Additive for improving performance of vanadium-titanium sinter and preparation method and application thereof

Abstract

The invention belongs to the technical field of vanadium-titanium sintering, and particularly relates to an additive for improving the performance of vanadium-titanium sinter and a preparation method and application thereof. In order to obviously improve the drum strength of the vanadium-titanium sinter and further improve the performance of the vanadium-titanium sinter, the invention provides an additive for improving the performance of the vanadium-titanium sinter, and the additive is obtained by mixing the following components in percentage by mass: 50-75% of composite calcium ferrite, 10-25% of waste glass powder, 10-20% of bentonite and 3-5% of quartz sand. When the additive prepared by the invention is added in a vanadium-titanium sinter sintering process, the drum strength of the sinter can be remarkably improved, the additive amount of the coke powder of the sinter is reduced, the quality of the sinter is improved, and a raw material foundation is laid for the stability of a blast furnace.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of vanadium-titanium sintering, and particularly relates to an additive for improving the performance of vanadium-titanium sinter and a preparation method and application thereof. BACKGROUND

[0002] As the main iron-containing raw material for blast furnace ironmaking, the metallurgical performance of sinter, especially the tumbler strength, is one of the core indicators for measuring the quality of sinter. High tumbler strength ensures that the sinter has sufficient wear resistance and impact resistance during transportation, charging and descending in the blast furnace, thereby maintaining good permeability and smooth state of the blast furnace, reducing the amount of dust blown out, and improving the utilization coefficient and production efficiency of the blast furnace.

[0003] However, the tumbler strength of vanadium-titanium sinter is generally lower than the average level of ordinary sinter. The tumbler strength of typical vanadium-titanium sinter often hovers in a low range, and there is still a significant gap from the ideal high strength target. This insufficient strength not only reduces the yield of sinter, but also limits the substantial strengthening of the blast furnace and the further reduction of the fuel ratio.

[0004] Therefore, under the premise of not significantly increasing production costs, not affecting environmental friendliness, and not relying on a large number of scarce minerals, it is of great practical significance and economic value to develop an innovative, efficient, reliable and easy-to-industrialize process method to significantly improve the tumbler strength of vanadium-titanium sinter. This is crucial for fully and efficiently utilizing valuable vanadium-titanium magnetite resources and improving the technical level and comprehensive competitiveness of the steel industry. SUMMARY

[0005] In order to significantly improve the tumbler strength of vanadium-titanium sinter and further improve the performance of vanadium-titanium sinter, the application provides an additive for improving the performance of vanadium-titanium sinter and a preparation method and application thereof. The additive prepared by the application can significantly improve the tumbler strength of sinter, reduce the addition amount of sinter coke powder, and improve the quality of sinter, thereby laying a raw material foundation for stable blast furnace operation.

[0006] To achieve the above application purposes, the technical solutions adopted by the application are as follows: In a first aspect, the application provides an additive for improving the performance of vanadium-titanium sinter, which comprises, by mass percentage, 50-75% of composite calcium ferrite, 10-25% of waste glass powder, 10-20% of bentonite, and 3-5% of quartz sand.

[0007] Further, the composite calcium ferrite contains, by mass percentage, 42-53% of TFe, 0.2-3% of SiO2, and 17-26% of CaO.

[0008] Further, the SiO2 content of the waste glass powder is greater than 75% by mass percentage.

[0009] Further, the SiO2 content of the waste glass powder is greater than 75% by mass percentage.

[0010] Further, the SiO2 content of the waste glass powder is greater than 75% by mass percentage.

[0011] Further, the SiO2 content of the waste glass powder is greater than 75% by mass percentage.

[0012] Further, the SiO2 content of the waste glass powder is greater than 75% by mass percentage.

[0013] Further, the SiO2 content of the waste glass powder is greater than 75% by mass percentage.

[0014] Thirdly, the application provides the application of the additive in improving the performance of vanadium-titanium sinter.

[0015] Further, the SiO2 content of the waste glass powder is greater than 75% by mass percentage. The mixture is obtained by mixing 42-43% of Pang ore concentrate, 25-30% of Guohao powder, 3-8% of 42 medium powder, 1-3% of gas ash, 1-3% of steel slag, 5-9% of limestone, 4-6% of active lime, 4-5% of coke powder, 2-8% of the additive and water.

[0016] Further, the SiO2 content of the waste glass powder is greater than 75% by mass percentage.

