Method for improving quality of vanadium-titanium sinter

Abstract

The invention belongs to the technical field of metallurgy, and particularly discloses a method for improving the quality of vanadium-titanium sinter. The method comprises the following steps: in a sintering mixture taking vanadium-titanium magnetite concentrate as a main iron material, a mixture with a wet sieve particle size of not less than 3 mm accounts for 60% or more, the mass fraction of limestone powder is not less than 8%, and the limestone powder contains a part of limestone powder with a particle size upper limit of not less than 3 mm; the upper limit of the granularity of the limestone powder is set to be in a range of 0.5-3mm. According to the scheme provided by the invention, the high-titanium vanadium-titanium sinter with high quality can be produced by optimizing the granularity of the limestone powder.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metallurgy, and particularly relates to a method for improving the quality of vanadium-titanium sinter. BACKGROUND

[0002] There are a large number of high-titanium vanadium-titanium magnetite resources in the Panxi region of China, and titanium and iron are symbiotic, so it is difficult to separate titanium and iron in the beneficiation process. Therefore, with the increase of the concentrate iron grade in the beneficiation process, the TiO2 content of the concentrate is also increased, and the TiO2 content in the concentrate is between 10-13.5%. TiO2 forms perovskite (CaO•TiO2) with CaO in the sintering process. The melting point of perovskite is as high as 1970℃, and perovskite is hard and brittle, which is the phase that crystallizes out early in the sintering process. Perovskite will hinder the flow between liquid phases, thereby hindering the formation of new minerals, and affecting the crystallization process of sinter. Therefore, the quality of high-titanium vanadium-titanium sinter is poorer than that of ordinary iron ore sinter, mainly manifested in: (1) the sinter drum strength is low, and the ISO drum index is about 73%; (2) the sinter yield is low, and the return ore rate is as high as 35%; (3) the sinter particle size is fine; (4) the sinter has poor metallurgical properties, and the low-temperature reduction pulverization index is high; (5) the sinter has poor storage performance and is easy to pulverize, especially in the case of high-alkali sintering, the longer the storage time, the easier the pulverization.

[0003] The above problems are not conducive to the intensified smelting of vanadium-titanium ore blast furnace, and ideal economic benefits cannot be achieved.

[0004] Generally, the quality of vanadium-titanium sinter is improved by optimizing the sintering material proportioning and process parameters. Limestone is an important flux for sintering. It is generally believed that when the limestone powder particle size is >3mm and accounts for a certain proportion, it is beneficial to the granulation of the mixture and the improvement of the permeability of the sintering material layer, and it is beneficial to the increase of the sintering yield, and the sintering quality is also good. Refining the limestone powder particle size can only slightly improve the sintering quality, but the permeability of the mixture is poor, and the sintering yield is greatly reduced.

[0005] Before 2024, the flux structure of Pangang sintering is "2% active lime + 5% ordinary lime + 2-4% lime stone powder ratio", the lime stone powder ratio is mainly used to adjust the sinter basicity, the lime stone powder ratio is relatively low, and the active lime and the ordinary lime are mainly used to strengthen the granulation, improve the proportion of the particle size > 3mm in the mixture and improve the sintering mixture permeability. In 2024, the active lime ratio in the sintering flux structure is increased from 2% to 3.0-4.0%, and the ordinary lime is stopped. Since the active lime can strengthen the granulation, the sintering mixture permeability is significantly improved after the active lime ratio is increased, the proportion of the particle size > 3mm in the mixture is between 55-65%, and the thick layer sintering needs can be fully met, so the lime stone powder is not needed to maintain the mixture permeability. Since the ordinary lime is stopped, the lime stone powder ratio is greatly increased, the lime stone powder ratio is between 10-15%, and the influence of the physicochemical properties of the lime stone powder on the sinter quality is significantly increased with the increase of the lime stone powder ratio. In 2024, the Pangang purchasing requirement for the lime stone powder is that the proportion of the particle size > 3mm in the lime stone powder is still required to be controlled within 10%, and in fact, the proportion is between 9-10%.

