In-situ preparation method for composite pigment of bismuth vanadate

Abstract

An in-situ preparation method for a composite pigment of bismuth vanadate, which method comprises: firstly dissolving a bismuth compound into an acidic solution, adding a surfactant thereto for full dissolution, and then adding titanium-nickel yellow particles to the solution; adding a vanadium compound to the mixed solution under the action of a strong shearing force; and reacting same at a certain temperature and pH value, then cleaning and drying the precipitate separated from the mixed solution, and subjecting same to a heat treatment to obtain a composite pigment powder of bismuth vanadate. A synthesis reaction of bismuth vanadate is uniformly performed on the surface of titanium-nickel yellow in situ under the action of a strong shearing force. By means of the method, not only is the in-situ composite reaction performed more quickly and uniformly, but a large amount of alkaline solution required by a conventional method is also avoided. The obtained composite pigment of bismuth vanadate has a high chromatic value, and a more effective covering power and dilution strength.

Description

In-situ preparation method of bismuth vanadate composite pigment Technical Field

[0001] The invention belongs to the technical field of inorganic pigment preparation, and in particular relates to an in-situ preparation method of a bismuth vanadate composite pigment. Background Art

[0002] Bismuth vanadate is a high-performance, green, and environmentally friendly yellow inorganic pigment, often used to replace heavy metal yellow pigments such as chrome yellow and cadmium yellow. Bismuth vanadate pigments offer numerous advantages, including easy dispersion, brilliant color, high weather resistance, and high tinting strength. However, high raw material costs result in a high price for bismuth vanadate pigments, more than ten times that of lead chrome yellow and organic yellow pigments. This has severely hindered the widespread market adoption of these green and environmentally friendly pigments. Currently, bismuth vanadate pigments are only used in high-end products or applications requiring high pigment performance and environmental friendliness, such as high-end coatings and food-contact plastics.

[0003] Bismuth vanadate composite pigments are one of the main methods for reducing costs. By combining them with low-cost materials, the use of expensive raw materials such as vanadium and bismuth can be reduced, thereby significantly reducing costs. The main methods for preparing bismuth vanadate composite pigments include solid-phase method, liquid-phase method, and twin-screw extrusion. Among the three preparation methods, the liquid-phase method can obtain bismuth vanadate pigments with the smallest particle size, high purity, and strong controllability. However, there is still the defect of uneven reaction, which makes it impossible to effectively and evenly combine the two materials, and the pigment performance is significantly lower than that of pure bismuth vanadate pigments.

[0004] Titanium nickel yellow pigment has a wide chromatographic range, is easy to disperse, has good hiding power and service life. Among the light yellow series of pigments, it has better gloss and color retention. Titanium nickel yellow is inexpensive and is often used in coatings such as construction, steel, painting, as well as general plastics, rubber, building materials, ceramics and other fields. Titanium nickel yellow is a light yellow pigment, weaker than the bright yellow of bismuth vanadate pigment. Strong shear force is generated under the relative high-speed movement of the stator and rotor, which can disperse quickly and effectively promote the uniformity of the reaction. The present invention utilizes the effect of strong shear force to simplify the bismuth vanadate synthesis reaction and promote the uniform in-situ compounding of bismuth vanadate and titanium nickel yellow. A low-cost, excellent-performance bismuth vanadate composite pigment is obtained.

[0005] Summary of the Invention

[0006] The purpose of the present invention is to provide an in-situ preparation method of a bismuth vanadate composite pigment, which overcomes the shortcomings of the existing technology. By combining the advantages of high color performance of bismuth vanadate pigment and low cost of titanium nickel yellow, it is proposed to use titanium nickel yellow as the core and, under the action of strong shear force, in-situ uniformly synthesize bismuth vanadate on the surface of titanium nickel yellow, ultimately forming a bismuth vanadate composite pigment with excellent performance.

[0007] To achieve the above object, the present invention is implemented through the following technical solutions:

[0008] An in-situ preparation method for a bismuth vanadate composite pigment comprises dissolving a bismuth compound in an acidic solution, adding an appropriate amount of surfactant to fully dissolve the bismuth compound, and then adding titanium nickel yellow pigment particles. A vanadium compound is then added to the mixed solution under strong shear. After reaction at a specific temperature and pH, the precipitate separated from the mixed solution is washed, dried, and then heat-treated to obtain a bismuth vanadate composite pigment powder.

