阅读说明：本技术 一种高品质低成本的氮化钒铁制备方法 (Preparation method of high-quality low-cost nitrided ferrovanadium ) 是由 张春雨 于 2020-12-08 设计创作，主要内容包括：一种高品质低成本的氮化钒铁合金制备方法,包括以下步骤：(1)将钒源化合物、铁源化合物、还原剂加入去离子水中,搅拌,得混合溶液；(2)往所得混合溶液中加入柠檬酸,进行超声搅拌反应4h以上,得到均匀溶胶；(3)将所得溶胶干燥,得到干凝胶,再研磨成粉末,得到固体粉末；(4)往固体粉末中加入相当于固体粉末重量0.06～0.08%的氧化石墨烯,在氮气气氛中,于360～370℃下,焙烧5小时以上,再急冷至室温,即得。本发明中,所得氮化钒铁合金中,钒元素的重量百分比为69.5-71.0％,氮元素的重量百分比为17.8-18.0％；合金的纯度大于99.2%。(A preparation method of high-quality low-cost nitrided ferrovanadium alloy comprises the following steps: (1) adding a vanadium source compound, an iron source compound and a reducing agent into deionized water, and stirring to obtain a mixed solution; (2) adding citric acid into the obtained mixed solution, and carrying out ultrasonic stirring reaction for more than 4 hours to obtain uniform sol; (3) drying the obtained sol to obtain dry gel, and grinding the dry gel into powder to obtain solid powder; (4) and adding graphene oxide which accounts for 0.06-0.08% of the weight of the solid powder into the solid powder, roasting for more than 5 hours at 360-370 ℃ in a nitrogen atmosphere, and then quenching to room temperature to obtain the graphene oxide. In the invention, in the obtained vanadium nitride ferrovanadium alloy, the weight percentage of vanadium element is 69.5-71.0%, and the weight percentage of nitrogen element is 17.8-18.0%; the purity of the alloy is more than 99.2 percent.)

1. A preparation method of a high-quality low-cost nitrided ferrovanadium alloy is characterized by comprising the following steps:

(1) adding a vanadium source compound, an iron source compound and a reducing agent into deionized water, and stirring to obtain a mixed solution; wherein the molar ratio of the vanadium element, the iron element and the reducing agent is 4: 1-1.1: 0.7-0.8;

the concentration of vanadium ions in the mixed solution is 0.3-0.4 mol/L;

(2) adding citric acid into the obtained mixed solution, and carrying out ultrasonic stirring reaction for more than 4 hours to obtain uniform sol;

in the step (2), the mass ratio of the citric acid to the metal ions in the mixed solution is 2-3: 1;

(3) drying the sol obtained in the step (2) to obtain dry gel, and grinding the dry gel into powder to obtain solid powder;

(4) and (4) adding graphene oxide which accounts for 0.06-0.08% of the weight of the solid powder into the solid powder obtained in the step (3), roasting for more than 5 hours at 360-370 ℃ in a nitrogen atmosphere, and then quenching to room temperature to obtain the vanadium nitride iron alloy.

2. The preparation method of the high-quality low-cost nitrided ferrovanadium alloy as claimed in claim 1, wherein in the step (2), the ultrasonic frequency is 20-22 KHz.

3. The method for preparing high-quality low-cost nitrided ferrovanadium alloy according to claim 1 or 2, wherein in the step (1), the stirring rate is 500 to 800 rpm/min.

4. The method for preparing high-quality low-cost nitrided ferrovanadium alloy according to claim 1 or 2, wherein in the step (1), the vanadium source compound is at least one of vanadium pentoxide, ammonium metavanadate, vanadium dioxide and vanadium trioxide.

5. The method for preparing high-quality low-cost nitrided ferrovanadium alloy according to claim 1 or 2, wherein in the step (1), the iron source compound is at least one of iron sesquioxide and iron tetroxide.

6. The method for preparing high-quality low-cost nitrided ferrovanadium alloy according to claim 1 or 2, wherein in the step (1), the reducing agent is at least one of oxalic acid and formic acid.

7. The method for preparing high-quality low-cost nitrided ferrovanadium alloy as claimed in claim 1 or 2, wherein in the step (3), in the step (4), the flow rate of nitrogen is 100-150m³/h。

Technical Field

The invention relates to the field of alloy preparation, in particular to a preparation method of high-quality low-cost ferrovanadium nitride.

