Method for smelting metal crude vanadium from calcium vanadate and crude vanadium

Abstract

The invention relates to the technical field of metallurgy, and discloses a method for smelting metal coarse vanadium from calcium vanadate, which comprises the following steps: S1, weighing calcium vanadate, aluminum particles and calcium particles according to the proportion; s2, calcium vanadate and aluminum particles are put into a mixer to be mixed, and a mixture is obtained; s3, calcium particles are laid at the bottom of a graphite crucible, then the mixture is laid, a metal thermal reduction reaction is triggered through ignition of an ignition agent, and after the temperature of the surface of the graphite crucible is reduced to a first temperature, the crucible is cooled in a water bath; and S4, after the metal surface is cooled to a second temperature, disassembling the furnace and removing slag to obtain metal crude vanadium. According to the method, calcium vanadate is adopted as a raw material, Al and Ca are used as reducing agents for preparing the metal crude vanadium, the obtained slag system is lower in melting point, lower in viscosity and good in slag and gold separation effect, meanwhile, the aluminum oxygen content in the metal crude vanadium is lower, and purification and refining of the metal crude vanadium in the next step are better facilitated. The invention also provides the crude vanadium prepared by the method.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a method for smelting crude vanadium with calcium vanadate and the crude vanadium. Background Art

[0002] Vanadium is a rare metal with strategic significance. Because of its good plasticity, corrosion resistance, low neutron irradiation activity and excellent high temperature strength, it has been widely used in aerospace, steel, energy, nuclear power and other fields. The preparation of metallic vanadium is generally divided into two steps, namely, firstly, by calcium thermal reduction method, magnesium thermal reduction method, vacuum carbon thermal reduction method or aluminum thermal reduction method and other preparation techniques to obtain metallic crude vanadium containing certain impurities, and then by molten salt electrolysis, electron beam refining and other methods to purify and refine the metallic crude vanadium to obtain high-purity metallic vanadium. However, the methods of the prior art have corresponding defects. For example, magnesium thermal reduction of vanadium chloride method can produce high-purity vanadium powder, but because vanadium chloride has a variety of existence forms, different existence forms can react and transform with each other, and different precursors have different corresponding reaction heat effects and yields, and reaction regulation is more difficult. On the other hand, vanadium chloride is easy to absorb moisture, and its stability is not as good as oxides, and it has certain requirements for the storage environment.

[0003] Therefore, there is a need in the prior art for improving the method of smelting crude vanadium metal with calcium vanadate. Summary of the invention

[0004] In view of this, the purpose of the embodiment of the present invention is to propose a method for smelting crude vanadium metal with calcium vanadate, using calcium vanadate as a raw material and Al and Ca as reducing agents to prepare crude vanadium metal. The resulting slag system has a lower melting point and a smaller viscosity, and the slag and gold separation effect is good. At the same time, the aluminum oxygen content in the crude vanadium metal is lower, which is more conducive to the purification and refining of the crude vanadium metal in the next step.

[0005] Based on the above purpose, an embodiment of the present invention provides a method for smelting crude vanadium metal using calcium vanadate, comprising: S1 weighs calcium vanadate, aluminum particles and calcium particles according to the ratio; S2: putting calcium vanadate and aluminum particles into a mixer and mixing them to obtain a mixture; S3: spreading calcium particles on the bottom of the graphite crucible and then spreading the mixture, igniting the ignition agent to trigger the metal thermal reduction reaction, and cooling the crucible in a water bath after the temperature of the surface of the graphite crucible drops to the first temperature; S4 After the metal surface is cooled to the second temperature, the furnace is dismantled and the slag is removed to obtain crude vanadium metal.

[0006] In some embodiments, in S1, the ratio of calcium vanadate, aluminum particles and calcium particles is 100: (34-36): (4-8) by mass.

[0007] In some embodiments, in S1, the particle size of calcium vanadate is ≤1 mm, the particle size of aluminum particles is 1-3 mm, and the particle size of calcium particles is 2-4 mm.

