Method for in-situ generation of CM2A8 high-quality multiphase refractory material

Abstract

The invention relates to the technical field of vanadium metallurgy, and discloses a method for in-situ generation of a CM2A8 high-quality multiphase refractory material, which comprises the following steps: arranging a knotting layer at the bottom of a reaction furnace, arranging a double-layer knotting layer at the side of the reaction furnace, the height of a magnesia layer at the side of the reaction furnace being 2.3-3.5 times of the expected thickness of molten iron to be smelted, and the thickness of a magnesia layer at the side of the reaction furnace being 2.3-3.5 times of the thickness of molten iron to be smelted; spraying a magnesium fireclay sintering layer on the knotting layer of the furnace bottom to prepare a reaction furnace barrel; the content of CaO in the corundum slag is adjusted to be lower than 4%, vanadium pentoxide, the aluminum product and the treated corundum slag are combined into a material, and the material is added into a furnace barrel of the reaction furnace at a time; and carrying out ignition smelting on the filled material to initiate a thermit reaction, after the smelting is finished, immediately blowing a refined material into the molten slag to initiate a secondary thermit reaction to supplement heat, and then cooling to obtain the CM2A8 multiphase refractory material. The method overcomes the defects of high energy consumption and long flow of the traditional method, and the CM2A8 multiphase refractory material with high additional value is synthesized in situ in the thermit reaction process through the coordination of the special furnace barrel structure design and the blowing refining process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vanadium metallurgy, and in particular to a method for in-situ generation of CM2A8 high-quality composite refractory. BACKGROUND

[0002] Corundum slag is a by-product produced during smelting of vanadium-iron alloy, and has the characteristics of large output and great potential for recycling. In the conventional smelting process of vanadium-iron alloy, in order to reduce the aluminum consumption of smelting vanadium-iron, vanadium pentoxide and aluminum beans are mainly used, and vanadium pentoxide is used as an auxiliary. Since the heat output of vanadium trioxide is insufficient, electricity needs to be supplied to supplement the heat to ensure that the reaction proceeds in the forward direction. At the same time, in order to reduce the melting point of the slag and improve the fluidity of the slag, a large amount of lime is often added to slagging. In addition, due to the extension of the smelting time, the low-melting-point slag fully infiltrates the furnace lining, causing more erosion of the furnace lining. As a result, the content of magnesium oxide in the molten slag is relatively high and fluctuates greatly. Therefore, the content of each substance in the corundum slag produced is as follows: aluminum trioxide (65%-75%), magnesium oxide (12-22%), calcium oxide (14-16%), vanadium oxide (1-2%), and other substances (1%). Since the content of aluminum trioxide in the corundum slag is relatively low, the refractoriness and melting point do not meet the requirements of high-end users, and the performance in a high-temperature erosion environment is poor. Therefore, the corundum slag can only be used as a low-value refractory material, which severely limits the expansion of its use range and the improvement of its use value. CM2A8 is a crystalline product composed of Al2O3, MgO, and CaO in a specific ratio. As a composite material with the dual performance advantages of calcium hexaluminate and magnesium aluminate spinel, CM2A8 has good applicability in extreme high-temperature refractory and corrosion-resistant scenarios, and has a wide range of uses and development prospects. According to the data, the preparation of traditional CM2A8 high-quality composite refractory is usually carried out by high-temperature solid-phase sintering of specific proportion of oxide powder. This method has a long process, high energy consumption, complex operation, and high cost.

[0003] Therefore, there is a need for improvement of CM2A8 high-quality composite refractory in the prior art. SUMMARY

[0004] Therefore, the purpose of the embodiments of the present application is to provide a method for in-situ generation of CM2A8 high-quality composite refractory, which overcomes the defects of high energy consumption and long process of traditional methods, and in-situ synthesis of high-value CM2A8 composite refractory in the aluminum thermal reaction process through special design of the structure of the furnace cylinder and the blowing refining process.

[0005] In order to achieve the above purpose, the embodiments of the present application provide a method for in-situ generation of CM2A8 high-quality composite refractory, which comprises the following steps: S1 sets a ramming layer at the bottom of the reaction furnace, the ramming layer comprises a corundum slag layer and a magnesia layer, sets a double-layer ramming layer at the side of the furnace, the double-layer ramming layer comprises a corundum slag layer and a magnesia layer, the height of the magnesia layer at the side of the furnace is 2.3-3.5 times of the expected thickness of the molten iron liquid, and a magnesia mortar sintering layer is sprayed on the ramming layer at the bottom to prepare a reaction furnace cylinder; S2 adjusts the CaO content in the corundum slag to be less than 4%, and combines vanadium pentoxide, aluminum products and the treated corundum slag as a material to be added into the reaction furnace cylinder at one time; S3 ignites and smelts the loaded material to initiate an aluminum thermal reaction, immediately after the smelting is completed, a refining material is sprayed into the molten slag to initiate a secondary aluminum thermal reaction to supplement heat, and then cooling is performed to obtain a CM2A8 composite refractory material.

