Sintered brick containing iron ore tail mud and preparation method thereof

Abstract

The invention provides a sintered brick containing iron ore tailing mud and a preparation method of the sintered brick. The sintered brick comprises the following components in parts by weight: 50-70 parts of iron ore tailing mud, 10-15 parts of concrete mixing plant sludge, 10-15 parts of coal gangue, 6-10 parts of fly ash, 10-15 parts of akermanite, 5-7 parts of magnesium cordierite and 2-4 parts of an auxiliary agent. The preparation method comprises the following steps: (1) uniformly stirring akermanite and magnesium cordierite, and carrying out hot-pressing treatment to obtain a first hot-pressed mixture; (2) pre-sintering the iron ore tailing mud and the concrete mixing plant sludge to obtain a pre-sintered material; (3) uniformly stirring coal gangue, fly ash, the first hot-pressed mixture and the pre-sintered material, adding water until the water content is 40-50wt%, and aging to obtain a mixture; (4) adding an auxiliary agent into the mixture, uniformly stirring, aging, and carrying out compression molding to obtain a green brick; and (5) drying and firing the green brick to obtain the sintered brick. The prepared sintered brick is high in yield, harmless and resource utilization of the iron ore tailing mud is achieved, and the obtained sintered brick is light in dead weight, high in compressive strength and good in weather resistance.

Description

Technical Field

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

[0002] Sintered bricks have a history of more than 2,000 years in my country and are still a widely used wall material today. There are many types of bricks, which can be divided into clay bricks, shale bricks, coal gangue bricks, fly ash bricks, lime sand bricks and slag bricks according to the raw materials used; they can be divided into sintered bricks and non-sintered bricks according to the production process; they can be divided into ordinary bricks, porous bricks and hollow bricks according to whether there are holes. Among them, sintered ordinary bricks have the disadvantages of heavy weight, small volume, high production energy consumption and low construction efficiency. In addition, in sintered brick technology, baking is the key link in the brick making process. Generally, the baking temperature is controlled between 900-1100℃ to make the bricks partially melted and sintered. If the baking temperature is too low or the time is insufficient, the sintered bricks obtained will have dull knocking sound, low strength, high water absorption and poor durability, which cannot meet national or industry standards.

[0003] Iron ore tailings are the waste after ore dressing and are also the main 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 to be used for 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 station sludge is mainly flocculent sludge produced after filtration and multi-stage sedimentation of sewage generated after washing concrete tankers and mixing equipment. Its main components are unhydrated cement particles, fly ash and sand. Leaving sludge in the open air and letting it dry naturally not only causes serious dust pollution and sewage flow problems, but also requires some mixing stations to spend money to regularly clean up the piled 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 in this way:

[0008] A sintered brick containing iron ore tailings, characterized in that it comprises 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 chalcedony, 5-7 parts of magnesia cordierite, and 2-4 parts of additives;

[0009] 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.

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

[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, grinding, and screening.

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

[0013] Furthermore, the magnesia chalcedony 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, the specific steps comprising:

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

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

[0017] (3) mixing the coal gangue, fly ash, the first hot-pressed mixed material 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 to form 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-sintering 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.

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

[0023] Furthermore, in step (5), the firing is first 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 chalcedony and magnesia cordierite to prepare sintered bricks with a high yield rate, realizes the harmless and resourceful utilization of iron ore tailings and concrete mixing station sludge, reduces the subsequent treatment cost of waste, and obtains sintered bricks with 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 of the concrete mixing station can be used to form calcium aluminum silicate mineral phases in sintered bricks, thereby improving the compression strength and weathering resistance of sintered bricks. Magnesia chalcite 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 brick; the special octahedral hexagonal ring of the magnesium cordierite crystal makes its structure and performance adjustable, increases stability, and improves the compressive strength of the sintered brick.

[0027] 3. The additives of the present invention are zinc nitrate, boron oxide and calcium titanate, wherein the zinc ions in zinc nitrate can replace the magnesium in magnesia feldspar, and the boron oxide can reduce the energy consumption of the sintering process, reduce the production cost, reduce the 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 embodiments are provided below to further illustrate the present invention.

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

[0030] Unless otherwise specified, the materials, reagents, etc. used in the embodiments 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 the present embodiment and the comparative example is greater than 93.4wt%, and the mass proportion of iron oxide is greater than 14.5wt%.

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

[0033] The required particle size of the iron ore tailings mentioned in the present embodiment and the 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 chalcedony (powder size 0.2mm), 6 parts of magnesia cordierite (powder 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 mixer at 90 rpm for 8 min to obtain a first mixed powder, and hot pressing the mixture at 180° C. and 3 MPa for 13 min to obtain a first hot-pressed mixture;

[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 reducing the temperature to 150°C for 13 minutes, to obtain pre-burned material;

[0039] (3) mixing the coal gangue, fly ash, the first hot pressed mixed material 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 to form 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 h. Then, cool it down to 550°C with the furnace and keep it for 1 h. 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 of particle sizes of 120±10μm and 40±2μm), 10 parts of sludge from a concrete mixing station, 10 parts of coal gangue (powder size of 0.5mm), 6 parts of fly ash, 10 parts of magnesia chalcedony (powder size of 0.1mm), 5 parts of magnesia cordierite (powder size of 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 mixer at 80 rpm for 5 min to obtain a first mixed powder, and hot pressing the mixture at 150° C. and 2 MPa for 10 min to obtain a first hot-pressed mixture;

