LU503206B1

LU503206B1 - Copper chrome black as well as preparation method and use thereof

Info

Publication number: LU503206B1
Application number: LU503206A
Authority: LU
Inventors: Yaping Dong; Jiaoyu Peng; Haitao Feng; Bo Li; Wu Li
Original assignee: Qinghai Inst Salt Lakes Cas
Priority date: 2022-12-19
Filing date: 2022-12-19
Publication date: 2024-06-19

Abstract

The present disclosure discloses copper chrome black as well as a preparation method and use thereof. The preparation method comprises: reacting a mixed reaction system containing a hexavalent chromium compound, a bivalent copper compound, a reducing agent, a solvent and other substances which are optionally added or not added to obtain an intermediate product; and carrying out high-temperature calcining treatment on the intermediate product to obtain a copper chrome black product. The copper chrome black product prepared by the present disclosure has the advantages of controllable size, stable micromorphology and crystal form, good dispersity, high stability and the like, is especially suitable for preparing high temperature-resisting coatings, plastics and coil coatings as well as long-acting coatings, engineering plastics and art pigments, etc., has a good application prospect, and is simple in process, energy-saving and environmental- friendly and suitable for large-scale production.

Description

BL-5600

COPPER CHROME BLACK AS WELL AS PREPARATION METHOD AND USE 0505206

THEREOF

TECHNICAL FIELD

[0001] The present disclosure belongs to the field of material sciences, and particularly relates to copper chrome black as well as a preparation method and use thereof.

BACKGROUND

[0002] Copper chrome black, commonly known as copper chromite, has a chemical formula of

CuCr204. The copper chrome black and other element-doping copper chrome black derivatives thereof are novel inorganic metal oxide mixed pigments. Compared with conventional black pigments, such as carbon black, iron manganese black, iron oxide black and melanin, the copper chrome black is a pigment with excellent performance, which has performances such as high temperature resistance, light resistance, weather resistance, acid and alkali resistance, solvent resistance, non migration and easy dispersion except for environmental friendliness and no toxicity, and therefore is widely applied to the fields of various high-grade coatings, high-temperature resistant plastics, building materials, ceramics and enamel, artistic colors and the like.

[0003] At present, preparation methods of copper chrome black mainly include a solid phase method and a liquid phase method. In the industry, considering the cost, process and convenience for mass production, the preparation method of the copper chrome black pigment often adopts a high-temperature solid phase large-scale method. The high-temperature solid phase method is that metal salts or metal oxides are mixed in a required proportion and ground, and the ground mixture is directly calcined at a high temperature, so as to obtain pigment powders. However, the high- temperature solid phase method has many defects, for example, if the particle size of the product is too large, the product can be subjected to posttreatment such as ball milling after high temperature calcining so that the product has the required particle size. However, this process can damage the crystal lattices of the pigment, leading to a fact that the product is low in quality and performance and difficult to meet the demand. Furthermore, this method is high in energy consumption, high in reaction temperature and serious in agglomeration and dust pollution, and 1s not suitable for use as a preparation method of a high-performance pigment. Meanwhile, when the high-temperature solid phase method is used, a crystal transformation reaction is difficult to sufficiently complete due to limited solid phase reaction conditions, and therefore transition metal manganese and vanadium as a catalyst is generally added in the process of production so that crystal transformation is sufficiently carried out to generate copper chromite, which allows the copper chrome black synthesized by the solid phase method generally contains a high proportion 1

BL-5600 of metal impurities such as manganese and vanadium, so that the copper chrome black has reduced 209200 visible light transmittance, and easily absorbs high-energy ultraviolet light, leading to aged colorants such as plastics, which further limits the application of corresponding copper chrome black products in the fields of plastics and the like. The preparation of the copper chrome black pigment with the liquid phase method is that the required reactants are evenly mixed under the liquid condition so that the reactants are fully reacted. Furthermore, this liquid phase method is convenient to control, mild in reaction conditions and low in treatment temperature during the posttreatment. Moreover, the prepared product is small in particle size and high in purity, and has good resistances such as temperature resistance, chemical resistance and weather resistance. The currently researched liquid phase method mainly includes a precipitation method, a sol-gel method and a micro-emulsion method. However, at present, the existing process for preparing the copper chrome black through the liquid phase method is often complicated, is relatively high in energy consumption and immature, and has high equipment requirement, so it difficultly meets the requirements of large-scale industrial production.

SUMMARY

[0004] The main objective of the present disclosure is to provide copper chrome black as well as a preparation method and use thereof in order to overcome the defects in the prior art.

