chloride, nitrate salts of aluminum; these aluminium salts have good solubility and can conveniently form a hydrogel by adjusting the pH, facilitating the entry of the remaining part of the components of the particles to be encapsulated into the gel network and reacting therein to give the precursor of the particles to be encapsulated. Thereby realizing the package.
The silicon source is preferably a silicon source that can be hydrolyzed in an aqueous environment to form a silica gel, such as silicate esters, water glass, and the like. The water glass has relatively low cost and good safety. In some examples, the silicon source is independently selected from water glass.
In a second aspect of the present invention, there is provided:
the hydrothermal preparation method of mullite coated cadmium sulfoselenide comprises the following steps:
s1) precursor liquid configuration: mixing aluminum salt, cadmium salt, thiourea, urea and a dispersing agent, and adjusting the pH to be 3-3.5;
s2) first hydrothermal reaction: transferring the precursor liquid into a hydrothermal kettle, preserving heat at 100-120 ℃, and carrying out a first hydrothermal reaction to form porous amorphous alumina-coated cadmium sulfide slurry;
s3) second hydrothermal reaction: dissolving selenium powder in a sulfide solution according to a molar ratio Se: S: Cd = (0.2-0.5): 1, adding the solution into amorphous alumina-coated cadmium sulfide slurry, preserving heat at 110-130 ℃, and carrying out a second hydrothermal reaction to ensure that selenium permeates into cadmium sulfide to form porous amorphous alumina-coated cadmium selenide sulfide slurry;
s4) a third hydrothermal reaction: adding water glass and a mineralizer into the amorphous alumina-coated selenium cadmium sulfide slurry, adjusting the pH to be 7-8, carrying out a third hydrothermal reaction on amorphous alumina-coated amorphous silicon hydroxide and heat preservation at 160-200 ℃ to obtain mullite-coated cadmium selenide sulfide slurry;
s5) carrying out solid-liquid separation, cleaning and drying on the mullite-coated cadmium selenide sulfide slurry to obtain the mullite-coated cadmium selenide sulfide.
In some examples, the precursor liquid has an aluminum salt concentration of 0.5 to 2mol/L in terms of Al, a cadmium salt concentration of 0.005 to 0.020mol/L in terms of Cd, a thiourea concentration of 0.005 to 0.03mol/L, and a urea concentration of 0.5 to 3 mol/L.
In some examples, the third hydrothermal reaction is carried out by adding a silicon source and a fluorine-containing mineralizer according to a molar ratio of Si: Al: F = (2-2.5) = (0.005-0.01).
In some examples, the sulfide salt is selected from at least one of ammonium sulfide, sodium sulfide.
In some examples, the aluminum salt is independently selected from at least one of a sulfate, chloride, nitrate salt of aluminum.
In some examples, the silicon source is independently selected from water glass.
The sintering temperature may be reduced by a mineralizer, which in some examples is selected from the group consisting of ammonium fluoride, lithium fluoride, sodium fluoride, potassium fluoride, sodium fluorosilicate, and other mineralizers commonly used in the ceramic color art.
The dispersing agent can reduce or avoid particle agglomeration, and is beneficial to obtaining particles with smaller particle size. In some examples, the dispersant is one or more of naphthalene-based dispersants, sulfamic acid-based dispersants, and the like, which are commonly used.
The time of the hydrothermal reaction can be adjusted according to the specific reaction condition, so that the reaction is sufficient. In some examples, the time of the first hydrothermal reaction is independently 4-24 hours;
the time of the second hydrothermal reaction is independently 4-24 h;
the time of the third hydrothermal reaction is independently 4-24 h.
The following examples are given to further illustrate the technical solutions of the present invention, but the scope of the present invention is not limited thereto.
Example 1
(1) Preparing a mixed solution of cadmium salt, aluminum salt, thiourea, urea and a naphthalene dispersant, and adjusting the pH to be =3 by using acid, wherein the concentration of the aluminum salt is 2mol/L, the concentration of the cadmium salt is 0.005mol/L, the concentration of the thiourea is 0.005mol/L, and the concentration of the urea is 3 mol/L;
(2) pouring the mixed weak acid solution obtained in the step (1) into a hydrothermal kettle, and preserving heat for 24 hours at 110 ℃ to carry out a first hydrothermal reaction;
(3) according to molar ratio Se (NH)4）2Cd =0.2: 0.2:1, dissolving selenium powder in ammonium sulfide liquid to form selenium-dissolved ammonium sulfide liquid;
(4) pouring the solution obtained in the step (3) into the slurry obtained in the step (2), preserving heat for 24 hours at 120 ℃, performing a second hydrothermal reaction to ensure that selenium permeates into cadmium sulfide to form porous amorphous alumina coated selenium cadmium sulfide slurry
(5) Adding water glass and ammonium fluoride to the slurry obtained in the step (4) according to a molar ratio of Si to Al to F =2 to 3 to 0.01, and adjusting the pH to =7 with an acid;
(6) preserving the temperature of the slurry obtained in the step (5) at 160 ℃ for 24h, and carrying out a third hydrothermal reaction;
(7) and (4) drying the slurry obtained in the step (6) at 300 ℃ to obtain the mullite-coated cadmium selenide sulfide scarlet pigment for ink-jet printing.