[0017] Further, the said national high powder refers to the high iron grade, low impurity content, fine particle size iron concentrate powder prepared by physical beneficiation and sintering process from the local mine in China, which includes: TFe 58-60%, SiO2 6-7%, CaO 1.8-2.5%, MgO 1-2%, Al2O3 1.5-2.9%, V2O5 0-0.15%, TiO2 1-4%, S <1%, P <0.08%, moisture 9.0-14% by mass percentage.

[0018] Further, the said 42 powder refers to the medium particle size domestic iron concentrate powder, which includes: TFe 40-43%, SiO2 25-28%, CaO 1.5-2.5%, Al2O3 5.5-7%, V2O5 0-0.1%, TiO2 0.3-0.8%, S <0.05%, P <0.2%, moisture 6-12%, average particle size 35-75 μm by mass percentage.

[0019] Further, the said gas ash includes: TFe 40-42%, SiO2 4.4-6.1%, CaO 4.5-6.5%, Al2O3 2-4.1%, V2O5 0.1-0.4%, TiO2 3-4.5%, S <0.4%, P <0.05%, moisture 5-8% by mass percentage.

[0020] Further, the said steel slag includes: TFe 18.4-23%, SiO2 10-12%, CaO 36-40%, Al2O3 3-4.5%, V2O5 0.6-2.1%, TiO2 0.6-2.0%, S <0.4%, P <0.05%, moisture 4-9% by mass percentage.

[0021] Further, the said limestone includes CaO content >50%.

[0022] Further, the said active ash includes CaO content >84%.

[0023] Further, the said coke powder includes fixed carbon >78%.

[0024] Further, in the above method, the moisture content of the mixture is 8.5-10%. The binary reduction is maintained at 2.1.

[0025] Further, in the above method, the mixture granulation time is 3-5 min.

[0026] Further, in the above method, the ignition temperature is 1200-1300℃.

[0027] Further, in the above method, the ignition negative pressure is 6-8 KPa.

[0028] Further, in the above method, the ignition time is 2-3 min.

[0029] Advantages: 1. The present application uses composite calcium ferrite, waste glass powder, bentonite and quartz sand as additives to improve the sintering performance of vanadium-titanium sintered ore, especially the drum strength. With the increase of the additives, the drum strength of the sintered ore prepared by the present application is improved by 2-4%.

[0030] 2. The additives of the present application reduce the return ore rate in sintering production, improve the yield, save the cost of raw materials and fuel, and improve the effective capacity of the sintering machine.

[0031] 3. Due to the addition of the additives, the powder is greatly reduced, the permeability of the blast furnace charge is greatly improved, the blast furnace operation is more stable and smooth, the pressure difference is reduced, thereby realizing the increase of the utilization coefficient, the decrease of the fuel ratio (coke ratio / coal ratio) and the increase of the coal injection amount, and finally reducing the production cost of pig iron and improving the smelting efficiency and yield in the whole process.

[0032] 4. The present application can also reduce the dust emission of the iron front system and improve the environmental benefits. DETAILED DESCRIPTION

[0033] In order to make the technical problems, technical solutions and advantages of the present application more clear, the present application will be further described in detail below in combination with the embodiments. Unless otherwise defined, all technical terms used in this text have the same meaning as understood by those of ordinary skill in the art.

[0034] In one embodiment of the present application, 50-75% composite calcium ferrite, 10-25% waste glass powder, 10-20% bentonite and 3-5% quartz sand are used as additives in the sintering process of sintered ore to improve the drum strength and yield of sintered ore. The additives finally contain 35-43% TFe, 19-22% CaO, 17-26% SiO2 and 3-6% water content.

[0035] The additives of the present application improve the drum strength of sintered ore by optimizing the liquid phase generation, bonding phase properties and microstructure, and the specific effects are as follows: Bentonite as a binder significantly improves the balling performance of the mixture and the permeability of the material layer, creating a prerequisite for uniform heating and sufficient mineral reaction. The bentonite content in the additives is limited to 10-20%. If the bentonite is insufficient, it will result in low balling rate, fragile wet ball, high reduction expansion rate and insufficient compressive strength of the pellet. Excessive bentonite will make the green ball too sticky, dry and easy to crack, increase energy consumption and cost, reduce the iron grade and deteriorate the reducibility, and the low-melting-point glass phase will cause ring formation.

[0036] Calcium ferrite is the key precursor of high-strength bonding phase (SFCA) that can promote the formation of high-quality and fluid liquid phase; the composite calcium ferrite content in the additive is limited to 50-75%. If the calcium ferrite is too low: the sintered ore cannot improve the stock strength, has poor reducibility, the amount of liquid phase is insufficient, which leads to loose particle combination, aggravation of low-temperature reduction disintegration (RDI), and high sintering temperature; if the calcium ferrite is too high: the cost increases, the fuel ratio is out of balance, and the generation of needle-like SFCA is inhibited.