[0009] The bismuth compound is at least one of bismuth nitrate, bismuth sulfate and bismuth oxide, and the concentration of the bismuth element in the acidic solution is 0.01-0.4 mol / L.

[0010] The acid solution is a nitric acid solution or a hydrochloric acid solution with a concentration of 1 to 3 mol / L.

[0011] The surfactant is any one of sodium lauryl sulfate, sodium dodecylbenzenesulfonate and polyvinyl pyrrolidone, and the added concentration is 0.001 mol / L to 0.2 mol / L.

[0012] The titanium nickel yellow particles have a size of less than 2 micrometers, and the added amount is 15% to 200% of the mass of the vanadium compound.

[0013] The vanadium compound is at least one of ammonium metavanadate, sodium metavanadate, potassium metavanadate and vanadium oxide.

[0014] The alkaline solution is one of sodium hydroxide, potassium hydroxide or ammonia water, and the concentration is 1-3 mol / L.

[0015] The strong shearing force is achieved by a high-speed shearing machine with a speed of 500 rpm to 8000 rpm.

[0016] The reaction temperature is 40° C. to 90° C., the pH value is 3.5 to 7, and the reaction time is 0.5 h to 3 h.

[0017] The heat treatment temperature is 350° C. to 500° C., and the treatment time is 1 hour to 2 hours.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1) By combining the high color performance of bismuth vanadate pigments with the low cost of titanium nickel yellow, a method for in-situ synthesis of a bismuth vanadate / titanium nickel yellow composite yellow inorganic pigment was proposed, using titanium nickel yellow as a substrate. The pigment's key properties, including Lab value, hiding power, and dilution strength, were significantly improved. 2) By applying strong shear forces, the uniformity of the bismuth vanadate synthesis reaction on the titanium nickel yellow surface was ensured, while avoiding the conventional method of using large amounts of alkaline solution as a base liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG1 is an XRD pattern of the bismuth vanadate composite pigments prepared in Examples 1-6 of the present invention and the pure bismuth vanadate prepared in the comparative example;

[0021] FIG2 is a UV spectrum of the bismuth vanadate composite pigments prepared in Examples 1-6 of the present invention and the pure bismuth vanadate prepared in the comparative example;

[0022] FIG3 is a test result of hiding power and tinting strength of Example 1 of the present invention and the comparative example. DETAILED DESCRIPTION

[0023] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0024] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the specific embodiments required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the specific embodiments described below are some implementation methods of the present invention. For ordinary technicians in this field, other specific embodiments can be obtained based on these specific embodiments without paying any creative work.

[0025] The components of the embodiments of the present invention generally described and shown in the specific embodiments herein can be arranged and designed in countless different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the specific embodiments is not intended to limit the scope of the claimed invention, but is merely representative of selected embodiments of the present invention.

[0026] Example 1

[0027] 9.7g of bismuth nitrate was weighed and added to 200mL of 1mol / L nitric acid solution. Magnetic stirring was applied until completely dissolved. 0.7g of sodium dodecylbenzenesulfonate was added and stirring continued until completely dissolved. 0.4g of titanium nickel yellow particles was then added and stirred until uniformly dispersed. 2.44g of sodium metavanadate was added to the mixture at 2000rpm using a high-speed shear. The mixture was heated to 70°C, the pH adjusted to 5, and the reaction was continued under high-speed shearing for 1.5h. The mixture was separated to obtain a precursor precipitate, which was washed three times with deionized water and anhydrous ethanol and then dried in a vacuum drying oven for 12h. Subsequently, the mixture was heat treated at 350°C for 1.5h to obtain a bismuth vanadate / titanium nickel yellow composite yellow inorganic pigment with an oil absorption of 20g / 100g. Its L*a*b* colorimetric values ​​are shown in Table 1.