FIG. 1 is a graph showing the particle size distribution of the mullite-coated pigment produced. As can be seen from the figure, the particle size distribution is more concentrated, and the particle sizes are all less than 1 μm. FIG. 3 is an SEM image of mullite-coated pigment of example 1, which shows that the particle size is uniform. FIG. 4 is a TEM image of the mullite-coated pigment of example 1, the particle-coated state is good, and the cadmium sulfoselenide color-developing core is uniformly dispersed in the coated particles. FIG. 5 EDS spectrum analysis of mullite coated pigment of example 1 shows that the molar ratio of Al to Si to O, 5.932: 2: 13.234, ratio close to mullite (3 Al)2O3.2SiO2) Theoretical ratio of (6): 2: 13.
example 2
(1) Preparing a mixed solution of cadmium salt, aluminum salt, thiourea, urea and sulfamic acid dispersant, and adjusting the pH value to be =3 by using acid, wherein the concentration of the aluminum salt is 2mol/L, the concentration of the cadmium salt is 0.01mol/L, the concentration of the thiourea is 0.01mol/L, and the concentration of the urea is 3 mol/L;
(2) pouring the mixed weak acid solution obtained in the step (1) into a hydrothermal kettle, and carrying out heat preservation for 12 hours at 100 ℃ to carry out a first hydrothermal reaction;
(3) according to molar ratio of Se to Na2Cd =0.3: 0.3:1, dissolving selenium powder in ammonium sulfide liquid to form selenium-dissolved ammonium sulfide liquid;
(4) pouring the solution obtained in the step (3) into the slurry obtained in the step (2), preserving heat for 12 hours at 120 ℃, and carrying out a second hydrothermal reaction;
(5) adding water glass and ammonium fluoride to the slurry obtained in the step (4) according to a molar ratio of Si to Al to F =2 to 3 to 0.01, and adjusting the pH to =7 with an acid;
(6) preserving the temperature of the slurry obtained in the step (5) at 180 ℃ for 12h, and carrying out a third hydrothermal reaction;
(7) and (4) drying the slurry obtained in the step (6) at 300 ℃ to obtain the mullite-coated cadmium selenide sulfide scarlet pigment for ink-jet printing.
Example 3
(1) Preparing a mixed solution of ferric salt, aluminum salt, urea and a sulfamic acid dispersant, and adjusting the pH to be =3 by using acid, wherein the concentration of the aluminum salt is 2mol/L, the concentration of the ferric salt is 0.01mol/L, the concentration of the thiourea is 0.01mol/L, and the concentration of the urea is 3 mol/L;
(2) pouring the mixed weak acid solution obtained in the step (1) into a hydrothermal kettle, and preserving heat at 110 ℃ for 12 hours to carry out a first hydrothermal reaction;
(3) pouring the rest ferric salt solution into the slurry obtained in the step (2), preserving heat for 12 hours at 120 ℃, and carrying out a second hydrothermal reaction;
(4) adding water glass and ammonium fluoride to the slurry obtained in the step (3) according to a molar ratio of Si to Al to F =2 to 3 to 0.01, and adjusting the pH to =7 with an acid;
(5) preserving the temperature of the slurry obtained in the step (4) at 180 ℃ for 12h, and carrying out a third hydrothermal reaction;
(6) and (5) drying the slurry obtained in the step (5) at 300 ℃ to obtain the mullite coated iron red pigment for ink-jet printing.
Comparative example 1
The traditional liquid phase precipitation is used for synthesizing the cadmium selenide sulfide coated pigment, and the process comprises the following steps: and (2) simultaneously dripping the mixed solution of zirconium oxychloride and cadmium sulfate and the mixed solution of sodium selenide sulfide and sodium hydroxide into water to form a precipitate, stirring while dripping, controlling the pH to be =9, stirring for 120min after dripping, then dripping into a water glass solution, stabilizing the pH to be =9 by using dilute sulfuric acid, and stirring for 120 min. And after the precipitation reaction is finished, carrying out suction filtration and water washing on the precipitate until the pH of the filtrate is =7, drying the precipitate for 24h at 120 ℃, adding lithium fluoride and calcining the semi-finished product for 30min at 920 ℃, carrying out acid soaking on the calcined product for 24h by concentrated nitric acid, and washing and sieving the acid soaked product by water to obtain the common cadmium sulfoselenide coated pigment. Wherein the molar ratio of Zr, Si, Cd, S, Se and F elements is 1:1:0.4:0.6:0.2: 0.1.
