Cobalt-free nickel-free acid-base environment color-stable medium-temperature black pigment and preparation method thereof

Abstract

The invention discloses a cobalt-free nickel-free medium-temperature black pigment Na2FexMn3-xO7 with stable color in an acid-base environment and a preparation method of the cobalt-free nickel-free medium-temperature black pigment, and belongs to the technical field of environment-friendly inorganic pigments. According to the pigment, harmless metal oxides are selected as main coloring components, cheap iron elements are used as core doping, high-valence heavy metals such as cobalt and nickel are completely abandoned through solid solution structural design of Fe < 3 + >, sodium oxide and manganese oxide, so that the cost of raw materials is reduced, and all the components are environment-friendly oxides. The chromaticity of the obtained pigment is not obviously changed after the pigment is soaked in acid and alkali environments, and the pigment shows excellent acid and alkali resistance; the pigment is mixed with ground color transparent slurry to prepare glaze, and the glaze slurry is coated on a sample made of high-whiteness clay by using a dipping technology. And air-drying the sample for 12 hours. And finally calcining at 1200 DEG C for 2 hours. The preparation method of the glaze is low in energy consumption, stable and controllable in process and free of reducing atmosphere protection in the whole process. The glaze is bright black with high saturation after being fired at medium temperature, is free of heavy metals such as cobalt, nickel and the like, and meets the environment-friendly requirement. The coating has the advantages of low cost, high stability and environmental friendliness, and can be widely applied to the fields of ceramics, building materials, chemical equipment coatings and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of material science and relates to a cobalt-free and nickel-free medium-temperature black pigment with stable color in an acid-base environment and a preparation method thereof. Background Art

[0002] Black pigments have found important applications in ceramics, coatings, laser radar (LiDAR) detection, paints, inks, and plastics. Black pigments are metal oxide powders that appear black and are commonly used as colorants in ceramic decorative materials. The most common black pigments are spinel-type black pigments, such as cobalt-iron black, cobalt-iron-nickel-chromium black, cobalt-iron-manganese black, and cobalt-iron-manganese-copper black. However, the preparation of black pigments with excellent coloring effects typically requires the addition of heavy metal elements (such as Co and Ni) to the pigment system. The high cost of these heavy metal raw materials and their biotoxicity are detrimental to human health, limiting the development of black pigments. Furthermore, the rapid growth of the new energy industry has significantly increased the prices of cobalt and nickel, making it difficult to control the production costs of cobalt- and nickel-containing pigments. Since 2015, cobalt and nickel prices have nearly tripled due to increased demand. Therefore, successfully screening suitable and low-cost raw materials is a pressing issue. In the field of photocatalysis, the introduction of iron ions reduces the band gap of the powder, enhancing its ability to absorb natural light energy and improving photocatalytic efficiency. Therefore, the introduction of iron ions into the pigment system is expected to enhance the color performance by increasing visible light absorption. Iron ions are known as the cheapest metal on earth. By introducing iron ions and replacing cobalt or nickel metals, it is expected to achieve the goal of no environmental pollution and considerable cost. At present, in the field of building coatings, it is often necessary to apply pigments on the surface of houses to achieve energy conservation and emission reduction and reduce the probability of heat island effect. Among them, there are some widely used commercial pigments such as ultramarine (Na6Al4Si6S4O 20 ), Prussian blue (Fe4[Fe(CN)6]3) and cobalt blue (CoAl2O4). However, ultramarine (Na6Al4Si6S4O 20 ) In actual application, it was found that its use was restricted due to its intolerance to high temperature and acid. Prussian blue (Fe4[Fe(CN)6]3) is not resistant to alkali and high temperature, and produces hydrogen cyanide (HCN) in mild acid, which means that it can only be used in alkaline environments. Cobalt blue (CoAl2O4) has high thermal stability and high chemical stability. It has good heat resistance, gas resistance, light resistance and chemical resistance. However, the disadvantage of cobalt blue (CoAl2O4) is that it is expensive and contains toxic metals. Therefore, the development of a colorant that is acid and alkali resistant and low in cost is also a problem that needs to be solved at present. For this reason, the use of a simple process to synthesize an efficient cobalt-free, nickel-free, acid and alkali resistant, medium-temperature black colorant is of great significance in the field of colorants. Summary of the Invention

[0003] The present invention addresses the problems of cobalt and nickel metals and insufficient acid and alkali resistance in black pigments. The present invention provides a cobalt-free and nickel-free medium-temperature black pigment material with stable color in acid and alkali environments and a preparation method thereof. At the same time, cheap iron is used to replace the manganese in the product and the iron content range that can effectively maintain the black color is defined.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A cobalt-free, nickel-free, acid-base-resistant, medium-temperature black pigment material, the expression is: Na2Fe x Mn 3-x O7, x=0-1.5.

