阅读说明：本技术 一种制备四方型纳米氧化锆用前驱体配料及低温条件下生产四方型纳米氧化锆的方法 (Precursor ingredient for preparing tetragonal nano zirconia and method for producing tetragonal nano zirconia under low temperature condition ) 是由 徐程浩 于 2020-09-25 设计创作，主要内容包括：本发明公开了一种制备四方型纳米氧化锆用前驱体配料,采用四方型纳米氧化锆原料、晶型诱导剂和水混合、并控制前驱体料液pH值为9.0～10.0。同时,本发明还公开了上述前驱体配料所适用的低温条件下生产四方型纳米氧化锆的方法。本发明可以在低温反应条件下直接制备出四方型超细氧化锆,无需高温烧结和气体粉碎等高耗能工序；经过喷雾造粒的过程一步完成干燥和造粒的过程,产品为球形度高的氧化锆粉体；原料无需高精度的除杂工序,可制备出合格纯度的氧化锆产品；制备工艺中不采用氨水,唯一的副产品氯化钠作为工业盐对外销售,使得本发明工艺系统是一个节能绿色环保的工业化生产技术。(The invention discloses a precursor ingredient for preparing tetragonal nano zirconia, which is prepared by mixing a tetragonal nano zirconia raw material, a crystal form inducer and water and controlling the pH value of a precursor liquid to be 9.0-10.0. Meanwhile, the invention also discloses a method for producing the tetragonal nano zirconia under the low-temperature condition suitable for the precursor ingredients. The method can directly prepare the tetragonal superfine zirconia under the low-temperature reaction condition without high-energy-consumption working procedures such as high-temperature sintering, gas crushing and the like; the drying and granulating process is completed in one step through the spray granulating process, and the product is zirconia powder with high sphericity; the raw materials do not need a high-precision impurity removal process, and a zirconium oxide product with qualified purity can be prepared; ammonia water is not adopted in the preparation process, and the only byproduct sodium chloride is sold as industrial salt, so that the process system is an energy-saving, green and environment-friendly industrial production technology.)

1. A precursor ingredient for preparing square nano zirconia is characterized in that a square nano zirconia raw material, a crystal form inducer and water are mixed, and the pH value of a precursor material liquid is controlled to be 9.0-10.0.

2. The precursor ingredient for preparing the tetragonal nano zirconia according to claim 1, wherein the crystal form inducer is one or a combination of alcohol or amine solvents with lone pair electrons in the molecule.

3. The precursor ingredient for preparing the tetragonal nano zirconia according to claim 1, wherein the molar ratio of the tetragonal nano zirconia to the crystal form inducer is 1: 0.5-1: 2.0; the adding amount of the water is controlled to control the molar concentration of zirconium ions in the precursor liquid to be 0.02-1.0 mol/L.

4. The precursor ingredient for preparing the tetragonal nano zirconia according to claim 1, wherein the crystal form inducer is one or more of ethylene glycol, glycerol, isopropanol, ethanolamine, triethanolamine and propanolamine.

5. The method for producing tetragonal nano zirconia by using the precursor ingredients in any one of claims 1 to 4 under the low-temperature condition is characterized by comprising the following steps:

(1) mixing a tetragonal nano zirconia raw material, a crystal form inducer and ultrapure water into a precursor feed liquid, and then adding liquid caustic soda to control the pH value to be 9.0-10.0;

(2) crystallizing the precursor liquid obtained in the step (1) by adopting a hydrothermal reaction mode to obtain zirconium oxide crystal slurry;

(3) washing the zirconium oxide crystal slurry obtained in the step (2) with ultrapure water until the content of chloride ions is less than or equal to 50ppm, and obtaining zirconium oxide wet crystal slurry;

(4) and (4) preparing the wet crystal slurry of zirconium oxide obtained in the step (3) into slurry liquid for spray granulation, and then drying the slurry liquid in a spray drying system to obtain a finished product.