[0008] In some embodiments, in S1, the purity of calcium vanadate is ≥99.0%, wherein Fe≤0.08%, Si≤0.08%; the purity of aluminum particles is ≥99.7%, wherein Fe≤0.01%, Si≤0.01%; the purity of calcium particles is ≥99.0%, Fe≤0.10%, Si≤0.10%.

[0009] In some embodiments, in S2, the time for mixing calcium vanadate and aluminum particles in the mixer is 10 to 20 minutes.

[0010] In some embodiments, in S3, the ignition agent is prepared by mixing aluminum powder and potassium chlorate, and the molar ratio of the aluminum powder to the potassium chlorate is (1.8-2):1.

[0011] In some embodiments, in S3, the first temperature is 700-900°C.

[0012] In some embodiments, in S4, the second temperature is 60-90°C.

[0013] In some embodiments, in S4, in the crude metallic vanadium, by weight percentage, V≥95.0wt%, Fe≤0.10wt%, Si≤0.10wt%, C≤0.06wt%, N≤0.04wt%, O≤1.0wt%, and Al≤0.7wt%.

[0014] In another aspect, the present invention provides crude vanadium prepared by the above method.

[0015] The present invention has at least the following beneficial technical effects: The present invention uses calcium vanadate as a raw material and uses Al and Ca as reducing agents to prepare crude vanadium metal. The reaction is an exothermic reaction, and the heat released by the reaction can make the reaction proceed spontaneously. The Al generated by the reaction 2 The O-CaO binary slag system is more efficient than the Al- 2 O 3 , has a lower melting point and smaller viscosity, so it is more conducive to the separation of slag and gold, and improves the vanadium yield. At the same time, it can also better isolate the air and reduce the oxidation and nitridation of crude vanadium during the cooling process. Compared with using vanadium oxide as raw material and then adding calcium oxide to adjust the slag system, the slag system composition of calcium vanadate is more uniform, and the release of reaction heat is more stable and controllable. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is a flow chart of an embodiment of the method for smelting crude vanadium metal with calcium vanadate provided by the present invention. DETAILED DESCRIPTION

[0018] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0019] The terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions; the terms "first", "second", etc. in the specification and claims of the present invention or the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order. "Multiple" means two or more, unless otherwise clearly and specifically defined.

[0020] In addition, reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0021] The existing crude vanadium preparation processes include calcium thermal reduction, magnesium thermal reduction, vacuum carbon thermal reduction, aluminum thermal reduction, etc. However, there are many problems and shortcomings.

[0022] The calcium thermal reduction method is usually used to reduce refractory metal oxides in a molten salt medium to prepare metal powders. 2 In the molten salt system, a thermal reduction reaction is carried out by adding a reducing agent, metallic calcium. This method has the following problems: (1) Product hardness and processing difficulty: The metallic vanadium prepared by the calcium thermal reduction method is quite hard, and it is difficult to process it because it contains a high amount of residual impurities. (2) Reaction exotherm: The reaction exotherm of calcium and vanadium oxide is small, which may require additional heating measures or heat enhancers to ensure the complete reaction.

[0023] The raw material of magnesium thermal reduction method is V 2 O 5Or ferrovanadium, the preparation process is mainly to chlorinate the raw materials at 500 ° C to obtain liquid VCl 4 , the main impurity FeCl in the solution is removed by distillation 3 . Use blowing method to make VCl 4 Decomposes into VCl 3 , and then remove VCl by distillation 3 SiCl 4 and VOCl 3 In an argon atmosphere, VCl 3 It is reduced to elemental vanadium by molten magnesium. This method has the following problems: (1) Difficulty in reaction control: Vanadium chloride exists in various forms, and different forms can react and transform with each other. Different precursors have different corresponding reaction heat effects and yields, which makes reaction control more difficult. (2) Difficulty in obtaining raw materials: Although the magnesium thermal reduction method can prepare high-purity vanadium powder, the acquisition of raw materials such as vanadium trioxide is relatively difficult and costly, and is not suitable as a raw material for industrial large-scale production.

