Method for preparing vanadium-titanium product from dechlorinated tailings

Abstract

The invention provides a method for preparing a vanadium-titanium product from dechlorinated tailings, which comprises the following steps: placing the dechlorinated tailings in a reactor, and carrying out carbonitriding treatment in the reactor through reaction gas to obtain the vanadium-titanium product, the reaction gas comprises a carbon source gas or a mixed system of the carbon source gas and a nitrogen source gas. Aiming at the technical problems that vanadium and titanium in titanium tetrachloride dechlorination tailings are not easy to separate, the comprehensive utilization rate is relatively low, the process flow is relatively long and the like, the invention provides the method for preparing the vanadium-titanium product from the dechlorination tailings, and the dechlorination tailings are subjected to carbonitriding treatment by using a carbon source gas or a mixed system of the carbon source gas and a nitrogen source gas; and therefore, high-quality vanadium-titanium products are obtained, high-added-value recycling of the dechlorinated tailings is achieved, and resource waste is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a method for preparing vanadium-titanium products from dechlorinated tailings. Background Art

[0002] Vanadium-titanium alloy is an important alloy material with high hardness. It has potential application value in the field of wear-resistant materials. It can also be added to steel as a micro-alloying additive to refine grains and improve comprehensive mechanical properties. In addition, it can also be used as a carbide cemented carbide additive to significantly improve the hardness, wear resistance and heat resistance of cemented carbide. At present, there is no report on the direct carbonitriding process of titanium tetrachloride dechlorination tailings.

[0003] The Chinese patent with publication number CN116121539A discloses a method for extracting vanadium from titanium tetrachloride refined tailings by water leaching, which comprises the following steps: adding a leaching agent to a vanadium-containing raw material, stirring and leaching for 15 to 180 minutes at 20 to 98°C, and then separating the solid and liquid to obtain a vanadium-containing leachate and a leaching residue. The Chinese patent with publication number CN112981141A discloses a method for preparing ferrovanadium alloy from titanium tetrachloride refined tailings, which comprises the following steps: (1) crushing and grinding the titanium tetrachloride refined tailings, oxidizing and roasting in a rotary kiln to obtain vanadium-containing roasted clinker; (2) mixing the vanadium-containing roasted clinker and vanadium oxide with iron particles, a reducing agent, a slag-making agent, and a heating agent to obtain a ferrovanadium smelting mixture, and then evenly distributing the ferrovanadium smelting mixture in a smelting furnace for smelting; (3) after the smelting is completed, the furnace body, slag, and gold are naturally cooled, and then the furnace is dismantled and the slag and gold are separated to obtain ferrovanadium alloy cakes and smelting slag. Chinese patent publication number CN114293019A discloses a method for extracting vanadium from titanium tetrachloride refined tailings, the method comprising: (1) roasting the titanium tetrachloride refined tailings at 100-300°C for 5-30 minutes to obtain pre-treated slag; (2) mixing the pre-treated slag obtained in step (1) with sodium carbonate, roasting at 600-900°C for 60-120 minutes to obtain roasted clinker; (3) adding water to the roasted clinker obtained in step (2), stirring and leaching, and then separating the solid and liquid to obtain a vanadium-containing leaching solution and a leaching residue.

[0004] From the above-mentioned patent disclosure, it can be seen that the comprehensive treatment direction of titanium tetrachloride dechlorination tailings is mainly to recycle vanadium in the slag by wet leaching or pyrometallurgy, while titanium in the slag is difficult to be effectively separated and utilized, and there is no report on the relevant process of carbonitridation treatment of titanium tetrachloride dechlorination tailings. Therefore, it is of great significance to provide a carbonitridation treatment of titanium tetrachloride dechlorination tailings to realize the recycling of vanadium and titanium. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a method for preparing vanadium-titanium products from dechlorinated tailings. The method provided in the present application can realize the selective carbonization and nitridation of vanadium and titanium in the dechlorinated tailings, thereby realizing the preparation of vanadium-titanium products.

[0006] In view of this, the present application provides a method for preparing vanadium-titanium products from dechlorinated tailings, comprising the following steps:

[0007] The dechlorination tailings are placed in a reactor, and carbonitridation treatment is carried out by passing a reaction gas into the reactor to obtain a vanadium-titanium product; the reaction gas includes a carbon source gas or a mixed system of a carbon source gas and a nitrogen source gas.