[0005] In order to achieve the above-mentioned objective, the technical solution adopted by the present disclosure is as follows:

[0006] Some embodiments of the present disclosure provide a preparation method of copper chrome black, comprising:

[0007] reacting a mixed reaction system containing a hexavalent chromium compound, a bivalent copper compound, a reducing agent, a solvent and other substances which are optionally added or not added to obtain an intermediate product; and

[0008] carrying out high-temperature calcining treatment on the intermediate product to obtain copper chrome black.

[0009] In some embodiments, the preparation method (hereinafter referred to as “hydrothermal synthesis method”) of the copper chrome black provided by one embodiment of the present disclosure specifically comprises:

[0010] carrying out hydrothermal reaction on the mixed reaction system comprising the hexavalent chromium compound, the bivalent copper compound, the reducing agent, the solvent and other substances which are optionally added or not added to obtain a composite precursor; and

[0011] carrying out high-temperature calcining treatment on the composite precursor to obtain the copper chrome black. 2

BL-5600

[0012] Further, the composite precursor comprises trivalent chromium and bivalent copper. 509206

[0013] In some embodiments, the hydrothermal synthesis method comprise: dissolving the hexavalent chromium salt and the bivalent copper salt into the solvent, and adding the reducing agent, and sufficiently mixing the above materials to form the mixed reaction system.

[0014] In some embodiments, the hexavalent chromium salt comprises a combination of one or more of sodium chromate, sodium dichromate, potassium chromate, chromic anhydride, potassium dichromate, ammonium chromate, ammonium dichromate, but is not limited thereto.

[0015] In some embodiments, the bivalent copper salt comprises copper chloride, copper nitrate and copper sulfate, but is not limited thereto. Preferably, the bivalent copper salt adopts copper sulfate. When the reducing agent is the chalcogenide reducing agent, high-purity sodium sulfate can also be by-produced while synthesizing the composite precursor, which can be recycled and has a high value.

[0016] In some embodiments, the reducing agent comprises a carbon-based reducing agent, preferably, the reducing agent comprises a combination of one or more of carbon, glucose, starch, methanol, ethanol, acetic acid, citric acid and ascorbic acid, but is not limited thereto.

[0017] In some embodiments, the reducing agent comprises the chalcogenide reducing agent, preferably, the chalcogenide reducing agent comprises sulphur or sodium sulfate, but is not limited thereto.

[0018] In some embodiments, the reducing agent can also be hydrogen.

[0019] In some embodiments, the solvent comprises water, preferably deionized water, but is not limited thereto.

[0020] In some embodiments, the other substances that can be optionally added or not added comprise a compound containing doping elements which comprise manganese or vanadium but is not limited thereto.

[0021] In some embodiments, a molar ratio of the hexavalent chromium salt to the bivalent copper salt to the reducing agent is 1:0.5:1.4-1.8.

[0022] In some embodiments, the temperature of the hydrothermal reaction is more than 80°C, preferably 120°C-280°C, more preferably 200°C-280°C. Specifically, when the chalcogenide reducing agent is used, the temperature of the hydrothermal reaction can be controlled to about 80°C, for example 80°C-100°C, of course, the reaction can also be smoothly carried out at 100°C- 280°C.

[0023] In some embodiments, the time of the hydrothermal reaction is more than 2 h, for example preferably 2 h -24 h.

[0024] In some embodiments, the hydrothermal reaction is carried out in a high-temperature reactor. 3

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[0025] In some embodiments, the hydrothermal synthesis reaction method comprises: naturally 93209 cooling the obtained reaction slurry after the hydrothermal reaction is ended, and then carrying out solid-liquid separation to obtain the composite precursor. Methods for solid-liquid separation include but are not limited to centrifugation, filtration (for example suction filtration and filter press), etc.

[0026] In some embodiments, the hydrothermal synthesis reaction method specifically comprises: filtering the naturally cooled reaction slurry, then washing and drying the filter cake obtained by separation, subsequently carrying out high-temperature calcining treatment, and then washing and drying again to obtain copper chrome black. Further, the filtrate obtained by separation can also be recycled after being treated via evaporation, concentration and other manners.

[0027] Further, the hydrothermal synthesis method further comprises: sufficiently washing the filter cake until the pH value of the washing water is about 7, and then drying the washed filter cake.

[0028] In some embodiments, the preparation method (hereinafter referred to as “low-temperature preparation method”) of the copper chrome black provided by another embodiment of the present disclosure specifically comprises: at least sufficiently mixing the hexavalent chromium compound, the bivalent copper compound, the chalcogenide reducing agent and the solvent, and reacting the formed mixed system under the condition of no less than room temperature to prepare a composite hydroxide comprising trivalent chromium and bivalent copper, and then carrying out high- temperature calcining treatment on the composite hydroxide to obtain the copper chrome black.

