Large particle size ammonium metavanadate and a method for preparing the same

Abstract

The application belongs to the technical field of wet vanadium extraction, and particularly relates to large-granularity ammonium metavanadate and a preparation method thereof. The preparation method comprises the following steps: (1) preparation of a vanadium-containing stock solution; (2) dissolving ammonium salt and high-molecular-weight polyethylene glycol in water, and adding alkali to adjust pH to obtain an ammonium salt solution; (3) adding low-molecular-weight polyethylene glycol to the vanadium-containing stock solution to obtain a modified vanadium-containing stock solution; (4) uniformly mixing the ammonium salt solution and the modified vanadium-containing stock solution, adjusting pH, and obtaining a mixture after reaction; and (5) filtering the mixture, washing the solid product, and obtaining large-granularity ammonium metavanadate. The low-molecular-weight polyethylene glycol mainly plays a role in reducing nucleation rate, and the high-molecular-weight polyethylene glycol has good adsorption and mainly plays a role in promoting crystal growth, so that the granularity of ammonium metavanadate is improved through the cooperation of polyethylene glycols with different molecular weights. The application has simple process, is environment-friendly, has no waste water and waste residue to be discharged, and is beneficial to industrial popularization and application.

Description

Technical Field

[0001] The invention belongs to the technical field of wet-process vanadium extraction, and particularly relates to large-particle ammonium metavanadate and a preparation method thereof. Background Art

[0002] Vanadium plays a vital role in modern industry, widely used in metallurgy, chemical engineering, aerospace, battery materials, and superconducting materials. With the continuous advancement of science and technology, vanadium is increasingly used in high-tech products such as vanadium batteries and vanadium catalysts. These high-tech products require ever-higher vanadium purity, necessitating research into the preparation of high-purity vanadium products. my country is a major vanadium resource country, possessing abundant vanadium-titanium magnetite reserves, ranking third in the world. my country possesses unique resource advantages for the research and production of high-purity vanadium, thus offering a promising future for the development of China's high-purity vanadium industry.

[0003] Vanadium and its compounds, particularly vanadium pentoxide, are currently primarily produced using hydrometallurgical methods. Vanadium exists in various states and valences, and the corresponding extraction processes vary. Hydrometallurgical vanadium extraction primarily involves leaching, solid-liquid separation, purification of the leachate, and precipitation of vanadium using ammonium salts. Ammonium metavanadate is a key intermediate in the vanadium extraction process and plays a crucial role in industrial vanadium production.

[0004] Ammonium metavanadate is not only an intermediate product in the production of V2O5 but also an important chemical product in its own right, with applications in industries such as chemical reagents, catalysts, driers, mordants, and mineral leaching. It is also used in glazes in the ceramic industry and as a reagent in instrumental analysis. Ammonium metavanadate is a white powder that appears dark yellow when it contains small amounts of impurities. It is soluble in hot water but poorly soluble in cold water and insoluble in organic solvents such as ethanol and acetone, making it an important component of vanadium hydrometallurgy. Currently, the annual production of ammonium metavanadate worldwide is experiencing rapid growth. Industrially produced ammonium metavanadate typically has a small particle size and is prone to agglomeration, shortcomings that limit its application. Therefore, research into the preparation of large-particle ammonium metavanadate is highly desirable. CN113753952A discloses a process for preparing ammonium polyvanadate using polyethylene glycol as a dispersant. While this process improves the vanadium precipitation rate, the resulting ammonium polyvanadate has a small particle size and low density, making it difficult to meet the requirements for industrial use. Summary of the Invention