[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 reducing 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 mixed material 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) Adding the additive to the mixture, stirring evenly, performing a second aging for 48 hours, and pressing to form 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 rate of 5°C / min and keep it for 4 h. Then, cool it down to 500°C with the furnace and keep it for 1 h. Then, cool it down 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 chalcedony (powder size 0.3mm), 7 parts of magnesia cordierite (powder 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 mixer at 100 rpm for 10 min to obtain a first mixed powder, and hot pressing the mixture at 200° C. and 5 MPa for 15 min 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 reducing the temperature to 200°C for 15 minutes to obtain pre-burned material;

[0055] (3) mixing the coal gangue, fly ash, the first hot pressed mixed material 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) Adding the additive to the mixture, stirring evenly, performing a second aging for 96 hours, and pressing to form 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 rate of 5°C / min and keep it for 3 h. Then, cool it down to 600°C and keep it for 2 h. Then, cool it down to room temperature 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 chalcedony (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 chalcedony is missing, and the rest is consistent with 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 reducing 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 until the water content is 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 to form 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 h. Then, cool it down to 550°C with the furnace and keep it for 1 h. 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 consistent with 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 reducing 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 until the water content is 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 to form 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 h. Then, cool it down to 550°C with the furnace and keep it for 1 h. 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 sludge from the concrete mixing station 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 mixer at 90 rpm for 8 min to obtain a first mixed powder, and hot pressing the mixture at 180° C. and 3 MPa for 13 min to obtain a first hot-pressed mixture;

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

[0080] (3) mixing the coal gangue, fly ash, the first hot pressed mixed material 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 to form 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 h. Then, cool it down to 550°C with the furnace and keep it for 1 h. 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 there is no auxiliary agent, 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 mixer at 90 rpm for 8 min to obtain a first mixed powder, and hot pressing the mixture at 180° C. and 3 MPa for 13 min to obtain a first hot-pressed mixture;

[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 reducing 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 mixed material 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 h. Then, cool it down to 550°C with the furnace and keep it for 1 h. 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 are 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 mixer at 90 rpm for 8 min to obtain a first mixed powder, and hot pressing the mixture at 180° C. and 3 MPa for 13 min to obtain a first hot-pressed mixture;

[0094] (2) mixing the coal gangue, fly ash, the first hot-pressed mixture, the sludge from the concrete mixing station and the iron ore tailings in a mixer to obtain a second mixed powder, adding water to the second mixed powder to obtain 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 to form 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 h. Then, cool it down to 550°C with the furnace and keep it for 1 h. Then, cool it down to room temperature with the furnace to obtain the target sintered bricks.

[0097] Test example

[0098] With reference to "Sintered Ordinary Bricks GB / T 5101-2017", the performance of the sintered bricks prepared in Examples 1-3 and Comparative Examples 1-6 was tested.

[0099] Among them, the strength grade test of sintered 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 standards for weathering resistance are as follows.

[0102]

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

[0104] Table 1

[0105]

[0106]

[0107] Table 2

[0108]

[0109] As can be seen from Table 1-2, the sintered bricks prepared in Examples 1-3 of the present invention have high yield, high compressive strength, good weathering resistance, no frosting, and at the same time achieve harmless and resourceful utilization of iron ore tailings, reduce processing costs, and have low energy consumption. Compared with Example 1, the various properties of the sintered bricks of Comparative Examples 1-6 are reduced to varying degrees.

[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 protection scope of the present invention.

Claims

1. A sintered brick containing iron ore tailings, characterized in that: According to weight proportions, the following raw materials are included: 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 chalcedony, 5-7 parts of magnesia cordierite, and 2-4 parts of additives; 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.

2. The sintered brick containing iron ore tailings according to claim 1, characterized in that: The mass proportion of oxides of silicon, calcium, aluminum, iron and magnesium in the iron ore tailings is greater than 93.4wt%, and the mass proportion of iron oxide is greater than 14.5wt%.

3. The sintered brick containing iron ore tailings according to claim 1, characterized in that: 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, grinding, and screening.

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

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

6. The method for preparing sintered bricks containing iron ore tailings according to claim 1, characterized in that: The specific steps include: (1) mixing magnesia chalcedony and magnesia cordierite in a mixer to obtain a first mixed powder, and performing hot pressing to obtain a first hot pressed mixed material; (2) pre-burning the iron ore tailings and the concrete mixing station sludge to obtain pre-burned material; (3) mixing the coal gangue, fly ash, the first hot-pressed mixed material 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 additive to the mixture, stir evenly, carry out a second aging for 48-96 hours, and press to form a brick; (5) Drying the bricks and firing them to obtain the target sintered bricks.

7. The method for preparing sintered bricks containing iron ore tailings according to claim 6, characterized in that: In step (1), the stirring speed is 80-100 rpm and the time is 5-10 min; the hot pressing treatment is carried out at 150-200° C. and 2-5 MPa for 10-15 min.

8. The method for preparing sintered bricks containing iron ore tailings according to claim 6, characterized in that: In step (2), the pre-sintering 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.

9. The method for preparing sintered bricks containing iron ore tailings according to claim 6, characterized in that: In step (5), the temperature of the bricks being dried is 90-110° C., and the moisture content is controlled to be 12%-14%.

10. The method for preparing sintered bricks containing iron ore tailings according to claim 6, characterized in that: 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.

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