[0006] With the development of vanadium-titanium ore blast furnace smelting technology, the quality requirement of the vanadium-titanium sinter into the furnace is higher and higher, improving the drum index of the vanadium-titanium sinter and improving the metallurgical properties are beneficial to reduce the ironmaking production cost and improve the economic benefit.

[0007] Therefore, the prior art still needs to be improved. SUMMARY

[0008] In order to solve the problem of poor quality of vanadium-titanium sinter, the present application proposes a method for improving the properties of sintering mixture by optimizing the particle size of lime stone powder, which can not only improve the drum strength of sinter, improve the yield and reduce the return rate, but also significantly improve the low temperature reduction and pulverization performance and storage performance of sinter.

[0009] In order to achieve the above purpose, the present application adopts the following technical scheme: According to the first aspect of the present application, a method for improving the quality of vanadium-titanium sinter is provided, which comprises: in the case that the wet sieve particle size of the mixture is not less than 3mm, the mass fraction of the lime stone powder is not less than 8%, and the lime stone powder contains a part of lime stone powder with a particle size upper limit not less than 3mm in the sintering mixture taking vanadium-titanium magnetite concentrate as the main iron material, the particle size upper limit of the lime stone powder is set to be within the range of 0.5mm-3mm.

[0010] According to the embodiment of the present application, the TiO2 mass fraction content in the vanadium-titanium magnetite concentrate is not less than 10%.

[0011] According to an embodiment of the present application, in the vanadium-titanium magnetite concentrate, the particles capable of passing through a 200-mesh screen account for more than 90%.

[0012] According to an embodiment of the present application, in the sintering mixture, the mass fraction of the vanadium-titanium magnetite concentrate is not less than 35%.

[0013] According to an embodiment of the present application, in addition to the iron material, the sintering mixture further comprises a flux, a fuel and an externally added return ore.

[0014] According to an embodiment of the present application, the limestone powder is used as the flux, and in addition to the limestone powder, the flux further comprises active quicklime.

[0015] According to an embodiment of the present application, in the sintering mixture, the mass fraction of the active quicklime is not less than 3.0%.

[0016] According to an embodiment of the present application, the proportion of the mixture with a particle size not less than 3 mm in the sintering mixture is increased by increasing the moisture of the sintering mixture.

[0017] According to an embodiment of the present application, the height of the sintering material layer is not less than 700 mm.

[0018] According to an embodiment of the present application, the upper limit of the particle size of the limestone powder is not more than 2 mm.

[0019] By adopting the technical scheme, the present application has at least the following beneficial effects: The scheme of the present application can produce high-quality vanadium-titanium sinter by optimizing the particle size of the limestone powder. Specifically, due to the refinement of the particle size of the limestone powder, the dispersion is improved during the mixing process in the primary mixer, and the mixing effect is improved. The uniformly dispersed and fine limestone powder is helpful for rapid decomposition into CaO during the sintering process, promotes the reaction of CaO and Fe2O3 in the iron ore to generate the binding phase calcium ferrite, and the uniform distribution of the liquid phase is conducive to the ore-forming reaction in the sintering process, reduces the solid fuel consumption, improves the sinter yield and the drum strength, greatly reduces the return ore rate, improves the storage performance of the sinter, and the sinter can be stored for a longer time. The optimization of the particle size of the limestone powder is not only conducive to improving the quality of the vanadium-titanium sinter, but also conducive to improving the technical and economic indicators, and has good economic benefits and application value. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The wet sieve particle size composition of the limestone powder used in the embodiment of the present application is shown; Figure 2 The material structure and layer parameters of each scheme of the embodiment are shown; Figure 3 The wet sieve particle size composition of the sintering mixture of the embodiment is shown; Figure 4The main indicators of sintered ore of each scheme of the embodiment are compared. Figure 5 The storage performance of sintered ore of each scheme of the embodiment is shown. Figure 6 The low-temperature reduction pulverization index of sintered ore of each scheme of the embodiment is shown. Figure 7 The main chemical components of the materials used in the embodiment of the application are shown. DETAILED DESCRIPTION

[0021] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0022] According to the need, specific embodiments of the present application are disclosed in the specification of the present application; however, it should be understood that the embodiments disclosed herein are only examples of the present application which can be implemented in various alternative forms. In the following description, a plurality of operating parameters and components are described in a plurality of embodiments conceived. These specific parameters and components are only used as examples in the specification and do not mean limitation.