[0037] The waste glass powder uses its low melting point characteristics to form a fluxing glass liquid phase at a relatively low temperature, to wet and bond the particles and fill the pores in advance, to improve the density and provide initial connection strength; the waste glass powder content in the additive is limited to 10-25%. If the waste glass is too high: the excess of high-temperature liquid phase leads to structural collapse, and the thermal expansion mismatch causes the risk of sintering ore cracking; if the waste glass is too low: the fluxing effect is insufficient, and the sintering densification is insufficient.

[0038] The quartz sand, as a basic component, mainly regulates the liquid phase chemical composition (especially the silicate content and properties) and the melt fluidity, and optimizes the CaO distribution under suitable alkalinity conditions, indirectly promoting the formation of more high-strength calcium ferrite phase. The quartz sand content in the additive is limited to 3-5%. If the amount is excessive, it will cause the melt to be rigid and the powder to be intensified, and if the amount is insufficient, it will cause the structure to be loose and the reducibility to be deteriorated.

[0039] Finally, these effects comprehensively reduce the internal pores of the sintered ore, make the structure more dense, and firmly connect the mineral particles with high-strength bonding phases (especially SFCA), thereby significantly improving its resistance to impact and friction, i.e., the tumbler strength.

[0040] The following specific examples will be listed to explain the scheme of the present application. Those skilled in the art will understand that the following examples are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. If the specific technology or condition is not specified in the examples, it is carried out according to the technology or condition described in the literature in the art or according to the product instruction. If the reagent or instrument is not specified by the manufacturer, it is a conventional product that can be obtained by market purchase.

[0041] Preparation of the additive in Example 1 Performance of raw materials: The composite calcium ferrite contains TFe of 52.1%, SiO2 of 0.2%, and CaO of 25.4%.

[0042] The waste glass powder contains SiO2 of 75.8% and CaO of 13.9%.

[0043] The bentonite contains SiO2 of 55.3%, Al2O3 of 14.3%, and CaO of 5.2%.

[0044] The quartz sand contains SiO2 of 95.6%.

[0045] 74% of composite calcium ferrite, 10-25% of waste glass powder, 10-20% of bentonite, 2% of quartz sand are crushed and ground, and then passed through a 150 mesh sieve, and then mixed uniformly to obtain the additive. The additive contains 41.5% of TFe, 18.14% of CaO, 21.31% of SiO2, and 1.1% of water content.

[0046] Application of the additive of test example 1 in sinter Under the same iron material configuration structure, different proportions of the additive are added for sintering test. The chemical composition of the raw materials used in the test and the sintering raw material configuration scheme are shown in Table 1 and Table 2: the content is in mass ratio. The CaO content in limestone is 52.52%. The CaO content in active lime is 92.31%. The fixed carbon in coke powder is 80%.

[0047] Table 1 Chemical analysis results of sintering test raw materials

[0048] Note: Ig represents loss on ignition.

[0049] Table 2 Iron ore ratio scheme for sintering test

[0050] The raw materials shown in Table 1 and the iron material ratio shown in Table 2 are prepared. The raw materials are mixed uniformly in a primary mixer with water, and the water content is controlled to be 8.5-9.5%; then the mixture is granulated in a secondary mixer for 3 minutes; the granulated mixture is uniformly distributed to the sintering device through a distributor, and the layer thickness is 700 mm; the sintering device is ignited by a sintering igniter, and the ignition fuel is natural gas, and the ignition time is 120 seconds; at the same time, the bottom of the sintering device starts to draw air to form a certain negative pressure under the grate, and the ignition negative pressure is 6 kPa; after ignition, the air is drawn from top to bottom through the sintering layer, and the sintering negative pressure is 15 kPa; after ignition, the combustion zone on the surface of the layer moves gradually to the lower layer as the upper fuel is burned out. When the combustion zone reaches the grate, the sintering process is completed, and the sinter is obtained. The quality performance index of the sinter is shown in Table 3. The sinter strength +6.3 mm, % is the drum strength = the mass of sinter with particle size greater than 6.3 mm / the total mass of the sample x 100%.