[0006] The method for preparing the cobalt-free and nickel-free acid- and alkali-resistant medium-temperature black pigment material comprises the following steps:

[0007] (1) Raw material mixing: The raw materials are corresponding oxides or carbonates. The valence of iron in the iron source must be trivalent, and the valence of manganese in the manganese source must be divalent. The raw materials are mixed in an agate mortar.

[0008] (2) Grinding and mixing: Add 3-5 ml of alcohol to the powdered raw materials mixed in step (1) and grind for 30-60 minutes to mix evenly.

[0009] (3) Calcination: Calcinate the mixed powder obtained in step (2).

[0010] The calcination temperature is 500-1000℃, the heating rate is 5-10℃ / min below 800℃, 1-5℃ / min above 800℃, the holding time is 4-8h, the atmosphere is air, the cooling rate is: 2-5℃ / min above 200℃, and cooling with the furnace below 200℃.

[0011] The pigment of the present invention uses harmless metal oxide as the main coloring component, and uses cheap iron as the core doping. 3+ The solid solution structure design with sodium and manganese oxides completely eliminates expensive heavy metals such as cobalt and nickel, reducing the cost of raw materials, and all components are environmentally friendly oxides. The obtained colorant does not show obvious color change after immersion in acidic and alkaline environments, showing excellent acid and alkali resistance; the colorant is mixed with a base color transparent slurry to prepare a glaze, and the glaze slurry is applied to a sample made of high-white clay using an impregnation technique. The sample is air-dried for 12 hours. Finally, it is calcined at 1200°C for 2 hours. This glaze preparation method has low energy consumption, a stable and controllable process, and does not require reducing atmosphere protection throughout the process. After medium-temperature firing, the glaze exhibits a highly saturated bright black color and does not contain heavy metals such as cobalt and nickel, meeting environmental protection requirements. The present invention combines low cost, high stability and environmental protection, and can be widely used in ceramics, building materials, chemical equipment coatings and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is the XRD pattern of the Na2Mn3O7 colorant prepared in Example 1 of the present invention.

[0013] Figure 2 This is the ultraviolet absorption spectrum of the Na2Mn3O7 colorant prepared in Example 1 of the present invention.

[0014] Figure 3 This is the ultraviolet absorption spectrum of the Na2Mn3O7 pigment prepared in Example 1 of the present invention after glazing.

[0015] Figure 4 This is an appearance diagram of the Na2Mn3O7 pigment prepared in Example 1 of the present invention.

[0016] Figure 5 This is the appearance of the Na2Mn3O7 colorant prepared in Example 1 of the present invention after glazing.

[0017] Figure 6 This is the ultraviolet absorption spectrum of the Na2Mn3O7 colorant prepared in Example 1 of the present invention after acid soaking.

[0018] Figure 7 This is the ultraviolet absorption spectrum of the acid-soaked Na2Mn3O7 pigment prepared in Example 1 of the present invention after glazing.

[0019] Figure 8 This is the appearance of the Na2Mn3O7 pigment after acid soaking prepared in Example 1 of the present invention.

[0020] Figure 9 This is the appearance of the Na2Mn3O7 pigment after acid soaking prepared in Example 1 of the present invention and glazing.

[0021] Figure 10 This is the ultraviolet absorption spectrum of the Na2Mn3O7 colorant prepared in Example 1 of the present invention after alkaline soaking.

[0022] Figure 11 This is the ultraviolet absorption spectrum of the Na2Mn3O7 pigment after glazing after alkali soaking prepared in Example 1 of the present invention.

[0023] Figure 12 This is the appearance of the Na2Mn3O7 pigment after alkaline soaking prepared in Example 1 of the present invention.

[0024] Figure 13 This is the appearance of the Na2Mn3O7 pigment after glazing after alkaline soaking prepared in Example 1 of the present invention.