[0023] The present application provides a method for improving the quality of vanadium-titanium sintered ore, which comprises: in the case that the mixed material with a wet sieve size of not less than 3mm accounts for more than 60% in the sintering mixture taking vanadium-titanium magnetite concentrate as the main iron material, the mass fraction of limestone powder is not less than 8%, and a part of the limestone powder in the limestone powder has a particle size upper limit of not less than 3mm, setting the particle size upper limit of the limestone powder in the range of 0.5mm-3mm.

[0024] In the scheme of the present application, the expression "taking vanadium-titanium magnetite concentrate as the main iron material" means that in the sintering mixture, in addition to vanadium-titanium magnetite concentrate, other iron materials are also included. The term "main" means that the proportion of vanadium-titanium magnetite concentrate in the sintering mixture is greater than the proportion of each of the other iron materials.

[0025] In the scheme of the present application, the terms "not less than" and "not lower than" both mean greater than or equal to, and the terms "above" and "within" are understood to include the number.

[0026] In the scheme of the present application, "the mixed material with a wet sieve size of not less than 3mm accounts for more than 60% in the sintering mixture" means that before optimizing the particle size of the limestone powder, the mass percentage M of the mixed material with a wet sieve size of not less than 3mm in the sintering mixture is greater than or equal to 60%.

[0027] In the scheme of the present application, "a part of the limestone powder in the limestone powder has a particle size upper limit of not less than 3mm" means that before optimizing the particle size of the limestone powder, the proportion of the limestone powder with a particle size upper limit of not less than 3mm in the limestone powder is greater than 0.

[0028] In the scheme of the present application, the phrase "setting the upper limit of the particle size of the limestone powder in the range of 0.5 mm to 3 mm" means setting the upper limit of the particle size of the limestone powder N≤χ mm, χ∈[0.5, 3].

[0029] In the scheme of the present application, when the wet sieve ≥3 mm particle size mass percentage M of the sintering mixture of the vanadium-titanium magnetite concentrate as the main iron material is ≥60% and the mass fraction Z of the limestone powder in the sintering material structure is ≥8% and the mass percentage L of the particle size ≥3 mm of the limestone powder is ∈[5%, 15%] under the normal sintering mixture moisture state, the particle size of the limestone powder can be refined, the upper limit of the particle size of the limestone powder N≤χ mm, χ∈[0.5, 3], and the comprehensive production index is better. The normal sintering mixture moisture state is generally 7.0-7.8%; that is, it is not necessary to deliberately increase the mixture moisture in order to increase the proportion of the sintering mixture ≥3 mm.

[0030] The method of the present application can produce high-quality high-titanium vanadium-titanium sinter by optimizing the particle size of the limestone powder. Specifically, due to the refinement of the particle size of the limestone powder, the dispersion is improved during the mixing process in the primary mixer, and the mixing effect is improved. The uniformly dispersed and fine limestone powder is helpful for rapid decomposition into CaO during the sintering process, promotes the reaction of CaO and Fe2O3 in the iron ore to generate the binding phase calcium ferrite, and the uniform distribution of the liquid phase is beneficial to the ore-forming reaction in the sintering process, reduces the solid fuel consumption, improves the sinter yield, significantly improves the drum strength, greatly reduces the return fines rate, improves the storage performance of the sinter, and can be stored for a longer time. The optimization of the particle size of the limestone powder not only helps to improve the quality of the vanadium-titanium sinter, but also helps to improve the technical and economic indicators, and has good economic benefits and application value.

[0031] Previously, due to the poor ballability of the vanadium-titanium ore, the proportion of the mixture particle size >3 mm was below 55%, generally about 50%. At this time, various methods were taken to improve the mixture particle size composition, increase the proportion of the mixture particle size >3 mm, and improve the mixture permeability. Therefore, the proportion of the limestone powder particle size >3 mm was generally controlled within 10% to maintain the proportion of the mixture particle size >3 mm. At this time, if the particle size of the limestone powder is refined, for example, the proportion of the particle size of the limestone powder >3 mm is controlled within 0% (i.e., the particle size of the limestone powder is controlled within 3 mm), the proportion of the mixture particle size >3 mm will be reduced, which is not conducive to improving the mixture permeability.