[0008] Preferably, the carbonitriding treatment is specifically:

[0009] First, the temperature is raised to 500-600°C at a heating rate of 10-15°C / min, and then raised to 900-2000°C at a heating rate of 5-8°C / min. After heat preservation, the protective gas is continuously introduced and the mixture is cooled.

[0010] Preferably, the dechlorination tailings contain 5 to 50 wt% V, 5 to 50 wt% Ti, and 0.5 to 10 wt% C.

[0011] Preferably, the carbon source gas includes one or more of CH4, C2H6 and C3H8, and the nitrogen source gas includes one or more of N2 and NH3.

[0012] Preferably, the flow ratio of the carbon source gas to the nitrogen source gas is (10:0) to (5:5).

[0013] Preferably, the flow ratio of the carbon source gas to the nitrogen source gas is (1-5):1.

[0014] Preferably, the flow rate of the carbon source gas is 0.2 to 1.0 L / min.

[0015] Preferably, the protective gas is a carbon source gas, a nitrogen source gas, or an inert gas other than the carbon source gas and the nitrogen source gas.

[0016] Preferably, the insulation temperature is 900-1600° C., the time is 1-3 hours, and the cooling is to below 200° C.

[0017] Preferably, the vanadium-titanium product includes a mixture of VC, V2O5 and TiO2, a mixture of VC and TiO2, a mixture of VC and TiC, a mixture of VC, VN and TiC, and a mixture of VN and TiN.

[0018] The present application provides a method for preparing vanadium-titanium products from dechlorinated tailings, which comprises placing the dechlorinated tailings in a reactor, and subjecting the reactor to carbonitriding treatment by reaction gas to obtain the vanadium-titanium products. In the method provided by the present application, a cracking reaction of a carbon source gas or a mixed gas of a carbon source gas and a nitrogen source gas is utilized, so that high-activity newly cracked carbon atoms or a combination of carbon atoms and nitrogen atoms undergo high-speed carburizing or carburizing and nitriding combined with carburizing and nitriding, thereby achieving the preparation of the vanadium-titanium products. Furthermore, the present application adjusts the equilibrium state of the carburizing and nitriding reactions by controlling the gas flow rate and the insulation time of the carbonitriding treatment, thereby adjusting the residual carbon and residual oxygen content in the reaction product, thereby achieving the control of the components in the vanadium-titanium products. DETAILED DESCRIPTION

[0019] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0020] In view of the technical problems that vanadium and titanium in titanium tetrachloride dechlorination tailings are difficult to separate, the comprehensive utilization rate is low, and the process flow is long, the present invention provides a method for preparing vanadium-titanium products from dechlorination tailings, which uses a carbon source gas (such as CH4) to carburize the dechlorination tailings, and uses a carbon source gas (such as CH4) and a nitrogen source gas (such as NH3) to carburize and nitride the dechlorination tailings, so that the carbon source gas and the nitrogen source gas are cracked at a specific temperature, and high-activity newly cracked carbon atoms and nitrogen atoms are used for high-speed carburization and nitriding, and further by controlling the reaction temperature to achieve selective carbonization and nitridation of vanadium and titanium in the dechlorination tailings, by controlling the reaction gas flow rate and the insulation time to adjust the carburization and nitriding to the equilibrium state, and then adjust the residual carbon and residual oxygen content in the reaction product, so as to achieve the one-step preparation of high-quality vanadium-titanium products, and control the content of components in the product, so as to achieve high-value-added recycling of dechlorination tailings and reduce resource waste. Specifically, the embodiment of the present invention discloses a method for preparing vanadium-titanium products from dechlorination tailings, comprising the following steps:

[0021] The dechlorination tailings are placed in a reactor, and carbonitridation treatment is carried out by passing a reaction gas into the reactor to obtain a vanadium-titanium product; the reaction gas includes a carbon source gas or a mixed system of a carbon source gas and a nitrogen source gas.

