A sintering mixture containing Brazilian MUSA powder and its sintering method, and sintered ore

Abstract

This invention discloses a sintering mixture containing Brazilian MUSA powder, its sintering method, and the resulting sinter. The sintering mixture is obtained by mixing mixture I and mixture II twice. Mixture I includes Brazilian MUSA powder, PB powder, BRBF powder, and flux. Mixture II includes iron ore powder and fuel. The iron ore powder includes FMG mixed powder, Mauritanian powder, iron smelting gas ash, iron oxide scale, blast furnace return ore, lump ore return powder, dust collector ash, sludge, direct-supply iron concentrate, steel slag magnetic separation powder, and South African powder. The sintering mixture is then distributed, ignited, sintered, and screened to obtain the sinter. The sinter prepared by this invention has high basicity, good RDI performance and drum strength, and the proportion of particles smaller than 10 mm is less than 18%.

Description

Technical Field

[0001] This invention relates to the field of metallurgical sintering technology, and particularly to a sintering mixture containing Brazilian MUSA powder, its sintering method, and sintered ore. Background Technology

[0002] Sintering is a process in which various powdered iron-containing raw materials are mixed with appropriate amounts of fuel and flux, and water. After mixing and pelletizing, the materials undergo a series of physicochemical changes on sintering equipment, agglomerating the mineral powder particles into lumps. Iron concentrate refers to the concentrate powder obtained from natural ore through crushing, grinding, and beneficiation. It is characterized by high grade, low S and P impurities, and low loss on ignition. It is an essential component of iron-containing materials in sintering blends and helps improve the yield. However, iron concentrate has a loss on ignition of 1.7% and a particle size of 0.1-0.2 mm. When too much is added, its pelletizing performance deteriorates due to the lack of pelletizing nuclei, reducing the permeability of the material layer. At the same time, its price is relatively high, increasing the cost of sintering blends. Brazilian MUSA powder has become an excellent substitute for iron concentrate in recent years. It has a high silica content and can form a large amount of liquid phase during sintering. However, it tends to reduce the basicity of the sinter, which in turn leads to a decrease in the low-temperature reduction pulverization (RDI) performance of the sinter and a decrease in drum strength.

[0003] Therefore, it is essential to study a sintering method that can reduce the cost of ore blending while improving the basicity and RDI performance of sinter and reducing the particle size of finished ore below 10 mm. Summary of the Invention

[0004] To address the shortcomings of the existing technology, this invention provides a sintering mixture containing Brazilian MUSA powder, a sintering method thereof, and sintered ore, comprising the following technical solutions:

[0005] A sintering mixture containing Brazilian MUSA powder includes mixture I and mixture II. Mixture I is mixed with water for the first time, then mixture II is added, and water is added for the second time to obtain the sintering mixture.

[0006] Mixture I includes Brazilian MUSA powder, PB powder, BRBF powder and flux, and Mixture II includes iron ore powder and fuel. Based on the mass of the iron-containing raw materials as 100%, Mixture I includes 6-8% Brazilian MUSA powder, 17-22% PB powder and 15-18% BRBF powder, and Mixture II includes 60% iron ore powder. The mass of the iron-containing raw materials is calculated as the sum of the masses of Brazilian MUSA powder, PB powder and BRBF powder in Mixture I and the iron ore powder in Mixture II.

[0007] Preferably, the mass ratio of iron-containing raw materials, flux and fuel is (81.0-81.9):(13.3-13.7):(4.8-4.9).

[0008] Preferably, before the first mixing, in addition to adding mixture I, sintering return ore is also added, and the mass of sintering return ore is 27% of the total mass of mixture I and mixture II.

[0009] Preferably, the iron ore powder in mixture II includes 26% FMG mixed powder, 13% Mauritanian powder, 17% iron smelting gas ash, 11% iron oxide scale, 15% blast furnace return ore, 9% lump ore return powder, 6% dust collector ash, 2% sludge, 0.6% direct-supply iron concentrate, 0.3% steel slag magnetic separation powder, and 0.1% South African powder.

[0010] Preferably, the average particle size of the iron-containing raw material is between 0.1 mm and 4.16 mm.

[0011] Preferably, the fuel is a mixture of coke powder and anthracite, with a fuel particle size of <23mm and an anthracite moisture content of <9%. More preferably, the coke powder particles with a size of less than 3mm account for 59-69% of the total coke powder mass, and the anthracite particles with a size of less than 3mm account for 63-73% of the total anthracite mass.

[0012] Preferably, the flux is a combination of quicklime, limestone, or dolomite, wherein ≥90% of the quicklime, limestone, or dolomite has a particle size of less than 3mm; the quicklime contains ≥83% CaO and has an activity of ≥220; the limestone has a moisture content of ≤5%; and the dolomite has a moisture content of ≤5%.