[0024] The vacuum carbothermal reduction method usually uses vanadium oxide (such as V 2 O 3 ) as raw materials, and a carbon thermal reduction reaction is carried out under vacuum conditions. This method has the following problems: (1) High equipment requirements: The vacuum carbon thermal reduction method has strict requirements on the reaction equipment, especially in a high-temperature vacuum environment, and has high requirements on the high-temperature strength of the equipment. (2) Long production cycle: The preparation process of this method is long, and the reaction cycle may be as long as dozens of hours, resulting in low production efficiency, high labor consumption, and excessive energy consumption and equipment loss. (3) High production cost: Due to the large one-time investment in equipment and the long production cycle, the production cost of the vacuum carbon thermal reduction method is relatively high.

[0025] The aluminothermic reduction method is to first react metallic aluminum with vanadium oxide (such as V 2 O 5 or V 2 O 3 )Vanadium aluminum alloy is generated by aluminothermic reduction, and then pure metallic vanadium is obtained through subsequent treatment. The specific steps are as follows: Vanadium oxide is mixed with metallic aluminum and an aluminothermic reaction is initiated at high temperature. The vanadium-aluminum alloy generated by the aluminothermic reaction is then subjected to vacuum high temperature or electron beam melting to remove the aluminum in the vanadium-aluminum alloy. Finally, pure metallic vanadium is obtained. This method has the following problems: (1) Complex process flow: The complete process route of aluminothermic reduction-vacuum electron beam melting is complex, and the electron beam refining step is often accompanied by evaporation loss of vanadium and its oxides, and the yield is low. (2) Energy consumption and cost: Although aluminothermic reduction is a commonly used method for preparing metallic vanadium, its energy consumption and cost are relatively high due to its complex process flow and the need for additional purification steps.

[0026] The present invention provides a method for smelting crude vanadium metal using calcium vanadate, comprising the following steps: S1 weighs calcium vanadate, aluminum particles and calcium particles according to the ratio; S2: putting calcium vanadate and aluminum particles into a mixer and mixing them to obtain a mixture; S3: spreading calcium particles on the bottom of the graphite crucible and then spreading the mixture, igniting the ignition agent to trigger the metal thermal reduction reaction, and cooling the crucible in a water bath after the temperature of the surface of the graphite crucible drops to the first temperature; S4 After the metal surface is cooled to the second temperature, the furnace is dismantled and the slag is removed to obtain crude vanadium metal.

[0027] Furthermore, in order to allow the reaction to proceed smoothly and fully, in S1, the ratio of calcium vanadate, aluminum particles and calcium particles is 100: (34-36): (4-8) by mass.

[0028] Furthermore, calcium vanadate (CaV 2 O 6 )’s particle size is ≤1mm, the particle size of aluminum particles is 1~3mm, and the particle size of calcium particles is 2~4mm.

[0029] Furthermore, the purity of calcium vanadate is ≥99.0%, wherein Fe≤0.08%, Si≤0.08%; the purity of aluminum particles is ≥99.7%, wherein Fe≤0.01%, Si≤0.01%; the purity of calcium particles is ≥99.0%, Fe≤0.10%, Si≤0.10%.

[0030] Furthermore, in S2, the time for mixing calcium vanadate and aluminum particles in the mixer is 10 to 20 minutes.

[0031] Furthermore, in order to avoid the introduction of other impurity elements, in S3, the first temperature is 700-900°C, and the ignition agent is prepared by mixing aluminum powder and potassium chlorate in a molar ratio of 1.8-2:1.

[0032] Furthermore, in order to obtain the crude vanadium metal with a dry surface and no moisture, in S4, the second temperature is a surface temperature of the crude vanadium metal of 60-90°C.

[0033] The present invention adopts calcium vanadate (CaV 2 O 6 ) The principle of smelting crude vanadium metal is as follows: 3C 2 O 6 +10Al=5Al 2 O 3 +6V+3CaO,△H 0 298 =-3272.725 kJ The reaction is exothermic, and the heat released by the reaction can make the reaction proceed spontaneously. The Al 2 O-CaO binary slag is more efficient than Al2O3 slag produced by using vanadium oxide as raw material. 2 O 3 , has a lower melting point and smaller viscosity, so it is more conducive to the separation of slag and gold, and improves the vanadium yield. At the same time, it can also better isolate the air and reduce the oxidation and nitridation of crude vanadium during the cooling process. Compared with using vanadium oxide as raw material and then adding calcium oxide to adjust the slag system, the slag system composition of calcium vanadate is more uniform, and the release of reaction heat is more stable and controllable.

