Sintered brick containing iron ore tailings and preparation method thereof

Abstract

The present invention provides a sintered brick containing iron ore tailings and a preparation method thereof. The sintered brick comprises, by weight, 50-70 parts of iron ore tailings, 10-15 parts of concrete mixing station sludge, 10-15 parts of coal gangue, 6-10 parts of fly ash, 10-15 parts of magnesia feldspar, 5-7 parts of magnesia cordierite, and 2-4 parts of additives. The preparation steps include: (1) mixing magnesia feldspar and magnesia cordierite uniformly, and hot pressing to obtain a first hot pressing mixture; (2) pre-burning the iron ore tailings and concrete mixing station sludge to obtain a pre-burned material; (3) mixing the coal gangue, fly ash, the first hot pressing mixture and the pre-burned material uniformly, adding water to a water content of 40-50wt%, aging, and obtaining a mixture; (4) adding the additive to the mixture, mixing uniformly, aging, and pressing to obtain a brick; and (5) drying the brick and firing to obtain a sintered brick. The prepared sintered bricks have a high yield rate, realize the harmless treatment and resource utilization of iron ore tailings, and the obtained sintered bricks have light weight, high compressive strength and good weathering resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, in particular to a sintered brick containing iron ore tailings and a preparation method thereof. Background Art

[0002] Sintered bricks have a history of over 2,000 years in my country and remain a widely used wall material today. There are many types of bricks, including clay bricks, shale bricks, coal gangue bricks, fly ash bricks, lime sand bricks, and slag bricks, based on the raw materials used. They can be divided into sintered and unsintered bricks based on the production process, and ordinary bricks, porous bricks, and hollow bricks based on the presence or absence of pores. Sintered ordinary bricks have disadvantages such as heavy weight, small size, high production energy consumption, and low construction efficiency. Furthermore, firing is a key step in the sintering process. The firing temperature is generally controlled between 900-1100°C to partially melt the bricks and sinter them. If the firing temperature is too low or the firing time is insufficient, the resulting sintered bricks will exhibit muteness, low strength, high water absorption, and poor durability, failing to meet national or industry standards.

[0003] Iron ore tailings are waste products after beneficiation and are also a major component of common industrial solid waste. The harmless treatment and efficient resource utilization of solid wastes such as tailings have become the focus of current scientific research and practice. The main components of iron ore tailings are kaolin, hematite, quartz, chlorite and other substances. Since the iron content in iron ore tailings is far more than 5%, it can be considered for use in the preparation of sintered bricks if it meets the standards for sintered brick production. The harmless and resource-based utilization of industrial solid waste iron ore tailings can achieve resource recycling.

[0004] Concrete mixing plant sludge is primarily generated by the wastewater generated after washing concrete trucks and mixing equipment. After filtration and multi-stage sedimentation, the resulting flocculent sludge primarily consists of unhydrated cement particles, fly ash, and sand. Leaving sludge in open-air storage and allowing it to dry naturally not only leads to severe dust pollution and wastewater runoff, but also requires some mixing plants to incur significant costs for regular cleaning of the stored sludge and waste residue.

[0005] Therefore, the present invention utilizes iron ore tailings and concrete mixing station sludge to prepare sintered bricks, thereby achieving harmless and resourceful utilization of various wastes and reducing subsequent waste treatment costs. Summary of the Invention

[0006] In view of this, the present invention proposes a sintered brick containing iron ore tailings and a preparation method thereof to solve the above technical problems. The obtained sintered brick has light weight, high compressive strength, high yield, good weathering resistance, low energy consumption, and has practical significance.

[0007] The technical solution of the present invention is achieved as follows:

[0008] A sintered brick containing iron ore tailings, characterized by comprising the following raw materials in parts by weight: 50-70 parts of iron ore tailings, 10-15 parts of concrete mixing station sludge, 10-15 parts of coal gangue, 6-10 parts of fly ash, 10-15 parts of magnesia feldspar, 5-7 parts of magnesia cordierite, and 2-4 parts of additives;

[0009] The auxiliary agents are zinc nitrate, boron oxide and calcium titanate in a mass ratio of 1:1.2-1.4:1.5-1.8.

[0010] Furthermore, the mass proportion of silicon, calcium, aluminum, iron and magnesium oxides in the iron ore tailings is greater than 93.4 wt%, and the mass proportion of iron oxide is greater than 14.5 wt%.