[0032] With the progress of beneficiation technology, the vanadium-titanium ore is ground very fine, and the ballability of the vanadium-titanium ore is significantly improved. At the same time, the balling equipment of the mixture is increasingly large-scale, the design parameters of the balling equipment are scientific and accurate, and the material structure optimization technology, the balling performance of the vanadium-titanium ore mixture is significantly improved, the proportion of the mixture particle size > 3mm is between 55-65%, the mixture particle size appears "excess" phenomenon, and it is necessary to appropriately reduce the proportion of the mixture particle size > 3mm to reduce the sintering speed and improve the sinter quality indexes, including the sinter drum strength and the sinter yield. With the optimization of the material structure, the proportion of limestone powder is greatly increased. Due to the great increase of the proportion of limestone powder, the limestone powder has a great influence on the sintering production, including the yield and the quality indexes (sinter drum strength and sinter yield). With the intensification of blast furnace production, the blast furnace puts forward higher and higher requirements for the sinter quality indexes. At this time, the further refinement of the limestone powder particle size, the more uniform distribution of the limestone powder, the faster reaction speed of the limestone powder, and the full mineralization will significantly improve the sinter quality. At the same time, due to the high proportion of the mixture > 3mm, the negative influence of the refinement of the limestone powder particle size on the yield is small, and the comprehensive score of the comprehensive indexes (yield, sinter drum strength, sinter yield and other indexes) of the sinter is increased.

[0033] In some embodiments, the vanadium-titanium magnetite concentrate is a high-titanium vanadium-titanium magnetite concentrate with a mass fraction of TiO2 of not less than 10%.

[0034] In some embodiments, in the vanadium-titanium magnetite concentrate, the particles capable of passing through a 200-mesh screen account for more than 90%, that is, the mass fraction of -200 mesh is ≥ 90%. Such vanadium-titanium magnetite concentrate has good balling performance, which is beneficial to the balling of the mixture and increases the proportion of the mixture with a particle size of not less than 3mm in the mixture.

[0035] In some embodiments, in the sintering mixture, the mass fraction of the vanadium-titanium magnetite concentrate is not less than 35%.

[0036] In addition to the iron material, the sintering mixture also includes flux, fuel and externally added return fines. Among them, the limestone powder is used as the flux.

[0037] In some embodiments, in addition to the limestone powder, the flux also includes active quicklime.

[0038] In some embodiments, in the sintering mixture, the mass fraction of the active quicklime is not less than 3.0%, that is, the mass fraction of the active quicklime P ≥ 3.0%. This proportion can significantly improve the permeability of the sintering mixture. Below this proportion, the permeability of the mixture will be poor.

[0039] In some embodiments, the sintering material structure is composed of three parts of "new material + return ore + plant circulating material", wherein the "new material" is composed of three parts of "iron material + flux + fuel", the total mass fraction of the three parts is about 100%, the iron material is composed of "vanadium-titanium magnetite concentrate + high-grade ordinary iron concentrate + medium-grade ordinary iron concentrate", the total mass fraction percentage of the three parts is 80%, under normal production conditions, the vanadium-titanium magnetite concentrate accounts for 35%-48%, the high-grade ordinary iron concentrate accounts for 23%-35%, and the medium-grade ordinary iron concentrate accounts for 1%-12%. The flux is composed of "active quicklime + limestone powder", and the fuel is composed of "coke powder + washed fine coal".

[0040] In some embodiments, the proportion of the mixture with a particle size not less than 3 mm in the sintering mixture is increased by increasing the moisture content of the sintering mixture.

[0041] In some embodiments, the sintering material layer height is set to be not less than 700 mm, that is, the sintering material layer L≥700 mm, by reducing the machine speed. Here, the "sintering material layer height" refers to the height of the sintering material layer when the mixture is added to the sintering machine for sintering.

