Method for preparing high-nitrogen vanadium-nitrogen alloy from vanadium-containing solution

Abstract

The invention provides a method for preparing a high-nitrogen vanadium-nitrogen alloy from a vanadium-containing solution, which comprises the following steps: S1) adjusting the pH value of the vanadium-containing solution, and adding organic amine to precipitate vanadium under a stirring condition to obtain a vanadium-containing precipitate; s2) mixing the vanadium-containing precipitate with carbon powder, and pressing to obtain pellets; and S3) heating the pellets in a nitrogen atmosphere, and cooling to obtain the high-nitrogen vanadium-nitrogen alloy. According to the method for preparing the high-nitrogen vanadium-nitrogen alloy from the vanadium-containing solution, the organic amine is added into the vanadium-containing solution under the stirring condition for vanadium precipitation, the organic amine and vanadate-containing complex precipitate is obtained, the organic part in the precipitate is equivalent to a nitrogen increasing agent, and the vanadate-containing part is equivalent to a vanadium source; the high-nitrogen vanadium-nitrogen alloy can be directly prepared by using the complex precipitate; according to the method, the preparation process of the high-nitrogen vanadium-nitrogen alloy is shortened, a nitrogen increasing agent does not need to be added again, the cost is saved, and the quality of the high-nitrogen vanadium-nitrogen alloy is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metallurgy, and particularly relates to a method for preparing high-nitrogen vanadium-nitrogen alloy from vanadium-containing solution. BACKGROUND

[0002] Vanadium-nitrogen alloy is a high-efficiency steel micro-alloying additive, which can realize high strength, high toughness, corrosion resistance and low cost of steel materials through fine-grain strengthening and precipitation strengthening mechanism, supplemented by solid solution and phase transformation control. The nitrogen content in vanadium-nitrogen alloy is an important indicator for evaluating the quality of vanadium-nitrogen alloy. The higher the nitrogen content, the higher the quality of vanadium-nitrogen alloy, and the better the performance of the corresponding produced steel. The national standard stipulates that the nitrogen content (mass fraction) in vanadium-nitrogen alloy is greater than or equal to 10% and less than 14% for VN12, greater than or equal to 14% and less than 18% for VN16, and 18-20% for VN19. At present, VN16 is mainly produced in industrial production of vanadium-nitrogen alloy, and there are still certain technical difficulties in producing VN19.

[0003] Adding nitrogen enhancer to the raw material for preparing vanadium-nitrogen alloy can improve the nitrogen content of the final vanadium-nitrogen alloy product. For example, the Chinese patent with the publication number CN104404333A discloses that melamine is added to vanadium compounds and carbonaceous reducing agents, and then the mixture is pressed into balls and calcined to prepare high-nitrogen vanadium-nitrogen alloy. The Chinese patent with the publication number CN110923558A discloses that vanadium oxide, carbonaceous reducing agents and nitrogen enhancer (one of urea, melamine and diammonium phosphate) are dry-mixed, and then the mixture is dry-pressed into raw material blocks, and then the raw material blocks are subjected to nitriding treatment to obtain high-nitrogen vanadium-nitrogen alloy. The Chinese patent with the publication number CN117488128A uses graphitic carbon nitride as a nitrogen enhancer, and the graphitic carbon nitride is mixed uniformly with carbonaceous reducing agents and vanadium source, and then a binder is added to prepare alloy raw material. The alloy raw material is pressed into balls, fired and cooled to obtain high-nitrogen vanadium-nitrogen alloy.