[0013] Preferably, the initial water addition is 11-13 t / h, the filling rate is 14-17%, the mixing time is 5-7 min, and the mixing speed is 9-10 r / min.

[0014] Preferably, the second mixing water addition is 5-7 t / h, the filling rate is 16-19%, the mixing time is 7-9 min, and the mixing speed is 9-10 r / min.

[0015] The present invention also provides a sintering method for the above-mentioned sintering mixture containing Brazilian MUSA powder, comprising the following steps:

[0016] The sintering mixture is placed on a trolley with a base material, and the particle size of the sintering mixture gradually increases from top to bottom; after ignition, sintering, cooling, and screening, sintered ore is obtained.

[0017] Preferably, the base material is composed of sintered ore with a particle size of 21-25 mm and a thickness of 25-29 mm.

[0018] Preferably, the ignition temperature is 1220–1400℃, the ignition time is 75–90s, and the holding time is 125–150s.

[0019] Preferably, the sintering negative pressure is 21–23 kPa.

[0020] The present invention also provides a sinter containing Brazilian MUSA powder, wherein the sinter contains, by mass fraction, 57-58% TFe, 5.26-5.31% SiO2, 2.31-2.42% Al2O3, 10.47-10.68% CaO, 1.76-1.99% MgO, and 9.91-10.16% FeO.

[0021] Compared with the prior art, the advantages of the present invention are:

[0022] 1. In the first mixing, after the Brazilian MUSA powder, PB powder, BRBF powder, and flux are mixed evenly, Mixture II is added. This allows Mixture I to adhere to the homogenized ore obtained from Mixture II. The flux and the high SiO2 content of the Brazilian MUSA powder can fully contact each other. During sintering under the coating of other iron ore powders, more low-melting-point substances are generated. Even with low solid burnup, sufficient liquid phase can be obtained to improve the physicochemical and metallurgical properties of the sinter. For example, the low-temperature reduction pulverization (RDI) performance of the sinter can reach over 68%, and the basicity of the sinter (R = CaO / SiO2) is 2.04-2.06. At the same time, the proportion of sinter with a particle size of less than 10mm is less than 18%, which improves the overall quality of the sinter and increases the yield. The use of Brazilian MUSA powder reduces the amount of iron concentrate used, reducing the cost of ore blending while obtaining high-quality sinter and high yield.

[0023] 2. When the sintering mixture is distributed, the particle size is gradually increased from top to bottom. This can increase the air permeability of the material layer and facilitate the complete combustion of flux and fuel and full contact with iron-containing raw materials during sintering. This increases the heat storage temperature of the sintering material layer and increases the amount of liquid phase generated by the overall sintering, which is beneficial to improving the sintering yield, sintering RDI and drum strength.

[0024] 3. The return ore in the sintering process is a defective product from the previous sintering. It is mixed in the first batch before this sintering and can become a good core for pelletizing. It helps to improve the permeability of the sintering material layer. In addition, it contains iron, so re-firing is environmentally friendly and economical, and also avoids the waste of iron. Detailed Implementation

[0025] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0026] This invention provides a preferred sintering method for a mixture containing Brazilian MUSA powder, specifically comprising the following steps:

[0027] Mixture I is added to a cylindrical mixer, and water is added at a rate of 11–13 t / h for the first mixing, with a filling rate of 14–17%, a mixing time of 5–7 min, and a mixer speed of 9–10 r / min. Then, mixture II is added, and water is added at a rate of 5–7 t / h for the second mixing, with a filling rate of 16–19%, a mixing time of 7–9 min, and a mixer speed of 9–10 r / min, to obtain the sintering mixture. The sintering mixture is evenly fed into the mixing trough of the sintering machine using a shuttle feeder. Then, a round roller feeder and a nine-roller feeder are used to evenly distribute the mixture onto a trolley with a base material. The base material consists of sintered ore with a particle size of 21–25 mm and a thickness of 25–29 mm. The particle size of the sintering mixture gradually increases from top to bottom due to segregation. Ignition is then performed at a temperature of 1220–1400℃ for 75–90 seconds, followed by a holding time of 125–150 seconds. A 260m... 2 Sintering is carried out in a belt-type exhaust sintering machine with a sintering negative pressure of 21-23 kPa. After cooling and screening, sintered ore is obtained.

[0028] Mixture I includes Brazilian MUSA powder, PB powder, BRBF powder and flux, and Mixture II includes iron ore powder and fuel. Based on the mass of iron-containing raw materials as 100%, Mixture I includes 6-8% Brazilian MUSA powder, 17-20% PB powder and 15-18% BRBF powder, and Mixture II includes 60% iron ore powder. The mass of iron-containing raw materials is the sum of the masses of Brazilian MUSA powder, PB powder and BRBF powder in Mixture I and the iron ore powder in Mixture II.