[0028] Example 2

[0029] 9.7g of bismuth nitrate was weighed and added to 200mL of 1mol / L nitric acid solution. Magnetic stirring was applied until completely dissolved. 0.9g of sodium dodecyl sulfate was added and stirring continued until completely dissolved. 0.6g of titanium nickel yellow particles was then added and stirred until uniformly dispersed. 2.44g of sodium metavanadate was added to the mixture at 3000rpm using a high-speed shear. The mixture was heated to 70°C, the pH adjusted to 5.5, and the reaction was continued under high-speed shearing for 1.5h. The mixture was separated to obtain a precursor precipitate, which was washed three times with deionized water and anhydrous ethanol and then dried in a vacuum drying oven for 12h. Subsequently, the mixture was heat treated at 400°C for 1.5h to obtain a bismuth vanadate / titanium nickel yellow composite yellow inorganic pigment with an oil absorption of 23g / 100g. Its L*a*b* colorimetric values ​​are shown in Table 1.

[0030] Example 3

[0031] Weigh 9.7g of bismuth nitrate into 200mL of 1mol / L nitric acid solution and stir magnetically until completely dissolved. Add 1.6g of polyvinyl pyrrolidone and continue stirring until completely dissolved. Then, add 0.8g of titanium nickel yellow particles and continue stirring until evenly dispersed. Add 2.44g of sodium metavanadate to the mixture at 4000rpm using a high-speed shear. The mixture is heated to 70°C, adjusted to a pH of 6, and reacted for 1.5h under continuous high-speed shearing. The mixture is separated to obtain a precursor precipitate, which is then washed three times with deionized water and anhydrous ethanol and dried in a vacuum oven for 12h. Subsequently, heat treat the mixture at 380°C for 1.5h to obtain a bismuth vanadate / titanium nickel yellow composite yellow inorganic pigment with an oil absorption of 22g / 100g. Its L*a*b* colorimetric values ​​are shown in Table 1.

[0032] Example 4

[0033] 9.7g of bismuth nitrate was weighed and added to 200mL of 1mol / L nitric acid solution. Stir magnetically until completely dissolved. 3.10g of sodium dodecyl sulfate was added and stirred continuously until completely dissolved. Then, 1.00g of titanium nickel yellow particles was added and stirred continuously until uniformly dispersed. 2.44g of sodium metavanadate was added to the mixture at 4000rpm using a high-speed shear. The mixture was heated to 70°C, the pH adjusted to 6, and the reaction was continued under high-speed shearing for 1.5h. The mixture was separated to obtain a precursor precipitate, which was washed three times with deionized water and anhydrous ethanol and then dried in a vacuum drying oven for 12h. Subsequently, the mixture was heat treated at 400°C for 1.0h to obtain a bismuth vanadate / titanium nickel yellow composite yellow inorganic pigment with an oil absorption of 23g / 100g. Its L*a*b* colorimetric values ​​are shown in Table 1.

[0034] Example 5

[0035] 9.7g of bismuth nitrate was weighed and added to 200mL of 1mol / L nitric acid solution. Stir magnetically until completely dissolved. 1.5g of sodium dodecyl sulfate was added and stirred continuously until completely dissolved. Then, 1.22g of titanium nickel yellow particles were added and stirred until uniformly dispersed. 2.44g of sodium metavanadate was added to the mixture at 4000rpm using a high-speed shear. The mixture was heated to 70°C, the pH adjusted to 6, and the reaction was continued under high-speed shearing for 1.5h. The mixture was separated to obtain a precursor precipitate, which was washed three times with deionized water and anhydrous ethanol and then dried in a vacuum drying oven for 12h. Subsequently, the mixture was heat treated at 400°C for 1.0h to obtain a bismuth vanadate / titanium nickel yellow composite yellow inorganic pigment with an oil absorption of 24g / 100g. Its L*a*b* colorimetric values ​​are shown in Table 1.