The particle size distribution diagram of the obtained zirconium silicate coated cadmium sulfoselenide bright red pigment is shown in figure 2, and the SEM image is shown in figure 6. As can be seen from the figure, the particles are large and difficult to meet the requirements of ink-jet printing.
Comparative example 2
The traditional solid phase method is used for synthesizing the iron oxide red coated pigment, and the process comprises the following steps: the zirconium oxide, the quartz powder, the iron oxide red pigment and the lithium fluoride are mixed in a ball mill for 24 hours in a ball-milling mode, the mixture is calcined for 1 hour at 1200 ℃, the calcined product is soaked for 24 hours in concentrated nitric acid, and the acid soaked product is washed and sieved to obtain the zirconium silicate coated iron oxide red pigment. Wherein the molar ratio of Zr, Si, Fe and F elements is 1:1:0.3: 0.08.
Color performance comparison:
and (3) respectively taking the pigments prepared in different examples, testing the pigments by a color difference meter, and verifying the color development effect.
Figure 665722DEST_PATH_IMAGE002
From the test results of the examples and the comparative examples, the mullite coated pigment prepared by the invention has great advantages in granularity, color saturation, environmental protection degree and cost compared with the traditional zirconium silicate coated pigment.

Claims (10)

1. A hydrothermal preparation method of mullite coated particles comprises the following steps:
sa-1) precursor liquid configuration: uniformly mixing aluminum salt, an auxiliary agent and part of precursor salt of the particles to be coated, and adjusting the pH value of the mixed solution;
sa-2) first hydrothermal reaction: transferring the precursor liquid into a hydrothermal kettle, and carrying out hydrothermal reaction to obtain amorphous alumina slurry;
sa-3) second hydrothermal reaction: adding the residual precursor salt solution of the particles to be coated into the amorphous alumina slurry, and carrying out a second hydrothermal reaction to obtain amorphous alumina-coated particles;
sa-4) third hydrothermal reaction: adding a silicon source into the particle slurry coated by the amorphous alumina, adjusting the pH, coating amorphous silicon hydroxide on the surface of the amorphous alumina, and carrying out a third hydrothermal reaction to obtain mullite-coated particle slurry;
s5) cleaning and drying to obtain finished mullite wrapped particles; or
Sb-1) precursor liquid configuration: uniformly mixing a silicon source, an auxiliary agent and part of precursor salt of the particles to be coated, and adjusting the pH value of the mixed solution;
sb-2) first hydrothermal reaction: transferring the precursor liquid into a hydrothermal kettle, and carrying out hydrothermal reaction to obtain amorphous silicon hydroxide slurry;
sb-3) second hydrothermal reaction: adding the residual precursor salt solution of the particles to be coated into the amorphous silicon hydroxide slurry, and carrying out a second hydrothermal reaction to obtain particles coated by amorphous silicon hydroxide;
sb-4) a third hydrothermal reaction: adding aluminum salt into the particle slurry coated by the amorphous silicon hydroxide, adjusting the pH value, coating amorphous alumina on the surface of the amorphous silicon hydroxide, and carrying out a third hydrothermal reaction to obtain mullite-coated particle slurry;
s5) cleaning and drying to obtain finished mullite wrapped particles; or
Sc-1) amorphous alumina coating: uniformly mixing aluminum salt, an auxiliary agent and the particles to be coated, adjusting the pH of the mixed solution, and carrying out a first hydrothermal reaction to obtain amorphous alumina-coated particles;
sc-2) second hydrothermal reaction: adding a silicon source into the particle slurry coated by the amorphous alumina, adjusting the pH, coating amorphous silicon hydroxide on the surface of the amorphous alumina, and performing a second hydrothermal reaction to obtain mullite-coated particle slurry;
s3) cleaning and drying to obtain finished mullite wrapped particles; or
Sd-1) amorphous silicon hydroxide coating: uniformly mixing a silicon source, an auxiliary agent and particles to be coated, adjusting the pH of the mixed solution, and carrying out a first hydrothermal reaction to obtain amorphous silicon hydroxide coated particles;
sd-2) second hydrothermal reaction: adding aluminum salt into the particle slurry coated by the amorphous silicon hydroxide, adjusting the pH value, coating amorphous alumina on the surface of the amorphous silicon hydroxide, and carrying out a second hydrothermal reaction to obtain mullite-coated particle slurry;
s3) cleaning and drying to obtain the finished mullite wrapped particles.