[0005] In response to the above-mentioned problem of low particle size of ammonium metavanadate, the present invention proposes a method for preparing large-particle ammonium metavanadate. The method can improve the physical properties of ammonium metavanadate and prepare large-particle ammonium metavanadate.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing large-particle ammonium metavanadate, comprising the following steps: (1) Preparation of vanadium-containing stock solution; (2) dissolving an ammonium salt and high molecular weight polyethylene glycol in water, and adding alkali to adjust the pH to obtain an ammonium salt solution; the high molecular weight polyethylene glycol has a number average molecular weight of 2000-4000, and a mass ratio of the high molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.04-0.08:1; (3) adding low molecular weight polyethylene glycol to the vanadium-containing stock solution and stirring uniformly to obtain a modified vanadium-containing stock solution; the low molecular weight polyethylene glycol has a number average molecular weight of 400-800, and a mass ratio of the low molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.01-0.04:1; (4) Evenly mixing the ammonium salt solution and the modified vanadium-containing stock solution, adjusting the pH to 8-10, and reacting to obtain a mixture; (5) The mixture is filtered and the solid product is washed to obtain large-particle ammonium metavanadate.

[0007] The key to preparing large-particle ammonium metavanadate is to reduce the supersaturation of ammonium metavanadate, reduce the number of nucleations, and increase the grain growth rate on the basis of reducing the nucleation rate. To this end, the present invention selects to add two surfactants, high molecular weight polyethylene glycol and low molecular weight polyethylene glycol. The inventors have selected polyvinyl pyrrolidone as a modifier in previous work, but polyvinyl pyrrole has low solubility and large molecular weight. It usually needs to be heated when removing impurities, which will cause the dissolution and waste of ammonium metavanadate. Polyethylene glycol has excellent solubility, is easy to wash, and is suitable for industrial production. High molecular weight polyethylene glycol has good adsorption properties and can be effectively adsorbed to the surface of ammonium metavanadate crystals to promote crystal growth; blending high molecular weight polyethylene glycol with ammonium salt in advance can solve the defect of its mobility to a certain extent, which is conducive to its adsorption to the surface of ammonium metavanadate crystals in advance. However, the nucleation rate of the early precipitation process is relatively fast, and the high molecular weight polyethylene glycol has a large molecular weight, and the molecular movement is difficult, making it difficult to play a role in rapid adsorption. To this end, the present invention adds a small amount of low-molecular-weight polyethylene glycol. The low-molecular-weight polyethylene glycol has good mobility and can quickly move to the surface of the ammonium metavanadate crystal, reducing the nucleation rate, which is conducive to the formation of larger crystal nuclei of ammonium metavanadate, making the ammonium metavanadate grain growth rate higher than the nucleation rate, and effectively increasing the size of the ammonium metavanadate. In general, the low-molecular-weight polyethylene glycol mainly plays a role in reducing the nucleation rate; while the high-molecular-weight polyethylene glycol has good adsorption properties and mainly plays a role in promoting crystal growth. The ammonium metavanadate particle size is improved by the mutual cooperation of polyethylene glycols of different molecular weights.

[0008] During this process, it is important to carefully control the mass ratio of high-molecular-weight polyethylene glycol (HMWPEG), low-molecular-weight polyethylene glycol (LMWPEG), and vanadium atoms in the vanadium-containing stock solution. Due to the long molecular chains of HMWPEG, excessive use can lead to molecular entanglement, forming a dense structure that is detrimental to crystal growth. Low use can also lead to low adsorption, failing to effectively increase the interfacial energy of the crystal nucleus and reducing the nucleation rate. Specifically, the number-average molecular weight of HMWPEG is 2500-3500, and the mass ratio of LMWPEG to vanadium atoms in the vanadium-containing stock solution is 0.015-0.025:1. The appropriate molecular weight and dosage can fully maximize its role in promoting crystal growth and improve the purity of ammonium metavanadate.

[0009] Furthermore, in step (1), vanadium slag is used as a raw material to prepare a vanadium-containing stock solution; the vanadium content in the vanadium-containing stock solution is 30-40 g / L.

[0010] Furthermore, the vanadium in the vanadium-containing stock solution in step (1) exists in the form of pentavalent vanadium. Specifically, the vanadium in the vanadium precipitation stock solution in the present invention mainly exists in the form of sodium metavanadate.

[0011] Furthermore, in step (2), the ammonium salt is one or more of ammonium carbonate, ammonium bicarbonate, ammonium sulfate, ammonium chloride, and ammonium nitrate; and the molar ratio of ammonium ions in the ammonium salt to vanadium atoms in the vanadium-containing stock solution is 3-5:1.