6. The method for producing tetragonal nano zirconia at low temperature according to claim 5, wherein the hydrothermal reaction process in the step (2) comprises heating, constant temperature aging and cooling of a hydrothermal reaction crystallization process; the temperature rise process is to slowly rise the temperature to 60-80 DEG C^oC, the temperature rise rate is 4-6^oC/h, then quickly heating to 180-200 DEG C^oC, the heating rate is 30-90^oC/h; the constant-temperature curing process is 180-200%^oC, curing at constant temperature for 2-12 h.

7. The method for producing tetragonal nanometer zirconia at low temperature according to claim 6, wherein the device suitable for the temperature reduction process in the hydrothermal reaction process in the step (2) is a high temperature reduction device, and the device comprises one or more of a high-efficiency wound heat exchanger and a plate heat exchanger.

8. The method for producing the tetragonal nanometer zirconia under the low temperature condition according to claim 5, wherein the mass ratio of the wet zirconia crystal slurry to the solvent water, the dispersant and the binder in the slurry liquid for spray granulation is 1: 0.05-0.2: 0.02-0.05: 0.01 to 0.03.

9. The method for producing tetragonal nano zirconia under the low temperature condition according to claim 8, wherein the dispersant is one or more of ethanol, fatty acid, glycerol and glycol; the binder is one or a combination of more of starch, dextrin, polyvinyl alcohol and carboxymethyl cellulose.

Technical Field

The invention belongs to the field of chemistry, and particularly relates to a precursor ingredient for preparing tetragonal nano zirconia and a method for producing the tetragonal nano zirconia at low temperature by adopting the ingredient.

Background

Zirconium dioxide is an important structural and functional material, and has very excellent physical and chemical properties, such as high melting point (2700 ℃) and boiling point, small thermal conductivity, large thermal expansion coefficient, high temperature resistance, good wear resistance, excellent corrosion resistance and the like. Nanometer level zirconium dioxide material has some unique performance, such as insulator at normal temperature and conductivity, sensitivity, toughness, etc. at high temperature, and thus has important use. It has wide applications in many different fields, such as ceramic pigments, engineering ceramics, gem industry, piezoelectric elements, ion exchangers, and solid electrolytes. Zirconium dioxide is also the only metal oxide with acidity, alkalinity, oxidizability and reducibility, and it is a type-I p-type semiconductor, which is easy to generate oxygen cavity as catalyst carrier and can interact with active component, therefore, the catalyst using zirconium dioxide as carrier shows considerable application prospect and important theoretical research value.

Zirconium dioxide has three crystal structures: monoclinic (m-ZrO 2), tetragonal (t-ZrO 2) and cubic (c-ZrO 2) phase transformation conditions were as follows:

the lattice parameters of zirconia are as follows:

the main fields of application of zirconium dioxide are as follows:

TABLE 1 field of application of zirconium dioxide

The production process of the conventional high-purity superfine zirconia comprises the following steps:

heating industrial zirconium oxychloride in dilute hydrochloric acid to dissolve, adding proper quantity of edible gelatin solution to remove silicon dioxide, fine filtering, making three-time recrystallization, making spectral analysis, and using ultrapure water to prepare the invented productZrOCl with certain concentration₂And (3) solution. Washing industrial liquid ammonia with 1% potassium permanganate aqueous solution, 2% sodium hydroxide aqueous solution and ultrapure water, strictly controlling flow rate, absorbing with ultrapure water, and obtaining high-purity ammonia water by spectral analysis when the concentration of ammonia water reaches 28%. Under the condition of violent stirring in a nonmetal container, injecting calculated amounts of ammonia water and zirconium hydroxide solution until the pH is 8-8.5, and repeatedly washing with ultrapure water until no Cl exists^-Until 250 to 300 ℃ after centrifugal separation^oC, drying, and then drying in 850-1100^oAnd C, firing at a high temperature to obtain the high-purity superfine zirconia (specifically shown in figure 1). Zirconium oxide