[0025] Figure 14 It is Na2Fe prepared in Example 2 of the present invention0.5 Mn 2.5 Appearance of O7 pigment.

[0026] Figure 15 It is Na2Fe prepared in Example 2 of the present invention 0.5 Mn 2.5 The appearance of O7 color after glazing.

[0027] Figure 16 It is Na2Fe prepared in Example 3 of the present invention 1.5 Mn 1.5 Appearance of O7 pigment.

[0028] Figure 17 It is Na2Fe prepared in Example 3 of the present invention 1.5 Mn 1.5 The appearance of O7 color after glazing. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0030] The chemical reagents used in the examples of the present invention are all analytical grade products; the examples are analyzed using a RINT2200V / PC X-ray diffractometer from Rigaku, Japan;

[0031] Example 1: The raw materials required for Na2Mn3O7 are Na2CO3 (0.3284g) and MnO (0.6593g).

[0032] (1) Weighing of raw materials: Na2CO3 and MnO. Mix all weighed raw materials in an agate mortar.

[0033] (2) Grinding and mixing: Add 5 ml of alcohol to the powdered raw materials mixed in step (1) and grind for 60 minutes to mix evenly.

[0034] (3) Calcination: The mixed powder obtained in step (2) was calcined. The calcination temperature was 700°C, the heating rate was 6°C / min below 800°C, the holding time was 6 hours, the atmosphere was air, the cooling rate was 2°C / min above 200°C, and the mixture below 200°C was cooled to room temperature to obtain the Na2Mn3O7 sample. The physical phase, UV absorption and acid-base test of the obtained sample are shown in the attached figure. Figure 1-13 The chromaticity parameters of the samples are shown in Table 1-3:

[0035] Table 1

[0036]

[0037] Table 2

[0038]

[0039] Table 3

[0040]

[0041] from Figure 1 It can be seen that the obtained product is a pure phase. Figure 2-3 This is the UV-visible absorption spectrum of Na2Mn3O7 pigment and after glazing. It can be seen that the sample shows strong absorption characteristics in the entire visible light range (400-700nm). Figure 4-5 This is a photo of the Na2Mn3O7 pigment and its glaze. You can see that both are bright black. Figure 6-9 It can be seen that there is no obvious change in the UV absorption performance and color appearance of the Na2Mn3O7 sample after acid immersion, indicating that the sample has a certain acid resistance. Figure 10-13 The color of the Na2Mn3O7 sample after alkali immersion shows no significant change compared to the normal sample, indicating that the sample has a certain degree of alkali resistance. The blackness index of the sample's color value parameters is L* = 17.27 (normal), L* = 19.81 (acid immersion), and L* = 22.17 (alkaline immersion), which is still significantly superior to commercially available black pigments and those reported in the literature.

[0042] Example 2: Na2Fe 0.5 Mn 2.5 The raw materials required for O7 are Na2CO3 (0.3270g), MnO (0.5471g), and Fe2O3 (0.1232g).

[0043] (1) Weighing of raw materials: Na2CO3, Fe2O3, and MnO. Mix all weighed raw materials in an agate mortar.

[0044] (2) Grinding and mixing: Add 5 ml of alcohol to the powdered raw materials mixed in step (1) and grind for 60 minutes to mix evenly.

[0045] (3) Calcination: Calcinate the mixed powder obtained in step (2). The calcination temperature is 500°C, the heating rate is 6°C / min below 800°C, the holding time is 8 hours, the atmosphere is air, the cooling rate is 2°C / min above 200°C, and below 200°C, the mixture is cooled to room temperature in the furnace to obtain Na2Fe 0.5 Mn 2.5 O7 sample. Obtained Na2Fe 0.5 Mn 2.5 The actual photos of O7 color and glaze are attached. Figure 14-15 It can be seen that it still has the characteristics of bright black. The chromaticity value parameters are shown in Table 4:

[0046] Table 4

[0047]

[0048] Example 3: Na2Fe 1.5 Mn 1.5 The raw materials required for O7 are Na2CO3 (0.3270g), MnO (0.3283g), Fe2O3 (0.3695g)

[0049] (1) Weighing of raw materials: Na2CO3, Fe2O3, and MnO. Mix all weighed raw materials in an agate mortar.