[0004] As can be seen from the above patents, the way of adding nitrogen enhancer to the raw material for preparing vanadium-nitrogen alloy is mainly mixing and grinding, but the above methods may have the problem of uneven mixing, which may affect the quality of the final vanadium-nitrogen alloy product. In addition, the vanadium source mixed with the nitrogen enhancer is mainly vanadium oxide, and the preparation of vanadium oxide needs to go through the links of vanadium precipitation and calcination, so the overall process is relatively long. SUMMARY

[0005] The present application provides a method for preparing high-nitrogen vanadium-nitrogen alloy from vanadium-containing solution. The organic amine precipitator added in the vanadium precipitation process is the nitrogen enhancer, which makes the mixing of the nitrogen enhancer and vanadium in the vanadium-containing solution more sufficient. The organic amine is used as both a vanadium precipitator and a nitrogen enhancer, which improves the utilization efficiency of N, reduces the cost, and shortens the preparation process by directly using the vanadium precipitation product as the vanadium source for preparing vanadium-nitrogen alloy.

[0006] Therefore, the application provides a method for preparing high-nitrogen vanadium-nitrogen alloy from vanadium-containing solution, which comprises the following steps:

[0007] S1) adjusting pH of the vanadium-containing solution, adding organic amine to precipitate vanadium under stirring to obtain vanadium-containing precipitate;

[0008] S2) mixing the vanadium-containing precipitate with carbon powder and then pressing to obtain material ball;

[0009] S3) heating the material ball in nitrogen atmosphere, and obtaining high-nitrogen vanadium-nitrogen alloy after cooling.

[0010] In some embodiments, in step S1), the pH is 2-3.

[0011] In some embodiments, the organic amine comprises melamine; and the melamine is added in a ratio of n(melamine):n(V in the vanadium-containing solution) = (0.2-0.3):1.

[0012] In some embodiments, in step S1), after the precipitation of vanadium, the obtained vanadium-containing precipitate is further filtered, washed and dried.

[0013] In some embodiments, in step S2), the carbon powder is added in a ratio of m(C):m(V) = (0.48-0.59):1.

[0014] In some embodiments, in step S3), the heating process specifically comprises:

[0015] The material ball is placed in a heating device, nitrogen is introduced into the heating device, after the gas in the heating device is exhausted, the heating device is heated to a first temperature at a rate of 10 ℃ / min, and then heated to a second temperature at a rate of 5 ℃ / min, and then kept at the second temperature.

[0016] In some embodiments, the first temperature is 550-650 ℃.

[0017] In some embodiments, the second temperature is 1450-1550 ℃, and the keeping time is 2-4 h.

[0018] In some embodiments, the cooling method specifically comprises:

[0019] The heating is stopped, and the nitrogen introduction is continued until cooling.

[0020] In some embodiments, the high-nitrogen vanadium-nitrogen alloy contains 18-20 wt% of N and 76-81 wt% of V.

[0021] In some embodiments, the vanadium-containing solution comprises calcified roasting acid leaching solution, sodiumized roasting water leaching solution or vanadium compound dissolving solution.

[0022] The present application provides a method for preparing high-nitrogen vanadium-nitrogen alloy from vanadium-containing solution, which first precipitates vanadium from vanadium-containing solution by using organic amine, the organic part in the vanadium-containing precipitate corresponds to nitrogen-increasing agent, and the vanadium-containing acid radical part corresponds to vanadium source. Since the -NH2 of the organic amine forms coordination bond with the vanadium-containing acid radical, the mixing of the nitrogen-increasing agent and the vanadium-containing acid radical at the molecular level can be realized under stirring condition, and this kind of mixing is more uniform and dispersed. The vanadium-containing precipitate is directly used to prepare high-nitrogen vanadium-nitrogen alloy after vanadium precipitation, and compared with the traditional preparation route of vanadium precipitation-calcination-preparation of vanadium pentoxide-addition of nitrogen-increasing agent-preparation of high-nitrogen vanadium-nitrogen alloy, the present application has shorter process and avoids the problem of nitrogen emission in the process of calcination for preparing vanadium pentoxide. Meanwhile, the organic amine part contained in the vanadium precipitation product corresponds to nitrogen-increasing agent, and high-nitrogen vanadium-nitrogen alloy can be prepared without adding nitrogen-increasing agent again, which can save raw materials and reduce cost. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The flowchart of the preparation of high-nitrogen vanadium-nitrogen alloy by the prior art and the present application. DETAILED DESCRIPTION

[0024] In order to further understand the present application, the preferred embodiments of the present application are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present application, but not for limiting the claims of the present application.