[0034] At the same time, because there is a reduction limit in metal thermal reactions, the aluminum content in crude vanadium is generally high, which is not conducive to the next step of refining and purification. The patented aluminum content can effectively reduce the aluminum content in crude vanadium, but due to insufficient reduction potential, the oxygen content in crude vanadium will also increase. Therefore, an appropriate amount of calcium with strong reducing properties is added to the bottom of the crucible, which can further deoxidize the crude vanadium during the floating process.

[0035] The present invention will be further explained below in conjunction with specific embodiments.

[0036] Example 1 Weigh 5kg of calcium vanadate (CaV 2 O 6 ) (purity of 99.3%, including 0.07% Fe and 0.06% Si, and particle size ≤1mm), 1.7kg aluminum particles (purity of 99.7%, including 0.009% Fe and 0.01% Si, and particle size 1-2mm) and 0.2kg calcium particles (purity of 99.1%, 0.08% Fe and 0.09% Si, and particle size 2-3mm), mix the weighed calcium vanadate and aluminum particles in a mixer for 10 minutes, spread the weighed calcium particles evenly on the bottom of the graphite crucible and then load the mixed materials, ignite the ignition agent (aluminum powder and potassium chlorate mixed in a molar ratio of 1.8:1) to trigger the metal thermal reduction reaction, when the surface temperature of the crucible drops to 700℃, put the crucible into water for cooling, and when the surface temperature of the crude vanadium metal is cooled to 60℃, dismantle the furnace and clean the slag to obtain crude vanadium metal.

[0037] After testing, the V content in the crude vanadium metal was 95.2wt%, Fe was 0.09wt%, Si was 0.08wt%, C was 0.05wt%, N was 0.04wt%, O was 0.9wt%, and Al was 0.6wt%.

[0038] Example 2 Weigh 10kg of calcium vanadate (CaV 2 O 6) (purity ≥99.5%, of which Fe is 0.06%, Si is 0.05%, and particle size is ≤1mm), 3.6kg aluminum particles (purity is 99.8%, of which F is 0.008%, Si is 0.009%, and particle size is 2~3mm) and 0.8kg calcium particles (purity is 99.0%, Fe is 0.09%, Si is 0.10%, and particle size is 3~4mm), the weighed calcium vanadate and aluminum particles are mixed in a mixer for 15 minutes, the weighed calcium particles are evenly spread on the bottom of the graphite crucible and then the mixed materials are loaded, the ignition agent (aluminum powder and potassium chlorate are mixed in a molar ratio of 2:1) is ignited to trigger the metal thermal reduction reaction, and when the surface temperature of the crucible drops to 900℃, the crucible is placed in water for cooling, and when the surface temperature of the crude vanadium metal is cooled to 90℃, the furnace is dismantled and the slag is removed to obtain the crude vanadium metal.

[0039] After testing, the V content in the crude vanadium metal was 95.3wt%, Fe was 0.08wt%, Si was 0.07wt%, C was 0.06wt%, N was 0.04wt%, O was 0.8wt%, and Al was 0.7wt%.

[0040] Example 3 Example 1: Weighing 20 kg of calcium vanadate (CaV 2 O 6 ) (purity of 99.0%, including 0.08% Fe and 0.07% Si, and particle size ≤1mm), 7kg aluminum particles (purity of 99.7%, including 0.01% Fe and 0.009% Si, and particle size 1-2mm) and 1.2kg calcium particles (purity of 99.2%, 0.09% Fe and 0.08% Si, and particle size 3-4mm), mix the weighed calcium vanadate and aluminum particles in a mixer for 20 minutes, spread the weighed calcium particles evenly on the bottom of the graphite crucible and then load the mixed materials, ignite the ignition agent (aluminum powder and potassium chlorate mixed in a molar ratio of 1.9:1) to trigger the metal thermal reduction reaction, and when the surface temperature of the crucible drops to 800℃, put the crucible into water for cooling, and when the surface temperature of the crude vanadium metal is cooled to 80℃, dismantle the furnace and clean the slag to obtain crude vanadium metal.