[0011] Furthermore, the iron ore tailings are composed of particles with a mass ratio of 1:2-4, with a particle size of 106-425 μm and a particle size of 38-74 μm; the particle size is obtained by drying the iron ore tailings to a moisture content of less than 1.0%, crushing and grinding, and screening.

[0012] Furthermore, the coal gangue is crushed by a ball mill and sieved to a powder size of 0.5-1.5 mm.

[0013] Furthermore, the magnesia chrysocolla and magnesia cordierite are crushed and sieved, and the powder particle size is 0.1-0.3 mm.

[0014] A method for preparing sintered bricks containing iron ore tailings, comprising the following steps:

[0015] (1) mixing magnesia chalcedony and magnesia cordierite in a mixer to obtain a first mixed powder, and hot pressing the mixed powder to obtain a first hot pressed mixed material;

[0016] (2) Pre-burning the iron ore tailings and concrete mixing station sludge to obtain pre-burned material;

[0017] (3) Mixing the gangue, fly ash, the first hot-pressed mixture and the pre-burned material in a mixer to obtain a second mixed powder, adding water to the second mixed powder to a water content of 40-50 wt%, and performing a first aging for 12-24 h to obtain a mixed material;

[0018] (4) Add the additive to the mixture, stir evenly, carry out a second aging for 48-96 hours, and press into shape to obtain a brick;

[0019] (5) Drying the bricks and firing them to obtain the target sintered bricks.

[0020] Furthermore, in step (1), the stirring speed is 80-100 rpm and the time is 5-10 min; and the hot pressing treatment is carried out at 150-200° C. and 2-5 MPa for 10-15 min.

[0021] Furthermore, in step (2), the pre-calcination treatment is to first raise the temperature to 300-400°C for 5-10 minutes, and then reduce the temperature to 100-200°C for 10-15 minutes.

[0022] Furthermore, in step (5), the temperature of the bricks being dried is 90-110° C., and the moisture content is controlled to be 12%-14%.

[0023] Furthermore, in step (5), the firing is firstly heated to 900-1000°C at a heating rate of 5°C / min and kept at that temperature for 3-4h, then cooled to 500-600°C and kept at that temperature for 1-2h, and then cooled to room temperature.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention utilizes iron ore tailings, concrete mixing station sludge, coal gangue, fly ash, magnesia feldspar and magnesia cordierite to prepare sintered bricks with a high yield, thus achieving harmless and resourceful utilization of iron ore tailings and concrete mixing station sludge, reducing the subsequent treatment cost of the waste, and the obtained sintered bricks have light weight, high compressive strength and good weathering resistance.

[0026] 2. The present invention controls the particle size and proportion of iron ore tailings, which will greatly save equipment and power loss in actual production. In addition, the shrinkage rate of the tailings after drying and sintering is within 1%, indicating that the risk of drying and cracking of the iron ore tailings is relatively small. The sludge particles from the concrete mixing station can form calcium aluminum silicate mineral phases when used in sintered bricks, thereby improving the compressive strength and weathering resistance of sintered bricks. Magnesium feldspar can release Ca 2+ and Si 2+ , forming a liquid phase, which can promote the bonding between particles during the sintering process and improve the density and strength of the sintered bricks; the special octahedral hexagonal rings of the magnesium cordierite crystals make its structure and performance adjustable, increase stability, and improve the compressive strength of the sintered bricks.

[0027] 3. The additives of the present invention are zinc nitrate, boron oxide and calcium titanate. The zinc ions in zinc nitrate can replace the magnesium position in magnesia feldspar. The combination with boron oxide can reduce the energy consumption of the sintering process, reduce production costs, reduce shrinkage during the sintering process, reduce deformation, and improve the yield rate. Calcium titanate can adjust its temperature stability, prevent it from being broken by heat, and improve the durability and reliability of the sintered bricks. DETAILED DESCRIPTION

[0028] In order to better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

[0029] Unless otherwise specified, the experimental methods used in the examples of the present invention are all conventional methods.

[0030] Unless otherwise specified, the materials, reagents, etc. used in the examples of the present invention can be obtained from commercial sources.

[0031] The mass proportion of silicon, calcium, aluminum, iron and magnesium oxides in the iron ore tailings mentioned in this embodiment and the comparative example is greater than 93.4 wt %, and the mass proportion of iron oxide is greater than 14.5 wt %.

