In-situ preparation method of bismuth vanadate composite pigment

Abstract

The present application belongs to the technical field of inorganic pigment preparation, and particularly relates to an in-situ preparation method of bismuth vanadate composite pigment, characterized in that: first, a bismuth compound is dissolved into an acidic solution, a surfactant is added for sufficient dissolution, and then titanium-nickel yellow particles are added; under the action of strong shearing force, a vanadium compound is added into the above-mentioned mixed solution; after reaction at a certain temperature and pH value, the precipitate separated from the mixed solution is washed and dried, and then is subjected to heat treatment to obtain bismuth vanadate composite pigment powder. The in-situ uniform bismuth vanadate synthesis reaction occurs on the surface of the titanium-nickel yellow under the action of strong shearing force. The method not only makes the in-situ composite reaction faster and more uniform, but also avoids a large amount of alkaline solution required by the conventional method. The obtained bismuth vanadate composite pigment has high color value, and excellent hiding power and dilution strength. The method is green, efficient, uniform in reaction, and excellent in sample performance, and is suitable for industrialized continuous production.

Description

Technical Field

[0001] This invention belongs to the field of inorganic pigment preparation technology, and particularly relates to an in-situ preparation method of bismuth vanadate composite pigment. Background Technology

[0002] Bismuth vanadate is a high-performance, environmentally friendly yellow inorganic pigment, often used to replace heavy metal yellow pigments such as chrome yellow and cadmium yellow. Bismuth vanadate pigments possess numerous excellent characteristics, including easy dispersibility, vibrant color, high weather resistance, and high tinting strength. However, the high cost of raw materials makes bismuth vanadate pigments expensive, costing more than ten times that of lead chrome yellow and organic yellow pigments. This severely hinders the widespread market application of environmentally friendly bismuth vanadate pigments. Currently, bismuth vanadate pigments are only used in high-end products or in fields with high requirements for pigment performance and environmental friendliness, such as high-end coatings and plastics that come into contact with food.

[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 lowering costs. The preparation methods for bismuth vanadate composite pigments mainly include solid-phase methods, liquid-phase methods, and twin-screw extrusion. Among these three methods, the liquid-phase method can yield bismuth vanadate pigments with the smallest particle size, high purity, and strong controllability. However, it still suffers from uneven reaction, making it impossible to effectively and uniformly combine the two materials, resulting in pigment performance significantly lower than that of pure bismuth vanadate pigments.

[0004] Titanium nickel yellow pigment possesses a wide chromatographic range, is easily dispersed, has good hiding power, and a long service life. Among pale yellow pigments, it exhibits good gloss and color retention. Titanium nickel yellow is inexpensive and is frequently used in coatings for construction, steel, painting, and in general plastics, rubber, building materials, and ceramics. Titanium nickel yellow is a pale yellow pigment, weaker than the bright yellow of bismuth vanadate pigments. Strong shear force is generated under the relative high-speed motion of the stator and rotor, enabling rapid dispersion and effectively promoting the homogeneity of the reaction. This invention utilizes the effect of strong shear force to simplify the bismuth vanadate synthesis reaction and promote the uniform in-situ composite of bismuth vanadate and titanium nickel yellow. This results in a low-cost, high-performance bismuth vanadate composite pigment. Summary of the Invention

[0005] The purpose of this invention is to provide an in-situ preparation method for bismuth vanadate composite pigments, overcoming the shortcomings of existing technologies. By combining the advantages of high color performance of bismuth vanadate pigments and low cost of titanium nickel yellow, this invention proposes to use titanium nickel yellow as the core and synthesize bismuth vanadate uniformly in situ on the surface of titanium nickel yellow under strong shear force, ultimately forming a high-performance bismuth vanadate composite pigment.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for in-situ preparation of bismuth vanadate composite pigment, characterized in that: firstly, a bismuth compound is dissolved in an acidic solution, and after complete dissolution with an appropriate amount of surfactant, titanium nickel yellow pigment particles are added; under strong shear force, a vanadium compound is added to the above mixed solution. After reaction at a certain temperature and pH value, the precipitate separated from the mixed solution is washed, dried, and then heat-treated to obtain bismuth vanadate composite pigment powder.