Background

Nitrogen element has an excellent strengthening effect on the precipitation of carbonitrides in the microalloyed steel. The nitrogen increase in the steel has the following effects: (1) the toughness and the plasticity of the steel can be obviously improved, (2) the heat resistance strength and the creep ability of the steel can be improved, (3) the interphase distribution of vanadium can be changed, and (4) the endurance strength of the steel can be improved. At present, nitriding methods in steel mainly comprise adding ferrovanadium nitride, vanadium nitride, ferrovanadium, nitrogen-rich ferromanganese, ferrosilicon nitride and the like.

The ferrovanadium nitride is a novel vanadium-nitrogen alloy additive, has performance superior to that of ferrovanadium and vanadium nitride, and is widely used for products such as high-strength twisted steel, high-strength pipeline steel, high-strength section steel and the like. The ferrovanadium nitride has higher specific gravity than vanadium nitride, higher absorptivity, higher grain refinement, strength improvement, toughness improvement, ductility improvement and other functions.

For example, CN105483507A discloses a nitrided ferrovanadium alloy and a preparation method thereof, in which vanadium oxide, iron oxide or iron and a carbonaceous reducing agent are proportionally mixed and pressed into a block, and the block is put into a high-temperature furnace to react to generate nitrided ferrovanadium. The high-temperature reaction of the method comprises two stages of high-temperature carbothermic reduction and medium-temperature nitridation reaction. The method has the advantages of simple process flow, but has the disadvantages of low nitrogen content in the ferrovanadium nitride and high temperature reaction.

CN104046824A discloses a nitrided ferrovanadium and a preparation method thereof, the method comprises the steps of mixing vanadium oxide, carbonaceous powder, iron powder, a water-containing binder and a nitriding accelerator, compacting into a block material, drying the material, and preparing the nitrided ferrovanadium through a preheating stage, a transition stage and a nitriding sintering stage under a high-temperature condition. Although the method increases the content of nitrogen, the process flow is relatively complex. CN103436770A discloses a preparation process of nitrided ferrovanadium, which comprises the steps of protecting with nitrogen atmosphere, keeping the oxygen content inside and outside a closed bin of a pushed slab kiln consistent through nitrogen cleaning, sequentially arranging four areas of a preheating area, a nitriding area, a cooling area and a cooling area in the pushed slab kiln, and then continuously conveying 50 ferrovanadium with the granularity of 5-20mm to the closed bin for nitridation reaction to obtain the nitrided ferrovanadium. The method also has the problems of complex process, low nitrogen content and the like. CN109182887A discloses a method for preparing nitrided ferrovanadium alloy, which contains higher nitrogen content, but does not mention the purity of the obtained nitrided ferrovanadium.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a preparation method of a nitrided ferrovanadium alloy with high quality and low cost, the method has simple flow and low energy consumption in the preparation process, the nitrogen content of the obtained nitrided ferrovanadium alloy is higher, and the purity of the obtained nitrided ferrovanadium alloy is higher.

The technical scheme adopted by the invention for solving the technical problems is that the preparation method of the high-quality low-cost vanadium nitride iron alloy comprises the following steps:

(1) adding a vanadium source compound, an iron source compound and a reducing agent into deionized water, and stirring to obtain a mixed solution; wherein the molar ratio of the vanadium element, the iron element and the reducing agent is 4: 1-1.1: 0.7-0.8;

the concentration of vanadium ions in the mixed solution is 0.3-0.4 mol/L; the yield is reduced when the concentration is too low, and the gel is not generated when the concentration is too high;

(2) adding citric acid into the obtained mixed solution, and carrying out ultrasonic stirring reaction for more than 4 hours (preferably 4-5 hours) to obtain uniform sol;

in the step (2), the mass ratio of the citric acid to the metal ions in the mixed solution is 2-3: 1.

Insufficient time for ultrasound can affect uniformity and can affect the bonding of the material to subsequent graphene oxide. The ultrasonic time is too long, the performance of the material is not greatly influenced, the cost is increased, and the requirement is not needed.

The homogeneous mixed material can be obtained by using a solution gel method, the stability of the mixed material can be obviously improved, and the nitrogen content can be improved.