[0029] The iron ore powder includes 26% FMG mixed powder, 13% Mauritanian powder, 17% ironmaking gas ash, 11% iron oxide scale, 15% blast furnace return ore, 9% lump ore return powder, 6% dust removal ash, 2% sludge, 0.6% direct-supply iron concentrate, 0.3% steel slag magnetic separation powder, and 0.1% South African powder;

[0030] The fuel is a mixture of coke powder and white coal; the flux is a combination of quicklime, limestone, and dolomite.

[0031] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Examples 1-5

[0033] Examples 1-5 provide a sintering method for a mixture containing Brazilian MUSA powder, specifically including the following steps:

[0034] Mixture I is added to a cylindrical mixer, water is added for the first mixing, then mixture II is added, water is added for the second mixing, resulting in a sintering mixture. A shuttle feeder is used to evenly feed the sintering mixture into the mixing trough of the sintering machine, and then a roller feeder and a nine-roller feeder are used to evenly distribute the mixture on a trolley with a base material. The sintering mixture segregates from top to bottom, gradually increasing in size. Ignition is then carried out using a 260m... 2 The belt-type exhaust sintering machine is used to sinter, cool, and screen the ore to obtain sintered ore.

[0035] The data of iron-containing raw materials used in Examples 1 to 5 are shown in Table 1, the specific raw material ratios are shown in Table 2, the process parameters for sintering are shown in Tables 3 and 4, and the chemical composition and performance indicators of the prepared sinter are shown in Table 5.

[0036] Example 6

[0037] Example 6 provides a sintering method for a mixture containing Brazilian MUSA powder, which is basically the same as Example 1. The difference is that before the first mixing, in addition to adding mixture I, sintering return ore is also added. The mass of the sintering return ore is 27% of the total mass of mixture I and mixture II.

[0038] The data of the iron-containing raw materials used in Example 6 are shown in Table 1, the specific raw material ratio is shown in Table 2, the process parameters for sintering are shown in Tables 3 and 4, and the chemical composition and performance indicators of the prepared sinter are shown in Table 5.

[0039] Comparative Example 1

[0040] Comparative Example 1 provides a sintering method for a sintering mixture, which is basically the same as that in Example 1, except that the Brazilian MUSA powder in mixture I is replaced entirely with PB powder.

[0041] The data of iron-containing raw materials used in Comparative Example 1 are shown in Table 1, the specific raw material ratio is shown in Table 2, the process parameters for sintering are shown in Tables 3 and 4, and the chemical composition and performance indicators of the prepared sinter are shown in Table 5.

[0042] Comparative Example 2

[0043] Comparative Example 2 provides a sintering method for a sintering mixture, which is basically the same as that of Example 1, except that the mixture I containing Brazilian MUSA powder is not pre-mixed, but the mixture I and the mixture II are put into the mixer together for mixing.

[0044] The data of iron-containing raw materials used in Comparative Example 2 are shown in Table 1, the specific raw material ratio is shown in Table 2, the process parameters for sintering are shown in Tables 3 and 4, and the chemical composition and performance indicators of the prepared sinter are shown in Table 5.

[0045] Table 1 Data on iron-containing raw materials

[0046]

[0047]

[0048] The particle size in Table 1 represents the average particle size of each iron-containing raw material.

[0049] Table 2 Raw material ratio

[0050]

[0051] In Table 2, the iron ore powder in Examples 1-6 and Comparative Examples 1-2 consists of 26% FMG mixed powder, 13% Mauritanian powder, 17% iron smelting gas ash, 11% iron oxide scale, 15% blast furnace return ore, 9% lump ore return powder, 6% dust removal ash, 2% sludge, 0.6% direct-supply iron concentrate, 0.3% steel slag magnetic separation powder, and 0.1% South African powder, so these components are omitted from the table.

[0052] In Table 2, the flux is a variety of quicklime, limestone, and dolomite. For example, in some examples, the flux is a mixture of quicklime and dolomite; in other examples, the flux is a mixture of quicklime, limestone, and dolomite.

[0053] Table 3 Control of process parameters during sintering

[0054]

[0055]

[0056] Table 4 is a continuation of Table 3.