[0042] In sintering production, good permeability of the mixture can improve the sintering of the material layer. If the material structure changes or the equipment changes, the balling performance of the mixture decreases, the proportion of the mixture not less than 3 mm decreases, and the permeability of the mixture becomes poor, which often reduces the sintering of the material layer. Laboratory tests show that when the particle size of the limestone powder is refined and the upper limit of the particle size of the limestone powder is 0.5 mm, that is, all the particle sizes of the limestone powder are less than 0.5 mm, the sintering drum strength and the average particle size of the sintering ore still have significant changes compared with the sintering of the 750 mm material layer with the reference period of the on-site limestone powder of 750 mm, but compared with the scheme 2 of all the particle sizes of the limestone powder being less than 0.5 mm and the material layer being 750 mm, the sintering drum strength and the average particle size of the sintering ore have a downward trend. Therefore, after refining the particle size of the limestone powder, in order to meet the needs of strengthening smelting of the sintering ore, the quality of the sintering ore is the first, at this time, measures such as reducing the machine speed or increasing the proportion of active quicklime and increasing the moisture content of the mixture can be taken to maintain the sintering material layer above 700 mm. In some embodiments, the upper limit of the particle size of the limestone powder is set to be not more than 2 mm, that is, the upper limit of the particle size of the limestone powder p≤2 mm. The sintering comprehensive score of this upper limit of the particle size is the highest, that is, the comprehensive score of the five indexes including yield, sintering ore yield, sintering ore average particle size, drum strength, and solid fuel consumption is the highest.

[0043] According to one embodiment, when the sinter raw material conditions and process conditions meet the following requirements, high-quality sinter can be produced by optimizing the particle size of limestone powder, the upper limit of the particle size of limestone powder N≤χmm, χ∈[0.5, 3]: ① The proportion of high-titanium concentrate-200 (mesh) is more than 90%, and the balling performance of high-titanium concentrate is good; ② The proportion of active quicklime is high, the mass fraction P≥3.0%, and the digestion is good; ③ The sintering layer L≥700mm; ④ The mass fraction of limestone powder Z≥8%.

[0044] That is, under the original basic sinter raw material and process conditions, the particle size of limestone and related process measures are optimized: ① Reduce the particle size of limestone powder and control it within N≤χmm, χ∈[0.5, 3], where N is the upper limit of the particle size of limestone powder; ② Increase the mass fraction of limestone powder to 8%-15% and use active quicklime with higher activity to replace quicklime; ③ Reduce the particle size of vanadium-titanium magnetite, with a proportion of-0.074mm particle size of 90%-98%, and improve the balling performance of iron concentrate powder.

[0045] The basic process flow of sinter production is as follows: After the materials (new material + return ore + in-plant circulating material) are proportioned according to the preset proportion and mixed uniformly in the primary mixer, they are then granulated in the secondary mixer, and then distributed to the sintering machine for sintering to produce sintered ore. The sintered ore is crushed, cooled, and screened to form finished sintered ore, which is then smelted in a blast furnace.