[0022] In the method for preparing vanadium-titanium products from dechlorinated tailings, the dechlorinated tailings are specifically titanium tetrachloride refined tailings, wherein the V content is 5-50wt%, the Ti content is 5-50wt%, and the C content is 0.5-10wt%. Specifically, the V content in the dechlorinated tailings is 21-45wt%, the Ti content is 20-40wt%, and the C content is 0.5-5wt%.

[0023] The present application first places the dechlorination tailings in a reactor, specifically, the reactor is a quartz boat, and then places the reactor in an atmosphere tube furnace.

[0024] After the above preparation, the reaction gas is introduced into the tubular furnace for carbonitriding treatment. In this process, the carbonitriding treatment is specifically as follows:

[0025] Passing a reaction gas into the tube furnace, removing the air in the tube furnace and adjusting the gas flow rate to a gas flow rate required for the reaction;

[0026] Then the furnace temperature is raised to the reaction temperature in stages and kept warm. After the insulation is completed, the heating is stopped, and the reaction gas or inert gas is continued to be introduced as a protective gas to maintain the oxygen partial pressure in the furnace, and the obtained sample is cooled.

[0027] In the above-mentioned carbonitriding treatment, the reaction gas includes a carbon source gas or a mixed system of a carbon source gas and a nitrogen source gas; the carbon source gas includes one or more of CH4, C2H6 and C3H8, and the nitrogen source gas includes one or more of N2 and NH3; specifically, the carbon source gas is selected from CH4, and the nitrogen source gas is selected from N2 or NH3; more specifically, the reaction gas is a gas system of CH4, CH4 and N2 or a gas system of CH4 and NH3. The flow ratio of the carbon source gas to the nitrogen source gas is (10:0) to (5:5), and specifically, the flow ratio of the carbon source gas to the nitrogen source gas is (1 to 5): 1. In a specific embodiment, the flow ratio of the carbon source gas to the nitrogen source gas is 10:0, 8:2, 5:5; more specifically, the flow ratio of CH4 and NH3 is 10:0, 8:2, 5:5; the flow ratio of CH4 and N2 is 8:2 or 5:5. The flow rate of the carbon source gas is 0.2 to 1.0 L / min. Specifically, the flow rate of the carbon source gas is 0.5 to 0.8 L / min.

[0028] The above-mentioned heating process is specifically as follows: heating to 500-600°C at a heating rate of 10-15°C / min, then heating to 900-2000°C at a heating rate of 5-8°C / min, and keeping at 1100-2000°C; specifically, heating from 20°C to 500-600°C at a heating rate of 10-12°C / min, then heating from 500-600°C to 1200-1600°C at a heating rate of 5-6°C / min, and keeping at 1200-1600°C. The insulation temperature is 900-2000°C, and the time is 1-5h. Specifically, the insulation temperature is 900-1600°C, and the time is 1-3h. In order to ensure that all Ti and V in the dechlorination tailings are converted into carbides, the heating temperature is ≥1500°C, and the insulation time is 1-3h. The cooling is below 200°C.

[0029] V and Ti in the dechlorination tailings exist in the form of oxides. In the carbon source gas such as methane high-temperature reducing atmosphere, they are V2O3 and TiO2. The reactions are as follows:

[0030] V2O3+5CH4=2VC+3CO+10H2 T>900℃ Theoretical △G<0, the reaction can occur;

[0031] TiO2+3CH4=TiC+2CO+6H2 T≥1500℃ Theoretical △G<0, the reaction can occur;

[0032] CH4=C+2H2;

[0033] Methane carburizing is carburizing using highly active newly generated carbon atoms cracked, and it is beneficial to increase the reactivity of C atoms in a hydrogen atmosphere. Compared with the traditional solid C carburizing reaction, the carburizing temperature can be reduced by about 200°C, and the uniformity of the gas-solid reaction of the carbon source gas is controllable. The above carburizing reactions are all endothermic reactions. As the reaction temperature increases, the reaction rate increases and the equilibrium shifts to the right, which is beneficial to the formation of carbonized products. Increasing the reaction gas flow rate can indirectly increase the amount of methane cracking, provide sufficient carbon source and help ensure a reducing atmosphere. When the flow rate is too large, the methane cracking rate may exceed the C consumption rate of the reduction reaction, so that there is free carbon that does not participate in the reaction in the alloy product. Therefore, the methane flow rate of the following embodiments does not exceed 1L / min.