[0012] Furthermore, the alkali in step (2) is one or more of potassium hydroxide, sodium hydroxide, and ammonia water, and the pH is 6-8.

[0013] Furthermore, the stirring rate in step (3) is 500-1000 r / min.

[0014] Furthermore, the reaction in step (4) is carried out at 30-40° C. for 30-60 min.

[0015] Furthermore, the washing in step (5) is performed in a countercurrent manner.

[0016] Furthermore, the washing in step (5) is performed at room temperature.

[0017] Compared with existing technologies, the present invention offers the following advantages: Addressing the high processing costs of existing vanadium extraction processes, the present invention uses vanadium slag as a raw material to prepare a vanadium-containing stock solution, and selectively adds two surfactants, high-molecular-weight polyethylene glycol and low-molecular-weight polyethylene glycol. The low-molecular-weight polyethylene glycol primarily reduces the nucleation rate, while the high-molecular-weight polyethylene glycol exhibits excellent adsorption properties and primarily promotes crystal growth. The interaction of the different molecular weight polyethylene glycols increases the particle size of ammonium metavanadate. The present invention also features a simple process, low byproduct count, and environmental friendliness, eliminating the need for wastewater or waste residue discharge, making it suitable for industrial application. DETAILED DESCRIPTION

[0018] It should be understood that the embodiments of the present invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments have been described in detail in the present invention, it is readily apparent to those skilled in the art that various modifications are feasible without departing substantially from the teachings of the subject matter of the present invention. Accordingly, all such modifications should be included within the scope of the present invention. Without departing from the gist of the present invention, other replacements, modifications, variations, and deletions may be made to the design, operating conditions, and parameters of the following exemplary embodiments.

[0019] The vanadium-containing stock solution used in the examples and comparative examples is prepared using vanadium slag as raw material, the vanadium exists in the form of pentavalent vanadium, and the V (g / L) concentration is 34.10 g / L; in step (2), the ammonium salt is ammonium sulfate, and the alkali is sodium hydroxide; and in step (5), washing is performed in a countercurrent manner at room temperature.

[0020] Example 1 A method for preparing large-particle ammonium metavanadate comprises the following steps: (1) Preparation of vanadium-containing stock solution; (2) dissolving an ammonium salt and high molecular weight polyethylene glycol in water, and adding alkali to adjust the pH to 6 to obtain an ammonium salt solution; the high molecular weight polyethylene glycol has a number average molecular weight of 2000, and a mass ratio of the high molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.04:1; and the molar ratio of ammonium ions in the ammonium salt to vanadium atoms in the vanadium-containing stock solution is 3:1; (3) adding low molecular weight polyethylene glycol to the vanadium-containing stock solution and stirring uniformly to obtain a modified vanadium-containing stock solution; the number average molecular weight of the low molecular weight polyethylene glycol is 400, and the mass ratio of the low molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.01:1; the stirring rate is 600 r / min; (4) The ammonium salt solution and the modified vanadium-containing stock solution were mixed evenly, the pH was adjusted to 8, and a mixture was obtained after reaction; the reaction was carried out at 30°C for 60 minutes; (5) The mixture is filtered and the solid product is washed to obtain large-particle ammonium metavanadate.

[0021] Example 2 A method for preparing large-particle ammonium metavanadate comprises the following steps: (1) Preparation of vanadium-containing stock solution; (2) dissolving an ammonium salt and high molecular weight polyethylene glycol in water, and adding alkali to adjust the pH to 8 to obtain an ammonium salt solution; the high molecular weight polyethylene glycol has a number average molecular weight of 4000, and the mass ratio of the high molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.08:1; the molar ratio of ammonium ions in the ammonium salt to vanadium atoms in the vanadium-containing stock solution is 5:1; (3) adding low molecular weight polyethylene glycol to the vanadium-containing stock solution and stirring uniformly to obtain a modified vanadium-containing stock solution; the number average molecular weight of the low molecular weight polyethylene glycol is 800, and the mass ratio of the low molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.03:1; the stirring rate is 800 r / min; (4) The ammonium salt solution and the modified vanadium-containing stock solution were mixed evenly, the pH was adjusted to 10, and a mixture was obtained after reaction; the reaction was carried out at 40°C for 30 minutes; (5) The mixture is filtered and the solid product is washed to obtain large-particle ammonium metavanadate.

