CN119265368A

CN119265368A - Method for hot-stewing and iron extraction of steel slag and building material by waste heat reduction of high-water-content iron-containing solid waste

Info

Publication number: CN119265368A
Application number: CN202411803602.0A
Authority: CN
Inventors: 崔新壮; 孙皓; 张小宁; 金青; 王艺霖; 崔社强; 张旭; 孟华铭
Original assignee: Chongqing University; Shandong University
Current assignee: Chongqing University; Shandong University
Priority date: 2024-12-10
Filing date: 2024-12-10
Publication date: 2025-01-07
Anticipated expiration: 2044-12-10
Also published as: CN119265368B

Abstract

The invention belongs to the technical field of solid waste resource utilization, and particularly discloses a method for carrying out heat stewing and iron extraction on steel slag of high-water-content iron-containing solid waste through waste heat reduction and a method for converting the steel slag into building materials, which comprises the following steps that S1, iron tailing ore pulp or/and red mud ore pulp are mixed with carbon powder uniformly according to a proportion to obtain mixed ore pulp; the method comprises the steps of S2, pouring molten steel slag into a slag stewing pond, S3, spraying mixed ore pulp on the surface of the molten steel slag, S4, crushing the steel slag after the water of the mixed ore pulp is evaporated to dryness, turning over the slag to form a steel slag mixture, S5, repeating S2-S4 until the steel slag mixture reaches the rated capacity of the slag stewing pond, covering a slag stewing pond cover, S6, injecting water into the slag stewing pond to stew the slag, S7, crushing the steel slag mixture after stewing the slag, extracting metal iron particles, S8, ball milling the residual materials, extracting iron fine powder, and S9, wherein the residual tailings are used as building materials. Realizes the cooperative treatment of multi-source solid waste and the secondary utilization of the waste heat of the molten steel slag and the pulp waste water.

Description

Method for extracting iron from steel slag by thermal stewing and converting waste heat into high-water-content iron-containing solid waste

Technical Field

The invention belongs to the technical field of solid waste resource utilization, and particularly relates to a method for carrying out heat stewing and iron extraction on steel slag of high-water-content iron-containing solid waste through waste heat reduction and a building material.

Background

The statements herein merely provide background information related to the present disclosure and may not necessarily constitute prior art.

The steel slag is a byproduct of converter steelmaking, the heat stewing method is one of the main treatment methods of the steel slag, and the method has the advantages of wide application range, good stability, high pulverization rate, full slag-iron separation and the like of the treated steel slag. The steel slag heat stewing method (also called as 'stewing slag') is to pour molten steel slag into a stewing pond, cover a heat stewing device cover on the stewing pond to seal, spray water inside, generate a large amount of saturated steam when the steel slag is in contact with water at high temperature, crush and pulverize the steel slag under high pressure formed by the steam, and react with water at high temperature to eliminate free CaO and free MgO in the steel slag. After crushing, sieving and magnetic separation, the steel slag after heat stewing is extracted into metal iron particles and iron fine powder, and the residual steel slag tailings have good stability and certain activity and can be applied to building materials. However, the method needs to consume a large amount of water, and the waste heat in the molten steel slag is not well recycled, or a special waste heat recovery device is needed to be added, so that the production cost is increased.

The iron tailings are solid waste remained after roughing or refining in the iron ore exploitation process, the total accumulated iron tailings in China currently exceeds 70 hundred million tons, and the comprehensive utilization rate is only 11%. The red mud is a strong alkaline solid waste generated when the bauxite extracts Al ₂O₃ in the alumina industry, the large amount of red mud is generated in China by about 1 hundred million tons each year, the accumulated stockpiling amount is about 5 hundred million tons, and the comprehensive utilization rate is only 4%. Iron tailings and red mud are two typical refractory high-water-content iron-containing solid wastes, and mainly account for the following reasons:

In the process of forming the iron tailings, iron tailing pulp with the concentration of 40% -60% is formed through wet grinding, wet magnetic separation, floatation and concentration, and is conveyed to a tailing pond through a pipeline. The red mud is also conveyed to a tailing pond through a pipeline in the form of red mud pulp with the concentration of 25-50%. After the ore pulp is conveyed to the tailing pond, a large amount of time is needed for deposition, the ore pulp backwater rate is low, the speed is low, the tailing pond is also caused to have a great safety risk, and the environment risk of pollution to underground water is also caused.

The iron tailings and the red mud have components such as SiO ₂、Al₂O₃, caO and the like, have a certain volcanic ash activity, can be used as cement admixture and concrete admixture, and can also be used for preparing solid waste-based cementing materials. However, the iron tailings and the red mud have low activity, and the activities of the iron tailings and the red mud are excited by methods such as high-temperature heating, mechanical grinding and the like, however, the methods have high energy consumption, high cost and high carbon emission, and restrict the application of the tailings and the red mud in building materials. In addition, in order to reduce the transportation cost, the iron tailings and the red mud need to be dried before being used, and a large amount of energy sources are consumed.

On the other hand, the iron tailings and the red mud contain a large amount of weak magnetic ferric oxide, the TFe content in the iron tailings is about 25%, and the TFe content in the red mud is between 40% and 50%. Part of the methods try to secondarily extract iron components by a magnetizing reduction roasting method, and the main steps are that iron tailings and red mud are roasted at high temperature in a reducing atmosphere of H ₂ and CO, weak magnetic Fe ₂O₃ is reduced into strong magnetic Fe ₃O₄, then iron concentrate is magnetically separated by a weak magnetic separation process, and the rest tailings are used as building materials. However, the method requires high-temperature roasting at 700-1000 ℃ and consumes a large amount of energy, which restricts the popularization and application of the method.

