Preparation method of sintered ore based on Bayan obo iron ore concentrate and langbridge ore

Abstract

The invention discloses a preparation method of sintered ore based on Bayan Obo iron ore concentrate and langbridge ore. The sintered ore is characterized by comprising the following raw materials in percentage by mass: 17.27-17.29% of Bayan Obo iron ore concentrate, 0-17.27% of first iron-containing fine ore, 6-7% of second iron-containing fine ore, 3-6% of third iron-containing fine ore, 2-3% of fourth iron-containing fine ore and 5-25% of langbridge ore. The raw materials comprise 3.4-3.60% of limestone, 3.9-4.0% of quick lime, 4.4-4.6% of dolomite, 3.9-4% of coke powder and 25-35% of blast furnace return mine; weighing the sintering materials according to the weight, pouring the sintering materials into a mixing device, stirring and uniformly mixing, and adding a proper amount of water in the uniformly mixing process to obtain uniformly mixed materials; putting the uniformly mixed material into a secondary mixing device for granulating; and after granulation is completed, feeding into a sintering device for ignition, sintering, crushing, cooling, falling, screening and drum strength detection.

Description

Technical Field

[0001] This invention relates to the field of sintering technology, and in particular to a method for preparing sintering based on Bayan Obo iron concentrate plus Lanqiao ore. Background Technology

[0002] The general method for preparing sinter is as follows: various powdered iron-containing materials, fuel, and flux are added in proportion, along with an appropriate amount of water. After mixing and granulation, the materials undergo a series of physicochemical reactions on sintering equipment, causing the mineral powder particles to agglomerate into sinter. Sinter is currently the main raw material for blast furnace production, and its quality directly affects the economic indicators of blast furnace production.

[0003] The Bayan Obo iron concentrate, located in northern Baotou City, Inner Mongolia Autonomous Region, is a super-large deposit containing 175 minerals, including iron, rare earth elements, and niobium, with very rich reserves. Bayan Obo iron concentrate is a special type of ore, characterized by low iron content and high levels of fluorine, potassium, and sodium; its mineral composition is complex, with silica primarily existing as complex silicates containing potassium and sodium; it has a fine grinding particle size and a wide melting temperature range. Due to these characteristics, Bayan Obo iron concentrate requires the addition of other iron concentrates to obtain high-quality sinter. Therefore, the study of adding a certain proportion of Lanqiao ore to Bayan Obo iron concentrate to improve the quality of sinter has significant research value. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing sintered ore based on Bayan Obo iron concentrate plus Lanqiao ore, thereby solving the problem of poor mineralization characteristics of Bayan Obo iron concentrate itself.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] This invention discloses a method for preparing sintered ore based on Bayan Obo iron concentrate and Lanqiao ore. The raw materials, by mass percentage, include: Bayan Obo iron concentrate 17.27-17.29%, iron-bearing ore powder I 0-17.27%, iron-bearing ore powder II 6-7%, iron-bearing ore powder III 3-6%, iron-bearing ore powder IV 2-3%, Lanqiao ore 5-25%; limestone 3.4-3.60%, quicklime 3.9-4.0%, dolomite 4.4-4.6%, coke powder 3.9-4%, and blast furnace return ore 25-35%. The sintering materials are weighed and poured into a mixing device for stirring and mixing. During the mixing process, an appropriate amount of water is added to obtain a homogenized material. The homogenized material is then loaded into a second mixing device for granulation. After granulation, the material is sent to a sintering device for ignition, sintering, crushing, cooling, dropping, screening, and drum strength testing.

[0007] Furthermore, the raw materials by weight percentage include: Bayan Obo iron concentrate 17.27%, iron-bearing ore powder I 17.27%, iron-bearing ore powder II 6.47%, iron-bearing ore powder III 5.40%, iron-bearing ore powder IV 2.16%, Lanqiao ore 5.40%; limestone 3.60%, quicklime 3.99%, dolomite 4.47%, coke powder 3.99%, and blast furnace return ore 30%.

[0008] Furthermore, the raw materials by weight percentage include: Bayan Obo iron concentrate 17.27%, iron-bearing ore powder I 12.41%, iron-bearing ore powder II 6.47%, iron-bearing ore powder III 4.86%, iron-bearing ore powder IV 2.16%, Lanqiao ore 10.79%; limestone 3.54%, quicklime 3.99%, dolomite 4.53%, coke powder 3.99%, and blast furnace return ore 30%.

[0009] Furthermore, the raw materials by weight percentage include: Bayan Obo iron concentrate 17.27%, iron-bearing ore powder I 7.55%, iron-bearing ore powder II 6.47%, iron-bearing ore powder III 4.32%, iron-bearing ore powder IV 2.16%, Lanqiao ore 16.19%; limestone 3.54%, quicklime 3.99%, dolomite 4.53%, coke powder 3.99%, and blast furnace return ore 30%.