[0006] In some embodiments, in S1, the preparation of the ramming layer at the bottom comprises: first laying a corundum slag layer with a thickness of greater than or equal to 200 mm, and then laying a magnesia layer with a thickness of 30-60 mm on the corundum slag layer.

[0007] In some embodiments, in S1, the thickness of the magnesia mortar sintering layer sprayed at the bottom is 10-20 mm.

[0008] In some embodiments, in S1, in the corundum slag, the portion with a particle size of 0-1 mm is greater than or equal to 35 wt%, the Al2O3 content is greater than or equal to 80 wt%, and the CaO content is less than or equal to 5.5 wt%.

[0009] In some embodiments, in S1, in the magnesia layer, the portion with a particle size of 0-1 mm is greater than or equal to 70 wt%, and the MgO content is greater than or equal to 98 wt%.

[0010] In some embodiments, in S1, in the magnesia mortar, the portion with a particle size of 0-120 mm is greater than or equal to 90 wt%, and the MgO content is greater than or equal to 98 wt%.

[0011] In some embodiments, in S1, the double-layer ramming layer at the side of the furnace is shaped by an iron sheet or an aluminum sheet.

[0012] In some embodiments, in S3, the refining material comprises, in parts by weight: 50-60 parts of iron oxide powder and 150-170 parts of aluminum powder.

[0013] In some embodiments, the Fe2O3 content in the iron oxide powder is greater than or equal to 90 wt%, and the Al content in the aluminum powder is greater than or equal to 98 wt%.

[0014] In some embodiments, in S3, a gradient cooling system is used: first cooling at a rate of 10-15 ℃ / min to 1000 ℃, and then naturally cooling the furnace to room temperature.

[0015] The present application has at least the following beneficial technical effects: (1) the present application is in the preparation stage of the furnace cylinder, wherein the side magnesium sand filling height is 2.3-2.5 times of the actual molten iron, other positions are filled with corundum slag, and the bottom magnesium sand is laid with a certain thickness of magnesium mortar, after the end of the aluminothermic reaction, the side magnesium sand is flash sintered, and by controlling the height of the side magnesium sand, the erosion of the side magnesium sand to the slag is further reduced; the bottom magnesium sand is sintered by laying a certain thickness of magnesium mortar, and the fine magnesium sand is sintered instantaneously by contacting with the molten iron, so as to prevent the bottom magnesium sand from penetrating into the slag, and the Al2O3-MgO-CaO slag system in the molten state is finely adjusted and controlled in temperature, so as to realize the control of magnesium oxide in the CM2A8 high-quality composite refractory material; (2) the refining material is sprayed into the molten slag to trigger secondary aluminothermic reaction to concentrate the system heat, break through the bottleneck of CM2A8 high melting point, and the reduced iron phase accelerates the aggregation and settlement of alloy particles to reduce vanadium loss, and the spraying airflow is used to strengthen the homogenization of the molten slag, so as to significantly improve the quality stability of CM2A8 composite refractory material. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other embodiments can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0017] Figure 1 The schematic diagram of the method for generating CM2A8 high-quality composite refractory material in situ provided by the present application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the present application more clear, the following will be further described in detail with reference to the drawings.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used herein in the specification are only for the purpose of describing specific embodiments and are not intended to limit the present application, for example, the terms "length", "width", "up", "down", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or position based on the orientation or position shown in the drawings, and are only for the purpose of description, and cannot be understood as a limitation on the technical scheme.

[0020] The terms "comprise", "comprising", "include", "including", "have" and "having" and any variations thereof in the Specification and in the claims of the application and in the above are intended to cover a non-exclusive inclusion; the terms "first", "second", and the like in the Specification and in the claims of the application or in the above are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. The term "a plurality" means two or more, unless expressly specified otherwise.

[0021] Furthermore, references herein to "embodiments" mean embodiments that include a particular feature, structure, or characteristic. Various appearances of the phrase "in one embodiment" in the specification do not necessarily all refer to the same embodiments, although they can. The disclosure is not limited to these preferred embodiments, but is intended to cover any and all modifications that would be apparent to those in the art upon a reading of the description herein of the preferred embodiment and best mode for carrying out the application.