(3) Drying the sol obtained in the step (2) to obtain dry gel, and grinding the dry gel into powder to obtain solid powder;

(4) and (3) adding graphene oxide which accounts for 0.06-0.08% of the weight of the solid powder into the solid powder obtained in the step (3), roasting for more than 5 hours (preferably 5 hours) at 360-370 ℃ in a nitrogen atmosphere, and then quenching to room temperature to obtain the vanadium nitride iron alloy.

Adding graphene oxide into the solid powder, wherein the graphene oxide can be compounded with the raw material to provide a large specific surface area for effectively dispersing the adhesion material, so that the material is uniformly distributed and is uniformly heated in the roasting process to help form a nano-pore structure; so that the material can form a stable structure at the lower roasting temperature and in the shorter roasting time in the step (4), and the nitrogen content is improved. Studies have shown that if the amount of graphene oxide added is reduced, the firing reaction may not be complete at low temperatures, affecting the purity of the ferrovanadium nitride. If the added amount of the graphene oxide is increased, excessive impurities can be introduced, and in the subsequent reaction process, the redundant graphene oxide cannot be removed by reaction, and the purity of the vanadium iron nitride can also be influenced.

Further, in the step (2), the ultrasonic frequency is 20-22 KHz.

Further, in the step (1), the stirring speed is 500-800 rpm/min.

Further, in the step (1), the vanadium source compound is at least one of vanadium pentoxide, ammonium metavanadate, vanadium dioxide and vanadium trioxide.

Further, in the step (1), the iron source compound is at least one of iron sesquioxide and ferroferric oxide.

Further, in the step (1), the reducing agent is at least one of oxalic acid and formic acid.

Further, in the step (4), the flow rate of the nitrogen gas may be 100-150m³/h。

The atmosphere used by the method is high-purity gas, and the purity is more than or equal to 99.99 percent.

In the step (3), the nitrogen content in the alloy can be increased by adopting rapid cooling.

The technical principle of the method is as follows: according to the invention, an acidic reducing agent and a vanadium-containing compound are used for generating a soluble compound, after an iron source is added, a solution gel method is used for obtaining uniform gel, sol is evaporated to dryness, and a small amount of graphene oxide is added, and we surprisingly find that the graphene oxide can be added into solid powder and can be compounded with raw materials, so that a large specific surface area is provided for effectively dispersing and adhering materials, the materials are uniformly distributed, and the materials are uniformly heated in the roasting process to help to form a nano-pore structure; because all elements in the solution are uniformly distributed and the pores are moderate, in the subsequent low-temperature roasting process, nitrogen elements in nitrogen enter the pores of the solid powder, the nitrogen-containing proportion of a final product can be improved, the temperature required by nitrogen fixation is low, the structure of the nitrided ferrovanadium alloy can be effectively stabilized, the performance of the nitrided ferrovanadium alloy can be improved, and the purity of the obtained product can be improved. Due to the fact that the addition amount of the graphene oxide is very small, the purity of a final product is not influenced while the performance of the material is improved, the performance of the obtained product is more stable, and the fluctuation range of the percentage content of the element is smaller. Furthermore, a part of the graphene oxide may be chemically reacted during the baking process to form carbon dioxide gas to be volatilized out.

In the invention, in the obtained vanadium nitride ferrovanadium alloy, the weight percentage of vanadium element is 69.5-71.0%, and the weight percentage of nitrogen element is 17.8-18.0%; the balance of iron and inevitable impurities, and the purity of the alloy is more than 99.2 percent.

Compared with the prior art, the invention at least has the following beneficial effects:

(1) according to the invention, citric acid is added, and through a solution gel method, the nitrogen content in the ferrovanadium nitride can be improved, the purity of the product can be effectively improved, the content of impurity elements such as oxygen and carbon is reduced, and the ferrovanadium nitride alloy product with excellent quality and high quality is obtained;

(2) the ferrovanadium nitride prepared by the method has higher specific gravity, and is more favorable for controlling the stability and accuracy of vanadium;

(3) the method has the advantages of simple process, common equipment, low energy consumption and low cost in the preparation process of the ferrovanadium nitride, and is more suitable for the production process of the microalloy steel.

Detailed Description

The present invention will be described in further detail with reference to specific examples. The following examples are merely illustrative of the present invention and do not represent or limit the scope of the claims, which are defined by the claims.