[0057]

[0058] Table 5 Chemical composition and performance indicators of sintered ore

[0059]

[0060] As shown in Table 5, the basicity of the sinter prepared in Examples 1 to 6 was 2.04 to 2.06, the drum strength all exceeded 78, the RDI reached more than 68%, and the proportion of sinter particles with a diameter <10mm was less than 20%. This indicates that while reducing the amount of iron concentrate, adding Lao powder can improve the low-temperature reduction pulverization and drum strength performance of the sinter. At the same time, the prepared sinter has high basicity and a small proportion of particles with a diameter less than 10mm, thus reducing the cost of ore blending.

[0061] Compared with Example 1, the basicity R, drum strength, and low-temperature reduction pulverization (RDI) performance of the sinter in Comparative Example 1 decreased significantly, and the proportion of particles with a diameter <10 mm in the sinter exceeded 30%. This was because the high SiO2 content Brazilian MUSA powder was not used, and instead refined powder was used, resulting in an unsatisfactory amount of liquid phase generated during the mixing and sintering process. This led to poor permeability of the material layer and incomplete combustion of fuel during the sintering process, ultimately resulting in poor sinter quality.

[0062] Compared with Example 1, the basicity R, drum strength, and low-temperature reduction pulverization (RDI) performance of the sinter in Comparative Example 2 decreased to a certain extent, and the proportion of sinter with a particle size <10mm reached 30.25%. This is because the mixture I containing Brazilian MUSA powder was not pre-pelletized, but was instead mixed together with mixture II in the mixer. This resulted in poor pelletizing effect, and the material layer could not provide good air permeability during the sintering process after the material was distributed. The amount of liquid phase generated was small, the consolidation effect was poor, and ultimately the quality of the sinter was poor.

[0063] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes 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.

Claims

1. A sintering mixture containing Brazilian MUSA powder, characterized in that, Mixture I with water for the first time, then add mixture II, add water for the second time, and then mix to obtain the final product; The mixture I includes Brazilian MUSA powder, PB powder, BRBF powder and flux, and the mixture II includes iron ore powder and fuel; based on the mass of the iron-containing raw materials as 100%, the mixture I includes 6-8% Brazilian MUSA powder, 17-20% PB powder and 15-18% BRBF powder, and the mixture II includes 60% iron ore powder. The mass of the iron-containing raw materials is calculated as the sum of the masses of Brazilian MUSA powder, PB powder, BRBF powder in the mixture I and the iron ore powder in the mixture II. The first mixing water addition is 11~13t / h, the filling rate is 14~17%, the mixing time is 5~7min, and the mixing speed is 9~10r / min; the second mixing water addition is 5~7t / h, the filling rate is 16~19%, the mixing time is 7~9min, and the mixing speed is 9~10r / min.

2. The sintering mixture according to claim 1, characterized in that, The mass ratio of the iron-containing raw material, the flux, and the fuel is (81.0~81.9):(13.3~13.7):(4.8~4.9).

3. The sintering mixture according to claim 1, characterized in that, Before the first mixing, in addition to adding the mixture I, sintered return ore was also added, and the mass of the sintered return ore was 27% of the total mass of the mixture I and the mixture II.

4. The sintering mixture according to claim 1, characterized in that, The iron ore powder contained in Mixture II includes 26% FMG mixed powder, 13% Mauritanian powder, 17% iron smelting gas ash, 11% iron oxide scale, 15% blast furnace return ore, 9% lump ore return powder, 6% dust removal ash, 2% sludge, 0.6% direct-supply iron concentrate, 0.3% steel slag magnetic separation powder, and 0.1% South African powder.

5. The sintering mixture according to claim 1, characterized in that, The fuel is a mixture of coke powder and aliphatic coal, the fuel particle size is <23mm, the aliphatic coal moisture content is <9%, the coke powder particles with a particle size of less than 3mm account for 59-69% of the total mass of the coke powder, and the aliphatic coal particles with a particle size of less than 3mm account for 63-73% of the total mass of the aliphatic coal.

6. A sintering method for a sintering mixture containing Brazilian MUSA powder, characterized in that, The application of the sintering mixture according to any one of claims 1 to 5 includes the following steps: The sintering mixture is placed on top of the bottom material layer, and the particle size of the sintering mixture gradually increases from top to bottom during the placement process; after ignition, sintering, cooling, and screening, sintered ore is obtained.

7. The sintering method according to claim 6, characterized in that, The temperature during the ignition process is 1220~1400℃, the ignition time is 75~90s, and the holding time is 125~150s.

8. A sinter containing Brazilian MUSA powder, characterized in that, Prepared by the method described in claim 6 or 7.

9. The sintered ore according to claim 8, characterized in that, The sintered ore contains, by mass percentage, 57-58% TFe, 5.26-5.31% SiO2, 2.31-2.42% Al2O3, 10.47-10.68% CaO, 1.76-1.99% MgO, and 9.91-10.16% FeO.

Images