[0010] Furthermore, the raw materials by weight percentage include: Bayan Obo iron concentrate 17.29%, iron-bearing ore powder I 0.0%, iron-bearing ore powder II 6.48%, iron-bearing ore powder III 3.24%, iron-bearing ore powder IV 2.16%, Lanqiao ore 24.85%; limestone 3.41%, quicklime 3.99%, dolomite 4.59%, coke powder 3.99%, and blast furnace return ore 30%.

[0011] Furthermore, the main components of the iron-containing powder by mass percentage include: TFe 59.82%, FeO <0.5%, CaO 0.225%, SiO2 4.52%, MgO 0.09%, P 0.085%, Al2O3 2.51%, Ig 5.99%.

[0012] Furthermore, the main components of the iron-containing ore powder by mass percentage include: TFe 55.01%, FeO 1.75%, CaO 1.17%, SiO2 13.4%, MgO 0.58%, P 0.064%, S 0.036%, K2O 0.043%, Na2O 0.02%, Al2O3 3.18%, and Ig 6.63%.

[0013] Furthermore, the main components of the iron-bearing ore powder by mass percentage include: TFe 58.28%, FeO <0.5%, CaO 0.05%, SiO2 5.30%, MgO 0.12%, P 0.079%, Al2O3 2.72%, and Ig 7.44%.

[0014] Furthermore, the main components of the iron-bearing ore powder by mass percentage include: TFe 62.69%, CaO 0.47%, SiO2 3.25%, MgO 3.17%, F 0.05%, P 0.051%, Al2O3 1.34%, and Ig 2.0%.

[0015] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0016] This invention develops a new type of ore by optimizing the ore blending structure, providing more ore blending schemes for subsequent sinter production and ensuring a smoother production process; Lanqiao ore is an economical material, and increasing its blending ratio will reduce the cost of the sintering process to a certain extent. Detailed Implementation

[0017] A method for producing sinter based on Bayan Obo iron concentrate blended with Lanqiao ore, the details of which are as follows:

[0018] I. Material Proportioning for Sintered Ore

[0019] A sintered ore based on Bayan Obo iron concentrate and Lanqiao ore is sintered from the following sintering materials: iron-bearing materials mainly include: Bayan Obo iron concentrate, iron-bearing ore powder one (imported ore powder), iron-bearing ore powder two (imported ore powder), iron-bearing ore powder three (imported ore powder), iron-bearing ore powder four (local ore powder), and Lanqiao ore. Sintering auxiliary materials mainly include limestone, dolomite, quicklime, coke powder, and blast furnace return ore. The material ratio is as follows:

[0020] Table 1 Material Proportioning Scheme, %

[0021]

[0022] II. Experimental Procedure

[0023] (1) Weigh the sintering materials according to their weight and pour them into a mixing device to stir and mix them evenly. During the mixing process, add an appropriate amount of water to obtain a mixed material.

[0024] (2) The mixed material is loaded into the secondary mixing device for granulation;

[0025] (3) After granulation, the pellets are fed into the sintering device for ignition, sintering, crushing, cooling, dropping, screening, and drum strength testing.

[0026] The technical solution of the present invention will be described in detail below with reference to the embodiments.

[0027] Chemical composition of the test materials

[0028] All experimental raw materials were obtained from the field. Iron-bearing raw materials included: Bayan Obo iron concentrate, iron-bearing fine ore I, iron-bearing fine ore II, iron-bearing fine ore III, iron-bearing fine ore IV, and Lanqiao ore. Fluxes included limestone, quicklime, and dolomite. Limestone and quicklime were used to adjust the basicity of the sinter, while dolomite was mainly used to adjust the MgO content of the sinter. Coke powder was used as fuel. Their chemical compositions are shown in Table 2.

[0029] Table 2. Chemical composition of the iron-containing raw materials and fluxes used in the experiment, %

[0030]

[0031] Table 3 Particle size distribution of LQ mixed ore powder, %

[0032]

[0033] As shown in Table 3, the particle size of this batch of LQ mixed ore powder is relatively fine, with the proportion of 3-7mm particles being only 7.73%, which is 38.59 percentage points lower than that of iron-containing ore powder. This is mainly reflected in the fact that the proportion of particles larger than 7mm is lower than that of iron-containing ore powder by 10.67 percentage points, while the proportion of particles smaller than 1mm is 51.82%, which is 30.9 percentage points higher than that of iron-containing ore powder. From the particle size composition analysis of this batch of Lanqiao ore, the proportion of small particles is relatively large, mainly concentrated in the range of particles smaller than 3mm, reaching more than 91%. After being added to the sintering, it affects the granulation effect of the sintering mixture and the air permeability of the sintering bed.