[0029] In some embodiments, the low-temperature preparation method comprises: dissolving the hexavalent chromium salt and the bivalent copper salt into the solvent, and then adding the chalcogenide reducing agent and sufficiently mixing the above materials, and then carrying out the reaction.

[0030] In some embodiments, the chalcogenide reducing agent comprises hydrogen sulfide or sodium sulfide, but is not limited thereto.

[0031] In some embodiments, the types of the hexavalent chromium salt, the bivalent copper salt and the solvent are all described above.

[0032] Preferably, when the bivalent copper salt adopts copper, high-purity sodium sulfate can also be by-produced while synthesizing the composite hydroxide, which can be recycled and has a high value.

[0033] In some embodiments, a molar ratio of the hexavalent chromium salt to the bivalent copper salt to the chalcogenide reducing agent is 1:0.5:1.4-1.8.

[0034] In some embodiments, the mixed system further comprises a doping agent comprising elements such as manganese or vanadium but not limited thereto. Where, a copper chrome black 4

BL-5600 product doped with manganese, vanadium and other elements can also be obtained by adding the 203606 doping agent into reaction raw materials, thereby further expanding its application range.

[0035] In some embodiments, the temperature of the reaction 1s preferably room temperature to a boiling point of water.

[0036] In some embodiments, the time of the reaction is more than 5 h, preferably 5 h-24 h.

[0037] In some embodiments, the reaction is carried out in an open or closed container.

[0038] In some embodiments, the low-temperature preparation method comprises:

[0039] naturally cooling the obtained reaction slurry after the reaction is ended, then carrying out solid-liquid separation to obtain the composite hydroxide; and

[0040] calcining the composite hydroxide at a high temperature, subsequently washing and drying to obtain the copper chrome black.

[0041] In some embodiments, the low-temperature preparation method further comprises: filtering the naturally cooled reaction slurry, and then washing and drying the filter cake obtained by separation to obtain the composite hydroxide.

[0042] In some embodiments, the low-temperature preparation method further comprises: sufficiently washing the filter cake with water until the washing water 1s neutral, and then drying the washed filter cake to obtain the composite hydroxide.

[0043] In some embodiments, the temperature of the high-temperature calcining treatment is 800- 1000°C.

[0044] In some embodiments, the time of the high-temperature calcining treatment is more than 1 h, preferably 1 h-4 h.

[0045] Some embodiments of the present disclosure also provide the copper chrome black prepared by any one method as described above.

[0046] Some embodiments of the present disclosure also provide use of the copper chrome black.

[0047] For example, some embodiments of the present disclosure provide use of copper chrome black in preparation of products including coatings, plastics, building materials, ceramic materials, enamel materials or pigments, but not limited thereto.

[0048] Compared with the prior art, the technical solution provided by the above embodiments of the present disclosure at least has the advantages:

[0049] (1) the preparation method of the copper chrome black provided by the present disclosure is simple in process, cheap and easily available in raw materials, low in equipment requirements, low in energy consumption, and controllable in product size and crystal form;

[0050] (2) the copper chrome black product provided by the present disclosure has the advantages of controllable size and micromorphology, stable crystal form, good dispersity, high stability and the like, is particularly suitable for use as high-temperature resistant coating, plastic and coil steel

BL-5600 coating, long-acting coating, engineering plastic coloring and art pigment, etc., and has a good 203606 application prospect in the field of material chemistry;

[0051] (3) the copper chrome black product doped with other elements such as manganese and vanadium can also be obtained by adding a compound containing doping elements into the reaction raw materials, thereby further expanding its application range.

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present application or the technical solution in the prior art, drawings required to be used in the embodiments or in the prior art will be simply discussed below, obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be made by persons of ordinary skill in the art according to these drawings without creative efforts.

[0053] Fig.1 is a scanning electron microscopy (SEM) picture of a copper chrome black product obtained in example 1, with a magnification of 100000 folds;

[0054] Fig.2 is an SEM picture of a copper chrome black product obtained in example 1, with a magnification of 150000 folds;

[0055] Fig. 3 1s an X-ray diffraction (XRD) picture of a copper chrome black product obtained in example 1.

[0056] Fig.4 1s an SEM picture of a copper chrome black product obtained in example 2, with a magnification of 10000 folds;

[0057] Fig.5 is an SEM picture of a copper chrome black product obtained in example 2, with a magnification of 30000 folds;

[0058] Fig. 61s an XRD picture of a copper chrome black product obtained in example 2.