[0022] As Figure 1 The method for in-situ generating CM2A8 high-quality composite refractory material provided by the application comprises the following steps: S1, setting a ramming layer on the bottom of the reaction furnace, the ramming layer comprising a corundum slag layer and a magnesia layer, setting a double-layer ramming layer on the side of the furnace, the double-layer ramming layer comprising a corundum slag layer and a magnesia layer, the height of the magnesia layer on the side of the furnace being 2.3-3.5 times the thickness of the expected molten iron, and spraying a magnesia mortar sintering layer on the ramming layer on the bottom of the furnace to prepare a reaction furnace shell; S2, adjusting the CaO content in the corundum slag to be less than 4%, and combining vanadium pentoxide, aluminum products and the treated corundum slag into a material and adding the material into the reaction furnace shell at one time; S3, igniting and smelting the loaded material to initiate an aluminum thermal reaction, immediately after the smelting is completed, spraying a refining material into the molten slag to initiate a secondary aluminum thermal reaction to supplement heat, and then cooling to obtain a CM2A8 composite refractory material.

[0023] Further, in S1, when the furnace shell is prepared, first, a corundum slag layer with a thickness of ≥200mm is laid on the bottom of the furnace, and then the side of the furnace is prepared, the filling height of the magnesia layer on the inside of the side of the furnace being 2.5-3.5 times the thickness of the molten iron, the other parts of the side of the furnace being filled with corundum slag, the ramming layer on the side of the furnace being shaped by iron sheet or aluminum sheet, after the material on the bottom and the side of the furnace is vibrated and compacted, a magnesia layer with a thickness of about 30-60mm is filled on the bottom, and a sintering layer with a thickness of 10-20mm is uniformly sprayed on the surface of the magnesia layer.

[0024] Specifically, the material composition requirements of the furnace cylinder preparation include: in the corundum slag, the part with a particle size of 0-1 mm is ≥ 35 wt%, the Al2O3 content is ≥ 80 wt%, and the CaO content is ≤ 5.5 wt%. In the magnesia layer, the part with a particle size of 0-1 mm is ≥ 70 wt%, and the MgO content is ≥ 98 wt%. In the magnesia mortar, the part with a particle size of 0-120 mm is ≥ 90 wt%, and the MgO content is ≥ 98 wt%.

[0025] Further, in S3, the refining material includes, in parts by weight: iron oxide powder 50-60 parts, aluminum powder 150-170 parts. The Fe2O3 content in the iron oxide powder is ≥ 90 wt%, and the Al content in the aluminum powder is ≥ 98 wt%. In some preferred embodiments, a gradient cooling system can be used: first cooled to 1000°C at a rate of 10-15°C / min, and then naturally cooled to room temperature.

[0026] The application will be further explained below in conjunction with specific embodiments.

[0027] Example 1 The furnace bottom is filled with a 220mm-thick corundum slag layer, the side of the furnace cylinder is shaped by iron sheet, the filling height of the magnesia inside the side is 2 times the theoretical liquid iron height, the other parts are filled with corundum slag, after the side material is vibrated and compacted, a 40mm-thick magnesia layer is filled at the bottom, and a 10mm-thick magnesia mortar sintering layer is uniformly sprayed on the surface of the magnesia layer.

[0028] Vanadium pentoxide: aluminum: corundum slag is mixed in a ratio of 2:0.98:0.03, the upper part is ignited for self-propagating reaction, after the reaction is completed, the injection material is mixed uniformly by 50 parts of iron oxide and 100 parts of aluminum powder, and then injected, after the smelting is completed, the high-vanadium iron meets the requirements of GB / T 4139-2012, the vanadium recovery rate is 98.38%, and the main component groups of the byproduct CM2A8 high-quality composite refractory material are as follows: Al2O3 content 87.5%, MgO content 7.5%, and CaO content 3.9%. The composite refractory is used for vanadium-iron spray gun preparation, and the service life of the spray gun is 101 furnaces / root.

[0029] Example 2 The furnace bottom is filled with a 220mm-thick corundum slag layer, the side of the furnace cylinder is shaped by iron sheet, the filling height of the magnesia inside the side is 2 times the theoretical liquid iron height, the other parts are filled with corundum slag, after the side material is vibrated and compacted, a 40mm-thick magnesia layer is filled at the bottom.