[0025] In view of the problems of the prior art, such as the uneven mixing of nitrogen-increasing agent and raw materials and the long overall process, the present application provides a method for preparing high-nitrogen vanadium-nitrogen alloy from vanadium-containing solution, which is obtained through research: organic amine compounds (melamine, urea, ethylenediamine, etc.) contain rich -NH2 groups and have the ability to complex with vanadium-containing acid radical. These organic amine compounds can be used as nitrogen-increasing agent for preparing vanadium-nitrogen alloy and as vanadium precipitant for extracting vanadium from solution. Therefore, the present application provides a method for preparing high-nitrogen vanadium-nitrogen alloy from vanadium-containing solution, which adds organic amine to the vanadium-containing solution to precipitate vanadium and obtain complex precipitate of organic amine and vanadium-containing acid radical. The organic part in the precipitate corresponds to nitrogen-increasing agent, and the vanadium-containing acid radical part corresponds to vanadium source. The complex precipitate can be directly used to prepare high-nitrogen vanadium-nitrogen alloy. Specifically, the present application discloses a method for preparing high-nitrogen vanadium-nitrogen alloy from vanadium-containing solution, which comprises the following steps:

[0026] S1) adjusting the pH of the vanadium-containing solution, adding organic amine to precipitate vanadium under stirring condition, and obtaining vanadium-containing precipitate;

[0027] S2) mixing the vanadium-containing precipitate with carbon powder and then pressing to obtain material balls;

[0028] S3) heating the material balls in nitrogen atmosphere, and obtaining high-nitrogen vanadium-nitrogen alloy after cooling.

[0029] In the method for preparing high-nitrogen vanadium-nitrogen alloy from vanadium-containing solution, as to step S1:

[0030] The pH of the vanadium-containing solution is adjusted, and the vanadium is precipitated by adding organic amine under stirring to obtain vanadium-containing precipitate;

[0031] The vanadium-containing solution includes but is not limited to calcified roasting acid leaching solution, sodiumized roasting water leaching solution, and solution obtained by dissolving vanadium compound, and in specific embodiments, the vanadium-containing solution is selected from calcified roasting leaching solution, sodiumized roasting water leaching solution, or sodium metavanadate solution.

[0032] The pH is 2-3, and the vanadium-containing solution is adjusted to this pH range, so that the vanadium in the solution after adjusting the pH exists in the form of polyvanadate ion, which can combine with organic amine to generate precipitate.

[0033] The organic amine includes one or more of melamine, urea, and ethylenediamine, and in specific embodiments, the organic amine is selected from melamine; the melamine is added in a ratio of n(melamine):n(V in vanadium-containing solution)=(0.2-0.3):1; preferably, the melamine is added in a ratio of n(melamine):n(V in vanadium-containing solution)=(0.23-0.28):1; the amount of melamine added should not be less than n(melamine):n(V in vanadium-containing solution)=0.2:1 according to the above ratio relationship, so as to ensure a certain vanadium precipitation rate and reduce vanadium loss; increasing the amount of melamine added can increase the vanadium precipitation rate, and if the vanadium precipitation rate is close to the limit, the additional melamine will mix into the precipitate due to its low solubility, which is equivalent to increasing the amount of nitrogen additive, but too high amount of nitrogen additive will lead to product defects, therefore, the amount of melamine added should not exceed n(melamine):n(V in vanadium-containing solution)=0.3:1 according to the above ratio relationship; when the melamine and vanadium are all precipitated, the content of melamine in the precipitate is m(melamine):m(V2O5)=(0.28-0.42):1 (V2O5 is the converted mass), which can ensure effective nitrogen increase and avoid the risk of product defects caused by excessive nitrogen additive.