[0059] Fig.7 is an SEM picture of a copper chrome black product obtained in example 3, with a magnification of 10000 folds;

[0060] Fig.8 is an SEM picture of a copper chrome black product obtained in example 3, with a magnification of 30000 folds;

[0061] Fig. 9 is an XRD picture of a copper chrome black product obtained in example 3.

[0062] Fig.10 is an SEM picture of a copper chrome black product obtained in example 4, with a magnification of 100000 folds;

[0063] Fig.11 is an SEM picture of a copper chrome black product obtained in example 4, with a magnification of 150000 folds;

[0064] Fig. 12 is an XRD picture of a copper chrome black product obtained in example 4.

[0065] Fig.13 is an SEM picture of a copper chrome black product obtained in example 5, with a magnification of 100000 folds; 6

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[0066] Fig.14 is an SEM picture of a copper chrome black product obtained in example 5, witha 209200 magnification of 150000 folds;

[0067] Fig. 15 is an XRD picture of a copper chrome black product obtained in example 5.

[0068] Fig.16 is an XRD picture of a copper sulfate product obtained in example 5;

[0069] Fig.17 is an SEM picture of a copper chrome black product obtained in example 7, with a magnification of 5000 folds;

[0070] Fig.18 is an SEM picture of a copper chrome black product obtained in example 7, with a magnification of 10000 folds;

[0071] Fig. 19 is an XRD picture of a copper chrome black product obtained in example 7.

[0072] Fig.20 is an XRD picture of a sodium sulfate product obtained in example 7,

[0073] Fig.21 is an SEM picture of a copper chrome black product obtained in example 8, with a magnification of 5000 folds;

[0074] Fig.22 is an SEM picture of a copper chrome black product obtained in example 8, with a magnification of 10000 folds;

[0075] Fig. 23 is an XRD picture of a copper chrome black product obtained in example 8.

[0076] Fig.24 is an SEM picture of a copper chrome black product obtained in example 9, with a magnification of 10000 folds;

[0077] Fig.25 is an SEM picture of a copper chrome black product obtained in example 9, with a magnification of 150000 folds;

[0078] Fig.26 is an XRD picture of a copper chrome black product obtained in example 9.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0079] The present disclosure will be more fully understood by reading the following specific embodiments in conjunction with the accompanying drawings. Detailed embodiments of the present disclosure are disclosed herein; however, it should be understood that the disclosed embodiments are only exemplary embodiments of the present disclosure, which can be embedded in various forms. Therefore, the specific functional details disclosed herein should not be interpreted as being restrictive, but only as a representative basis for teaching those skilled in the art to adopt the present disclosure in different ways in virtually any appropriate detailed embodiment.

[0080] A hydrothermal synthesis method of copper chrome black provided by some typical embodiments of the present disclosure is mainly that a composite precursor having uniform morphology and comprising trivalent chromium and bivalent copper is prepared by hydrothermal reaction of a hexavalent chromium compound, a bivalent copper compound and other substances which are optionally added or not added and a reducing agent, and then the composite precursor 7

BL-5600 is calcined at a high temperature to obtain a copper chrome black product. The hydrothermal * 2 synthesis method specifically comprises the following steps:

[0081] Step 1: mixing a hexavalent chromium salt, a bivalent copper salt and a carbon-based reducing agent in a chemical reaction molar ratio of 1:0.5:1.4-1.8 according to a pre-determined proportion to prepare a reaction solution;

[0082] Step 2: carrying out hydrothermal reaction on the above reaction solution in a temperature environment of more than 80°C for more than 2 h so that hexavalent chromium and bivalent copper in the solution are completely converted into trivalent chromium and bivalent copper, carrying out solid-liquid separation after the reaction slurry is naturally cooled to obtain a composite hydroxide comprising trivalent chromium and bivalent copper which is defined as a composite precursor; and

[0083] Step 3: calcining the composite hydroxide obtained in Step 2 under the condition of 800- 1000°C for 1-4 h, washing and drying to obtain the copper chrome black product.