[0046] In some embodiments, the method for improving the quality of high-titanium vanadium-titanium sinter includes the following specific steps: Step 1: Weigh the materials according to the proportioning principles of vanadium-titanium sinter indicators, for example, vanadium-titanium magnetite: Tengchong powder: 42 medium powder: domestic high powder: blast furnace slag: South African powder: dust ash: limestone: active quicklime: coke powder: coal powder = 35-48%: 0-15%: 0-15%: 15-38%: 0-5%: 0-8%: 0-5%: 8-15%: 3-5%: 2-5%: 2-5%, the proportion of return ore is 30-60%, and the materials are added to the primary mixer in turn for mixing, with a mixing time of 6-10min, preferably 8min, and simultaneous spraying of atomized water, with an atomized water addition amount of 80% of the total water amount, to form a mosaic structure of mixed materials 1 of powder ore, fuel, flux, and return ore; Step 2: Add the mosaic structure of mixed materials 1 to the secondary mixer for water granulation, with a water addition amount of 20% of the total water amount, and set the secondary mixing granulation time to 4-8min, preferably 5min, to allow the mosaic structure of mixed materials 1 to roll uniformly into balls to form mixed materials 2; Step 3: Put the prepared mixture 2 into a sintering cup (diameter 300 mm, height 800 mm), and the sintering cup is paved with sinter with a particle size of 10 mm-16 mm, the paving thickness is 20 mm, and the layer thickness (including paving) is 700 mm-800 mm; Step 4: Ignition and air draft sintering is performed on the mixture in the sintering cup, the ignition temperature is 1050℃-1150℃, the ignition time is 2.5-3.5 min, the ignition negative pressure is 5.0-6.0 kPa, the sintering air draft negative pressure is 11-13 kPa, and the air draft flow rate is 5-15 m 3 / min; Step 5: When the exhaust gas temperature of the air draft pipeline at the lower end of the sintering cup rises to the highest and then drops to 50℃, the sintering process is completed, the sinter cake is poured out and coarsely broken (the spacing of the crusher is 50 mm), and then the sinter cake is subjected to three times of dropping treatment (the dropping height is 2 m) and is screened according to 40-25 mm, 25-16 mm, 16-10 mm, 10-5 mm and <5 mm, the proportion of >5 mm is calculated, and the drum strength is detected according to the standard requirements.

[0047] The application is further described below in combination with specific embodiments.

[0048] Specific embodiments, taking the material structure of a new 1# sintering machine (360 m 2 ) as a benchmark, perform limestone powder sintering influence tests of different particle sizes, wherein the main parameters of the sintering cup test are as follows: ① the sintering air draft negative pressure of the sintering fan is-15.5 kPa; ② the ignition negative pressure of the sintering fan is-6 kPa; ③ the time of the primary mixer is 8 minutes; ④ the time of the secondary mixer is 5 minutes; ⑤ the paving is 4 kg; ⑥ the ignition temperature is 1080℃; ⑦ the fixed carbon of the mixture is 3.0%, and the sinter solid fuel consumption calculation formula (kgce / t)=loading amount (kg)×(1-mixture moisture (%))×C 固 (%) / product ore amount (t), C 固 is the fixed carbon content of the mixture, %; ⑧ the layer thickness is 750 mm; and ⑨ the particle size of the limestone powder >3 mm accounts for 9.1%.

[0049] The particle size of the limestone powder in the benchmark period is the particle size composition of the limestone powder Figure 1 ; before the experiment, the limestone powder is screened, scheme 1 is screened by a round hole screen with a size of 0.5 mm, the undersize is matched into the sintering mixture to participate in sintering; scheme 2 is screened by a round hole screen with a size of 0.5 mm, the undersize is matched into the sintering mixture to participate in sintering; scheme 3 is screened by a round hole screen with a size of 1.0 mm, the undersize is matched into the sintering mixture to participate in sintering; scheme 4 is screened by a round hole screen with a size of 2.0 mm, the undersize is matched into the sintering mixture to participate in sintering; and scheme 5 is screened by a round hole screen with a size of 3.0 mm, the undersize is matched into the sintering mixture to participate in sintering.

[0050] The material structure of each scheme is shown below. Figure 2 In this document, all contents are by mass percentage. "Panjing concentrate" refers to the vanadium-titanium magnetite concentrate mentioned in this invention, specifically vanadium-titanium magnetite concentrate with a TiO2 mass fraction content ≥10%. The main chemical components of each material are listed below. Figure 7 .

[0051] The wet screening particle size distribution of the mixtures for each scheme is shown in the figure. Figure 3 .from Figure 3 It can be seen that the particle size of limestone powder has a certain influence on the particle size composition of the mixture. As the particle size of limestone powder becomes finer, the average particle size of the mixture becomes smaller.

[0052] The main sintering parameters for each scheme are shown below. Figure 4 The solid fuel consumption (kgce / t sinter) = charge amount (kg) × (1 - moisture content of mixture (%)) × 1.122 / (finished product weight (kg) / 1000), where 1.122 is the ratio of the heat of combustion of 1 kg pure carbon (J) / the heat of combustion of 1 kg standard coal (J).

