Process for producing vanadium-titanium sinter

Abstract

The application discloses a production process of vanadium-titanium sintered ore, which comprises the following steps: ingredient mixing, material mixing, balling, material distribution, ignition and sintering, wherein the ingredient mixing comprises the following steps: mixing of ore, fuel and flux, the activity of the flux is 13.9-23.4 DEG C / min, the particle size of the fuel is 0.5-3 mm, and the layer thickness in the material distribution is 700-750 mm. The sintering quality is comprehensively improved, and the sintering energy consumption is reduced by adjusting the activity of the flux, the fuel particle size and the layer thickness.

Description

Technical Field

[0001] This invention relates to the field of iron and steel metallurgy technology, specifically to a production process for vanadium-titanium sinter. Background Technology

[0002] China's steel industry is a long-process steelmaking industry mainly consisting of coking, sintering and agglomeration, blast furnace ironmaking and converter steelmaking. In 2021, my country's steel production reached 1.033 billion tons. As the world's largest single-unit ironmaking equipment with the most mature supporting facilities, the longest service life and the highest smelting efficiency, the blast furnace will continue to dominate for a long time.

[0003] Vanadium-titanium sintering is a production process preceding blast furnace ironmaking and steelmaking. Its purpose is to mix various powdered iron-containing raw materials with appropriate amounts of fuel and flux, add water, and then, after mixing and pelletizing, sinter them into blocks on sintering equipment, causing a series of physicochemical changes. The quality of the sintered parts directly affects the production and product quality of subsequent ironmaking and steelmaking processes.

[0004] In the vanadium-titanium sintering process, improper matching of flux activity, fuel particle size, and bed thickness can all affect the performance of the sinter. Improving sintering quality, reducing sintering costs, and simultaneously achieving energy conservation and enhanced environmental protection are current requirements for sintering production. Summary of the Invention

[0005] In order to overcome the deficiencies in the prior art, this invention provides a production process for vanadium-titanium sinter, which comprehensively improves sintering quality and reduces sintering energy consumption by adjusting the flux activity, fuel particle size, and material layer thickness.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a production process for vanadium-titanium sinter, including batching, mixing, pelletizing, spreading, ignition and sintering. The batching includes ore, fuel and flux. The flux has an activity of 13.9 to 23.4 °C / min. The fuel has a particle size of 0.5 to 3 mm. The material layer thickness in the spreading process is 700 to 750 mm.

[0008] Preferably, the flux is selected from one or more of quicklime, limestone, dolomite, and dust-removing lime.

[0009] Preferably, the activity of the flux is 23.4 °C / min.

[0010] Preferably, the fuel is coke powder and / or anthracite.

[0011] Preferably, the fuel has a particle size of 0.5-1 mm and 1-3 mm, and the content of 1-3 mm particles is greater than or equal to the content of 0.5-1 mm particles.

[0012] Preferably, the mineral material includes one or more of recycled ore and blended powder.

[0013] Preferably, the minerals, fuels, and fluxes in the ingredients are, by weight percentage: 28-38% recycled ore, 0-1% dust-removing lime, 0% limestone powder, 2-4.5% dolomite powder, 50-55% mixed powder, 3-5% coke powder, and 5-11% quicklime.

[0014] More preferably, the minerals, fuels and fluxes in the ingredients are, by weight percentage: 28% recycled ore, 5% coke powder, 0% anthracite, 10.5% quicklime, 1% dust-removing lime, 0% limestone powder, 2% dolomite powder, and 53.5% blending powder.

[0015] Preferably, the chemical composition of the vanadium-titanium sinter is Fe 47.00%, SiO2 6.34%, CaO 14.02%, MgO 3.11%, Al2O3 3.19%, S 0.12%, TiO2 5.40%, H2O 8.00%, and lg 7.83%.

[0016] The beneficial effects of this invention are:

[0017] This invention has found that the activity of the flux has a significant impact on the quality of sinter. As the activity increases, the drum strength, yield, vertical sintering speed, and low-temperature reduction pulverization index (RDI) of the sinter also increase. +3.15 While the trend is upward, exceeding the scope of this invention will affect the quality of sinter. Simultaneously, effectively controlling the particle size of the fuel can improve production efficiency, increase output, and reduce carbon consumption. Furthermore, controlling the content of 1-3mm particles to be greater than or equal to the content of 0.5-1mm particles can improve the yield of sinter, vertical sintering speed, and utilization coefficient, but this will lead to a faster vertical sintering speed and a slight decrease in drum strength. This can be balanced by increasing the material layer thickness; therefore, the material layer thickness needs to be controlled at 700mm-750mm to improve the drum strength of the sinter and enhance its metallurgical properties, thus mitigating the decrease in sinter strength caused by changing the coke powder particle size. Attached Figure Description

[0018] Figure 1 A schematic diagram of the apparatus for determining the activity of lime by the temperature rise method (1: JJ-A precision booster electric stirrer display instrument; 2: support frame; 3: JJ-A precision booster electric stirrer motor; 4: thermocouple; 5: container; 6: 85-2 digital display thermometer).