[0084] The low-temperature preparation method of the copper chrome black provided by other typical embodiments of the present application is mainly that the hexavalent chromium compound, the bivalent copper compounds and the chalcogenide reducing agent are reacted under mild conditions to prepare the composite hydroxide comprising trivalent chromium and bivalent copper, and then the composite hydroxide is roasted at a high temperature to obtain the copper chrome black product. The low-temperature preparation method specifically comprises the following steps:

[0085] Step 1: mixing a hexavalent chromium salt, a bivalent copper salt and a chalcogenide reducing agent in a chemical reaction molar ratio of 1:0.5:1.4-1.8 according to a pre-determined proportion to prepare a reaction solution;

[0086] Step 2: carrying out hydrothermal reaction on the above reaction solution in a temperature environment of no less than room temperature for more than 5 h so that the hexavalent chromium and bivalent copper in the solution are completely converted into a trivalent chromium and bivalent copper, and then carrying out solid-liquid separation after the reaction slurry is naturally cooled to obtain the composite hydroxide comprising trivalent chromium and bivalent copper; and

[0087] Step 3: calcining the composite hydroxide obtained in Step 2 under the condition of 800- 1000°C for more than 1 h, washing and drying to obtain the copper chrome black product.

[0088] The technical solution provided by the above embodiments of the present disclosure at least has the following advantages:

[0089] first, the used chromium source is the hexavalent chromium salt whose cost is superior to that of the trivalent chromium salt used in other methods;

[0090] second, hexavalent chromium can be reduced to trivalent chromium at a relatively low reaction temperature by using the chalcogenide reducing agent so as to obtain the composite 8

BL-5600 hydroxide comprising trivalent chromium and bivalent copper; or the composite precursor 209200 comprising trivalent chromium and bivalent copper can also be obtained by reducing and converting hexavalent chromium into trivalent chromium through the hydrothermal method in the presence of carbon-based organics without additional addition of acidic and alkaline reagents, and meanwhile, the pH value of the system gradually increases with the proceeding of the redox reaction, and therefore the composite hydroxide precursor are more uniform and controllable in morphology and element distribution.

[0091] Next, the technical solution of the present disclosure will be further explained and illustrated in combination with several embodiments.

[0092] Example 1 A hydrothermal synthesis method of copper chrome black comprises:

[0093] 10 g of CrO3 and 12.5 g of CuSO4-5H20 were dissolved into 100 ml of deionized water to form a uniform and transparent solution, wherein a ratio of chromium to copper was 2:1, and then 3.0 g of starch was added, so as to form a mixed reaction solution;

[0094] the prepared mixed reaction solution was transferred to 150 ml of stainless steel high- temperature reactor and heated to 280°C to react for 2 h, and then the reaction product was naturally cooled to room temperature, filtered at reduced pressure, washed and dried at 60°C to obtain a composite precursor comprising trivalent chromium and bivalent copper;

[0095] the dried composite precursor was calcined for 4 h at 800°C, washed and then dried at 60°C to obtain a copper chrome black product.

[0096] Fig.1 and Fig.2 are SEM images of a copper chrome black product prepared in example 1.

Fig.3 is an XRD graph of a copper chrome black product prepared in example 1.

[0097] Example 2 A hydrothermal synthesis method of copper chrome black comprises:

[0098] 14.9 g of Na:Cr207:2H20 and 12.5 g of CuSO4 SH20O were dissolved into 100 ml of deionized water to form a uniform and transparent solution, wherein a ratio of chromium to copper was 2:1, and then 4.05 g of glucose was added, so as to form a mixed reaction solution;

[0099] the prepared mixed reaction solution was transferred to 150 ml of stainless steel high- temperature reactor and heated to 200°C to react for 24 h, and then the reaction product was naturally cooled to room temperature, filtered at reduced pressure, washed and dried at 60°C to obtain a composite precursor comprising trivalent chromium and bivalent copper;

[00100] the dried composite precursor was calcined for 2 h at 1000°C, washed and then dried at 60°C to obtain a copper chrome black product.

[00101] Fig.4 and Fig.5 are SEM images of a copper chrome black product prepared in example 2.

Fig.6 is an XRD graph of a copper chrome black product prepared in example 2.

[00102] Example 3 A hydrothermal synthesis method of copper chrome black comprises: 23.4 g of Na;CrO4 4H20 and 17.1 g of CuCl,:2H20 were dissolved into 100 ml of deionized water to 9

BL-5600 form a uniform and transparent solution, wherein a ratio of chromium to copper was 2:1, and then 203606 3.7 g of ascorbic acid was added, so as to form a mixed reaction solution;

[00103]the prepared mixed reaction solution was transferred to 150 ml of stainless steel high- temperature reactor and heated to 280°C to react for 2 h, and then the reaction product was naturally cooled to room temperature, filtered at reduced pressure, washed and dried at 60°C to obtain a composite precursor comprising trivalent chromium and bivalent copper;

[00104]the dried composite precursor was calcined for 1 h at 1000°C, washed and then dried at 60°C to obtain a copper chrome black product.