[0030] Vanadium pentoxide: aluminum: corundum slag is mixed according to the ratio of 2:0.98:0.03, and the upper part is ignited to carry out the self-propagating reaction, after the reaction is completed, the injection material is mixed uniformly according to 50 parts of iron oxide and 100 parts of aluminum powder, and then sprayed, after the smelting is completed, the high vanadium iron quality meets the requirements of GB / T 4139-2012, the vanadium recovery rate is 98.4%, and the main component groups of the by-product CM2A8 high-quality composite refractory material generated are as follows: the Al2O3 content is 83%, the MgO content is 9.5%, and the CaO content is 3.5%. The composite refractory material is used for vanadium-iron spray gun preparation, and the service life of the spray gun is 99 furnaces / root.

[0031] Example 3 The furnace bottom is filled with a 220mm-thick corundum slag layer, the furnace cylinder side is shaped by relying on the iron sheet, the material of the inner side of the side is magnesia, and the filling height is 2 times the theoretical iron liquid height, and the other parts are filled with corundum slag, and then a 40mm-thick magnesia layer is filled on the furnace bottom after the side material is vibrated and compacted.

[0032] Vanadium pentoxide: aluminum: lime is mixed according to the ratio of 2:0.98:0.03, and the upper part is ignited to carry out the self-propagating reaction, after the reaction is completed, the injection material is mixed uniformly according to 50 parts of iron oxide and 100 parts of aluminum powder, and then sprayed, after the smelting is completed, the high vanadium iron quality meets the requirements of GB / T 4139-2012, the vanadium recovery rate is 98.4%, and the main component groups of the by-product CM2A8 high-quality composite refractory material generated are as follows: the Al2O3 content is 83%, the MgO content is 9.5%, and the CaO content is 3.5%. The composite refractory material is used for vanadium-iron spray gun preparation, and the service life of the spray gun is 99 furnaces / root.

[0033] Comparative example The furnace bottom and the furnace side are wetted and knotted by magnesia and brine mainly containing magnesium chloride, and then dried after being knitted; vanadium iron is smelted by electric aluminum hot method by using vanadic oxide, aluminum beans as main raw materials and vanadic oxide as auxiliary raw materials, and then refined by spraying aluminum powder after smelting, after the smelting is completed, the high vanadium iron quality meets the requirements of GB / T 4139-2012, the vanadium recovery rate is 97.1%, and the main component groups of the by-product ordinary corundum slag are as follows: the Al2O3 content is 70%, the MgO content is 14%, and the CaO content is 11%. The composite refractory material is used for vanadium-iron spray gun preparation, and the service life of the spray gun is 12 furnaces / root.

[0034] Compared with the prior art, the special furnace cylinder structure of the present application cooperates with the spraying refining process, and the vanadium iron smelting waste slag is directly converted into high-end CM2A8 composite refractory material, and the following improvements are realized: (1) Component upgrading: the Al2O3 content of the by-product CM2A8 high-quality composite refractory material reaches 81.5-87.5%, the MgO content is reduced to 7.5-10.5%, and the CaO content is reduced to 3.5-4.2%, which meets the CM2A8 phase composition requirements; (2) Performance breakthrough: the material is used for vanadium-iron lance service life of 92-101 furnace, which is 7.6 times higher than 12 furnaces of the comparative example.

[0035] The method of the application is in the furnace cylinder preparation stage, wherein the side magnesium sand filling height is 2.3-2.5 times of the actual molten iron, other positions are filled with corundum slag, and the bottom magnesium sand is paved with a certain thickness of magnesium mortar. After the aluminum thermal reaction is completed, the side magnesium sand is flash sintered, and by controlling the height of the side magnesium sand, the erosion of the side magnesium sand to the slag is further reduced; the bottom magnesium sand is sintered instantaneously by being paved with a certain thickness of magnesium mortar, the fine and dense magnesium sand is prevented from penetrating into the slag, the Al2O3-MgO-CaO slag system in the molten state is finely adjusted and controlled in temperature and property, and thus the control of magnesium oxide in the CM2A8 high-quality composite refractory material is realized. The application sprays iron oxide powder and aluminum powder into the molten slag after the reaction is completed, the iron oxide powder in the molten slag reacts with aluminum to generate a large amount of heat, and the excessive aluminum powder is mixed to react with the residual vanadium oxide in the molten slag to release a large amount of heat, so that the problem of high melting point is overcome by supplementing chemical heat into the molten slag, and a certain amount of iron oxide is sprayed into the molten slag, so that the reduced iron accelerates the aggregation and settlement of alloy particles in the molten slag, and the loss of vanadium is further reduced. The airflow auxiliary stirring in the spraying process accelerates the homogenization of the molten slag, and improves the quality of the final CM2A8 composite refractory material.