Example 1

The preparation method of the high-quality low-cost vanadium nitride ferroalloy of the embodiment comprises the following steps:

(1) adding vanadium pentoxide, ferroferric oxide and oxalic acid into deionized water, and stirring to obtain a mixed solution; wherein the molar ratio of the vanadium element, the iron element and the reducing agent is 4: 1: 0.7;

the concentration of vanadium ions in the mixed solution is 0.3 mol/L; the yield is reduced when the concentration is too low, and the gel is not generated when the concentration is too high; the stirring rate was 500 rpm/min.

(2) Adding citric acid into the obtained mixed solution, and carrying out ultrasonic stirring reaction for 4 hours to obtain uniform sol;

the mass ratio of the citric acid to the metal ion in the mixed solution in the step (2) is 3: 1.

The homogeneous mixed material can be obtained by using a solution gel method, the stability of the mixed material can be obviously improved, and the nitrogen content can be improved.

The ultrasonic frequency is 20 KHz.

(3) Drying the sol obtained in the step (2) to obtain dry gel, and grinding the dry gel into powder to obtain solid powder;

(4) and (4) adding graphene oxide which accounts for 0.06 percent of the weight of the solid powder into the solid powder obtained in the step (3), roasting for 5 hours at 360 ℃ in a nitrogen atmosphere, and then quenching to room temperature to obtain the vanadium nitride iron alloy.

The flow rate of nitrogen gas may be 100m³/h。

Through detection, according to the mass percentage, the nitrogen element in the nitrided ferrovanadium product obtained in the embodiment accounts for 17.9 wt% of the mass of the nitrided ferrovanadium, the vanadium element accounts for 70.9 wt% of the mass of the nitrided ferrovanadium, and the purity of the alloy is 99.6%.

Example 2

The preparation method of the high-quality low-cost vanadium nitride ferroalloy of the embodiment comprises the following steps:

(1) adding ammonium metavanadate, ferric oxide and oxalic acid into deionized water, and stirring to obtain a mixed solution; wherein the molar ratio of the vanadium element, the iron element and the reducing agent is 4: 1.1: 0.8;

the concentration of vanadium ions in the mixed solution is 0.4 mol/L; the yield is reduced when the concentration is too low, and the gel is not generated when the concentration is too high; the stirring rate was 800 rpm/min.

(2) Adding citric acid into the obtained mixed solution, and carrying out ultrasonic stirring reaction for 5 hours to obtain uniform sol;

the mass ratio of the citric acid to the metal ion in the mixed solution in the step (2) is 2: 1.

The homogeneous mixed material can be obtained by using a solution gel method, the stability of the mixed material can be obviously improved, and the nitrogen content can be improved.

The ultrasonic frequency is 22 KHz.

(3) Drying the sol obtained in the step (2) to obtain dry gel, and grinding the dry gel into powder to obtain solid powder;

(4) and (4) adding graphene oxide which accounts for 0.08 percent of the weight of the solid powder into the solid powder obtained in the step (3), roasting for 5 hours at 370 ℃ in a nitrogen atmosphere, and then quenching to room temperature to obtain the vanadium nitride iron alloy.

The flow rate of nitrogen gas is 150m³/h。

Through detection, according to the mass percentage, the nitrogen element in the nitrided ferrovanadium product obtained in the embodiment accounts for 17.8 wt% of the mass of the nitrided ferrovanadium, the vanadium element accounts for 69.5 wt% of the mass of the nitrided ferrovanadium, and the purity of the alloy is 99.3%.

Example 3

The preparation method of the high-quality low-cost vanadium nitride ferroalloy of the embodiment comprises the following steps:

(1) adding vanadium dioxide, ferric oxide and formic acid into deionized water, and stirring to obtain a mixed solution; wherein the molar ratio of the vanadium element, the iron element and the reducing agent is 4: 1.1: 0.7;

the concentration of vanadium ions in the mixed solution is 0.4 mol/L; the yield is reduced when the concentration is too low, and the gel is not generated when the concentration is too high; the stirring rate was 800 rpm/min.

(2) Adding citric acid into the obtained mixed solution, and carrying out ultrasonic stirring reaction for 4 hours to obtain uniform sol;

the mass ratio of the citric acid to the metal ion in the mixed solution in the step (2) is 3: 1.