[0034] In this step, when the organic amine is selected from melamine, each melamine molecule contains three -NH2 groups, and under acidic conditions, -NH2 combines with H + to form -NH3 + , which is easy to form coordination bonds with polyvanadate ions in the solution to generate complex precipitate; since the precipitation reaction is carried out under stirring, -NH3 + can be uniformly dispersed with polyvanadate, and the organic part in the obtained precipitate corresponds to the nitrogen additive, and the vanadate part corresponds to the vanadium source, which can be used for the preparation of high-nitrogen vanadium-nitrogen alloy.

[0035] As to step S2:

[0036] The vanadium-containing precipitate is mixed with carbon powder and then pressed to obtain a material pellet.

[0037] The carbon powder is added in a mass ratio of m(C):m(V) = 0.48-0.59, preferably in a mass ratio of m(C):m(V) = 0.50-0.56.

[0038] In this step, the carbon powder is added as a reducing agent for the deoxidation and carburization process in the above-mentioned ratio, which can ensure that the vanadium source is fully deoxidized and reduced while the residual carbon content is controlled at a low level.

[0039] Regarding step S3:

[0040] The material pellet is heated in a nitrogen atmosphere, and a high-nitrogen vanadium-nitrogen alloy is obtained after cooling; further, the process is specifically as follows:

[0041] The material pellet is placed in a heating device, nitrogen is introduced into the heating device, after the gas in the heating device is exhausted, the heating device is heated to a first temperature at a rate of 10℃ / min, and then heated to a second temperature at a rate of 5℃ / min, and then kept at the second temperature, and the nitrogen is continuously introduced throughout the process.

[0042] The heating is stopped, and the nitrogen introduction is continued until cooling, to obtain a high-nitrogen vanadium-nitrogen alloy.

[0043] The first temperature is 550-650℃, and the heating rate is 10℃ / min; the second temperature is 1450-1550℃, and the heating rate is 5℃ / min, and the holding time is 2-4h; the slow heating mode is beneficial to ensure the cracking temperature and time of the organic matter, and to convert all the carbon into carbonaceous reducing gas, so as to avoid excessive carbon content in the final product.

[0044] In this step, the vanadium-containing precipitate is slowly heated at a rate of 10℃ / min in a nitrogen atmosphere, part of the H and O elements in the vanadium-containing precipitate are gradually removed in the form of water vapor, the polyvanadate skeleton is cracked into V2O5 and gradually reduced into low-valence vanadium oxide; as the temperature continues to rise, melamine is cracked into NH3 and carbonaceous gas molecules, the production of NH3 can form pores to facilitate subsequent nitriding, on the other hand, NH3 itself can nitride, and its activity is higher than that of N2, and finally heating to 1450-1550℃ and holding for 2-4h can fully deoxidize and nitride to obtain a high-nitrogen vanadium-nitrogen alloy.

[0045] Nitrogen is continuously introduced during the cooling process to avoid oxygen entering the heating device to oxidize the vanadium-nitrogen alloy, and the high-nitrogen vanadium-nitrogen alloy product can be taken out after natural cooling to a temperature at which oxygen cannot oxidize the vanadium-nitrogen alloy.

[0046] The high vanadium-vanadium-nitrogen alloy prepared in this application has an N content of 18-20 wt% and a V content of 76-81 wt%; specifically, the high vanadium-vanadium-nitrogen alloy has an N content of 18.3-19.5 wt% and a V content of 78.0-78.5 wt%.