[0019] Figure 2 The graph in Table 3 of Example 2 shows the temperature rise curve of quicklime in comparative experimental group 1.

[0020] Figure 3 The graph in Table 3 of Example 2 shows the temperature rise curve of quicklime in comparative experimental group 2.

[0021] Figure 4 The graph shows the effect of the ratio of self-produced ash to purchased ash on the maximum temperature time in Example 2.

[0022] Figure 5 This is a graph showing the effect of the ratio of self-produced ash to purchased ash on the activity of quicklime in Example 2. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solution of the invention, the invention will be further described in detail below with reference to specific embodiments.

[0024] Example 1: Production process of vanadium-titanium sinter

[0025] This embodiment provides a production process for vanadium-titanium sinter, the specific steps of which are as follows:

[0026] Ingredients:

[0027] The minerals, fuels, and quicklime used in this embodiment were all provided by the Desheng Group sintering plant. The chemical composition of the raw materials is shown in Table 1. The raw materials in Table 1 were mixed together.

[0028] Table 1. Chemical composition of raw materials (%)

[0029]

[0030]

[0031] The weight percentages of each raw material are as follows: 28% recycled ore, 5% coke powder, 0% anthracite, 10.5% quicklime, 1% dust-removing lime, 0% limestone powder, 2% dolomite powder, and 53.5% blending powder.

[0032] The ingredients are then subjected to a series of processes, including mixing, pelletizing, spreading, ignition and sintering, hot crushing, cooling in a ring cooler, and screening of the finished product.

[0033] Example 2: Effect of quicklime activity on the properties of vanadium-titanium sinter

[0034] Experimental Design:

[0035] The quality of quicklime is often measured by its "activity," which reflects its reactivity with other substances. This example demonstrates seven different ratios of quicklime, varying the proportions of self-produced and purchased quicklime. To minimize experimental error, control experiments were included for each group. The experimental scheme is shown in Table 2. This experiment employed the temperature rise rate method, and the experimental setup was as follows: Figure 1 As shown, 225 ml of deionized water at 24°C was poured into a 1000 ml insulated container. The stirrer was turned on and the speed was controlled at 300 r / min. Then, 75 g of quicklime sample with a particle size of less than 1 mm, prepared according to the experimental plan, was poured into the container. At the same time, timing and temperature measurement were started, and the temperature value was read every 10 seconds until the temperature dropped. The time t when the highest temperature first appeared and the highest temperature Tmax reached were recorded. The temperature rise rate was calculated according to formula (1), which is the activity of quicklime. A control group was set up for each group of samples, and the average activity was taken. The activity results of samples with different quicklime ratios are shown in Table 3.

[0036]

[0037] Table 2 Sample ratio for activity level

[0038]

[0039] Table 3. Test data for quicklime activity.

[0040]

[0041]

[0042] Results and Analysis:

[0043] 1. Quicklime activity test

[0044] Test results are shown Figures 2-5 ,Depend on Figure 2 , Figure 3 It can be seen that the temperature rise rate initially increases rapidly, then slows down significantly at the reaction endpoint until the maximum temperature is reached, and this maximum temperature remains essentially unchanged regardless of the ratio of self-produced ash to purchased ash; Figure 4 and Figure 5 It can be seen that as the proportion of self-generated ash added decreases, the time to reach the highest temperature increases from 107s to 251s, and the activity also decreases from 29.1℃ / min to 13.6℃ / min.

[0045] 2. The Influence of Quicklime Activity on the Technical Indicators of Sintered Ore

[0046] The results of the effect of quicklime activity on the quality of sinter are shown in Table 6.

[0047] (1) Effect on the strength of the sinter drum

[0048] Table 6 shows that the overall drum strength of sinter increases with the increase of the proportion of self-produced ash (or the decrease of the proportion of purchased ash), indicating that the higher the activity of quicklime, the better the drum strength. The strength of sinter is mainly related to the formation of calcium ferrite. Higher activity of self-produced ash is conducive to the formation of fine needle-like and acicular calcium ferrite, leading to an overall upward trend in the drum strength of sinter. When the proportion of self-produced ash is 80% and 100%, the drum strength decreases, which is likely due to the cooling rate being the dominant factor. The amount of calcium ferrite precipitation mainly depends on the cooling rate; the faster the cooling rate, the less calcium ferrite is precipitated. Therefore, the drum strength of sinter is better when the activity of quicklime is between 13.9 and 23.4 °C / min, with the highest activity being 23.4 °C / min.

