阅读说明：本技术 溶液燃烧法制备尖晶石结构铝酸钴颜料的方法 (Method for preparing cobalt aluminate pigment with spinel structure by solution combustion method ) 是由 陈岩 张琪 于 2019-11-08 设计创作，主要内容包括：本发明的溶液燃烧法制备尖晶石结构铝酸钴颜料的方法,属于无机合成技术领域。利用溶液燃烧法,以金属硝酸盐作为原料、有机胺作为燃料和水配成溶液,控制反应温度和原料比例选择性合成不同元素比例的Co<Sub>x</Sub>Al<Sub>2</Sub>O<Sub>3+x</Sub>(x＝0～1)系列尖晶石结构钴蓝粉体颜料,实现高纯度和高产率的钴蓝纳米粉体的制备要求。本发明为钴蓝颜料提供了一条新的绿色、高产率反应路线,具有原料成本低、产率高、能耗低、无污染、可选择性合成等优势。(The invention discloses a method for preparing cobalt aluminate pigment with a spinel structure by a solution combustion method, and belongs to the technical field of inorganic synthesis. By using solution combustion method, metal nitrate as raw material, organic amine as fuel and water are mixed into solution, and Co with different element proportions is selectively synthesized by controlling reaction temperature and raw material proportion x Al 2 O 3+x The (x ═ 0-1) series spinel structure cobalt blue powder pigment meets the preparation requirement of cobalt blue nano powder with high purity and high yield. The invention provides a new green and high-yield reaction route for the cobalt blue pigment, and has the advantages of low raw material cost, high yield, low energy consumption, no pollution, selective synthesis and the like.)

1. A method for preparing cobalt aluminate pigment with a spinel structure by a solution combustion method comprises the steps of taking cobalt nitrate or cobalt acetate as a cobalt source, aluminum nitrate as an aluminum source and organic amine as a combustion agent, wherein the molar ratio of cobalt element to aluminum element is 0-1: 2, and the molar ratio of the total amount of nitrate radicals in the cobalt source and the aluminum source to the total amount of amine radicals in the organic amine is 4: 6; mixing a cobalt source, an aluminum source and a combustion agent, adding distilled water for dissolving to obtain a reaction precursor solution, heating to 350-600 ℃ for reaction after the solution is clarified, quickly concentrating the solution, combusting to generate a powdery product, and performing secondary calcination on the powdery product at 700-1200 ℃ for 2-8 hours to obtain the spinel-structure cobalt aluminate pigment with the yield of more than 95%.

2. The method for preparing spinel-structured cobalt aluminate pigment by solution combustion as claimed in claim 1, wherein, in the solution combustion reaction, the reaction conditions are a reaction at a temperature of 400 ℃ for 15 minutes; in the calcination process, the calcination temperature was 900 ℃ and the calcination time was 4 hours.

3. The method for preparing the cobalt aluminate pigment with the spinel structure by the solution combustion method according to claim 1, wherein a combustion improver is added to improve the crystallization degree of a sample during the combustion of the solution when a reaction precursor is prepared, wherein the combustion improver is citric acid or boric acid, and the mass ratio of the combustion improver to the combustion improver is 2: 15.

4. The method for preparing cobalt aluminate pigment with spinel structure by using solution combustion method according to any one of claims 1-3, characterized in that the organic amine is urea, glycine or beta-alanine.

Technical Field

The invention belongs to the technical field of inorganic synthesis. In particular to green, high-yield and controllable preparation of Co with different Co element contents_xAl₂O_3+x(x-0-1) solution combustion method of cobalt blue pigment.

Technical Field

Spinel aluminates are an important industrial material and are used as ceramics, pigments, optical materials, nanomaterials, catalysts, and the like. Wherein the cobalt blue CoAl₂O₄Is a nontoxic and environment-friendly inorganic pigment and has excellent covering power, tinting strength and dispersibility. Ultramarine Na with another common blue inorganic pigment₆Al₄Si₆S₄O₂₀In contrast, because of cobaltThe blue has the structural characteristics of spinel, so free cobalt metal ions are not separated out, and the blue has stable chemical properties, high temperature resistance and acid and alkali resistance. The paint can be widely applied to the fields of high-temperature paint, engineering plastics, high-grade art paint, food packaging and containers, children toys and the like.

At present, the research on the preparation process of the cobalt blue pigment mainly focuses on synthesizing a nano-grade product with good dispersibility. The industrial preparation of the nano cobalt blue powder is mainly divided into a dry method and a wet method. The dry method is mainly to prepare large-particle cobalt blue dye by a high-temperature solid phase method, and then to crush the large particles by mechanical force by using a ball mill to obtain nano-scale powder. The preparation method is simple and suitable for large-scale production, but has the disadvantages of high energy consumption in the synthesis process, uneven particle size distribution of the product, unstable chemical distribution and easy agglomeration, and influences the performance of the dye. The main wet synthesis methods include precipitation, microemulsion and sol-gel methods. The wet method is easy to control the shape, granularity and chemical composition of the product compared with the dry method, but has high cost and complex operation, and is not beneficial to large-scale production. In addition, the gas phase method can also prepare the nano-scale cobalt blue, and the problems of high cost and complex operation are faced like the wet method, so that the scale production is difficult.