[0008] The bismuth compound is at least one of bismuth nitrate, bismuth sulfate, and bismuth oxide, and the concentration of bismuth element in acidic solution is 0.01–0.4 mol / L.

[0009] The acid solution is a nitric acid solution or a hydrochloric acid solution with a concentration of 1–3 mol / L.

[0010] The surfactant is any one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and polyvinylpyrrolidone, with an addition concentration of 0.001 mol / L to 0.2 mol / L.

[0011] The titanium nickel yellow particles are smaller than 2 μm in size and are added at 15% to 200% of the mass of the vanadium compound.

[0012] The vanadium compound is at least one of ammonium metavanadate, sodium metavanadate, potassium metavanadate, and vanadium oxide.

[0013] The alkaline solution is one of sodium hydroxide, potassium hydroxide, or ammonia water, with a concentration of 1–3 mol / L.

[0014] The strong shearing force is achieved using a high-speed shearing machine. The high-speed shearing machine operates at 500 rpm to 8000 rpm.

[0015] The reaction temperature is 40℃~90℃, the pH value is 3.5~7, and the reaction time is 0.5h~3h.

[0016] The heat treatment temperature is 350℃~500℃, and the treatment time is 1h~2h.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 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 using titanium nickel yellow as a base is proposed. The main pigment properties, Lab value, hiding power, and dilution strength, are significantly improved. 2) Under strong shear force, the synthesis reaction of bismuth vanadate on the titanium nickel yellow surface is ensured to be uniform, while avoiding the use of large amounts of alkaline solution as a base liquid in conventional methods. Attached Figure Description

[0019] Figure 1These are the XRD patterns of the bismuth vanadate composite pigments prepared in Examples 1-6 of this invention and the pure bismuth vanadate prepared in the comparative examples;

[0020] Figure 2 These are the ultraviolet spectra of the bismuth vanadate composite pigments prepared in Examples 1-6 of this invention and the pure bismuth vanadate prepared in the comparative examples;

[0021] Figure 3 These are the test results of the hiding power and tinting strength of Embodiment 1 and the comparative example of the present invention. Detailed Implementation

[0022] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the specific embodiments used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the specific embodiments described below are some embodiments of the present invention. For those skilled in the art, other specific embodiments can be obtained based on these specific embodiments without creative effort.

[0024] The components of the embodiments of the invention 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 invention provided in the specific embodiments is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0025] Example 1

[0026] 9.7 g of bismuth nitrate was weighed and added to 200 mL of nitric acid solution (1 mol / L). The solution was magnetically stirred until completely dissolved. Then, 0.7 g of sodium dodecylbenzenesulfonate was added and stirring continued until completely dissolved. Next, 0.4 g of titanium nickel yellow granules were added and stirring continued until evenly dispersed. 2.44 g of sodium metavanadate was added to the mixture at 2000 rpm using a high-speed shear press. The mixture was heated to 70 °C, the pH was adjusted to 5, and the reaction was carried out under continuous high-speed shear press for 1.5 h. The mixture was then separated to obtain the precursor precipitate, which was washed three times with deionized water and anhydrous ethanol, and then dried in a vacuum drying oven for 12 h. Subsequently, it was heat-treated at 350 °C for 1.5 h to obtain a bismuth vanadate / titanium nickel yellow composite yellow inorganic pigment with an oil absorption of 20 g / 100 g. Its L*a*b* chromaticity values ​​are shown in Table 1.