[0047] This invention provides a method for preparing high-nitrogen vanadium-nitrogen alloys from vanadium-containing solutions, the process flow diagram of which is shown below. Figure 1 As shown, an organic amine is added to a vanadium-containing solution under stirring to precipitate vanadium, resulting in a vanadium-containing precipitate. The vanadium-containing precipitate and reducing agent carbon powder are then used to prepare pellets. Finally, the pellets are heated at high temperature to obtain a high-nitrogen vanadium-nitrogen alloy. In this method, organic amine is used for vanadium precipitation. The organic portion of the precipitate acts as a nitrogen-raising agent, and the vanadate portion acts as a vanadium source. Because the -NH2 group of the organic amine can form coordinate bonds with the vanadate, compared to mixing, grinding, and adding nitrogen-raising agents, stirring and precipitation allows the nitrogen-raising agent and vanadate to mix at the molecular level. This mixing method is more uniform and dispersed. Compared to the traditional route of vanadium precipitation-calcination to prepare vanadium pentoxide-adding nitrogen-preparing agent-preparing high-nitrogen vanadium-nitrogen alloy (…), this method… Figure 1 Compared with the existing technical route, the present invention directly prepares high-nitrogen vanadium-nitrogen alloy using the vanadium precipitation product after vanadium precipitation, which is a shorter process and avoids the problem of nitrogen emission during the calcination preparation of vanadium pentoxide; in addition, the organic amine part contained in the vanadium precipitation product of the present invention is equivalent to a nitrogen-increasing agent, so there is no need to add a nitrogen-increasing agent again to prepare high-nitrogen vanadium-nitrogen alloy, which can save raw materials and reduce costs.

[0048] To further understand the present invention, the method for preparing high-nitrogen vanadium-nitrogen alloys from vanadium-containing solutions provided by the present invention will be described in detail below with reference to embodiments. The scope of protection of the present invention is not limited by the following embodiments.

[0049] Example 1

[0050] S1, take the vanadium leaching solution obtained by calcination and roasting, adjust the pH of the vanadium solution to 3, and under stirring conditions, add melamine to the solution at a ratio of n(melamine):n(V) = 0.2:1 to precipitate vanadium, and then filter, wash and dry the vanadium precipitate.

[0051] S2, after the vanadium-containing precipitate treated in S1 is mixed with carbon powder, it is pressed into pellets, wherein the carbon powder is added in a ratio of m(C):m(V)=0.48:1;

[0052] S3. Place the pellets from S2 into the heating equipment and introduce nitrogen into the equipment. After the original gas in the equipment is exhausted, raise the temperature of the heating equipment to 600°C at 10°C / min, then raise it to 1450°C at 5°C / min and keep it at that temperature for 4 hours. Nitrogen is continuously introduced throughout the process.

[0053] S4, stop heating, continue to keep nitrogen gas into, until cooling, get high nitrogen vanadium nitrogen alloy (N content 18.3wt%, V content 78.0wt%).

[0054] Example 2

[0055] S1, take sodium roasting leaching vanadium solution, adjust the pH of vanadium solution = 2, under the condition of stirring, according to the proportion of n (melamine) : n (V) = 0.3:1, add melamine to the solution to precipitate vanadium, get vanadium containing precipitate, filter, wash, dry treatment to the obtained vanadium containing precipitate;

[0056] S2, mix the treated vanadium containing precipitate in S1 with carbon powder, and press into balls, wherein the carbon powder is added according to the proportion of m (C) : m (V) = 0.59:1;

[0057] S3, place the balls in S2 into a heating device, introduce nitrogen gas into the device, after the original gas in the device is exhausted, heat the device to 600℃ at a rate of 10℃ / min, then heat to 1550℃ at a rate of 5℃ / min, and keep for 2h, the whole process keeps the continuous introduction of nitrogen gas;

[0058] S4, stop heating, continue to keep nitrogen gas into, until cooling, get high nitrogen vanadium nitrogen alloy (N content 19.2wt%, V content 78.2wt%).