[0034] Since the reaction is an endothermic reaction, extending the holding time is beneficial to the forward progress of the carbonization process, so that the reactants can be completely carbonized. Increasing the reaction temperature to increase the carburizing reaction rate can reduce the holding time accordingly.

[0035] The present invention aims at the technical problems that vanadium and titanium in titanium tetrachloride dechlorination tailings are difficult to separate, the comprehensive utilization rate is low, the process flow is long, etc., and the dechlorination tailings are subjected to carbonitriding treatment by using carbon source gas and nitrogen source gas (such as CH4-NH3 system) to obtain high-quality vanadium-titanium products, thereby realizing high-value-added recycling of the dechlorination tailings and reducing resource waste; the vanadium-titanium nitride product prepared by the present invention can be used as an alloy additive, and the elements such as V, Ti, Fe, C, etc. in the dechlorination tailings can be effectively utilized. At the same time, the dechlorination tailings can be selectively carbonized / nitrided by controlling the reaction conditions to prepare VC-TiO2, VN-TiO2 and other systems, thereby providing a new process direction for the subsequent separation of vanadium and titanium, and having obvious social and economic benefits.

[0036] In order to further understand the present invention, the method for preparing vanadium-titanium products from dechlorinated tailings provided by the present invention is described in detail below in conjunction with examples. The protection scope of the present invention is not limited by the following examples.

[0037] Example 1

[0038] 10 g of dechlorination tailings (including 21.2 wt% of V, 20.8 wt% of Ti, and 0.5 wt% of C) were loaded into a quartz boat as a reactant, and the quartz boat was placed in a tube furnace. Reaction gas was introduced into the tube furnace, and the flow ratio of reaction gas CH4:NH3 was 10:0, and the flow rate of CH4 was 0.2 L / min; the tube furnace was heated from 20°C to 500°C at a heating rate of 10°C / min, and then heated from 500°C to 900°C at a heating rate of 5°C / min, and then kept at 900°C for 1 hour;

[0039] Implementation effect: According to the above test conditions, heating was stopped after the insulation was completed, and the reaction gas was continuously introduced as a protective gas to maintain the oxygen partial pressure in the furnace. The sample was cooled to below 200°C with the furnace to obtain a V(C, O)-TiO2 product, wherein the VC content was 8.2%, the V2O3 content was 33.7%, the TiO2 content was 49.3%, and the C content was 7.1%. In this embodiment, heating was performed at 900°C and insulation was performed for 1h. The temperature and insulation time were insufficient, only a small amount of vanadium carbide phase was generated, and the initial carburizing temperature of TiO2 was not reached. The subsequent embodiments continued to increase the insulation temperature and insulation time.

[0040] Example 2

[0041] 10 g of dechlorination tailings (including 21.2 wt% of V, 20.8 wt% of Ti, and 0.5 wt% of C) were loaded into a quartz boat as a reactant, and the quartz boat was placed in a tube furnace. Reaction gas was introduced into the tube furnace, and the flow rate of reaction gas CH4:NH3 was 10:0, and the flow rate of CH4 was 0.5 L / min; the tube furnace was heated from 20°C to 500°C at a heating rate of 10°C / min, and then heated from 500°C to 1200°C at a heating rate of 5°C / min, and then kept at 1200°C for 3 h;

[0042] Implementation effect: According to the above test conditions, heating was stopped after the insulation was completed, and the reaction gas was continuously introduced as a protective gas to maintain the oxygen partial pressure in the furnace. The sample was cooled to below 200°C with the furnace to obtain a VC-TiO2 product, in which the VC content was 37.7%, the TiO2 content was 54.1%, and the C content was 5.1%. In this embodiment, the vanadium-containing phase was completely converted into vanadium carbide by insulation at 1200°C for 3h. Increasing the temperature, methane flow rate and insulation time were all conducive to promoting the transformation of the vanadium oxygen phase to the vanadium carbide phase, and the product was a VC-TiO2 mixed phase.