[0022] Example 3 A method for preparing large-particle ammonium metavanadate comprises the following steps: (1) Preparation of vanadium-containing stock solution; (2) dissolving an ammonium salt and high molecular weight polyethylene glycol in water, and adding alkali to adjust the pH to 8 to obtain an ammonium salt solution; the high molecular weight polyethylene glycol has a number average molecular weight of 2500, and the mass ratio of the high molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.08:1; the molar ratio of ammonium ions in the ammonium salt to vanadium atoms in the vanadium-containing stock solution is 5:1; (3) adding low molecular weight polyethylene glycol to the vanadium-containing stock solution and stirring uniformly to obtain a modified vanadium-containing stock solution; the number average molecular weight of the low molecular weight polyethylene glycol is 800, and the mass ratio of the low molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.01:1; the stirring rate is 700 r / min; (4) The ammonium salt solution and the modified vanadium-containing stock solution were mixed evenly, the pH was adjusted to 8, and a mixture was obtained after reaction; the reaction was carried out at 30°C for 50 minutes; (5) The mixture is filtered and the solid product is washed to obtain large-particle ammonium metavanadate.

[0023] Example 4 A method for preparing large-particle ammonium metavanadate comprises the following steps: (1) Preparation of vanadium-containing stock solution; (2) dissolving an ammonium salt and high molecular weight polyethylene glycol in water, and adding alkali to adjust the pH to 7 to obtain an ammonium salt solution; the high molecular weight polyethylene glycol has a number average molecular weight of 4000, and the mass ratio of the high molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.04:1; the molar ratio of ammonium ions in the ammonium salt to vanadium atoms in the vanadium-containing stock solution is 3:1; (3) adding low molecular weight polyethylene glycol to the vanadium-containing stock solution and stirring uniformly to obtain a modified vanadium-containing stock solution; the number average molecular weight of the low molecular weight polyethylene glycol is 800, and the mass ratio of the low molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.03:1; the stirring rate is 600 r / min; (4) The ammonium salt solution and the modified vanadium-containing stock solution were mixed evenly, the pH was adjusted to 8, and a mixture was obtained after reaction; the reaction was carried out at 38°C for 40 minutes; (5) The mixture is filtered and the solid product is washed to obtain large-particle ammonium metavanadate.

[0024] Example 5 A method for preparing large-particle ammonium metavanadate comprises the following steps: (1) Preparation of vanadium-containing stock solution; (2) dissolving an ammonium salt and high molecular weight polyethylene glycol in water, and adding alkali to adjust the pH to 8 to obtain an ammonium salt solution; the high molecular weight polyethylene glycol has a number average molecular weight of 2500, and a mass ratio of the high molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.06:1; and the molar ratio of ammonium ions in the ammonium salt to vanadium atoms in the vanadium-containing stock solution is 3.5:1; (3) adding low molecular weight polyethylene glycol to the vanadium-containing stock solution and stirring uniformly to obtain a modified vanadium-containing stock solution; the number average molecular weight of the low molecular weight polyethylene glycol is 500, and the mass ratio of the low molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.015:1; the stirring rate is 700 r / min; (4) The ammonium salt solution and the modified vanadium-containing stock solution were mixed evenly, the pH was adjusted to 9, and a mixture was obtained after reaction; the reaction was carried out at 32°C for 50 minutes; (5) The mixture is filtered and the solid product is washed to obtain large-particle ammonium metavanadate.