[0051] Table 3 Changes in sintering performance and drum strength

[0052] From the examples 1-4 of table 3, it can be seen that with the increase of the additive content in the sintering process, the drum strength and the yield of the sintered ore are improved in different degrees compared with before the addition, when the additive content is 6%, i.e. example 4, the drum strength and the yield of the sintered ore reach the highest value, which are increased by 3.53 and 1.36 percentage points respectively compared with before the addition (example 1). In addition, from the examples 5-7 of table 3, it can be seen that after the prepared additive is mixed into the vanadium-titanium sintered ore, the drum strength and the yield of the sintered ore are obviously increased compared with before the addition (example 1) when the coke powder is reduced by 6.6%, and the additive content is 6% (example 7), the drum strength and the yield of the sintered ore are increased by 1.37 and 0.83 percentage points respectively.

[0053] Through the experiment, it can be seen that the additive is added in the sintering, the drum strength of the sintered ore is improved, the content of high powder, 42 medium powder, active ash and coke powder of the sintered ore is reduced, the carbon emission is reduced, the quality of the sintered ore is improved, the yield is improved, and the sintering cost is reduced.

Claims

1. An additive for improving the properties of vanadium-titanium sinter, characterized in that: By mass percentage, the composition includes 50-75% composite calcium ferrite, 10-25% waste glass powder, 10-20% bentonite, and 3-5% quartz sand.

2. The additive according to claim 1, characterized in that: By weight percentage The composite calcium ferrite contains 42-53% TFe, 0.2-3% SiO2, and 17-26% CaO. The waste glass powder has an SiO2 content greater than 75%; The bentonite contains 55-70% SiO2 and 12-25% Al2O3. The quartz sand has a SiO2 content greater than 95%.

3. The additive according to claim 2, characterized in that: The additive, by mass percentage, contains 35-43% TFe, 19-22% CaO, 17-26% SiO2, and 3-6% water.

4. The method for preparing the additive according to any one of claims 1 to 3, characterized in that: The raw materials are pulverized and sieved according to the following mass percentages: 50-75% composite calcium ferrite, 10-25% waste glass powder, 10-20% bentonite, and 3-5% quartz sand. The mixture is then thoroughly mixed. The raw material ratio is determined and adjusted based on the final additive having a TFe content of 35-43%, a CaO content of 19-22%, a SiO2 content of 17-26%, and a moisture content of 3-6%.

5. The application of the additive according to any one of claims 1 to 3 in improving the performance of vanadium-titanium sinter.

6. The application according to claim 5, characterized in that, The method of using the additives includes the following steps: by mass percentage, add 42-43% Panzhihua concentrate, 25-30% Guogao powder, 3-8% 42 medium powder, 1-3% gas ash, 1-3% steel slag, 5-9% limestone, 4-6% active ash, 4-5% coke powder, and 2-8% additives, add water, mix well and granulate to obtain a mixture. The mixture is then spread, ignited, and sintered to obtain sintered ore.

7. The application according to claim 6, characterized in that, Meet at least one of the following: The concentrate, by mass percentage, comprises: TFe 52.5–56%, SiO2 3.0–5.5%, CaO 1.0–2.5%, MgO 2.2–4.5%, Al2O3 2.8–4.5%, V2O5 0.4–0.65%, TiO2 10.8–13.5%, S <1%, P <0.05%, and moisture 8–12%. The high-quality powder, by mass percentage, comprises: 58-60% TFe, 6-7% SiO2, 1.8-2.5% CaO, 1-2% MgO, 1.5-2.9% Al2O3, 0-0.15% V2O5, 1-4% TiO2, S<1%, P<0.08%, and 9.0-14% moisture. The 42 powders, by mass percentage, comprise: 40-43% TFe, 25-28% SiO2, 1.5-2.5% CaO, 5.5-7% Al2O3, 0-0.1% V2O5, 0.3-0.8% TiO2, <0.05% S, <0.2% P, 6-12% moisture, and an average particle size of 35-75 μm. The gas ash, by mass percentage, comprises: 40-42% TFe, 4.4-6.1% SiO2, 4.5-6.5% CaO, 2-4.1% Al2O3, 0.1-0.4% V2O5, 3-4.5% TiO2, <0.4% S, <0.05% P, and 5-8% moisture. The steel slag, by mass percentage, comprises: 18.4–23% TFe, 10–12% SiO2, 36–40% CaO, 3–4.5% Al2O3, 0.6–2.1% V2O5, 0.6–2.0% TiO2, S < 0.4%, P < 0.05%, and moisture 4–9%. The limestone contains >50% CaO. The active ash contains >84% CaO; The coke powder contains >78% fixed carbon.

8. The application according to claim 6, characterized in that, The moisture content of the mixture is 8.5-10%.

9. The application according to claim 6, characterized in that, The pelleting time for the mixture is 3 to 5 minutes.

10. The application according to claim 6, characterized in that, Ignition temperature 1200~1300℃, ignition negative pressure 6~8KPa.

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