[0034] Test Plan

[0035] The experiment was based on a configuration of 17% iron concentrate from Bayan Obo and approximately 22% iron powder. The test points were sintered in sintering cups by adjusting different iron materials. The specific test plan is shown in Table 4.

[0036] Table 4 Material Allocation Scheme, %

[0037]

[0038] The experimental scheme designed a total of 5 test points for sintering cup tests. Test point JZ was based on the iron material with a proportion of 17% of Bayan Obo ore. Test points used 5.4%, 10.79%, 16.19%, and 24.85% of Lanqiao ore to replace the currently used iron-containing powder ore one in different proportions. At the same time, the proportion of iron-containing powder ore three was adjusted to keep the SiO2 of the sinter consistent. The proportions of other iron materials were not adjusted.

[0039] Sintering cup test process parameter control

[0040] The experiment used a 200mm diameter sintering cup from the Ironmaking Research Institute of Baogang Technology Center, with a material layer thickness of 700mm, an ignition negative pressure of 6Kpa, and a sintering negative pressure of 10Kpa. The basicity of the sinter was controlled at 2.15±0.01, the MgO content of the sinter was 2.0%±0.1%, and the SiO2 content was 5.2%±0.01%.

[0041] Example 1

[0042] According to the proportions in the table, put iron ore powder and sintering auxiliary materials such as limestone and dolomite into a mixer and mix them evenly. During the mixing process, add an appropriate amount of water to obtain a mixed material.

[0043] The mixed material is placed into a cylindrical mixer for granulation;

[0044] The granulated material was placed in a sintering cup with a diameter of 200 mm. Sintering was carried out under the following sintering parameters: a mixed material layer height of 700 mm, a bottom material thickness of 20 mm, an ignition temperature of 1050℃, an ignition time of 120 seconds, and a negative pressure of 10 kPa. The sintered ore was obtained, and after crushing, cooling, and screening, the finished sintered ore was obtained. The particle size and other performance indicators of the sintered ore are shown in the table.

[0045] The chemical composition of the sinter after adding Lanqiao ore is shown in Table 5.

[0046] Table 5 Chemical composition (%) of sintered ore after adding LQ mixed ore powder

[0047]

[0048] According to the chemical composition calculated by theoretical analysis of sinter, the grade of sinter increased from 55.21% to 55.39% after adding Lanqiao ore, an increase of 0.18 percentage points. The Al2O3 content increased by 0.34 percentage points, while other chemical components remained largely unchanged.

[0049] The data results of the sinter quality indicators after adding Lanqiao ore to the sinter are shown in Table 6.

[0050] Table 6 Changes in Sinter Quality Indicators

[0051]

[0052] As shown in Table 6:

[0053] After partially or completely replacing iron-containing ore powder with Lanqiao ore, the yield tended to decrease; after partially or completely replacing iron-containing ore powder with Lanqiao ore, the solid fuel content tended to increase. To investigate the changes in sintering vertical velocity at different test points, the moisture content of the mixture was kept relatively constant during the sintering test. The vertical velocity at the test points decreased compared to the baseline point. The increase in Lanqiao ore with a higher proportion of fine particles at the test points led to a decrease in vertical velocity compared to the baseline point. Analysis suggests that fine-grained iron ore powder tends to form excessive liquid phase during sintering, resulting in poor permeability of the sintered material layer and a decrease in vertical velocity. After partially or completely replacing iron-containing ore powder with Lanqiao ore, the utilization coefficient showed a decreasing trend, decreasing by 0.14–0.22 t / m compared to the baseline point. 2 In the comparative test of h.1#, the drum strength did not change. However, when the proportion of Lanqiao ore was increased to 20%, the drum strength began to decrease, dropping by 0.27 to 1.87 percentage points compared to the benchmark.

[0054] Comprehensive analysis suggests that the addition of Lanqiao ore increases the amount of fine-grained iron ore powder, worsens the particle size distribution of the mixture, affects the permeability of the sintering bed during sintering, leads to a decrease in the sintering utilization coefficient, an increase in fuel consumption, and a deterioration in the strength of the sinter drum.

[0055] Table 7. Variation in particle size composition of sintered ore

[0056]

[0057] As shown in Table 7:

[0058] (1) Particle size composition: As the proportion of Lanqiao ore increases, the proportion of sinter with a particle size of >40mm gradually decreases, decreasing by 1.85 to 6.69 percentage points compared to the benchmark, while the proportion of 25 to 16mm particle size gradually increases, increasing by 2.6 to 5.97 percentage points compared to the benchmark.

[0059] (2) Average particle size: After the iron-containing powder ore was partially or completely replaced by Lanqiao ore, the average particle size of the sinter showed a downward trend. With the increase of the addition ratio, the average particle size decreased by 0.37 to 2.43 mm.