[0025] Example 6 A method for preparing large-particle ammonium metavanadate comprises the following steps: (1) Preparation of vanadium-containing stock solution; (2) dissolving an ammonium salt and high molecular weight polyethylene glycol in water, and adding alkali to adjust the pH to 8 to obtain an ammonium salt solution; the high molecular weight polyethylene glycol has a number average molecular weight of 3500, and a mass ratio of the high molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.07:1; and the molar ratio of ammonium ions in the ammonium salt to vanadium atoms in the vanadium-containing stock solution is 4.4:1; (3) adding low molecular weight polyethylene glycol to the vanadium-containing stock solution and stirring uniformly to obtain a modified vanadium-containing stock solution; the number average molecular weight of the low molecular weight polyethylene glycol is 700, and the mass ratio of the low molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.02:1; the stirring rate is 800 r / min; (4) The ammonium salt solution and the modified vanadium-containing stock solution were mixed evenly, the pH was adjusted to 9, and a mixture was obtained after reaction; the reaction was carried out at 36°C for 40 minutes; (5) The mixture is filtered and the solid product is washed to obtain large-particle ammonium metavanadate.

[0026] Example 7 A method for preparing large-particle ammonium metavanadate comprises the following steps: (1) Preparation of vanadium-containing stock solution; (2) dissolving the ammonium salt and high molecular weight polyethylene glycol in water, adjusting pH to 7 by adding alkali to obtain an ammonium salt solution; the high molecular weight polyethylene glycol has a number average molecular weight of 3000, and the mass ratio of the high molecular weight polyethylene glycol to vanadium atoms in the vanadium-containing stock solution is 0.06:1; the molar ratio of ammonium ions in the ammonium salt to vanadium atoms in the vanadium-containing stock solution is 4.5:1; (3) adding low molecular weight polyethylene glycol to the vanadium-containing stock solution, stirring uniformly to obtain a modified vanadium-containing stock solution; the low molecular weight polyethylene glycol has a number average molecular weight of 600, and the mass ratio of the low molecular weight polyethylene glycol to vanadium atoms in the vanadium-containing stock solution is 0.02:1; the stirring rate is 600 r / min; (4) mixing the ammonium salt solution and the modified vanadium-containing stock solution uniformly, adjusting pH to 9, and obtaining a mixture after reaction; the reaction is carried out at 35°C for 45 min; (5) filtering the mixture, and washing the solid product to obtain large-size ammonium metavanadate.

[0027] Example 8 A preparation method of large-size ammonium metavanadate, comprising the following steps: (1) preparation of a vanadium-containing stock solution; (2) dissolving the ammonium salt and high molecular weight polyethylene glycol in water, adjusting pH to 7 by adding alkali to obtain an ammonium salt solution; the high molecular weight polyethylene glycol has a number average molecular weight of 4000, and the mass ratio of the high molecular weight polyethylene glycol to vanadium atoms in the vanadium-containing stock solution is 0.06:1; the molar ratio of ammonium ions in the ammonium salt to vanadium atoms in the vanadium-containing stock solution is 4.5:1; (3) adding low molecular weight polyethylene glycol to the vanadium-containing stock solution, stirring uniformly to obtain a modified vanadium-containing stock solution; the low molecular weight polyethylene glycol has a number average molecular weight of 600, and the mass ratio of the low molecular weight polyethylene glycol to vanadium atoms in the vanadium-containing stock solution is 0.02:1; the stirring rate is 600 r / min; (4) mixing the ammonium salt solution and the modified vanadium-containing stock solution uniformly, adjusting pH to 9, and obtaining a mixture after reaction; the reaction is carried out at 35°C for 45 min; (5) filtering the mixture, and washing the solid product to obtain large-size ammonium metavanadate.