[0053] Combination Figure 3 and Figure 4 It can be seen that as the limestone powder particle size is refined, the yield of sintered ore, the average particle size of sintered ore, the drum strength of sintered ore, and the solid fuel consumption index of sintered ore all improve, while the utilization coefficient of the sintering machine generally shows a downward trend. Comprehensive scoring according to the weighted evaluation system shows that, with the refinement of limestone powder particle size, the comprehensive scores for schemes 1-5 are all higher than the baseline scheme, indicating that under the current raw material and process conditions, refining the limestone powder particle size can achieve good economic benefits. The comprehensive scoring according to the weighted evaluation system refers to calculating the comprehensive score by assigning a weight of 30% to the yield, 20% to the utilization coefficient, 30% to the drum strength, 10% to the solid fuel consumption, and 10% to the average particle size of sintered ore.

[0054] pass Figure 2 As can be seen from Scheme 4, by appropriately increasing the moisture content of the sintering mixture, the proportion of >3mm in the mixture can be increased, which can not only increase the output of sinter, but also improve the drum strength of sinter, increase the particle size distribution, and reduce the solid fuel consumption per ton of sinter.

[0055] The sinter storage performance of each scheme is shown in the figure. Figure 5 The table shows the decrease in average sinter particle size by % = (average sinter particle size on day 1 (mm) - average sinter particle size on day 4 (mm)) / average sinter particle size on day 1 (mm) × 100%. From... Figure 5 It can be seen that as the limestone powder particle size is refined, the decrease in the average particle size of the sinter on the fourth day is significantly reduced, indicating that the storage performance of the sinter is improved. The main reason is the reduction in the number of free quicklime particles in the sinter.

[0056] The low-temperature reduction pulverization index of sinter for each scheme is shown in the figure. Figure 6 .from Figure 6 It can be seen that as the limestone powder particle size is refined, the low-temperature reduction pulverization index of sinter is significantly improved. The main reason is that the number of free quicklime particles decreases, the porosity of sinter decreases and the bulk density increases, which improves the low-temperature reduction pulverization performance of sinter.

[0057] In summary, the present invention can produce high-quality high-titanium vanadium-titanium sinter by optimizing the limestone powder particle size.

[0058] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0059] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0060] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for improving the quality of vanadium-titanium sinter, characterized in that, The application relates to a sintering mixture containing vanadium-titanium magnetite as main iron material, wherein the content of the sintering mixture with a particle size not less than 3mm is more than 60%, the mass fraction of limestone powder is not less than 8%, and the limestone powder contains a part of limestone powder with a particle size not less than 3mm. The vanadium-titanium magnetite contains TiO2 with a mass fraction not less than 10%.

2. The method for improving the quality of vanadium-titanium sinter according to claim 1, characterized in that, In the vanadium-titanium magnetite, the particles capable of passing through a 200-mesh screen account for more than 90%.

3. The method for improving the quality of vanadium-titanium sinter according to claim 2, characterized in that, In the sintering mixture, the mass fraction of the vanadium-titanium magnetite is not less than 35%.

4. The method for improving the quality of vanadium-titanium sinter according to claim 3, characterized in that, In addition to the iron material, the sintering mixture further contains flux, fuel and externally added return ore.

5. The method for improving the quality of vanadium-titanium sinter according to claim 4, characterized in that, The limestone powder is used as the flux, and the flux further contains active quicklime in addition to the limestone powder.

6. The method for improving the quality of vanadium-titanium sinter according to claim 5, characterized in that, In the sintering mixture, the mass fraction of the active quicklime is not less than 3.0%.

7. The method for improving the quality of vanadium-titanium sinter according to claim 6, characterized in that, The content of the sintering mixture with a particle size not less than 3mm is increased by increasing the moisture content of the sintering mixture.

8. The method for improving the quality of vanadium-titanium sinter according to claim 7, characterized in that, The height of the sintering material layer is not less than 700mm.

9. The method for improving the quality of vanadium-titanium sinter according to claim 8, characterized in that, The particle size of the limestone powder is not more than 2mm.

10. The method for improving the quality of vanadium-titanium sinter according to claim 9, characterized in that, ​

Images