[0060] Based on comprehensive analysis, this batch of Lanqiao ore can replace iron-containing ore powder in the sintering process, and it is recommended to use it in combination with iron-containing ore powder at a ratio of less than 20%.

[0061] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing sintered ore based on Bayan Obo iron concentrate plus Lanqiao ore, characterized in that: The raw materials, by weight percentage, include: Bayan Obo iron concentrate 17.27-17.29%, iron-bearing ore powder I 0-17.27%, iron-bearing ore powder II 6-7%, iron-bearing ore powder III 3-6%, iron-bearing ore powder IV 2-3%, Lanqiao ore 5-25%; limestone 3.4-3.60%, quicklime 3.9-4.0%, dolomite 4.4-4.6%, coke powder 3.9-4%, and blast furnace return ore 25-35%. The sintering materials are weighed and poured into a primary mixing device for stirring and homogenization. During homogenization, an appropriate amount of water is added to obtain a homogenized material. This homogenized material is then loaded into a secondary mixing device for granulation. After granulation, the material is sent to a sintering device for ignition, sintering, crushing, cooling, dropping, screening, and drum strength testing.

2. The method for preparing sintered ore based on Bayan Obo iron concentrate and Lanqiao ore according to claim 1, characterized in that: The raw materials, by weight percentage, include: Bayan Obo iron concentrate 17.27%, iron-bearing ore powder I 17.27%, iron-bearing ore powder II 6.47%, iron-bearing ore powder III 5.40%, iron-bearing ore powder IV 2.16%, Lanqiao ore 5.40%; limestone 3.60%, quicklime 3.99%, dolomite 4.47%, coke powder 3.99%, and blast furnace return ore 30%.

3. The method for preparing sintered ore based on Bayan Obo iron concentrate and Lanqiao ore according to claim 1, characterized in that: The raw materials, by weight percentage, include: Bayan Obo iron concentrate 17.27%, iron-bearing ore powder I 12.41%, iron-bearing ore powder II 6.47%, iron-bearing ore powder III 4.86%, iron-bearing ore powder IV 2.16%, Lanqiao ore 10.79%; limestone 3.54%, quicklime 3.99%, dolomite 4.53%, coke powder 3.99%, and blast furnace return ore 30%.

4. The method for preparing sintered ore based on Bayan Obo iron concentrate and Lanqiao ore according to claim 1, characterized in that: The raw materials, by weight percentage, include: Bayan Obo iron concentrate 17.27%, iron-bearing ore powder I 7.55%, iron-bearing ore powder II 6.47%, iron-bearing ore powder III 4.32%, iron-bearing ore powder IV 2.16%, Lanqiao ore 16.19%; limestone 3.54%, quicklime 3.99%, dolomite 4.53%, coke powder 3.99%, and blast furnace return ore 30%.

5. The method for preparing sinter based on Bayan Obo iron concentrate and Lanqiao ore according to claim 1, characterized in that: The raw materials, by weight percentage, include: Bayan Obo iron concentrate 17.29%, iron-bearing ore powder I 0.0%, iron-bearing ore powder II 6.48%, iron-bearing ore powder III 3.24%, iron-bearing ore powder IV 2.16%, Lanqiao ore 24.85%; limestone 3.41%, quicklime 3.99%, dolomite 4.59%, coke powder 3.99%, and blast furnace return ore 30%.

6. The method for preparing sinter based on Bayan Obo iron concentrate and Lanqiao ore according to claim 1, characterized in that: The main components of the iron-bearing ore powder by mass percentage include: TFe 59.82%, FeO <0.5%, CaO 0.225%, SiO2 4.52%, MgO 0.09%, P 0.085%, Al2O3 2.51%, Ig 5.99%.

7. The method for preparing sintered ore based on Bayan Obo iron concentrate and Lanqiao ore according to claim 1, characterized in that: The main components of the iron-bearing ore powder by mass percentage include: TFe 55.01%, FeO 1.75%, CaO 1.17%, SiO2 13.4%, MgO 0.58%, P 0.064%, S 0.036%, K2O 0.043%, Na2O 0.02%, Al2O3 3.18%, and Ig 6.63%.

8. The method for preparing sinter based on Bayan Obo iron concentrate and Lanqiao ore according to claim 1, characterized in that: The main components of the iron-bearing ore powder by mass percentage are: TFe 58.28%, FeO <0.5%, CaO 0.05%, SiO2 5.30%, MgO 0.12%, P 0.079%, Al2O3 2.72%, Ig 7.44%.

9. The method for preparing sinter based on Bayan Obo iron concentrate and Lanqiao ore according to claim 1, characterized in that: The main components of the iron-bearing ore powder by mass percentage are: TFe 62.69%, CaO 0.47%, SiO2 3.25%, MgO 3.17%, F 0.05%, P 0.051%, Al2O3 1.34%, Ig 2.0%.

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