阅读说明：本技术 铜铬黑、其低温制备方法及应用 (Copper-chromium black, low-temperature preparation method and application thereof ) 是由 李波 冯海涛 董亚萍 崔燕峰 刘鑫 张波 李武 于 2021-11-15 设计创作，主要内容包括：本申请公开了一种铜铬黑、其低温制备方法及应用。本申请通过使六价铬化合物、二价铜化合物与硫属还原剂等在温和条件下进行反应,制备得到三价铬和二价铜的复合氢氧化物,之后将该复合氢氧化物高温焙烧制备得到铜铬黑产品。本申请制备得到的铜铬黑产品的晶型、微观形貌和尺寸稳定可控,分散性高,在涂料、颜料、填料等领域的应用前景广阔,且工艺简单、节能环保,适于规模化生产。(The application discloses copper-chromium black, a low-temperature preparation method and application thereof. According to the method, a hexavalent chromium compound, a divalent copper compound and a chalcogen reducing agent react under mild conditions to prepare a trivalent chromium and divalent copper composite hydroxide, and then the composite hydroxide is roasted at a high temperature to prepare a copper-chromium black product. The prepared copper-chromium black product has stable and controllable crystal form, micro appearance and size, high dispersibility, wide application prospect in the fields of coatings, pigments, fillers and the like, simple process, energy conservation and environmental protection, and is suitable for large-scale production.)

1. A low-temperature preparation method of copper-chromium black is characterized by comprising the following steps: fully mixing a hexavalent chromium compound, a divalent copper compound, a chalcogen reducing agent and a solvent, reacting the formed mixed system at a temperature of not lower than room temperature to prepare a composite hydroxide of trivalent chromium and divalent copper, and calcining the composite hydroxide at a high temperature to obtain the copper-chromium black.

2. The method of claim 1, comprising: dissolving hexavalent chromium salt and divalent copper salt in a solvent, adding a chalcogen reducing agent, fully mixing, and then carrying out the reaction.

3. The method according to claim 1 or 2, characterized in that: the hexavalent chromium salt comprises one or more of sodium chromate, sodium dichromate, potassium chromate, potassium dichromate, ammonium chromate, ammonium dichromate and chromic anhydride; and/or, the chalcogen reducing agent is a chalcogen reducing agent, preferably, the chalcogen reducing agent comprises hydrogen sulfide or sodium sulfide; and/or, the solvent comprises water, preferably deionized water; and/or, the mixed system further comprises a dopant comprising manganese or vanadium; and/or the molar ratio of the hexavalent chromium salt, the divalent copper salt and the chalcogen reducing agent is 1: 0.5: 1.4-1.8.

4. The method of claim 1, wherein: the reaction temperature is from room temperature to the boiling point of water; and/or the reaction time is more than 5 hours, preferably 5 to 24 hours; and/or the reaction is carried out in an open or closed vessel.

5. The method of claim 1, comprising:

after the reaction is finished, naturally cooling the obtained reaction slurry, and then carrying out solid-liquid separation to obtain the composite hydroxide;

and calcining the composite hydroxide at high temperature, and then washing and drying to obtain the copper-chromium black.

6. The method of claim 5, further comprising: and naturally cooling the reaction slurry, filtering, washing the separated filter cake, and drying to obtain the composite hydroxide.

7. The method of claim 6, further comprising: and fully washing the filter cake with water until the washing water is neutral, and then drying to obtain the composite hydroxide.

8. The method according to claim 1 or 5, characterized in that: the high-temperature calcination temperature is 800-1000 ℃; and/or the high-temperature calcination time is more than 1h, preferably 1 h-4 h.

9. A copper chromium black is characterized in that: the copper chromium black is prepared by the method of any one of claims 1 to 8.

10. Use of the copper chromium black according to claim 9 for the production of coatings, plastics, building materials, ceramic materials, enamel materials or pigments.

Technical Field

The application belongs to the field of material science, and particularly relates to copper-chromium black, a low-temperature preparation method and application thereof.