[0050] (2) Grinding and mixing: Add 5 ml of alcohol to the powdered raw materials mixed in step (1) and grind for 60 minutes to mix evenly.

[0051] (3) Calcination: Calcinate the mixed powder obtained in step (2). The calcination temperature is 1000°C, the heating rate is 6°C / min below 800°C, 1°C / min above 800°C, the holding time is 4 hours, the atmosphere is air, the cooling rate is 2°C / min above 200°C, and the temperature below 200°C is cooled to room temperature in the furnace to obtain Na2Fe 1.5 Mn 1.5 O7 sample. Obtained Na2Fe 1.5 Mn 1.5 The actual photos of O7 color and glaze are attached. Figure 16-17 , we can see that it still has the bright black characteristics. The chromaticity value parameters are shown in Table 5:

[0052] Table 5

[0053]

Claims

1. A cobalt-free and nickel-free black pigment with stable color in acid-base environment and medium temperature, characterized in that: The expression of the cobalt-free and nickel-free acid-base environment color-stable medium-temperature black pigment is Na2Fe x Mn 3-x O7, x=0~1.

5.

2. The method for preparing the cobalt-free and nickel-free acid- and alkali-resistant medium-temperature black pigment material according to claim 1, characterized in that: The following steps are involved: (1) Mixing raw materials: The raw materials are corresponding oxides or carbonates, the valence of iron in the iron source must be positive trivalent, and the valence of manganese in the manganese source must be positive divalent; the raw materials are mixed in an agate mortar according to the proportions described in claim 1; (2) Grinding and mixing: Add 3-5 ml of alcohol to the powdered raw materials mixed in step (1) and grind for 30-60 minutes to mix evenly; (3) Calcination: calcining the mixed powder obtained in step (2); the calcination temperature is 500-1000°C, the heating rate is 5-10°C / min below 800°C, 1-5°C / min above 800°C, the holding time is 4-8h, the atmosphere is air, the cooling rate is 2-5°C / min above 200°C, and cooling with the furnace below 200°C.

3. The preparation method according to claim 2, characterized in that step: (1) Raw material mixing: x is 0, the raw materials used are Na2CO3 and MnO, and all weighed raw materials are mixed in an agate mortar; (2) Grinding and mixing: Add 5 ml of alcohol to the powdered raw materials mixed in step (1) and grind for 60 minutes to mix evenly; (3) Calcination: Calcinate the mixed powder obtained in step (2); the calcination temperature is 700°C to obtain a Na2Mn3O7 sample; during calcination, the heating rate is 6°C / min below 800°C, the holding time is 6 hours, and the atmosphere is air; during calcination, the cooling rate is 2°C / min above 200°C, and the sample is cooled to room temperature with the furnace below 200°C.

4. The preparation method according to claim 2, characterized in that step: (1) Mixing raw materials: According to the ratio described in claim 1, x is greater than 0 and less than 1.5, and the raw materials used are Na2CO3, Fe2O3 and MnO; all weighed raw materials are mixed in an agate mortar; (2) Grinding and mixing: Add 5 ml of alcohol to the powdered raw materials mixed in step (1) and grind for 60 minutes to mix evenly; (3) Calcination: Calcinate the mixed powder obtained in step (2); the calcination temperature is 500°C to obtain Na2Fe 0.5 Mn 2.5 O7 sample; During calcination, the heating rate is: 6℃ / min below 800℃, the holding time is 8h, and the atmosphere is air; During calcination, the cooling rate is: 2℃ / min above 200℃, and cool to room temperature with the furnace below 200℃.

5. The preparation method according to claim 2, characterized in that step: (1) Raw material mixing: x is greater than 0 and less than 1.5, and the raw materials used are Na2CO3, Fe2O3 and MnO; all weighed raw materials are mixed in an agate mortar; (2) Grinding and mixing: Add 5 ml of alcohol to the powdered raw materials mixed in step (1) and grind for 60 minutes to mix evenly; (3) Calcination: Calcinate the mixed powder obtained in step (2); the calcination temperature is 1000°C to obtain Na2Fe 1.5 Mn 1.5 O7 sample; During calcination, the heating rate is 6°C / min below 800°C, 1°C / min above 800°C, the holding time is 4 hours, and the atmosphere is air; during calcination, the cooling rate is 2°C / min above 200°C, and cool to room temperature with the furnace below 200°C.

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