[00105]Fig.7 and Fig.8 are SEM images of a copper chrome black product prepared in example 3.

Fig.9 is an XRD graph of a copper chrome black product prepared in example 3.

[00106] Example 4 A hydrothermal synthesis method of copper chrome black comprises:

[00107]23.4 g of NaxCrO4-4H20 and 12.1 g of Cu(NO3)2-:3H20 were dissolved into 100 ml of deionized water to form a uniform and transparent solution, wherein a ratio of chromium to copper was 2:1, and then 6.3 g of citric acid was added, so as to form a mixed reaction solution;

[00108]the prepared mixed reaction solution was transferred to 150 ml of stainless steel high- temperature reactor and heated to 240°C to react for 12 h, and then the reaction product was naturally cooled to room temperature, filtered at reduced pressure, washed and dried at 60°C to obtain a composite precursor comprising trivalent chromium and bivalent copper;

[00109] the dried composite precursor was calcined for 2 h at 800°C, washed and then dried at 60°C to obtain a copper chrome black product.

[00110]Fig.10 and Fig.11 are SEM images of a copper chrome black product prepared in example 4. Fig.12 is an XRD graph of a copper chrome black product prepared in example 4.

[00111] Example 5 A hydrothermal synthesis method of copper chrome black comprises:

[00112]23.4 g of NaxCrO44H20 and 12.5 g of CuSO4 5H,0 were dissolved into 100 ml of deionized water to form a uniform and transparent solution, wherein a ratio of chromium to copper was 2:1, and then 12.6 g of Na:S-9H,0 was added, so as to form a mixed reaction solution;

[00113]the prepared mixed reaction solution was transferred to 150 ml of stainless steel high- temperature reactor and heated to 120°C to react for 18 h, then the reaction product was naturally cooled to room temperature and filtered at reduced pressure, the filter cake was washed and dried at 60°C to obtain a composite precursor comprising trivalent chromium and bivalent copper, and the filtrate was evaporated and dried to obtain high-purity sodium sulfate;

[00114]the dried composite precursor was calcined for 2 h at 1000°C, washed and then dried at 60°C to obtain a copper chrome black product.

[00115]Fig.13 and Fig. 14 are SEM images of a copper chrome black product prepared in example 5. Fig.15 is an XRD graph of a copper chrome black product prepared in example 5. Fig.16 is an

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XRD graph of the sodium sulfate product prepared in example 5. 509206

[00116] Example 6 A hydrothermal synthesis method of copper chrome black provided by this example is basically the same as that in example 5 except that: the prepared mixed reaction solution was transferred to a stainless steel high-temperature reactor and then heated to 80°C to react for 24 h.

[00117] The copper chrome black product prepared in this example also has ideal quality.

[00118] Comparative example 1 The synthesis method of copper chrome black provided by this comparative example is basically the same as that in example 1 except that:

[00119] the prepared mixed reaction solution was transferred to a stainless steel high-temperature reactor and then heated to 110°C to react for 2 h. However, in this comparative example, since hexavalent chromium cannot be converted into trivalent chromium, the precursor comprising bivalent copper and trivalent chromium cannot be obtained, and then the copper chrome black product cannot be obtained.

[00120] In addition, to meet the application requirement in some special scenes, those skilled in the art can also add an appropriate amount of manganese, vanadium and other elements into raw material systems of example 1-example 6, especially in the mixed solution, so as to finally obtain the copper chrome black product doped with manganese, vanadium and the like. But as described above, application of such the copper chrome black product doped with manganese, vanadium and other elements may be limited for the fields such as plastics.

[00121] Example 7 A low-temperature preparation method of copper chrome black comprises:

[00122]14.9 g of Na:Cr207:2H20 and 12.5 g of CuSO4 SH20O were dissolved into 100 ml of deionized water to form a uniform and transparent solution, wherein a ratio of chromium to copper was 2:1, and then 12.6 g of Na:S-9H,0 was added, so as to form a mixed reaction solution;

[00123] the prepared mixed reaction solution was heated to 60°C to react for 24 h, then the reaction product was naturally cooled to room temperature and filtered at reduced pressure, the filter cake obtained by separation was washed and dried at 60°C to obtain a composite hydroxide comprising trivalent chromium and bivalent copper;

[00124] the dried composite precursor was calcined for 1 h at 1000°C, washed and then dried at 60°C to obtain a copper chrome black product.

[00125] In addition, the filtrate obtained by separation can be crystallized and evaporated to obtain a Na2SO4 byproduct with a purity of more than 99%.