[0028] Example 9 A preparation method of large-size ammonium metavanadate, comprising the following steps: (1) preparation of a vanadium-containing stock solution; (2) dissolving the ammonium salt and high molecular weight polyethylene glycol in water, adjusting pH to 7 by adding alkali to obtain an ammonium salt solution; the high molecular weight polyethylene glycol has a number average molecular weight of 3000, and the mass ratio of the high molecular weight polyethylene glycol to vanadium atoms in the vanadium-containing stock solution is 0.06:1; the molar ratio of ammonium ions in the ammonium salt to vanadium atoms in the vanadium-containing stock solution is 4.5:1; (3) adding low molecular weight polyethylene glycol to the vanadium-containing stock solution and stirring uniformly to obtain a modified vanadium-containing stock solution; the number average molecular weight of the low molecular weight polyethylene glycol is 600, and the mass ratio of the low molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.04:1; the stirring rate is 600 r / min; (4) The ammonium salt solution and the modified vanadium-containing stock solution were mixed evenly, the pH was adjusted to 9, and a mixture was obtained after reaction; the reaction was carried out at 35°C for 45 minutes; (5) The mixture is filtered and the solid product is washed to obtain large-particle ammonium metavanadate.

[0029] Comparative Example 1 A method for preparing large-particle ammonium metavanadate comprises the following steps: (1) Preparation of vanadium-containing stock solution; (2) dissolving an ammonium salt and high molecular weight polyethylene glycol in water, and adding alkali to adjust the pH to 7 to obtain an ammonium salt solution; the high molecular weight polyethylene glycol has a number average molecular weight of 3000, and a mass ratio of the high molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.08:1; and the molar ratio of ammonium ions in the ammonium salt to vanadium atoms in the vanadium-containing stock solution is 4.5:1; (3) The ammonium salt solution and the vanadium-containing stock solution were mixed evenly, the pH was adjusted to 9, and a mixture was obtained after reaction; the reaction was carried out at 35°C for 45 minutes; (4) The mixture is filtered and the solid product is washed to obtain large-particle ammonium metavanadate.

[0030] Comparative Example 2 A method for preparing large-particle ammonium metavanadate comprises the following steps: (1) Preparation of vanadium-containing stock solution; (2) dissolving the ammonium salt in water and adding alkali to adjust the pH to 7 to obtain an ammonium salt solution; the molar ratio of ammonium ions in the ammonium salt to vanadium atoms in the vanadium-containing stock solution is 4.5:1; (3) adding low molecular weight polyethylene glycol to the vanadium-containing stock solution and stirring uniformly to obtain a modified vanadium-containing stock solution; the number average molecular weight of the low molecular weight polyethylene glycol is 600, and the mass ratio of the low molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.08:1; the stirring rate is 600 r / min; (4) The ammonium salt solution and the modified vanadium-containing stock solution were mixed evenly, the pH was adjusted to 9, and a mixture was obtained after reaction; the reaction was carried out at 35°C for 45 minutes; (5) The mixture is filtered and the solid product is washed to obtain large-particle ammonium metavanadate.

[0031] Comparative Example 3 A method for preparing large-particle ammonium metavanadate comprises the following steps: (1) Preparation of vanadium-containing stock solution; (2) dissolving an ammonium salt and high molecular weight polyethylene glycol in water, and adding alkali to adjust the pH to 7 to obtain an ammonium salt solution; the high molecular weight polyethylene glycol has a number average molecular weight of 3000, and a mass ratio of the high molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.1:1; and the molar ratio of ammonium ions in the ammonium salt to vanadium atoms in the vanadium-containing stock solution is 4.5:1; (3) adding low molecular weight polyethylene glycol to the vanadium-containing stock solution and stirring uniformly to obtain a modified vanadium-containing stock solution; the number average molecular weight of the low molecular weight polyethylene glycol is 600, and the mass ratio of the low molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.02:1; the stirring rate is 600 r / min; (4) The ammonium salt solution and the modified vanadium-containing stock solution were mixed evenly, the pH was adjusted to 9, and a mixture was obtained after reaction; the reaction was carried out at 35°C for 45 minutes; (5) The mixture is filtered and the solid product is washed to obtain large-particle ammonium metavanadate.

[0032] The performance tests of the large-particle ammonium metavanadate prepared in Examples 1-9 and Comparative Examples 1-3 were carried out: the purity of ammonium metavanadate (%) was tested using a spectrometer; the bulk density of ammonium metavanadate (g / cm 3 ); and the particle size D50 (μm) of ammonium metavanadate was tested using a laser particle size analyzer.