2. The hydrothermal preparation method of claim 1, wherein: the temperature of each hydrothermal reaction is independently:
the temperature of the hydrothermal reaction in the step Sa-2) is 100-120 ℃;
the temperature of the hydrothermal reaction in the step Sa-3) is 110-130 ℃;
the temperature of the hydrothermal reaction in the step Sa-4) is 160-200 ℃;
the temperature of the hydrothermal reaction in the step Sb-2) is 100-120 ℃;
the temperature of the hydrothermal reaction in the step Sb-3) is 110-130 ℃;
the temperature of the hydrothermal reaction in the step Sb-4) is 160-200 ℃;
the temperature of the hydrothermal reaction in the step Sc-1) is 110-130 ℃;
the temperature of the hydrothermal reaction in the step Sc-2) is 160-200 ℃;
the temperature of the hydrothermal reaction in the step Sd-1) is 110-130 ℃;
the temperature of the hydrothermal reaction in the step Sd-2) is 160-200 ℃.
3. The hydrothermal preparation method according to claim 1 or 2, characterized in that: the molar ratio of Si in the silicon source to Al in the aluminum salt is (2-2.5): 3.
4. the hydrothermal preparation method according to claim 1 or 2, characterized in that: the aluminum salt is independently selected from sulfate, chloride and nitrate of aluminum; the silicon source is independently selected from water glass.
5. The hydrothermal preparation method of mullite-coated cadmium sulfoselenide is characterized by comprising the following steps: the method comprises the following steps:
s1) precursor liquid configuration: mixing aluminum salt, cadmium salt, thiourea, urea and a dispersing agent, and adjusting the pH to be 3-3.5;
s2) first hydrothermal reaction: transferring the precursor liquid into a hydrothermal kettle, preserving heat at 100-120 ℃, and carrying out a first hydrothermal reaction to form porous amorphous alumina-coated cadmium sulfide slurry;
s3) second hydrothermal reaction: dissolving selenium powder in a sulfide solution according to a molar ratio Se: S: Cd = (0.2-0.5): 1, adding the solution into amorphous alumina-coated cadmium sulfide slurry, preserving heat at 110-130 ℃, and carrying out a second hydrothermal reaction to ensure that selenium permeates into cadmium sulfide to form porous amorphous alumina-coated cadmium selenide sulfide slurry;
s4) a third hydrothermal reaction: adding a silicon source and a mineralizer into the amorphous alumina-coated selenium cadmium sulfide slurry, adjusting the pH to be 7-8, carrying out a third hydrothermal reaction on amorphous alumina-coated amorphous silicon hydroxide and heat preservation at 160-200 ℃ to obtain mullite-coated cadmium sulfoselenide slurry;
s5) carrying out solid-liquid separation, cleaning and drying on the mullite-coated cadmium selenide sulfide slurry to obtain the mullite-coated cadmium selenide sulfide.
6. The hydrothermal preparation method of claim 5, wherein: in the precursor liquid, the concentration of aluminum salt is 0.5-2 mol/L calculated by Al, the concentration of cadmium salt is 0.005-0.020 mol/L calculated by Cd, the concentration of thiourea is 0.005-0.03 mol/L, and the concentration of urea is 0.5-3 mol/L.
7. The hydrothermal preparation method of claim 5, wherein: and in the third hydrothermal reaction, a silicon source and a fluorine-containing mineralizer are added according to the mol ratio of Si to Al to F = (2-2.5) to 3 (0.005-0.01).
8. The hydrothermal preparation method according to any one of claims 5 to 7, characterized in that: the mineralizer is selected from ammonium fluoride, lithium fluoride, sodium fluoride, potassium fluoride and sodium fluosilicate.
9. The hydrothermal preparation method according to any one of claims 5 to 7, characterized in that: the dispersant is one or more than two of naphthalene dispersant and sulfamic acid dispersant.
10. The hydrothermal preparation method according to any one of claims 5 to 7, characterized in that:
the time of the first hydrothermal reaction is independently 4-24 h;
the time of the second hydrothermal reaction is independently 4-24 h;
the time of the third hydrothermal reaction is independently 4-24 h.
CN202011313540.7A 2020-11-21 2020-11-21 Hydrothermal preparation method of mullite coated particles Pending CN112409823A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114620937A (en) * 2022-03-28 2022-06-14 江西金环颜料有限公司 Titanium sphene coated cadmium sulfoselenide pigment and preparation method and application thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114620937A (en) * 2022-03-28 2022-06-14 江西金环颜料有限公司 Titanium sphene coated cadmium sulfoselenide pigment and preparation method and application thereof
CN114620937B (en) * 2022-03-28 2023-11-03 江西金环颜料有限公司 Titanium sphene-coated cadmium sulfoselenide pigment and preparation method and application thereof

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