The homogeneous mixed material can be obtained by using a solution gel method, the stability of the mixed material can be obviously improved, and the nitrogen content can be improved.

The ultrasonic frequency is 22 KHz.

(3) Drying the sol obtained in the step (2) to obtain dry gel, and grinding the dry gel into powder to obtain solid powder;

(4) and (4) adding graphene oxide which accounts for 0.07 percent of the weight of the solid powder into the solid powder obtained in the step (3), roasting for 6 hours at 370 ℃ in a nitrogen atmosphere, and then quenching to room temperature to obtain the vanadium nitride iron alloy.

The flow rate of nitrogen can be 150m³/h。

Through detection, according to the mass percentage, the nitrogen element in the nitrided ferrovanadium product obtained in the embodiment accounts for 17.8 wt% of the mass of the nitrided ferrovanadium, the vanadium element accounts for 69.5 wt% of the mass of the nitrided ferrovanadium, and the purity of the alloy is 99.2%.

Comparative example 1

Compared with the example 1, the conditions are the same as the example 1 except that the concentration of vanadium ions in the mixed solution in the step (1) is 0.20 mol/L.

Through detection, according to the mass percentage, the nitrogen element in the vanadium nitride iron product obtained by the comparative example accounts for 15.3 wt% of the mass of the vanadium nitride iron, the vanadium element accounts for 67.8 wt% of the mass of the vanadium nitride iron, and the purity of the alloy is 94.2%.

Comparative example 2

Compared with the example 1, the step (2) is not added with citric acid; gel cannot be formed in the step (2), the drying difficulty in the step (3) is high, high temperature is required, and the drying time is long.

And detecting to obtain an uneven nitrided ferrovanadium product. According to the mass percentage, the nitrogen element in the ferrovanadium nitride product obtained in the comparative example accounts for 12.2 wt% of the mass of the ferrovanadium nitride, the vanadium element accounts for 64.2 wt% of the mass of the ferrovanadium nitride, and the purity of the alloy is 91.0%.

Comparative example 3

Compared with example 1, except that the amount ratio of citric acid to metal ion in the mixed solution in step (2) was 1: 1. Other conditions were exactly the same as in example 1.

Through detection, according to the mass percentage, the nitrogen element in the vanadium nitride iron product obtained by the comparative example accounts for 13.5 wt% of the mass of the vanadium nitride iron, the vanadium element accounts for 66.8 wt% of the mass of the vanadium nitride iron, and the purity of the alloy is 97.2%. It can be seen that too little citric acid is added to prevent gel formation.

Comparative example 4

Compared with example 1, except that the amount ratio of citric acid to metal ion in the mixed solution in step (2) was 4: 1. Other conditions were exactly the same as in example 1.

Through detection, according to the mass percentage, the nitrogen element in the vanadium nitride iron product obtained by the comparative example accounts for 13.9 wt% of the mass of the vanadium nitride iron, the vanadium element accounts for 68.5 wt% of the mass of the vanadium nitride iron, and the purity of the alloy is 98.5%. It can be seen that too much citric acid added can also affect the quality of the final product. Probably because the pH of the product is affected.

Comparative example 5

Compared with example 1, the conditions were exactly the same as example 1 except that graphene oxide was not added in step (4).

And detecting to obtain the nitrided ferrovanadium alloy. If the roasting temperature in the step (4) is increased to more than 500 ℃, the ferrovanadium nitride alloy can be obtained, and according to the mass percentage, the nitrogen element in the obtained ferrovanadium nitride product accounts for 16.5 wt% of the mass of the ferrovanadium nitride, the vanadium element accounts for 66.2 wt% of the mass of the ferrovanadium nitride, and the purity of the alloy is 98.1%. The addition of the graphene oxide can reduce the roasting temperature.

Comparative example 6

The conditions were exactly the same as in example 1 except that the sonication time in step (2) was 3 hours, compared to example 1.

Through detection, the nitrogen element in the obtained vanadium nitride ferrovanadium product accounts for 16.8 wt% of the mass of the vanadium nitride ferrovanadium, the vanadium element accounts for 67.2 wt% of the mass of the vanadium nitride ferrovanadium, and the purity of the alloy is 98.5%. It can be seen that the ultrasonic time is not enough, the sol is not uniform enough, and the quality and purity of the final vanadium iron nitride product are affected.