[0036] Example 6

[0037] 9.7g of bismuth nitrate was weighed and added to 200mL of 1mol / L nitric acid solution. Magnetic stirring was applied until completely dissolved. 2.0g of sodium dodecyl sulfate was added and stirring continued until completely dissolved. Then, 2.44g of titanium nickel yellow particles were added and stirring continued until uniformly dispersed. At 4000rpm, 2.44g of sodium metavanadate was added to the mixture. The mixture was heated to 70°C, the pH adjusted to 6, and the reaction was continued under high-speed shearing for 1.5h. The mixture was separated to obtain a precursor precipitate. After washing three times with deionized water and anhydrous ethanol, the precipitate was dried in a vacuum oven for 12h. Subsequently, the precipitate was heat treated at 400°C for 1.0h to obtain a bismuth vanadate / titanium nickel yellow composite yellow inorganic pigment with an oil absorption of 23g / 100g. Its L*a*b* colorimetric values ​​are shown in Table 1.

[0038] Comparative Example

[0039] 9.7g bismuth nitrate was weighed and added to 200mL of nitric acid solution (1mol / L), magnetically stirred until completely dissolved, and 1.44g of sodium lauryl sulfate was added and continued to stir until completely dissolved. At a speed of 4000rpm of a high-speed shearing machine, 2.44g of sodium metavanadate was added to the above-mentioned mixed solution. The mixed solution was heated to 70°C, the pH was adjusted to 6, and the reaction was carried out for 1.5h under the shearing of a continuous high-speed shearing machine; the mixed solution was separated to obtain a precursor precipitate, which was washed three times with deionized water and anhydrous ethanol and then dried in a vacuum drying oven for 12h. Subsequently, at 400°C, heat treated for 1.0h to obtain a pure bismuth vanadate yellow inorganic pigment with an oil absorption of 22g / 100g. Its L*a*b* chromaticity values ​​are shown in Table 1. Table 1 is a comparison of the Lab chromaticity values, band gaps, and weathering grades of the bismuth vanadate composite pigments prepared in Examples 1-6 of the present invention and the comparative examples.

[0040] Table 1

[0041] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An in-situ preparation method of bismuth vanadate composite pigment, characterized in that, firstly, dissolve bismuth compound into an acidic solution, after adding an appropriate amount of surfactant and fully dissolving it, add titanium nickel yellow pigment particles thereto; under the action of strong shear force, add vanadium compound to the above-mentioned mixed solution. After reacting at a certain temperature and pH value, wash and dry the precipitate separated from the mixed solution, and then obtain bismuth vanadate composite pigment powder through heat treatment.

2. The in-situ preparation method of bismuth vanadate composite pigment according to claim 1, characterized in that, the bismuth compound is at least one of bismuth nitrate, bismuth sulfate, and bismuth oxide, and the concentration of bismuth element in the acidic solution is 0.01 - 0.4 mol / L. The molar ratio of vanadium element to bismuth element is 1:0.8 - 1:1.

5.

3. The in-situ preparation method of bismuth vanadate composite pigment according to claim 1, characterized in that, the acid solution is nitric acid solution or hydrochloric acid solution, and the concentration is 1 - 3 mol / L.

4. The in-situ preparation method of bismuth vanadate composite pigment according to claim 1, characterized in that, the surfactant is any one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and polyvinylpyrrolidone, and the addition concentration is 0.001 mol / L - 0.2 mol / L.

5. The in-situ preparation method of bismuth vanadate composite pigment according to claim 1, characterized in that, the particle size of the titanium nickel yellow is less than 2 μm. The addition amount is 15% - 200% of the mass of the vanadium compound.

6. The in-situ preparation method of bismuth vanadate composite pigment according to claim 1, characterized in that, the vanadium compound is at least one of ammonium metavanadate, sodium metavanadate, potassium metavanadate, and vanadium oxide.

7. The in-situ preparation method of bismuth vanadate composite pigment according to claim 1, characterized in that, the strong shear force is realized by a high-speed shear machine. The rotation speed of the high-speed shear machine is 500 rpm - 8000 rpm.

8. The in-situ preparation method of bismuth vanadate composite pigment according to claim 1, characterized in that, the reaction temperature is 40°C - 90°C, the pH value is 3.5 - 7, and the reaction time is 0.5 h - 3 h.

9. The in-situ preparation method of bismuth vanadate composite pigment according to claim 1, characterized in that, the heat treatment temperature is 350°C - 500°C, and the treatment time is 1 h - 2 h.

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