[0027] Example 2

[0028] 9.7 g of bismuth nitrate was weighed and added to 200 mL of nitric acid solution (1 mol / L). The solution was magnetically stirred until completely dissolved. Then, 0.9 g of sodium dodecyl sulfate was added and stirring continued until completely dissolved. Next, 0.6 g of titanium nickel yellow granules were added and stirring continued until evenly dispersed. 2.44 g of sodium metavanadate was added to the mixture at 3000 rpm using a high-speed shear press. The mixture was heated to 70 °C, the pH was adjusted to 5.5, and the reaction was carried out under continuous high-speed shear press for 1.5 h. The mixture was then separated to obtain the precursor precipitate, which was washed three times with deionized water and anhydrous ethanol, and then dried in a vacuum drying oven for 12 h. Subsequently, it was heat-treated at 400 °C for 1.5 h to obtain a bismuth vanadate / titanium nickel yellow composite yellow inorganic pigment with an oil absorption of 23 g / 100 g. Its L*a*b* chromaticity values ​​are shown in Table 1.

[0029] Example 3

[0030] 9.7 g of bismuth nitrate was weighed and added to 200 mL of nitric acid solution (1 mol / L). The solution was magnetically stirred until completely dissolved. 1.6 g of polyvinylpyrrolidone was added, and stirring continued until completely dissolved. Then, 0.8 g of titanium nickel yellow granules were added, and stirring continued until evenly dispersed. 2.44 g of sodium metavanadate was added to the mixture at 4000 rpm using a high-speed shear press. The mixture was heated to 70 °C, the pH was adjusted to 6, and the reaction was carried out under continuous high-speed shear press for 1.5 h. The mixture was then separated to obtain the precursor precipitate, which was washed three times with deionized water and anhydrous ethanol, and then dried in a vacuum drying oven for 12 h. Subsequently, it was heat-treated at 380 °C for 1.5 h to obtain a bismuth vanadate / titanium nickel yellow composite yellow inorganic pigment with an oil absorption of 22 g / 100 g. Its L*a*b* chromaticity values ​​are shown in Table 1.

[0031] Example 4

[0032] 9.7 g of bismuth nitrate was weighed and added to 200 mL of nitric acid solution (1 mol / L). The solution was magnetically stirred until completely dissolved. Then, 3.10 g of sodium dodecyl sulfate was added and stirring continued until completely dissolved. Next, 1.00 g of titanium nickel yellow granules was added and stirring continued until evenly dispersed. 2.44 g of sodium metavanadate was added to the mixture at 4000 rpm using a high-speed shear press. The mixture was heated to 70 °C, the pH was adjusted to 6, and the reaction was carried out under continuous high-speed shear press for 1.5 h. The mixture was then separated to obtain the precursor precipitate, which was washed three times with deionized water and anhydrous ethanol, and then dried in a vacuum drying oven for 12 h. Subsequently, it was heat-treated at 400 °C for 1.0 h to obtain a bismuth vanadate / titanium nickel yellow composite yellow inorganic pigment with an oil absorption of 23 g / 100 g. Its L*a*b* chromaticity values ​​are shown in Table 1.

[0033] Example 5

[0034] 9.7 g of bismuth nitrate was weighed and added to 200 mL of nitric acid solution (1 mol / L). The solution was magnetically stirred until completely dissolved. Then, 1.5 g of sodium dodecyl sulfate was added and stirring continued until completely dissolved. Next, 1.22 g of titanium nickel yellow granules were added and stirring continued until evenly dispersed. 2.44 g of sodium metavanadate was added to the mixture at 4000 rpm using a high-speed shear press. The mixture was heated to 70 °C, the pH was adjusted to 6, and the reaction was carried out under continuous high-speed shear press for 1.5 h. The mixture was then separated to obtain the precursor precipitate, which was washed three times with deionized water and anhydrous ethanol, and then dried in a vacuum drying oven for 12 h. Subsequently, it was heat-treated at 400 °C for 1.0 h to obtain a bismuth vanadate / titanium nickel yellow composite yellow inorganic pigment with an oil absorption of 24 g / 100 g. Its L*a*b* chromaticity values ​​are shown in Table 1.