The conventional preparation process of the high-purity superfine zirconia product adopts a high-temperature sintering mode for crystallization, so that raw materials must be strictly purified, a precursor prepared by a precipitation reaction is mostly an amorphous product, the specific surface area is large, a large amount of impurity ions are easily adsorbed, a large amount of washing water is needed for washing, otherwise, non-volatile impurities are remained in or on the zirconia crystal in the sintering process, and the purity of the product is influenced.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a precursor ingredient for preparing square nano zirconia aiming at the defects of the prior art.

The invention also aims to provide a method for producing the tetragonal nanometer zirconia at low temperature by adopting the precursor ingredients.

The technical scheme is as follows: in order to achieve the above object, the present invention is specifically as follows: a precursor ingredient for preparing square nano zirconia is characterized in that a square nano zirconia raw material, a crystal form inducer and water are mixed, and the pH value of a precursor material liquid is controlled to be 9.0-10.0.

Wherein, the crystal form inducer is one or the combination of alcohols or amine solvents with lone pair electrons in molecules.

Wherein the mixing addition molar ratio of the tetragonal nano zirconia to the crystal form inducer is 1: 0.5-1: 2.0; the adding amount of the water is preferably controlled to control the molar concentration of zirconium ions in the precursor liquid to be 0.02-1.0 mol/L.

Wherein, the crystal form inducer is one or a combination of more of ethylene glycol, glycerol, isopropanol, ethanolamine, triethanolamine and propanolamine.

The method for producing the tetragonal nanometer zirconia by using the precursor ingredients under the low-temperature condition comprises the following steps:

(1) mixing a tetragonal nano zirconia raw material, a crystal form inducer and ultrapure water into a precursor feed liquid, and then adding liquid caustic soda to control the pH value to be 9.0-10.0;

(2) crystallizing the precursor liquid obtained in the step (1) by adopting a hydrothermal reaction mode to obtain zirconium oxide crystal slurry;

(3) washing the zirconium oxide crystal slurry obtained in the step (2) with ultrapure water until the content of chloride ions is less than or equal to 50ppm, and obtaining zirconium oxide wet crystal slurry;

(4) and (4) preparing the wet crystal slurry of zirconium oxide obtained in the step (3) into slurry liquid for spray granulation, and then drying the slurry liquid in a spray drying system to obtain a finished product.

Wherein, the hydrothermal reaction process in the step (2) comprises heating, constant-temperature curing and cooling in the hydrothermal reaction crystallization process; the temperature rise process is to slowly rise the temperature to 60-80 DEG C^oC, the temperature rise rate is 4-6^oC/h, then quickly heating to 180-200 DEG C^oC, the heating rate is 30-90^oC/h; the constant-temperature curing process is 180-200%^oC, curing at constant temperature for 2-12 h.

And (3) wherein the device suitable for the temperature reduction process in the hydrothermal reaction process in the step (2) is a high temperature reduction device and comprises one or more combinations of a high-efficiency wound heat exchanger and a plate heat exchanger.

Wherein the mass ratio of the wet crystal slurry of zirconium oxide to the solvent water, the dispersant and the binder in the slurry liquid for spray granulation is 1: 0.05-0.2: 0.02-0.05: 0.01 to 0.03. The dispersant is one or more of ethanol, fatty acid, glycerol and glycol; the binder is one or a combination of more of starch, dextrin, polyvinyl alcohol and carboxymethyl cellulose.

The method for producing the tetragonal nanometer zirconia under the low temperature condition mainly comprises the processes of precursor material preparation, hydrothermal reaction crystallization, solid-liquid separation and washing, spray drying and sodium chloride byproduct recovery.

The device for completing the solid-liquid separation and washing process can be selected from one or a combination of a self-rotating ceramic membrane, a tubular centrifuge and a disc centrifuge, and the amount of washing water is 4-6 times of the mass of a zirconia product.