[0036] The above is the exemplary embodiment disclosed by the application, but it should be noted that various changes and modifications can be made without departing from the scope of the embodiment disclosed by the application defined in the claims. The functions, steps and / or actions of the method claims described herein do not need to be performed in any particular order. In addition, although the elements of the embodiment disclosed by the application can be described or claimed in singular form, they can also be understood as plural unless explicitly limited as singular.

[0037] It should be understood that, as used herein, the singular forms "a", "an" and "the" are intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that "and / or" as used herein refers to any and all possible combinations of one or more of the associated listed items.

[0038] The above embodiment number of the embodiment disclosed by the application is only for description, and does not represent the advantages and disadvantages of the embodiment.

[0039] Those skilled in the art should understand that the above discussion of any embodiment is only exemplary, and is not intended to mean that the scope of the embodiments disclosed by the present application (including claims) is limited to these examples; under the idea of the embodiments of the present application, the above embodiments or technical features in different embodiments can also be combined, and there are many other changes of different aspects of the embodiments of the present application as above. In order to be brief, they are not provided in details. Therefore, any omission, modification, equivalent replacement, improvement, etc. made in the spirit and principle of the embodiments of the present application shall be included in the protection scope of the embodiments of the present application.

Claims

1. A method for in-situ generation of high-quality CM2A8 multiphase refractory material, characterized in that, include: S1 A bridging layer is set at the bottom of the reactor, the bridging layer including a corundum slag layer and a magnesia layer. A double bridging layer is set on the side of the furnace, the double bridging layer including a corundum slag layer and a magnesia layer. The height of the magnesia layer on the side of the furnace is 2.3-3.5 times the expected thickness of the molten iron. A magnesia sintering layer is sprayed onto the bridging layer at the bottom of the furnace to prepare the reactor shell. S2 adjusts the CaO content in the corundum slag to below 4%, and combines vanadium pentoxide, aluminum products and the treated corundum slag into one material and adds it into the reactor drum at one time. S3 ignites and smelts the loaded material to initiate an aluminothermic reaction. After smelting, it immediately injects refined material into the molten slag to initiate a secondary aluminothermic reaction to replenish the heat. Then it is cooled to obtain CM2A8 multiphase refractory material.

2. The method for in-situ generation of high-quality CM2A8 multiphase refractory material according to claim 1, characterized in that, In S1, the preparation of the furnace bottom bridging layer includes: first laying a corundum slag layer with a thickness of ≥200mm, and then laying a magnesia sand layer with a thickness of 30-60mm on the corundum slag layer.

3. The method for in-situ generation of high-quality CM2A8 multiphase refractory material according to claim 1, characterized in that, In S1, the thickness of the sintered magnesia mud layer sprayed on the furnace bottom is 10-20 mm.

4. The method for in-situ generation of high-quality CM2A8 multiphase refractory material according to claim 1, characterized in that, In S1, the portion of the corundum slag with a particle size of 0-1 mm is ≥35 wt%, the Al2O3 content is ≥80 wt%, and the CaO content is ≤5.5 wt%.

5. The method for in-situ generation of high-quality CM2A8 multiphase refractory material according to claim 1, characterized in that, In S1, within the magnesia layer, the portion with a particle size of 0-1 mm is ≥70% by weight, and the MgO content is ≥98 wt%.

6. The method for in-situ generation of high-quality CM2A8 multiphase refractory material according to claim 1, characterized in that, In S1, the magnesia molten mud has a particle size of 0-120mm of ≥90wt% and an MgO content of ≥98wt%.

7. The method for in-situ generation of high-quality CM2A8 multiphase refractory material according to claim 1, characterized in that, In S1, the double-layer knotted layer on the furnace side is shaped by sheet metal or aluminum sheet.

8. The method for in-situ generation of high-quality CM2A8 multiphase refractory material according to claim 1, characterized in that, In S3, the refined material comprises, by weight, 50-60 parts of iron oxide powder and 150-170 parts of aluminum powder.

9. The method for in-situ generation of high-quality CM2A8 multiphase refractory material according to claim 8, characterized in that, The iron oxide powder contains ≥90wt% Fe2O3, and the aluminum powder contains ≥98wt% Al.

10. The method for in-situ generation of high-quality CM2A8 multiphase refractory material according to claim 1, characterized in that, In S3, a gradient cooling regime is adopted: first, the temperature is cooled to 1000℃ at a rate of 10-15℃ / min, and then the furnace is naturally cooled to room temperature.

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