[0049] (2) Impact on vertical sintering speed and yield of sintered ore

[0050] As shown in Table 6, with the increase of the proportion of self-produced ash (or the decrease of the proportion of purchased ash), the yield and vertical sintering speed of sintered ore both show an increasing trend. The sintered ore reaches the highest yield of 90.76% when the quicklime activity is 23.4℃ / min. High-activity lime generally has small lime crystals, large specific surface area, many pores, good chemical reactivity, fast water digestion speed, and high degree of digestion. The Ca(OH)2 particles generated after contact with water have extremely strong binding properties, which can improve the pelleting of the mixture, increase the strength of green pellets, improve the permeability of the material layer, and strengthen the sintering process, thus increasing the vertical sintering speed and yield.

[0051] (3) Effect on the low-temperature reduction pulverization index

[0052] As shown in Table 6, with the increase of the proportion of self-produced ash (or the decrease of the proportion of purchased ash), the Low Temperature Reduction Pulverization Index (RDI) decreases. +3.15 The trend is upward. This is mainly related to the amount of calcium ferrite binder phase generated. Highly active quicklime generates more liquid calcium ferrite, which is beneficial for improving the low-temperature reduction pulverization index and has a more obvious effect on thick material layers.

[0053] Table 6. Effect of quicklime activity on sinter.

[0054]

[0055] Example 3: Effect of coke powder particle size on the properties of vanadium-titanium sinter

[0056] Experimental Design:

[0057] To study the effect of different coke powder particle sizes on the quality of sinter, this embodiment sets the material layer thickness at 750 mm. The specific experimental scheme is shown in Table 4. The study investigates the effect by varying the proportion of different coke powder particle sizes, while keeping the total coke powder proportion constant. The experimental scheme is shown in Table 5. Due to the small scale of the experiment (100 kg of mixed material per cup), even slight variations in lime, limestone, and dolomite make moisture control difficult. Therefore, quantitative water addition was adopted. During material distribution, 3 kg of sinter with a particle size of 10–16 mm was first added to the bottom of the sintering cup as a base material to protect the grate. The material level was measured. The ignition temperature was 1150℃ ± 50℃. The ignition exhaust negative pressure was adjusted to 8 kPa. After ignition, the igniter was removed. The exhaust negative pressure was adjusted to approximately 16 kPa. The sintering time was recorded when the exhaust gas temperature reached its highest value. The height of the material surface from the sintering cup opening was measured, and the sinter was poured out and weighed.

[0058] Sinter performance testing includes indicators such as sinter yield, utilization coefficient, and particle size distribution of the finished ore. Low Reduction Diffusion Index (RDI) is also a key metric. +3.15 The degree of pulverization of iron ore is indicated by the formula (2).

[0059]

[0060] Wherein, m0 is the mass of the sample before the drum rotates, in grams;

[0061] m D0 —Mass of the sample after drum rotation, in grams;

[0062] m D1 —The mass of the sample remaining on the 6.3mm sieve, in grams;

[0063] m D2 —The mass of the sample remaining on the 3.15mm sieve, in grams;

[0064] Table 4 Sintering Test Mix Ratio (wt%)

[0065]

[0066] Table 5. Test schemes for different coke powder particle sizes (%)

[0067]

[0068] Results and Analysis:

[0069] 1. The effect of coke powder particle size on sintering composition

[0070] Table 7 shows the composition of sinter with different coke powder particle sizes. As can be seen from Table 7, changes in coke powder particle size have little impact on the overall composition of the sinter, which remains essentially unchanged. This indirectly indicates that the ore blending in this experiment was accurate, the process control was good, and the experiment has high reference value.

[0071] Table 7. Mineral composition (%) of coke powder combustion sintering cup test

[0072]

[0073] 2. The Influence of Coke Powder Particle Size on the Technical Indicators of Sinter

[0074] Table 8 shows the test results of sintering cups with different coke powder particle sizes. It can be seen that as the proportion of coke powder particles smaller than 1 mm decreases (or the proportion of 1-3 mm increases), the drum strength decreases. The coarser coke powder particle size leads to an increase in vertical sintering speed. This increase in vertical sintering speed results in insufficient crystallization of the sinter, and a decrease in the amount of liquid phase generated and fluidity, leading to a decrease in the overall strength of the sinter. This results in an increase in the amount of sinter powder smaller than 0.5 mm, causing an increase in the abrasion resistance index of the sinter. As the proportion of coke powder particles smaller than 1 mm decreases (or the proportion of 1-3 mm increases), the utilization coefficient increases. As the proportion of coke powder particles smaller than 1 mm decreases (or the proportion of 1-3 mm increases), the firing rate and yield increase. This shows that increasing the coarser coke powder particle size has a significant effect on accelerating production efficiency. As the proportion of coke powder particles smaller than 1 mm decreases (or the proportion of 1-3 mm increases), the RDI (Relative Dioxide) also increases. +3.15 It showed a slight decrease, but remained basically stable with a small range of variation.