[0035] Example 6

[0036] 9.7 g of bismuth nitrate was weighed and added to 200 mL of nitric acid solution (1 mol / L). The solution was magnetically stirred until completely dissolved. Then, 2.0 g of sodium dodecyl sulfate was added and stirring continued until completely dissolved. Next, 2.44 g of titanium nickel yellow granules were added and stirred until evenly dispersed. 2.44 g of sodium metavanadate was added to the mixture at 4000 rpm using a high-speed shear press. The mixture was heated to 70 °C, the pH was adjusted to 6, and the reaction was carried out under continuous high-speed shear press for 1.5 h. The mixture was then separated to obtain the precursor precipitate, which was washed three times with deionized water and anhydrous ethanol, and then dried in a vacuum drying oven for 12 h. Subsequently, it was heat-treated at 400 °C for 1.0 h to obtain a bismuth vanadate / titanium nickel yellow composite yellow inorganic pigment with an oil absorption of 23 g / 100 g. Its L*a*b* chromaticity values ​​are shown in Table 1.

[0037] Comparative Example

[0038] 9.7 g of bismuth nitrate was weighed and added to 200 mL of nitric acid solution (1 mol / L). The solution was magnetically stirred until completely dissolved. Then, 1.44 g of sodium dodecyl sulfate was added and stirring continued until completely dissolved. 2.44 g of sodium metavanadate was added to the mixture at 4000 rpm using a high-speed shear press. The mixture was heated to 70°C, the pH was adjusted to 6, and the reaction was carried out under continuous high-speed shear press for 1.5 h. The mixture was then separated to obtain the precursor precipitate, which was washed three times with deionized water and anhydrous ethanol, and then dried in a vacuum drying oven for 12 h. Subsequently, it was heat-treated at 400°C for 1.0 h to obtain pure bismuth vanadate yellow inorganic pigment with an oil absorption of 22 g / 100 g. Its L*a*b* chromaticity values ​​are shown in Table 1. Table 1 compares the Lab chromaticity values, band gaps, and weather resistance grades of the bismuth vanadate composite pigments prepared in Examples 1-6 of this invention with those of the comparative examples.

[0039] Table 1

[0040] sample L* a* b* Forbidden zone Weather resistance rating Example 1 90.47 -5.14 74.23 2.48eV 5 Example 2 91.31 -4.23 73.48 2.47eV 5 Example 3 90.57 -5.24 74.90 2.49eV 5 Example 4 90.11 -4.50 72.39 2.48eV 5 Example 5 89.81 -3.61 71.46 2.47eV 5 Example 6 89.74 -3.37 71.84 2.49eV 5 Comparative Example 90.20 -3.32 71.21 2.50eV 5

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

Claims

1. A method for in-situ preparation of a bismuth vanadate composite pigment, characterized in that, First, the bismuth compound is dissolved in an acidic solution. After the appropriate amount of surfactant is added and fully dissolved, titanium nickel yellow pigment particles are added to the solution. Under strong shear force, vanadium compound is added to the above mixed solution. After reacting at a certain temperature and pH value, the precipitate separated from the mixed solution is washed, dried, and then heat-treated to obtain bismuth vanadate composite pigment powder. The bismuth compound is at least one of bismuth nitrate, bismuth sulfate, and bismuth oxide, and the concentration of bismuth in the acidic solution is 0.01~0.4 mol / L; the molar ratio of vanadium to bismuth is 1:0.8~1:1.

5. The acid solution is a nitric acid solution or a hydrochloric acid solution with a concentration of 1~3 mol / L; The surfactant is any one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and polyvinylpyrrolidone, with an addition concentration of 0.001 mol / L to 0.2 mol / L; The titanium nickel yellow particles are smaller than 2 μm in size; the amount added is 15% to 200% of the mass of the vanadium compound. The vanadium compound is at least one of ammonium metavanadate, sodium metavanadate, potassium metavanadate, and vanadium oxide. The strong shearing force is achieved by a high-speed shearing machine; the high-speed shearing machine rotates at a speed of 500 rpm to 8000 rpm. The reaction temperature is 40℃~90℃, the pH value is 3.5~7, and the reaction time is 0.5h~3h; the heat treatment temperature is 350℃~500℃, and the treatment time is 1h~2h.

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