Wherein, the atomizing nozzle in the device for completing the spray drying process is one or the combination of two fluids and a high-speed centrifugal type, the pressure of compressed air is 0.3-0.7 MPa, the gas-liquid mass ratio of the compressed air to the crystal slurry is 5: 1-10: 1, and the temperature of a hot air inlet is 210-260%^oC, preferably 105 to 120^oC。

Wherein, the system for completing the recovery process of the sodium chloride byproduct comprises sodium chloride evaporative crystallization, solid-liquid separation, steam condensate water and recycling of residual mother liquor; the solid-liquid separation equipment is one or two combination of a double-stage piston pusher centrifuge and a horizontal spiral filtering centrifuge. The evaporation crystallization temperature is 80-90 DEG C^oC。

Has the advantages that: compared with the prior art, the invention has the following advantages:

(1) the tetragonal superfine zirconia can be directly prepared under the low-temperature reaction condition, and high-energy-consumption procedures such as high-temperature sintering, gas crushing and the like are not needed;

(2) the drying and granulating process is completed in one step through the spray granulating process, and the product is zirconia powder with high sphericity;

(3) the raw materials do not need a high-precision impurity removal process, and a zirconium oxide product with qualified purity can be prepared;

(4) the ammonia-free process is adopted, and the only byproduct sodium chloride is sold as industrial salt, so that the process system is an energy-saving, green and environment-friendly industrial production technology.

Drawings

FIG. 1 is a flow chart of the conventional high-temperature gel method for producing high-purity superfine zirconia.

FIG. 2 is a schematic process diagram of the system of the present invention.

FIG. 3 is a photograph of a crystal of tetragonal zirconia of example 1.

Figure 4 is a crystal XRD pattern of tetragonal zirconia of example 1.

Detailed Description

Example 1:

fig. 1 shows that a tetragonal nano zirconia industrial production system suitable for the process comprises: a dissolution, precursor dosing system; a hydrothermal reaction crystallization system; a solid-liquid separation and washing system; a spray drying system; sodium chloride evaporative crystallization system.

(1) Dissolving and precursor compounding: dissolving ZrOCl2 & 8H2O and solvent (ultrapure water for the first time, residual mother liquor of sodium chloride evaporative crystallization, steam condensate and make-up water) in a dissolving tank to prepare the ZrOCl in the solution₂The content reaches 21.5 percent, and the dissolution temperature is 20 ℃. Dripping crystal form inducer with the addition amount ratio of [ Zr⁴⁺]: [ Crystal form inducer]=1:1.0 (molar ratio). Adding a proper amount of bottom water into a precursor preparation reaction kettle, starting stirring, and simultaneously dropwise adding ZrOCl₂The pH of the feed liquid is controlled to be 9.5.

(2) Hydrothermal reaction crystallization process: transferring the prepared precursor liquid into a hydrothermal reaction crystallizer, sealing, starting stirring, and slowly heating to 70 deg.C^oC, the temperature rising rate is 5oC/h, and then the temperature rises to 180 ℃ rapidly^oC, the heating rate is 60^oAnd C/h and 180 ℃ constant-temperature curing is carried out for 10h, after the reaction is finished, the zirconium oxide crystal slurry is cooled through a high-efficiency winding type heat exchanger, the zirconium oxide crystal slurry is conveyed to a crystal slurry buffer tank, a crystal photo is shown in figure 2, and the XRD diffraction of the crystal is shown in figure 3.

(3) Solid-liquid separation and washing: and (3) carrying out solid-liquid separation and continuous washing processes by adopting a rotary ceramic membrane, wherein the consumption of washing water is 5.5 times of that of the zirconia product, and the content of chloride ions in the washing separation mother liquor is detected to be less than or equal to 50 ppm.