Background

At present, the copper-chromium black is mainly prepared in a large scale by a high-temperature solid phase method, but the high-temperature solid phase method has a plurality of defects, for example, because ball milling treatment is needed after high-temperature calcination, product lattices can be seriously damaged, the product quality and performance are lower, the energy consumption is high, and the dust pollution is serious. In recent years, many researchers try to prepare the copper-chromium black by adopting a precipitation method, a sol-gel method, a microemulsion method and other liquid phase methods, and the methods have the advantages of good process controllability, mild reaction conditions, sufficient reaction and the like, and the product has small granularity, high purity, and excellent temperature resistance, chemical resistance and weather resistance. However, the existing liquid phase method for preparing the copper-chromium black generally has the disadvantages of complex process, high energy consumption, high requirement on equipment and difficulty in adapting to the requirement of large-scale industrial production.

Disclosure of Invention

The application mainly aims to provide copper-chromium black, a low-temperature preparation method and application thereof, so as to overcome the defects in the prior art.

In order to achieve the above purpose, the present application adopts a technical solution comprising:

some embodiments of the present application provide a low temperature preparation method of copper chromium black, comprising: fully mixing a hexavalent chromium compound, a divalent copper compound, a chalcogen reducing agent and a solvent, reacting the formed mixed system at a temperature of not lower than room temperature to prepare a composite hydroxide of trivalent chromium and divalent copper, and calcining the composite hydroxide at a high temperature to obtain the copper-chromium black.

In some embodiments, the low temperature manufacturing process comprises: dissolving hexavalent chromium salt and divalent copper salt in a solvent, adding a chalcogen reducing agent, fully mixing, and then carrying out the reaction.

In some embodiments, the hexavalent chromium salt includes a combination of one or more of sodium chromate, sodium dichromate, potassium chromate, potassium dichromate, chromic anhydride, ammonium chromate, ammonium dichromate.

In some embodiments, the divalent copper salt includes copper chloride, copper nitrate, copper sulfate, and the like, and is not limited thereto. Preferably, when copper sulfate is used as the cupric salt, high-purity sodium sulfate can be obtained as a byproduct in the synthesis of the composite hydroxide, and the high-purity sodium sulfate can be recycled and has high value.

In some embodiments, the chalcogen reducing agent includes hydrogen sulfide or sodium sulfide, and the like, but is not limited thereto.

In some embodiments, the solvent comprises water, preferably deionized water, but is not limited thereto.

In some embodiments, the molar ratio of hexavalent chromium salt, the divalent copper salt, and the chalcogen reducing agent is 1: 0.5: 1.4 to 1.8.

In some embodiments, the mixed system further comprises a dopant comprising an element such as, but not limited to, manganese or vanadium. The doping agent is added into the reaction raw materials, so that copper-chromium black products doped with other elements such as manganese, vanadium and the like can be obtained, and the application range of the copper-chromium black products is further expanded.

In some embodiments, the temperature of the reaction is preferably from room temperature to the boiling point of water.

In some embodiments, the reaction time is above 5h, preferably between 5h and 24 h.

In some embodiments, the reaction is performed in an open or sealed vessel.

In some embodiments, the low temperature manufacturing process comprises:

after the reaction is finished, naturally cooling the obtained reaction slurry, and then carrying out solid-liquid separation to obtain the composite hydroxide;

and calcining the composite hydroxide at high temperature, and then washing and drying to obtain the copper-chromium black.

In some embodiments, the low temperature production process further comprises: and naturally cooling the reaction slurry, filtering, washing the separated filter cake, and drying to obtain the composite hydroxide.

In some embodiments, the low temperature production process further comprises: and fully washing the filter cake with water until the washing water is neutral, and then drying to obtain the composite hydroxide.

In some embodiments, the high temperature calcination treatment is at a temperature of 800 to 1000 ℃.

In some embodiments, the high-temperature calcination treatment is performed for 1 hour or more, preferably 1 hour to 4 hours.

Some embodiments of the present application also provide a copper chromium black made by any of the foregoing methods.

Some embodiments of the present application also provide for the use of the copper chromium black.

For example, some embodiments of the present application provide a use of the copper chromium black in the preparation of products such as paints, plastics, building materials, ceramic materials, enamel materials, or pigments, but are not limited thereto.