[0032] The particle sizes of the coal gangue, magnesia cordierite and magnesia cordierite mentioned in the present embodiment and comparative example are obtained by crushing with a ball mill and screening.

[0033] The required particle size of the iron ore tailings mentioned in this embodiment and comparative example is obtained by drying the iron ore tailings to a moisture content of less than 1.0%, crushing, grinding, and screening.

[0034] Example 1

[0035] A sintered brick containing iron ore tailings comprises the following raw materials, in parts by weight: 60 parts of iron ore tailings (particle size 250±20μm and particle size 50±5μm in a mass ratio of 1:3), 13 parts of concrete mixing station sludge, 13 parts of coal gangue (powder size 1.0mm), 8 parts of fly ash, 13 parts of magnesia feldspar (powder particle size 0.2mm), 6 parts of magnesia cordierite (powder particle size 0.2mm), and 3 parts of additives (zinc nitrate, boron oxide, and calcium titanate in a mass ratio of 1:1.3:1.7).

[0036] The method for preparing the sintered brick containing iron ore tailings comprises the following specific steps:

[0037] (1) stirring magnesia chalcedony and magnesia cordierite in a blender at 90 rpm for 8 min to obtain a first mixed powder, and hot pressing the mixed powder at 180° C. and 3 MPa for 13 min to obtain a first hot-pressed mixed material;

[0038] (2) Pre-burning the iron ore tailings and concrete mixing plant sludge, specifically: first raising the temperature to 350 ° C for 8 minutes, then lowering the temperature to 150 ° C for 13 minutes to obtain pre-burned material;

[0039] (3) Mixing the gangue, fly ash, the first hot-pressed mixture and the pre-burned material in a mixer to obtain a second mixed powder, adding water to the second mixed powder to a water content of 45 wt %, and performing a first aging for 18 h to obtain a mixed material;

[0040] (4) Add the additive to the mixture, stir evenly, carry out a second aging for 72 hours, and press into shape to obtain a brick;

[0041] (5) Dry the bricks at 100°C to control the moisture content of the bricks to 13%±1%. First, heat the temperature to 900°C at a heating rate of 5°C / min and keep it for 3 hours. Then cool it down to 550°C with the furnace and keep it for 1 hour. Then cool it down to room temperature with the furnace to obtain the target sintered bricks.

[0042] Example 2

[0043] A sintered brick containing iron ore tailings comprises the following raw materials in parts by weight: 50 parts of iron ore tailings (with a mass ratio of 1:2 and a particle size of 120±10μm and a particle size of 40±2μm), 10 parts of sludge from a concrete mixing station, 10 parts of coal gangue (powder size 0.5mm), 6 parts of fly ash, 10 parts of magnesia feldspar (powder size 0.1mm), 5 parts of magnesia cordierite (powder size 0.1mm), and 2 parts of additives (zinc nitrate, boron oxide, and calcium titanate in a mass ratio of 1:1.2:1.5).

[0044] The method for preparing the sintered brick containing iron ore tailings comprises the following specific steps:

[0045] (1) stirring magnesia chalcedony and magnesia cordierite in a blender at 80 rpm for 5 min to obtain a first mixed powder, and hot pressing the mixed powder at 150° C. and 2 MPa for 10 min to obtain a first hot-pressed mixed material;

[0046] (2) Pre-burning the iron ore tailings and concrete mixing plant sludge, specifically: first raising the temperature to 300 ° C for 5 minutes, then lowering the temperature to 100 ° C for 10 minutes to obtain pre-burned material;

[0047] (3) Mixing the coal gangue, fly ash, the first hot-pressed mixture and the pre-burned material in a mixer to obtain a second mixed powder, adding water to the second mixed powder to a water content of 40 wt %, and performing a first aging for 12 h to obtain a mixed material;

[0048] (4) Add the additive to the mixture, stir evenly, carry out a second aging for 48 hours, and press into shape to obtain a brick;

[0049] (5) Dry the bricks at 90°C to control the moisture content of the bricks to 13%±1%. First, heat the temperature to 950°C at a heating rate of 5°C / min and keep it for 4 hours. Then cool it to 500°C with the furnace and keep it for 1 hour. Then cool it to room temperature with the furnace to obtain the target sintered bricks.