[0043] Example 3

[0044] 10 g of dechlorination tailings (including 21.2 wt% of V, 20.8 wt% of Ti, and 0.5 wt% of C) were loaded into a quartz boat as a reactant, and the quartz boat was placed in a tube furnace. Reaction gas was introduced into the tube furnace, and the flow rate of reaction gas CH4:NH3 was 10:0, and the flow rate of CH4 was 1 L / min; the tube furnace was heated from 20°C to 500°C at a heating rate of 10°C / min, and then heated from 500°C to 1500°C at a heating rate of 5°C / min, and then kept at 1500°C for 2 h;

[0045] Implementation effect: According to the above test conditions, heating is stopped after the insulation is completed, and the reaction gas is continuously introduced as a protective gas to maintain the oxygen partial pressure in the furnace. The sample is cooled to below 200°C with the furnace to obtain a (V, Ti) C product, wherein the VC content is 47.5%, the TiC content is 47.9%, and the C content is 2.8%. In this embodiment, the temperature is kept at 1500°C for 2h, at which time the common carburizing temperature of V and Ti is reached, and the demand for reaction gas increases, and at this time, a vanadium-titanium carbide alloy (V, Ti) C is obtained.

[0046] Example 4

[0047] 10 g of dechlorination tailings (including 21.2 wt% of V, 20.8 wt% of Ti, and 0.5 wt% of C) were loaded into a quartz boat as a reactant, and the quartz boat was placed in a tube furnace. Reaction gas was introduced into the tube furnace, and the flow rate of reaction gas CH4:NH3 was 8:2, and the flow rate of CH4 was 1 L / min; the tube furnace was heated from 20°C to 500°C at a heating rate of 10°C / min, and then heated from 500°C to 1500°C at a heating rate of 5°C / min, and then kept at 1500°C for 3 h;

[0048] Implementation effect: According to the above test conditions, heating was stopped after the insulation was completed, and the reaction gas was continued to be introduced as a protective gas to maintain the oxygen partial pressure in the furnace. The sample was cooled to below 200°C with the furnace. At this time, part of VC was converted into VN to obtain V(C, N)-TiC product, in which VC content was 27.3%, VN content was 19.1%, TiC content was 47.5%, and C content was 6%.

[0049] Example 5

[0050] 10 g of dechlorination tailings (including 21.2 wt% of V, 20.8 wt% of Ti, and 0.5 wt% of C) were loaded into a quartz boat as a reactant, and the quartz boat was placed in a tube furnace. Reaction gas was introduced into the tube furnace, and the flow rate of reaction gas CH4:NH3 was 5:5, the flow rate of CH4 was 0.5 L / min, and the flow rate of NH3 was 0.5 L / min; the tube furnace was heated from 20°C to 500°C at a heating rate of 10°C / min, and then from 500°C to 1500°C at a heating rate of 5°C / min, and then kept at 1500°C for 2 h;

[0051] Implementation effect: According to the above test conditions, heating was stopped after the insulation was completed, and the reaction gas was continued to be introduced as a protective gas to maintain the oxygen partial pressure in the furnace. The sample was cooled to below 200°C with the furnace. At this time, the experimental conditions were in the dominant range of vanadium and titanium nitrides, and a (V,Ti)N product was obtained, in which the VN content was 47.1%, the TiN content was 48.2%, and the C content was 3.1%.

[0052] Example 6

[0053] 10 g of dechlorination tailings (including 21.2 wt% of V, 20.8 wt% of Ti, and 0.5 wt% of C) were loaded into a quartz boat as a reactant, and the quartz boat was placed in a tube furnace. Reaction gas was introduced into the tube furnace, and the flow rate of reaction gas CH4:N2 was 8:2, the flow rate of CH4 was 0.8 L / min, and the flow rate of N2 was 0.2 L / min; the tube furnace was heated from 20°C to 500°C at a heating rate of 10°C, and then from 500°C to 1500°C at a heating rate of 5°C / min, and then kept at 1500°C for 3 h;

[0054] Implementation effect: According to the above test conditions, heating was stopped after the insulation was completed, and the reaction gas was continued to be introduced as a protective gas to maintain the oxygen partial pressure in the furnace. The sample was cooled to below 200°C with the furnace to obtain a V(C, N)-TiC product, in which the VC content was 38.1%, the VN content was 10.8%, the TiC content was 47.5%, and the C content was 4%. It can be seen that the nitridation efficiency of N2 as a nitrogen source is lower than that of NH3.