[0033] Table 1 Performance of large particle size ammonium metavanadate prepared in Examples 1-9 and Comparative Examples 1-3 Table 1 As can be seen from Table 1, low molecular weight polyethylene glycol mainly plays the effect of reducing nucleation rate; And high molecular weight polyethylene glycol has good adsorptivity, mainly plays the effect of promoting crystal growth, and the polyethylene glycol of different molecular weights cooperates with each other to improve ammonium metavanadate granularity and purity. Especially, as can be seen from embodiment 1-9 and comparative example 1-2, suitable high molecular weight polyethylene glycol obtains ammonium metavanadate density and scale larger; By regulating the low molecular weight polyethylene glycol consumption, both can give full play to the good characteristics of low molecular weight polyethylene glycol mobility, can avoid again the excessive obstruction of polyethylene glycol consumption crystal growth, be conducive to ammonium metavanadate to form larger crystal nucleus, make ammonium metavanadate grain growth rate higher than nucleation rate, effectively improve ammonium metavanadate size. Comparative example 3 shows that due to the long high molecular weight polyethylene glycol molecular chain, when its consumption is too much, can cause the mutual entanglement between molecules, form dense structure, be unfavorable for crystal growth.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing large-particle ammonium metavanadate, characterized in that: The following steps are involved: (1) Preparation of vanadium-containing stock solution; (2) dissolving an ammonium salt and high molecular weight polyethylene glycol in water, and adding alkali to adjust the pH to obtain an ammonium salt solution; the high molecular weight polyethylene glycol has a number average molecular weight of 2000-4000, and a mass ratio of the high molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.04-0.08:1; (3) adding low molecular weight polyethylene glycol to the vanadium-containing stock solution and stirring uniformly to obtain a modified vanadium-containing stock solution; the low molecular weight polyethylene glycol has a number average molecular weight of 400-800, and a mass ratio of the low molecular weight polyethylene glycol to the vanadium atoms in the vanadium-containing stock solution is 0.01-0.04:1; (4) Evenly mixing the ammonium salt solution and the modified vanadium-containing stock solution, adjusting the pH to 8-10, and reacting to obtain a mixture; (5) The mixture is filtered and the solid product is washed to obtain large-particle ammonium metavanadate.

2. The method for preparing large-particle ammonium metavanadate according to claim 1, wherein: Step (1) prepares a vanadium-containing stock solution using vanadium slag as a raw material; the vanadium content in the vanadium-containing stock solution is 30-40 g / L.

3. The method for preparing large-particle ammonium metavanadate according to claim 1, wherein: The vanadium in the vanadium-containing stock solution in step (1) exists in the form of pentavalent vanadium.

4. The method for preparing large-particle ammonium metavanadate according to claim 1, wherein: In step (2), the ammonium salt is one or more of ammonium carbonate, ammonium bicarbonate, ammonium sulfate, ammonium chloride, and ammonium nitrate; and the molar ratio of ammonium ions in the ammonium salt to vanadium atoms in the vanadium-containing stock solution is 3-5:

1.

5. The method for preparing large-particle ammonium metavanadate according to claim 1, wherein: In step (2), the alkali is one or more of potassium hydroxide, sodium hydroxide, and ammonia water, and the pH is 6-8.

6. The method for preparing large-particle ammonium metavanadate according to claim 1, wherein: The stirring rate in step (3) is 500-1000 r / min.

7. The method for preparing large-particle ammonium metavanadate according to claim 1, wherein: The reaction in step (4) is carried out at 30-40°C for 30-60 minutes.

8. The method for preparing large-particle ammonium metavanadate according to claim 1, wherein: In step (5), the washing is performed in a countercurrent manner.

9. The method for preparing large-particle ammonium metavanadate according to claim 1, wherein: The washing in step (5) is carried out at room temperature.

10. A large-particle ammonium metavanadate, characterized by: The invention discloses a method for preparing large-particle ammonium metavanadate according to any one of claims 1 to 9.