[0050] Example 3

[0051] A sintered brick containing iron ore tailings comprises the following raw materials, in parts by weight: 70 parts of iron ore tailings (particle size 400±20μm and particle size 70±2μm in a mass ratio of 1:4), 15 parts of concrete mixing station sludge, 15 parts of coal gangue (powder size 1.5mm), 10 parts of fly ash, 15 parts of magnesia feldspar (powder particle size 0.3mm), 7 parts of magnesia cordierite (powder particle size 0.3mm), and 4 parts of additives (zinc nitrate, boron oxide, and calcium titanate in a mass ratio of 1:1.4:1.8).

[0052] The method for preparing the sintered brick containing iron ore tailings comprises the following specific steps:

[0053] (1) stirring magnesia chalcedony and magnesia cordierite in a blender at 100 rpm for 10 minutes to obtain a first mixed powder, and hot pressing the mixture at 200° C. and 5 MPa for 15 minutes to obtain a first hot-pressed mixture;

[0054] (2) Pre-burning the iron ore tailings and concrete mixing plant sludge, specifically: first raising the temperature to 400 ° C for 10 minutes, then lowering the temperature to 200 ° C for 15 minutes to obtain pre-burned materials;

[0055] (3) Mixing the coal gangue, fly ash, the first hot-pressed mixture and the pre-burned material in a mixer to obtain a second mixed powder, adding water to the second mixed powder to a water content of 50 wt %, and performing a first aging for 24 h to obtain a mixed material;

[0056] (4) Add the additive to the mixture, stir evenly, carry out a second aging for 96 hours, and press into shape to obtain a brick;

[0057] (5) Dry the bricks at 110°C to control the moisture content of the bricks to 13%±1%. First, heat the temperature to 1000°C at a heating rate of 5°C / min and keep it for 3 hours. Then cool it to 600°C with the furnace and keep it for 2 hours. Then cool it to room temperature with the furnace to obtain the target sintered bricks.

[0058] Comparative Example 1

[0059] The difference from Example 1 is that the particle size of the iron ore tailings is 250±20 μm, and the rest is consistent with Example 1.

[0060] That is, a sintered brick containing iron ore tailings in this comparative example includes the following raw materials in parts by weight: 60 parts of iron ore tailings (particle size 250±20μm), 13 parts of concrete mixing station sludge, 13 parts of coal gangue (powder size 1.0mm), 8 parts of fly ash, 13 parts of magnesia feldspar (powder particle size 0.2mm), 6 parts of magnesium cordierite (powder particle size 0.2mm), and 3 parts of additives (zinc nitrate, boron oxide and calcium titanate in a mass ratio of 1:1.3:1.7).

[0061] Comparative Example 2

[0062] The difference from Example 1 is that magnesia feldspar is missing, and the rest is the same as Example 1.

[0063] The preparation method of the sintered brick containing iron ore tailings in this comparative example is:

[0064] (1) Pre-burning the iron ore tailings and concrete mixing plant sludge, specifically: first raising the temperature to 350 ° C for 8 minutes, then lowering the temperature to 150 ° C for 13 minutes to obtain pre-burned material;

[0065] (2) Mixing coal gangue, fly ash, magnesia cordierite and pre-burned material in a mixer to obtain a mixed powder, adding water to the mixed powder to a water content of 45 wt %, and performing a first aging for 18 h to obtain a mixed material;

[0066] (3) Add the additive to the mixture, stir evenly, carry out a second aging for 72 hours, and press into shape to obtain a brick;

[0067] (4) Dry the bricks at 100°C to control the moisture content of the bricks to 13%±1%. First, heat the temperature to 900°C at a heating rate of 5°C / min and keep it for 3 hours. Then cool it down to 550°C with the furnace and keep it for 1 hour. Then cool it down to room temperature with the furnace to obtain the target sintered bricks.

[0068] Comparative Example 3

[0069] The difference from Example 1 is that magnesium cordierite is missing, and the rest is the same as Example 1.

[0070] The preparation method of the sintered brick containing iron ore tailings in this comparative example comprises the following specific steps:

[0071] (1) Pre-burning the iron ore tailings and concrete mixing plant sludge, specifically: first raising the temperature to 350 ° C for 8 minutes, then lowering the temperature to 150 ° C for 13 minutes to obtain pre-burned material;

[0072] (2) Mixing coal gangue, fly ash, magnesia cordierite and pre-burned material in a mixer to obtain a mixed powder, adding water to the mixed powder to a water content of 45 wt %, and performing a first aging for 18 h to obtain a mixed material;

[0073] (3) Add the additive to the mixture, stir evenly, carry out a second aging for 72 hours, and press into shape to obtain a brick;

[0074] (4) Dry the bricks at 100°C to control the moisture content of the bricks to 13%±1%. First, heat the temperature to 900°C at a heating rate of 5°C / min and keep it for 3 hours. Then cool it down to 550°C with the furnace and keep it for 1 hour. Then cool it down to room temperature with the furnace to obtain the target sintered bricks.