[0055] Example 7

[0056] 10 g of dechlorination tailings (including 21.2 wt% of V, 20.8 wt% of Ti, and 0.5 wt% of C) were loaded into a quartz boat as a reactant, and the quartz boat was placed in a tube furnace. Reaction gas was introduced into the tube furnace, and the flow rate of reaction gas CH4:N2 was 5:5, the flow rate of CH4 was 0.5 L / min, and the flow rate of N2 was 0.5 L / min; the temperature of the tube furnace was increased from 20°C to 500°C at 10°C / min, and then increased from 500°C to 1500°C at 5°C / min, and then kept at 1500°C for 3 h;

[0057] Implementation effect: According to the above test conditions, heating was stopped after the insulation was completed, and the reaction gas was continued to be introduced as a protective gas to maintain the oxygen partial pressure in the furnace. The sample was cooled to below 200°C with the furnace to obtain a (V, Ti) N product with a VN content of 47.1%, a TiN content of 22.1%, a TiC content of 25.8%, and a C content of 3.5%.

[0058] Example 8

[0059] 10 g of dechlorination tailings (including 21.2 wt% of V, 20.8 wt% of Ti, and 0.5 wt% of C) were loaded into a quartz boat as a reactant, and the quartz boat was placed in a tube furnace. Reaction gas was introduced into the tube furnace, and the flow rate of reaction gas CH4:N2 was 5:5, the flow rate of CH4 was 0.5 L / min, and the flow rate of N2 was 0.5 L / min; the tube furnace was heated from 20°C to 500°C at a heating rate of 10°C / min, and then heated from 500°C to 1600°C at a heating rate of 5°C / min, and then kept at 1600°C for 3 h;

[0060] Implementation effect: According to the above test conditions, heating was stopped after the insulation was completed, and the reaction gas was continued to be introduced as a protective gas to maintain the oxygen partial pressure in the furnace. The sample was cooled to below 200°C with the furnace to obtain a (V,Ti)N product with a VN content of 47.3%, a TiN content of 48.3%, and a C content of 3.6%.

[0061] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0062] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing vanadium-titanium products from dechlorinated tailings, comprising the following steps: The dechlorination tailings are placed in a reactor, and carbonitridation treatment is carried out by passing a reaction gas into the reactor to obtain a vanadium-titanium product; the reaction gas includes a carbon source gas or a mixed system of a carbon source gas and a nitrogen source gas.

2. The method according to claim 1, characterized in that The carbonitriding treatment is specifically as follows: First, the temperature is raised to 500-600°C at a heating rate of 10-15°C / min, and then raised to 900-2000°C at a heating rate of 5-8°C / min. After heat preservation, the protective gas is continuously introduced and the mixture is cooled.

3. The method according to claim 1 or 2, characterized in that: The dechlorination tailings have a V content of 5-50 wt %, a Ti content of 5-50 wt %, and a C content of 0.5-10 wt %.

4. The method according to claim 1 or 2, characterized in that: The carbon source gas includes one or more of CH4, C2H6 and C3H8, and the nitrogen source gas includes one or more of N2 and NH3.

5. The method according to claim 4, characterized in that The flow ratio of the carbon source gas to the nitrogen source gas is (10:0) to (5:5).

6. The method according to claim 1 or 5, characterized in that: The flow ratio of the carbon source gas to the nitrogen source gas is (1-5):

1.

7. The method according to claim 6, characterized in that The flow rate of the carbon source gas is 0.2-1.0 L / min.

8. The method according to claim 2, characterized in that: The protective gas is a carbon source gas, a nitrogen source gas, or an inert gas other than the carbon source gas and the nitrogen source gas.

9. The method according to claim 2, characterized in that: The insulation temperature is 900-1600° C., the time is 1-3 hours, and the cooling is to below 200° C.

10. The method according to any one of claims 1 to 9, characterized in that: The vanadium-titanium products include a mixture of VC, V2O5 and TiO2, a mixture of VC and TiO2, a mixture of VC and TiC, a mixture of VC, VN and TiC, and a mixture of VN and TiN.