Although the cobalt blue has outstanding performance, the cobalt blue is expensive due to the cobalt contained in the component, and the application range of the high-quality pigment is severely limited. Thus, it is commercially valuable to develop new synthesis processes and new products that reduce the Co content of their components without affecting color appearance and performance. The invention can directly regulate and control the content of Co ions in the spinel structure by a simple synthesis method to reduce the production cost of cobalt blue.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects in the background technology, and utilizes a solution combustion method to prepare a solution by using metal nitrate as a raw material and organic amine as fuel and water, and selectively synthesize Co with different element proportions by controlling the reaction temperature and the raw material proportion_xAl₂O_3+x(x is 0-1) series cobalt blue powder pigment with spinel structure, and high-purity and high-yield cobalt blue nano powder preparation is realizedAnd (5) preparing.

The specific technical scheme is as follows:

a method for preparing cobalt aluminate pigment with a spinel structure by a solution combustion method comprises the steps of taking cobalt nitrate or cobalt acetate as a cobalt source, aluminum nitrate as an aluminum source and organic amine as a combustion agent, wherein the molar ratio of cobalt element to aluminum element is 0-1: 2, and the molar ratio of the total amount of nitrate radicals in the cobalt source and the aluminum source to the total amount of amine radicals in the organic amine is 4: 6; mixing a cobalt source, an aluminum source and a combustion agent, adding distilled water for dissolving to obtain a reaction precursor solution, heating to 350-600 ℃ for reaction after the solution is clarified, quickly concentrating the solution, combusting to obtain a powdery product, and calcining the powdery product for 2-8 hours at 700-1200 ℃ to obtain the spinel-structure cobalt aluminate pigment Co with the yield of more than 95%_xAl₂O_3+x(x＝0～1)。

In the solution combustion reaction process, the reaction conditions are preferably at 400 ℃ for 15 minutes; the calcination temperature is preferably 900 ℃ and the calcination time is preferably 4 hours.

When the reaction precursor is prepared, a combustion improver can be added to improve the crystallization degree of a sample during solution combustion, and the combustion improver can be citric acid (C)₆H₈O₇) Or boric acid (H)₃BO₃) The mass ratio of the combustion improver to the combustion agent is preferably 2: 15.

In the present invention, the organic amine may be urea (CH)₄N₂O), glycine (C)₂H₅NO₂) Beta-alanine (C)₃H₇NO₂)；

The reaction equation for using urea as fuel is:

xCo(NO₃)₂+2Al(NO₃)₃+(x+5)CH₄N₂O→Co_xAl₂O_3+x+(2x+10)H₂O+(8+2x)N₂+(x+5)CO₂

the reaction equation for using glycine as fuel is:

xCo(NO₃)₂+2Al(NO₃)₃+(6+2x)C₂H₅NO₂→Co_xAl₂O_3+x+(15+5x)H₂O+(6+2x)N₂+(12+4x)CO₂

the reaction equation for using beta-alanine as fuel is:

xCo(NO₃)₂+2Al(NO₃)₃+(2x/3+2)C₃H₇NO₂→Co_xAl₂O_3+x+(7x/3+7)H₂O+(8x/3+8)N₂+(2x+6)CO₂

the invention is in the preparation of Co_xAl₂O_3+x(x is 0 to 1) white Al when the sample is free from cobalt₂O₃The blue color of the sample gradually deepens with the increase of the content of the Co element in the composition. Powder X-ray analysis of the solid phase sample showed the product to be a pure phase spinel structure with no diffraction peaks of the hetero-phase being found. The scanning electron microscope shows that the sample is spongy porous powder formed by gathering nano-scale particles. In the experiment, the maximum yield of the sample obtained was 98% (mole percent). The sample loss is the artificial loss caused in the sample processing process.

Has the advantages that:

the invention is to prepare Co with controllable Co content_xAl₂O_3+xThe (x ═ 0-1) cobalt blue pigment provides a feasible reaction route and a green preparation method. The cobalt blue pigment has wide application, and the cobalt blue with controllable Co content has great potential advantages as an industrial pigment. The preparation method is green, high in efficiency and high in yield. Therefore, the present invention has important practical significance in terms of environmental protection and resource utilization efficiency.

Drawings

FIG. 1 shows the hydrothermal synthesis of Co in examples 1, 3, 5, 7, 9 and 11 of the present invention_xAl₂O_3+x(x ═ 0,0.2,0.4,0.6,0.8,1) digital photographs of the pigments.

FIG. 2 shows Al prepared in example 1 of the present invention₂O₃Scanning electron micrographs.

FIG. 3 shows Al prepared in example 1 of the present invention₂O₃Powder XRD diffractogram compared to standard lines.

FIG. 4 shows Co prepared in example 3 of the present invention_0.2Al₂O_3.2Scanning electron micrographs.

FIG. 5 shows Co prepared in example 3 of the present invention_0.2Al₂O_3.2Powder XRD diffractogram compared to standard lines.

FIG. 6 shows Co prepared in example 5 of the present invention_0.4Al₂O_3.4Scanning electron micrographs.

FIG. 7 shows Co prepared in example 5 of the present invention_0.4Al₂O_3.4Powder XRD diffractogram compared to standard lines.

FIG. 8 is Co prepared according to example 7 of the present invention_0.6Al₂O_3.6Scanning electron micrographs.

FIG. 9 is Co prepared according to example 7 of the present invention_0.6Al₂O_3.6Powder XRD diffractogram compared to standard lines.

FIG. 10 shows Co prepared in example 9 of the present invention_0.8Al₂O_3.8Scanning electron micrographs.

FIG. 11 shows Co prepared in example 9 of the present invention_0.8Al₂O_3.8Powder XRD diffractogram compared to standard lines.

FIG. 12 is a CoAl prepared in example 11 of the present invention₂O₄Scanning electron micrographs.

FIG. 13 is a CoAl prepared in example 11 of the present invention₂O₄Powder XRD diffractogram compared to standard lines.

Detailed Description