Compared with the prior art, the technical scheme provided by the embodiment of the application has the advantages that:

(1) the provided copper-chromium black preparation process has the advantages of simple process, cheap and easily-obtained raw materials, low equipment requirement, low energy consumption and high controllability of product size and crystal form;

(2) the provided copper-chromium black product has the advantages of controllable size and micro-morphology, stable crystal form, good dispersibility, high stability and the like, is particularly suitable for being used as high-temperature resistant paint, plastic and coil steel paint, long-acting paint, coloring and art pigment of engineering plastic and the like, and has wide application prospect.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is an SEM photograph of a copper chromium black product obtained in example 1, at a magnification of 0.5 ten thousand times;

FIG. 2 is an SEM photograph of the copper chromium black product obtained in example 1, at a magnification of 1.0 ten thousand times;

FIG. 3 is an XRD photograph of the copper chromium black product obtained in example 1;

FIG. 4 is an XRD photograph of the sodium sulfate product obtained in example 1;

FIG. 5 is an SEM photograph of the copper chromium black product obtained in example 2, at a magnification of 0.5 ten thousand times;

FIG. 6 is an SEM photograph of the copper chromium black product obtained in example 2, at a magnification of 1.0 ten thousand times;

FIG. 7 is an XRD photograph of the copper chromium black product obtained in example 2;

FIG. 8 is an SEM photograph of the copper chromium black product obtained in example 3, at a magnification of 1.0 ten thousand times;

FIG. 9 is an SEM photograph of the copper chromium black product obtained in example 3, at a magnification of 15.0 ten thousand times;

FIG. 10 is an XRD photograph of the copper chromium black product obtained in example 3.

Detailed Description

The present application will be more fully understood from the following detailed description, which should be read in conjunction with the accompanying drawings. Detailed embodiments of the present application are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the application, which may be embodied in various forms. Therefore, specific functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present application in virtually any appropriately detailed embodiment.

Some exemplary embodiments of the present application provide a method for preparing copper-chromium black at a low temperature, which includes the following steps:

step one, mixing hexavalent chromium salt, cupric salt and chalcogen reducing agent according to a predetermined ratio and a chemical reaction molar ratio of 1: 0.5: 1.4-1.8 to prepare a reaction solution;

step two, reacting the reaction solution at a temperature not lower than room temperature for more than 5 hours to completely convert hexavalent chromium and divalent copper in the solution into a trivalent chromium and divalent copper composite hydroxide, and after the reaction slurry is naturally cooled, performing solid-liquid separation to obtain a trivalent chromium and divalent copper composite hydroxide;

and step three, calcining the composite hydroxide obtained in the step two for more than 1h at 800-1000 ℃, and washing and drying to obtain a copper-chromium black product.

The technical scheme provided by the above embodiment of the application has at least the following advantages:

firstly, the adopted chromium source is hexavalent chromium salt, and the cost is superior to that of trivalent chromium salt used by other methods;

and secondly, by adopting a chalcogen reducing agent, hexavalent chromium can be reduced into trivalent chromium at a lower reaction temperature to obtain a composite hydroxide of the trivalent chromium and the divalent copper, and meanwhile, the pH value of the system is gradually increased along with the oxidation-reduction reaction without introducing an additional acid-base reagent, so that the appearance and element distribution of the composite hydroxide are more uniform and controllable.

The technical solution of the present application is further explained below with reference to several embodiments.

Example 1 a low temperature method for making copper chromium black comprises:

14.9g of Na were taken₂Cr₂O₇·2H₂O，12.5g CuSO₄·5H₂Dissolving O in 100ml deionized water to form a uniform transparent solution with a ratio of chromium to copper of 2: 1, and adding 12.6g Na₂S·9H₂O, forming a mixed reaction solution;

heating the prepared mixed reaction liquid to 60 ℃, reacting for 24 hours, then naturally cooling to room temperature, filtering, washing the separated filter cake, and drying at 60 ℃ to obtain the compound hydroxide of trivalent chromium and divalent copper;

and calcining the composite hydroxide at 1000 ℃ for 1h, washing and drying at 60 ℃ to obtain a copper-chromium black product.