[0075] Comparative Example 4

[0076] The difference from Example 1 is that the concrete mixing station sludge is missing, and the rest is the same as Example 1.

[0077] The preparation method of the sintered brick containing iron ore tailings in this comparative example comprises the following specific steps:

[0078] (1) stirring magnesia chalcedony and magnesia cordierite in a blender at 90 rpm for 8 min to obtain a first mixed powder, and hot pressing the mixed powder at 180° C. and 3 MPa for 13 min to obtain a first hot-pressed mixed material;

[0079] (2) Pre-burning the iron ore tailings, specifically: first raising the temperature to 350°C for 8 minutes, then lowering the temperature to 150°C for 13 minutes to obtain pre-burned material;

[0080] (3) Mixing the gangue, fly ash, the first hot-pressed mixture and the pre-burned material in a mixer to obtain a second mixed powder, adding water to the second mixed powder to a water content of 45 wt %, and performing a first aging for 18 h to obtain a mixed material;

[0081] (4) Add the additive to the mixture, stir evenly, carry out a second aging for 72 hours, and press into shape to obtain a brick;

[0082] (5) Dry the bricks at 100°C to control the moisture content of the bricks to 13%±1%. First, heat the temperature to 900°C at a heating rate of 5°C / min and keep it for 3 hours. Then cool it down to 550°C with the furnace and keep it for 1 hour. Then cool it down to room temperature with the furnace to obtain the target sintered bricks.

[0083] Comparative Example 5

[0084] The difference from Example 1 is that the auxiliary agent is missing, and the other aspects are the same as Example 1.

[0085] The preparation method of the sintered brick containing iron ore tailings in this comparative example comprises the following specific steps:

[0086] (1) stirring magnesia chalcedony and magnesia cordierite in a blender at 90 rpm for 8 min to obtain a first mixed powder, and hot pressing the mixed powder at 180° C. and 3 MPa for 13 min to obtain a first hot-pressed mixed material;

[0087] (2) Pre-burning the iron ore tailings and concrete mixing plant sludge, specifically: first raising the temperature to 350 ° C for 8 minutes, then lowering the temperature to 150 ° C for 13 minutes to obtain pre-burned material;

[0088] (3) Mixing the coal gangue, fly ash, the first hot-pressed mixture and the pre-burned material in a mixer to obtain a second mixed powder, adding water to the second mixed powder to a water content of 45 wt%, performing a first aging for 90 h, and pressing to obtain a brick;

[0089] (4) Dry the bricks at 100°C to control the moisture content of the bricks to 13%±1%. First, heat the temperature to 900°C at a heating rate of 5°C / min and keep it for 3 hours. Then cool it down to 550°C with the furnace and keep it for 1 hour. Then cool it down to room temperature with the furnace to obtain the target sintered bricks.

[0090] Comparative Example 6

[0091] The difference from Example 1 is that the iron ore tailings and concrete mixing station sludge were not pre-burned, and the rest is the same as Example 1.

[0092] The preparation method of the sintered brick containing iron ore tailings in this comparative example comprises the following specific steps:

[0093] (1) stirring magnesia chalcedony and magnesia cordierite in a blender at 90 rpm for 8 min to obtain a first mixed powder, and hot pressing the mixed powder at 180° C. and 3 MPa for 13 min to obtain a first hot-pressed mixed material;

[0094] (2) mixing the coal gangue, fly ash, the first hot-pressed mixture, the concrete mixing plant sludge and the iron ore tailings in a mixer to obtain a second mixed powder, adding water to the second mixed powder to a water content of 45 wt %, and performing a first aging for 18 h to obtain a mixture;

[0095] (3) Add the additive to the mixture, stir evenly, carry out a second aging for 72 hours, and press into shape to obtain a brick;

[0096] (4) Dry the bricks at 100°C to control the moisture content of the bricks to 13%±1%. First, heat the temperature to 900°C at a heating rate of 5°C / min and keep it for 3 hours. Then cool it down to 550°C with the furnace and keep it for 1 hour. Then cool it down to room temperature with the furnace to obtain the target sintered bricks.