[0059] Example 3

[0060] S1, take sodium metavanadate solution, adjust the pH of sodium metavanadate solution = 2.8, under the condition of stirring, according to the proportion of n (melamine) : n (V) = 0.28:1, add melamine to the solution to precipitate vanadium, get vanadium containing precipitate, filter, wash, dry treatment to the obtained vanadium containing precipitate;

[0061] S2, mix the treated vanadium containing precipitate in S1 with carbon powder, and press into balls, wherein the carbon powder is added according to the proportion of m (C) : m (V) = 0.52:1;

[0062] S3, place the balls in S2 into a heating device, introduce nitrogen gas into the device, after the original gas in the device is exhausted, heat the device to 600℃ at a rate of 10℃ / min, then heat to 1490℃ at a rate of 5℃ / min, and keep for 2.5h, the whole process keeps the continuous introduction of nitrogen gas;

[0063] S4, stop heating, continue to keep nitrogen gas into, until cooling, get high nitrogen vanadium nitrogen alloy (N content 18.8wt%, V content 78.5wt%).

[0064] Example 4

[0065] S1, taking sodium metavanadate solution, adjusting the pH of the sodium metavanadate solution to 2.5, under stirring, adding melamine to the solution to precipitate vanadium at a ratio of n(melamine):n(V) = 0.25:1, to obtain a vanadium-containing precipitate, and filtering, washing and drying the vanadium-containing precipitate;

[0066] S2, mixing the treated vanadium-containing precipitate in S1 with carbon powder, and pressing into a material ball, wherein the carbon powder is added at a ratio of m(C):m(V) = 0.56:1;

[0067] S3, placing the material ball in S2 into a heating device, introducing nitrogen into the device, after the original gas in the device is exhausted, heating the device to 600℃ at a rate of 10℃ / min, then to 1520℃ at a rate of 5℃ / min, and maintaining the temperature for 2.5h, and continuously introducing nitrogen during the whole process;

[0068] S4, stopping heating, and continuously introducing nitrogen until cooling, to obtain a high-nitrogen vanadium-nitrogen alloy (N content 18.7wt%, V content 78.5wt%).

[0069] The above description of the embodiments is only used to help understand the method of the present application and its core idea. It should be noted that, for those skilled in the art, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

[0070] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing high-nitrogen vanadium-nitrogen alloy from vanadium-containing solution, comprising the following steps: S1) adjusting pH of the vanadium-containing solution, adding organic amine to precipitate vanadium under stirring to obtain vanadium-containing precipitate; S2) mixing the vanadium-containing precipitate with carbon powder and then pressing to obtain material ball; S3) heating the material ball in nitrogen atmosphere, and obtaining high-nitrogen vanadium-nitrogen alloy after cooling.

2. The method of claim 1, wherein, In step S1), the pH is 2-3.

3. The method of claim 1, wherein, The organic amine comprises melamine; the melamine is added in a ratio of n(melamine):n(V in vanadium-containing solution) = (0.2-0.3):

1.

4. The method of claim 1, wherein, In step S1), after the precipitation of vanadium, the obtained vanadium-containing precipitate is further filtered, washed and dried.

5. The method of claim 1, wherein, In step S2), the carbon powder is added in a ratio of m(C):m(V) = (0.48-0.59):

1.

6. The method of claim 1, wherein, In step S3), the heating process is specifically as follows: The material ball is placed in a heating device, nitrogen is introduced into the heating device, after the gas in the heating device is exhausted, the heating device is heated to a first temperature at a rate of 10℃ / min, and then heated to a second temperature at a rate of 5℃ / min, and then kept at the second temperature.

7. The method of claim 6, wherein, The first temperature is 550-650℃.

8. The method of claim 6, wherein, The second temperature is 1450-1550℃, and the keeping time is 2-4h.

9. The method of claim 1, wherein, The cooling mode is specifically as follows: Stop heating, and continue to introduce nitrogen until cooling.

10. The method according to any one of claims 1 to 9, characterized in that, The high-nitrogen vanadium-nitrogen alloy contains 18-20wt% of N and 76-81wt% of V; And / or, the vanadium-containing solution comprises calcified roasting acid leaching solution, sodiumized roasting water leaching solution or vanadium compound dissolving solution.

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