[00126] Fig.17 and Fig. 18 are SEM images of a copper chrome black product prepared in example 7. Fig.19 is an XRD graph of a copper chrome black product prepared in example 7. Fig.20 is an

XRD graph of a Na2:SO4 byproduct prepared in example 7.

[00127] Example 8 A low-temperature preparation method of copper chrome black comprises: 11

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[00128]23.4 g of NazCrO4:4H20 and 17.1 g of CuCl, 2H20 were dissolved into 150 ml of 209200 deionized water to form a uniform and transparent solution, wherein a ratio of chromium to copper was 2:1, so as to form a mixed reaction solution;

[00129]the prepared mixed reaction solution was heated to 80°C and then 2.3 g of HS gas was slowly introduced, the above materials reacted for 24 h, and then the reaction product was naturally cooled to room temperature, filtered at reduced pressure, washed and dried at 60°C to obtain a composite hydroxide comprising trivalent chromium and bivalent copper;

[00130] the composite hydroxide was calcined for 2 h at 1000°C, washed and dried at 60°C to obtain a copper chrome black product.

[00131]Fig.21 and Fig.22 are SEM images of a copper chrome black product prepared in example 8. Fig.23 is an XRD graph of a copper chrome black product prepared in example 8.

[00132] Example 9 A low-temperature preparation method of copper chrome black comprises:

[00133]23.4 g of NaxCrO4-4H20 and 12.1 g of Cu(NO3)2-:3H20 were dissolved into 150 ml of deionized water to form a uniform and transparent solution, wherein a ratio of chromium to copper was 2:1, and then 16.2 g of Na:S-9H:0 so as to form a mixed reaction solution;

[00134] the prepared mixed reaction solution was heated to 90°C to react for 12 h, and then the reaction product was naturally cooled to room temperature, filtered at reduced pressure, washed and dried at 60°C to obtain a composite hydroxide comprising trivalent chromium and bivalent copper;

[00135] the composite hydroxide was calcined for 2 h at 800°C, washed and dried at 60°C to obtain a copper chrome black product.

[00136] Fig.23 and Fig.24 are SEM images of a copper chrome black product prepared in example 9. Fig.25 is an XRD graph of a copper chrome black product prepared in example 9.

[00137] Example 10 A low-temperature preparation method of copper chrome black is basically the same as that in example 7 except that: the prepared mixed reaction solution was heated to about 40°C to react for 24 h, and then the reaction product was naturally cooled to room temperature.

The copper chrome black product prepared in this example is similar to that in example 7.

[00138] Comparative example 2 A synthesis method of copper chrome black provided in this comparative example is basically the same as that in example 7 except that: Na;S-9H,O was replaced with glucose in the same amount. The hexavalent chromium in this comparative example cannot be reduced and converted into trivalent chromium, and therefore the precursor comprising bivalent copper and trivalent chromium cannot be obtained, and then the copper chrome black product cannot be obtained.

[00139] Comparative example 3 A synthesis method of copper chrome black provided in this comparative example is basically the same as that in example 7 except that: Na;S-9H,O was 12

BL-5600 replaced with starch in the same amount. The hexavalent chromium in this comparative example 203606 cannot be reduced and converted into trivalent chromium, and therefore the precursor comprising bivalent copper and trivalent chromium cannot be obtained, and then the copper chrome black product cannot be obtained.

[00140]In addition, those skilled in the art can add an appropriate amount of soluble manganese salt, vanadium salt and the like into the mixed reaction solutions of example 7-example 10 to finally obtain copper chrome black products doped with manganese, vanadium and the like so as to meet the application needs of some special fields. However, if the contents of manganese and vanadium in the copper chrome black product are too high, the copper chrome black product will have reduced visible light transmittance and absorb high-energy ultraviolet light. Moreover, application of such the copper chrome black product to plastics and other products may lead to plastic aging.

[00141] Although the present disclosure has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions and/or additions can be made without departing from the spirit and scope of the present disclosure and the elements in the embodiments can be replaced with substantial equivalents. In addition, many modifications can be made without departing from the scope of the present disclosure so that specific situations or materials are adaptive to the teachings of the present disclosure. Therefore, it is not intended herein to limit the present disclosure to implement the specific embodiments disclosed in the present disclosure. In addition, unless specifically stated, any use of terms first, second or the like does not indicate any order or importance, but one element is distinguished from another element by using the terms first, second or the like. 13

Claims

BL-5600 Claims LU503206

1. À preparation method of copper chrome black, comprising: reacting a mixed reaction system containing a hexavalent chromium compound, a bivalent copper compound, a reducing agent, a solvent and other substances which are optionally added or not added to obtain an intermediate product; and carrying out high-temperature calcining treatment on the intermediate product to obtain copper chrome black.