[0041] After testing, the V content in the crude vanadium metal was 95.3wt%, Fe was 0.09wt%, Si was 0.09wt%, C was 0.05wt%, N was 0.04wt%, O was 0.9wt%, and Al was 0.7wt%.

[0042] The above are exemplary embodiments disclosed in the present invention, but it should be noted that various changes and modifications may be made without departing from the scope disclosed in the embodiments of the present invention as defined in the claims. The functions, steps and / or actions of the method claims according to the disclosed embodiments described herein do not need to be performed in any particular order. In addition, although the elements disclosed in the embodiments of the present invention may be described or required in individual form, they may also be understood as multiple unless explicitly limited to the singular.

[0043] It should be understood that, as used herein, the singular forms "a", "an" are intended to include the plural forms as well, unless the context clearly supports an exception. It should also be understood that, as used herein, "and / or" refers to any and all possible combinations including one or more of the associated listed items.

[0044] The serial numbers of the embodiments disclosed in the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0045] A person skilled in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the above embodiments of the present invention, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the embodiments of the present invention.

Claims

1. A method for smelting crude vanadium metal with calcium vanadate, characterized in that: include: S1 weighs calcium vanadate, aluminum particles and calcium particles according to the ratio; S2 putting the calcium vanadate and the aluminum particles into a mixer and mixing them to obtain a mixture; S3: spreading the calcium particles on the bottom of a graphite crucible and then spreading the mixture, igniting the ignition agent to trigger a metal thermal reduction reaction, and cooling the crucible in a water bath after the temperature of the surface of the graphite crucible drops to a first temperature; S4 After the metal surface is cooled to the second temperature, the furnace is dismantled and the slag is removed to obtain crude vanadium metal.

2. The method for smelting crude vanadium metal with calcium vanadate according to claim 1, characterized in that: In S1, the ratio of the calcium vanadate, aluminum particles and calcium particles is 100: (34-36): (4-8) by mass.

3. The method for smelting crude vanadium metal with calcium vanadate according to claim 1, characterized in that: In S1, the particle size of the calcium vanadate CaV2O6 is ≤1 mm, the particle size of the aluminum particles is 1-3 mm, and the particle size of the calcium particles is 2-4 mm.

4. The method for smelting crude vanadium metal with calcium vanadate according to claim 1, characterized in that: In S1, the purity of calcium vanadate is ≥99.0%, of which Fe≤0.08% and Si≤0.08%; the purity of aluminum particles is ≥99.7%, of which Fe≤0.01% and Si≤0.01%; the purity of calcium particles is ≥99.0%, Fe≤0.10% and Si≤0.10%.

5. The method for smelting crude vanadium metal with calcium vanadate according to claim 1, characterized in that: In S2, the calcium vanadate and aluminum particles are mixed in the mixer for 10 to 20 minutes.

6. The method for smelting crude vanadium metal with calcium vanadate according to claim 1, characterized in that: In S3, the ignition agent is prepared by mixing aluminum powder and potassium chlorate, and the molar ratio of the aluminum powder to potassium chlorate is (1.8-2):

1.

7. The method for smelting crude vanadium metal with calcium vanadate according to claim 1, characterized in that: In S3, the first temperature is 700-900°C.

8. The method for smelting crude vanadium metal with calcium vanadate according to claim 1, characterized in that: In S4, the second temperature is 60-90°C.

9. The method for smelting crude vanadium metal with calcium vanadate according to claim 1, characterized in that: In S4, in the crude metal vanadium, by weight percentage, V≥95.0wt%, Fe≤0.10wt%, Si≤0.10wt%, C≤0.06wt%, N≤0.04wt%, O≤1.0wt%, and Al≤0.7wt%.

10. A crude vanadium, characterized in that: Prepared by the method according to any one of claims 1 to 9.

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