Alternatively, the separated filtrate may be crystallized and evaporated to obtain Na with purity of more than 99%₂SO₄By-products.

Fig. 1 and 2 are SEM images of the copper chromium black product prepared in example 1. Fig. 3 is an XRD pattern of the copper chromium black product prepared in this example 1. FIG. 4 shows Na prepared in example 1₂SO₄XRD pattern of by-product.

Embodiment 2 a low temperature method for preparing copper chromium black comprises:

23.4g of Na was taken₂CrO₄·4H₂O，17.1g CuCl₂·2H₂Dissolving O in 150ml of deionized water to form a uniform transparent solution, wherein the ratio of chromium to copper is 2: 1, and forming a mixed reaction solution;

heating the prepared mixed reaction liquid to 80 ℃, and then slowly introducing 2.3g H₂S gas, and reacting for 24 hours. Then naturally cooling to room temperature, and obtaining the compound hydroxide of trivalent chromium and divalent copper after suction filtration, washing and drying at 60 ℃;

and calcining the composite hydroxide at 1000 ℃ for 2h, washing and drying at 60 ℃ to obtain a copper-chromium black product.

Fig. 5 and 6 are SEM images of the copper chromium black product prepared in example 2. Fig. 7 is an XRD pattern of the copper chromium black product prepared in this example 2.

Embodiment 3 a low temperature method for preparing copper chromium black comprises:

23.4g of Na was taken₂CrO₄·4H₂O，12.1gCu(NO₃)₂·3H₂O was dissolved in 150ml of deionized water to form a uniform transparent solution with a chromium to copper ratio of 2: 1, and then 16.2g of Na was added₂S·9H₂O, forming a mixed reaction solution;

heating the prepared mixed reaction liquid to 90 ℃ and reacting for 12 h. Then naturally cooling to room temperature, and obtaining the compound hydroxide of trivalent chromium and divalent copper after suction filtration, washing and drying at 60 ℃;

and calcining the composite hydroxide at 800 ℃ for 2h, washing and drying at 60 ℃ to obtain a copper-chromium black product.

Fig. 8 and 9 are SEM images of the copper chromium black product prepared in example 3. Fig. 10 is an XRD pattern of the copper chromium black product prepared in this example 3.

Example 4 a low temperature preparation method of copper chromium black is substantially the same as example 1 except that: heating the prepared mixed reaction liquid to about 40 ℃, reacting for 24 hours, and naturally cooling to room temperature. The copper chromium black product obtained in this example is similar to that of example 1.

Comparative example 1 this comparative example provides a copper chromium black synthesis method substantially the same as example 1, except that: the same amount of glucose is used to replace Na₂S·9H₂And O. In the comparative example, hexavalent chromium cannot be reduced and converted into trivalent chromium, so that precursors of divalent copper and trivalent chromium cannot be obtained, and further, a copper-chromium black product cannot be obtained.

Comparative example 2 this comparative example provides a copper chromium black which is substantially the same as example 1 except that: the same amount of starch is used to replace Na₂S·9H₂And O. In the comparative example, hexavalent chromium cannot be reduced and converted into trivalent chromium, so that precursors of divalent copper and trivalent chromium cannot be obtained, and further, a copper-chromium black product cannot be obtained.

In addition, a person skilled in the art can also add a proper amount of soluble manganese salt, vanadium salt and the like into the mixed reaction liquid of the embodiments 1 to 4 to finally obtain a copper-chromium black product doped with manganese, vanadium and the like so as to meet the application requirements of some special fields. However, if the content of manganese and vanadium in the copper-chromium black product is too high, the visible light transmittance of the copper-chromium black product is reduced, and high-energy ultraviolet light is absorbed, so that when the copper-chromium black product is applied to products such as plastics, the plastics can be aged.

Although the present application has been described with reference to illustrative embodiments, it will be understood by those skilled in the art that various other changes, omissions and/or additions may be made and substantial equivalents may be substituted for elements thereof without departing from the spirit and scope of the application. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the application without departing from the scope thereof. Therefore, it is not intended that the application be limited to the specific embodiments disclosed for carrying out this application. Moreover, unless specifically stated any use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another.