2. The preparation method according to claim 1, wherein the hexavalent chromium salt comprises a combination of one or more of sodium chromate, sodium dichromate, potassium chromate, potassium dichromate, chromic anhydride, ammonium chromate and ammonium dichromate; and/or the solvent comprises water, preferably deionized water; and/or a molar ratio of the hexavalent chromium salt to the bivalent copper salt to the reducing agent is 1:0.5:1.4-1 8; and/or the other substances which are optionally added or not added comprise compounds containing doping elements comprising manganese or vanadium.

3. The preparation method according to claim 1, specifically comprising: carrying out hydrothermal reaction on the mixed reaction system comprising the hexavalent chromium compound, the bivalent copper compound, the reducing agent, the solvent, and other substances which are optionally added or not added to obtain a composite precursor; and carrying out high-temperature calcining treatment on the composite precursor to obtain the copper chrome black.

4. The preparation method according to claim 3, comprising: dissolving the hexavalent chromium salt and the bivalent copper salt into the solvent, and adding the reducing agent, and then sufficiently mixing the above materials to form the mixed reaction system.

5. The preparation method according to claim 3, wherein the reducing agent comprises a carbon-based reducing agent, preferably, the reducing agent comprises a combination of one or more of a carbon simple substance, glucose, starch, methanol, ethanol, acetic acid, citric acid and ascorbic acid, or the reducing agent comprises a chalcogenide reducing agent, preferably, the chalcogenide reducing agent comprises sulphur or sodium sulfide, or the reducing agent comprises hydrogen. 14

BL-5600

6. The preparation method according to claim 3, wherein the temperature of the hydrothermal 100 reaction is more than 80°C, preferably 120°C-280°C, more preferably 200°C-280°C; and/or the time of the hydrothermal reaction is more than 2 h, preferably 2 h-24 h; and/or the hydrothermal reaction is carried out in a high-temperature reactor; and/or, the preparation method further comprises: naturally cooling the obtained reaction slurry after the hydrothermal reaction is ended, and then carrying out solid-liquid separation to obtain the composite precursor.

7. The preparation method according to claim 6, further comprising: filtering the naturally cooled reaction slurry, then washing and drying the filter cake obtained by separation, subsequently carrying out high-temperature calcining treatment followed by washing and drying again to obtain copper chrome black; preferably, the preparation method further comprising: sufficiently washing the filter cake with water until the pH value of the washing water is 7, and then drying the washed filter cake.

8. The preparation method according to claim 1, specifically comprising: sufficiently mixing the hexavalent chromium compound, the bivalent copper compound, the chalcogenide reducing agent and the solvent, reacting the formed mixed system under the condition of no less than room temperature to prepare a composite hydroxide comprising trivalent chromium and bivalent copper, and then carrying out high-temperature calcining treatment on the composite hydroxide to obtain the copper chrome black.

9. The preparation method according to claim 8, comprising: dissolving the hexavalent chromium salt and the bivalent copper salt into the solvent, then adding the chalcogenide reducing agent and sufficiently mixing the above materials, and then carrying out the reaction; and/or, the chalcogenide reducing agent comprising hydrogen sulfide or sodium sulfide.

10. The preparation method according to claim 8, wherein the temperature of the reaction is from room temperature to a boiling point of water; and/or, the time of the reaction is more than 5 h, preferably 5 h-24 h; and/or, the reaction is carried out in an open or closed container.

11. The preparation method according to claim 8, comprising: naturally cooling the obtained reaction slurry after the reaction is ended, and then carrying out solid-liquid separation to obtain the composite hydroxide; and calcining the composite hydroxide at a high temperature, subsequently washing and drying

BL-5600 to obtain the copper chrome black. 7903208

12. The preparation method according to claim 11, further comprising: filtering the naturally cooled reaction slurry, and washing and drying the filter cake obtained by separation to obtain the composite hydroxide; preferably, the preparation method further comprising: sufficiently washing the filter cake with water until the washing water is neutral, and then drying the washed filter cake to obtain the composite hydroxide.

13. The preparation method according to claim 1 or 3 or 8, wherein the temperature of the high-temperature calcining treatment is 800-1000°C; and/or, the time of the high-temperature calcining treatment is more than 1 h, preferably 1 h-4 h.

14. The copper chrome black prepared by the method according to any one of claims 1-13.

15. Use of the copper chrome black according to claim 14 in preparation of paint, plastics, building materials, ceramic materials, enamel materials or pigments. 16