[0097] Test example

[0098] With reference to GB / T 5101-2017 for fired ordinary bricks, the performance of the fired bricks prepared in Examples 1-3 and Comparative Examples 1-6 was tested.

[0099] Among them, the strength grade test of fired bricks is carried out according to the method specified in GB / T2542. The strength grades are divided into five levels: MU30, MU25, MU20, MU15, and MU10. The corresponding average compressive strength values ​​and strength standard values ​​are shown in the following table.

[0100]

[0101] The weathering resistance and frost resistance of fired bricks are tested according to the test method specified in GB / T2542, and the standard for weathering resistance is shown in the figure below.

[0102]

[0103] The test results are shown in Table 1-2.

[0104] Table 1

[0105]

[0106]

[0107] Table 2

[0108]

[0109] As shown in Table 1-2, the sintered bricks prepared in Examples 1-3 of the present invention have a high yield rate, high compressive strength, good weathering resistance, and no blooming. They also achieve harmless and resourceful utilization of iron ore tailings, reducing processing costs and energy consumption. Compared to Example 1, the sintered bricks in Comparative Examples 1-6 exhibit varying degrees of degradation in various properties.

[0110] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A sintered brick containing iron ore tailings, characterized in that: The raw materials include the following in parts by weight: 50-70 parts of iron ore tailings, 10-15 parts of concrete mixing plant sludge, 10-15 parts of coal gangue, 6-10 parts of fly ash, 10-15 parts of magnesia feldspar, 5-7 parts of magnesia cordierite, and 2-4 parts of additives; The iron ore tailings are composed of particles with a mass ratio of 1:2-4, with a particle size of 106-425µm and a particle size of 38-74µm; the particle size is obtained by drying the iron ore tailings to a moisture content of less than 1.0%, crushing, grinding, and screening; The mass ratio of silicon, calcium, aluminum, iron and magnesium oxides in the iron ore tailings is greater than 93.4wt%, and the mass ratio of iron oxide is greater than 14.5wt%; The auxiliary agent is zinc nitrate, boron oxide and calcium titanate in a mass ratio of 1:1.2-1.4:1.5-1.8; The sintered brick containing iron ore tailings is prepared by the following preparation method: (1) Magnesium chrysocolla and magnesium cordierite are uniformly stirred in a mixer to obtain a first mixed powder, and hot-pressed at 150-200° C. and 2-5 MPa for 10-15 minutes to obtain a first hot-pressed mixture; (2) Pre-burning the iron ore tailings and concrete mixing plant sludge to obtain pre-burned material, wherein the pre-burning treatment is to first increase the temperature to 300-400°C for 5-10 minutes, and then reduce the temperature to 100-200°C for 10-15 minutes; (3) Mixing the gangue, fly ash, the first hot-pressed mixture and the pre-burned material in a mixer to obtain a second mixed powder, adding water to the second mixed powder to a water content of 40-50 wt%, and performing a first aging for 12-24 h to obtain a mixed material; (4) Add the additives to the mixture, stir evenly, carry out a second aging for 48-96 hours, and press into shape to obtain a brick; (5) Dry the bricks and then fire them. Specifically, heat the temperature to 900-1000℃ at a heating rate of 5℃ / min and keep it there for 3-4h. Then cool it down to 500-600℃ and keep it there for 1-2h. Then cool it down to room temperature to obtain sintered bricks.

2. The sintered brick containing iron ore tailings according to claim 1, characterized in that: The coal gangue is crushed by a ball mill and sieved to obtain a powder size of 0.5-1.5 mm.

3. The sintered brick containing iron ore tailings according to claim 1, characterized in that: The magnesia chrysocolla and magnesia cordierite are crushed and sieved, and the powder particle size is 0.1-0.3 mm.

4. The sintered brick containing iron ore tailings according to claim 1, characterized in that: In step (1) of the method for preparing sintered bricks, the stirring speed is 80-100 rpm and the stirring time is 5-10 min.

5. The sintered brick containing iron ore tailings according to claim 1, characterized in that: In step (5) of the method for preparing sintered bricks, the temperature of the bricks is dried at 90-110° C., and the moisture content is controlled at 12%-14%.

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