(4) Spray drying: mixing the wet crystal slurry subjected to solid-liquid separation with solvent water, a dispersing agent and a binder according to a mass ratio of 1: 0.15: 0.05:0.02, conveying the slurry to a spray drying system by a screw conveying pump, adopting a two-fluid atomization nozzle, controlling the gas-liquid ratio of the flow of compressed air to the flow of crystal slurry to be 7:1, and controlling the pressure of the compressed air0.4MPa, hot air inlet temperature of 250^oC, hot air outlet temperature 105^oAnd C, conveying the dried product to a product bin through a caking air flow, and packaging the finished product.

(5) Sodium chloride evaporative crystallization system: the residual mother liquor and washing water after solid-liquid separation enter a sodium chloride continuous evaporation crystallization system together to crystallize and separate out sodium chloride crystals with uniform granularity, and the evaporation crystallization temperature is 85 DEG^oAnd C, the purity of the sodium chloride reaches 98.23%, and the steam condensate and the evaporation mother liquor residual liquid return to the dissolving and batching process.

Example 2:

another tetragonal nano zirconia industrial production system suitable for the process as shown in fig. 1 comprises: a dissolution, precursor dosing system; a hydrothermal reaction crystallization system; a solid-liquid separation and washing system; a spray drying system; sodium chloride evaporative crystallization system.

(1) Dissolving and precursor compounding: taking ZrOCl₂·8H₂Dissolving and proportioning O and a solvent (ultrapure water for the first time, residual mother liquor of sodium chloride evaporative crystallization, steam condensate and make-up water for the later time) in a dissolving tank to ensure that ZrOCl in the solution₂The content reaches 16.5 percent, and the dissolving temperature is 25 percent_oC. Dripping crystal form inducer with the addition amount ratio of [ Zr⁴⁺]: [ Crystal form inducer]=1:0.8 (molar ratio). Adding a proper amount of bottom water into a precursor preparation reaction kettle, starting stirring, and simultaneously dropwise adding ZrOCl₂The pH of the feed liquid is controlled to be 10.0.

(2) Hydrothermal reaction crystallization process: transferring the prepared precursor liquid into a hydrothermal reaction crystallizer, sealing, starting stirring, and slowly heating to 60 deg.C^oC, the heating rate is 4^oC/h, then quickly heating to 190^oC, the heating rate is 50^oC/h，190^oC, curing at constant temperature for 8h, cooling through a high-efficiency wound heat exchanger after the reaction is finished, and conveying the zirconium oxide crystal slurry to a crystal slurry buffer tank.

(3) Solid-liquid separation and washing: and (3) carrying out solid-liquid separation and continuous washing processes by adopting a rotary ceramic membrane, wherein the consumption of washing water is 5 times of that of the zirconia product, and the content of chloride ions in the washing separation mother liquor is detected to be less than or equal to 50 ppm.

(4) Spray drying: mixing the wet crystal slurry subjected to solid-liquid separation with solvent water, a dispersing agent and a binder according to a mass ratio of 1: 0.1: 0.04: 0.03, conveying the slurry to a spray drying system by a screw rod conveying pump, adopting a two-fluid atomization nozzle, wherein the gas-liquid ratio of the flow of compressed air to the flow of crystal slurry is 8:1, the pressure of the compressed air is 0.5MPa, and the temperature of a hot air inlet is 230^oC, hot air outlet temperature 110^oAnd C, conveying the dried product to a product bin through a caking air flow, and packaging the finished product.

(5) Sodium chloride evaporative crystallization system: the residual mother liquor and washing water after solid-liquid separation enter a sodium chloride continuous evaporation crystallization system together to crystallize and separate out sodium chloride crystals with uniform granularity, and the evaporation crystallization temperature is 80 DEG^oAnd C, the purity of the sodium chloride reaches 98.63 percent, and the steam condensate and the evaporation mother liquor residual liquid return to the dissolving and proportioning process.