[0075] Table 8. Effect of coke powder particle size on sinter.

[0076]

[0077]

[0078] Fuel particle sizes larger than 3mm and smaller than 0.5mm are undesirable in sintering. Both excessively coarse and excessively fine fuel particles are detrimental to combustion and heat transfer rates, reducing fuel utilization and consequently affecting product quality and solid fuel consumption. The sintering combustion reaction rate is primarily controlled by sintering temperature, fuel particle size, and combustion atmosphere. In the high-temperature zone, the reaction rate is controlled by fuel particle size and permeability. Therefore, controlling fuel particle size can improve production efficiency, increase output, and reduce carbon consumption. However, this may lead to a faster vertical sintering speed and a slight decrease in drum strength, which can be balanced by increasing the material layer thickness.

[0079] Example 4: Effect of bed thickness on the properties of vanadium-titanium sinter

[0080] Experimental Design:

[0081] To investigate the effect of different quicklime reactivity on the bed thickness, sintering cup experiments with bed thicknesses of 700 mm and 750 mm were conducted. Specific batching schemes are shown in Table 4. The sinter quality testing indicators and methods were the same as in Example 3.

[0082] Results and Analysis:

[0083] 1. The effect of material layer thickness on sintering composition

[0084] The chemical composition analysis results of sinter with different bed thicknesses are shown in Table 8. As can be seen from Table 8, the effect of the change in bed thickness on the TFe content of the sinter is almost negligible. When the bed height is 700 mm, the FeO content is 10.40%, which decreases to 7.39% when the bed thickness is 750 mm. Other components and basicity remain almost unchanged, indicating that different bed thicknesses have little effect on the composition of the sinter.

[0085] Table 8. Effect of different bed thicknesses on the composition of sinter (%)

[0086]

[0087] 2. The Influence of Material Layer Thickness on the Technical Indicators of Sintered Ore

[0088] Table 9 shows the technical indicators of sinter with different material layer thicknesses. As can be seen from the table, different material layer thicknesses have different effects on the drum strength, sintering speed, yield, and low-temperature reduction pulverization index of the sinter. When the material layer thickness is increased from 700 mm to 750 mm, the yield decreases from 91.46% to 88.39%, and the sintering speed decreases from 30.17 mm / min. -1 It becomes 30.30 mm·min -1 The utilization coefficient is 2.18t / (m 2 The concentration of ·h) decreased to 2.06t / (m 2 (h) The strength of the sinter drum increased from 54.70% to 57.30%. With the increased sinter bed height, the automatic heat storage effect of the bed was enhanced, thus improving the strength of the sinter. The low-temperature reduction pulverization index (RDI) increased. +3.15 The percentage increased from 75.31% to 79.03%, indicating a certain improvement in metallurgical performance.

[0089] Table 9. Effect of different material layer thicknesses on sinter.

[0090]

[0091] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A process for the production of vanadium titano-magnetite characterized in that, The method comprises batching, mixing, pelletizing, distributing, igniting and sintering, wherein the batching comprises mineral material, fuel and flux, the activity of the flux is 13.9-23.4 ℃ / min, the layer thickness in the distributing is 700-750 mm; the fuel is divided into 0.5-1 mm and 1-3 mm in size, and the content of 1-3 mm is greater than or equal to the content of 0.5-1 mm, the fuel is coke powder and / or anthracite; the chemical composition of the sintered ore is Fe 47.00%, SiO2 6.34%, CaO 14.02%, MgO 3.11%, Al2O3 3.19%, S 0.12%, TiO2 5.40%, H2O 8.00%, Lg 7.83%.

2. The production process according to claim 1, characterized in that, The flux is selected from one or more of quicklime, limestone, dolomite and dedusting lime.

3. The production process according to claim 1 or 2, characterized in that, The activity of the flux is 23.4 ℃ / min.

4. The production process according to claim 1, characterized in that, The mineral material comprises return fines and / or mixed powder.

5. The production process according to claim 1, characterized in that, In the batching, the mineral material, fuel and flux are 28-38% return fines, 0-1% dedusting lime, 2-4.5% dolomite powder, 50-55% mixed powder, 3-5% coke powder and 5-11% quicklime.

6. The production process according to claim 5, characterized in that, In the batching, the mineral material, fuel and flux are 28% return fines, 5% coke powder, 10.5% quicklime, 1% dedusting lime, 2% dolomite powder and 53.5% mixed powder.

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