Disclosure of Invention

Aiming at the defects existing in the prior art, the invention aims to provide a method for carrying out heat stewing and iron extraction on steel slag with high water content and iron-containing solid waste through waste heat reduction and a building material.

In order to achieve the above object, the present invention is realized by the following technical scheme:

The method for carrying out heat stewing iron extraction and building material treatment on the steel slag with high water content and iron-containing solid waste by waste heat reduction comprises the following steps:

S1, uniformly mixing iron tailing ore pulp or/and red mud ore pulp and carbon powder according to a proportion to obtain mixed ore pulp;

s2, pouring the molten steel slag into a slag stewing pond;

s3, spraying the mixed ore pulp on the surface of the molten steel slag;

S4, crushing and turning the steel slag after the water of the mixed ore pulp is evaporated to dryness, so that the dried and reduced iron tailings and/or red mud and the residual carbon powder are mixed into the steel slag to form a steel slag mixture;

S5, repeating S2-S4 until the steel slag mixture reaches the rated capacity of the slag disintegrating pool, and covering the slag disintegrating pool cover;

s6, injecting water into the slag disintegrating pool, and stewing slag;

s7, crushing the steel slag mixture after slag stewing, and extracting metal iron particles;

S8, extracting iron fine powder after ball milling the rest materials;

And S9, using the residual tailings as building materials.

In some embodiments, the moisture content in the iron tailings pulp is 10% -60%,% is mass percent;

the water content in the red mud pulp is 20% -75%, and the percentage is mass percent.

Preferably, the moisture content in the iron tailing pulp is 40% -60%, and the% is mass percent;

The water content in the red mud pulp is 40% -60%, and the percentage is mass percent.

Preferably, the mass ratio of the solid in the iron tailing ore pulp or/and the red mud ore pulp to the carbon powder is 100:1-5.

In some embodiments, the mixed pulp comprises 20% -40% of the mass of the molten steel slag. The carbon powder and water generate reducing gases such as H ₂, CO and the like in a high-temperature environment provided by molten steel slag, and the reducing gases reduce the weak magnetic hematite in the iron tailings and/or the red mud into strong magnetic magnetite in the high-temperature environment, so that the iron concentrate can be magnetically separated by adopting a weak magnetic separation process, and the iron components in the iron tailings or the red mud can be effectively recovered.

In some embodiments, the time to stew the slag is 4-8 hours.

Preferably, the water injection mode is water injection at the top or at the bottom of the slag stewing pond.

Preferably, the grain diameter of the pulverized steel slag after slag stewing is smaller than 5mm.

In some embodiments, the iron remover is used to extract metallic iron particles therein. The metal iron particles are small iron blocks or particles remained in steelmaking, and the TFe grade of the metal iron particles is more than 90 percent. The residual material after extracting the metal iron particles contains a large amount of nonmagnetic gangue (non-metal minerals which are useless for iron and steel smelting), the magnetism is weak at the moment, the iron smelting efficiency is unfavorable, further grinding is needed to separate the ferromagnetic Fe ₃O₄ from the nonmagnetic gangue, and then the ferromagnetic Fe ₃O₄ is extracted through magnetic separation.

In some embodiments, the particle size of the remaining material after wet ball milling is less than 0.075mm.

In some embodiments, the weak magnetic separation device is used for extracting the fine iron powder, and the TFe grade of the fine iron powder is above 40%.

In some embodiments, the remaining tailings serve as a raw material for cement mixes, concrete admixtures, or solid waste-based cementitious materials.

The beneficial effects achieved by one or more embodiments of the present invention described above are as follows:

The waste heat of the molten steel slag is utilized to realize the drying, reduction magnetization roasting and thermal activation of the iron tailings or the red mud (after the iron tailings or the red mud is heated at 700-800 ℃, clay minerals in the iron tailings or the red mud are completely decomposed into active SiO ₂ and Al ₂O₃, and the activity of the iron tailings or the red mud serving as building materials is improved), so that the heat energy consumption is saved, and the iron components in the iron tailings or the red mud are effectively recovered.

The molten steel slag is cooled by utilizing the moisture in the iron tailing ore pulp or the red mud ore pulp, so that the secondary utilization of the ore pulp moisture is realized. The mechanical activation of the iron tailings or the red mud is realized by utilizing the ball milling of the steel slag mixture. The red mud containing a large amount of A1 ₂O₃ and OH ^- can supplement the aluminum component of the slag mixture tailings, provide alkali environment, and the iron tailings containing a large amount of SiO ₂ can supplement the silicon component of the slag mixture tailings, so that the proportion of aluminum, calcium and silicon in the slag mixture tailings is adjusted, the slag mixture tailings have higher activity, and can be better used as building materials.

The invention realizes the cooperative treatment of multi-source solid waste, realizes the secondary utilization of the waste heat of the molten steel slag and the pulp waste water, and has remarkable economic and environmental benefits.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention.

FIG. 1 is a process flow diagram of an embodiment of the present invention.

Detailed Description

It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

The invention is further illustrated below with reference to examples.

Example 1

S1, uniformly mixing 0.12 ton of carbon powder with 9 tons of iron tailing pulp to form mixed pulp, wherein the concentration of the iron tailing pulp is 45%, the main chemical components of the iron tailings are shown in a table 1, and the main components of the carbon powder are shown in a table 2, wherein the percentages in the following tables are all percentages by mass.

TABLE 1 main chemical composition ratio of iron tailings (%)

TABLE 2 carbon powder major component fraction (%)

S2, pouring the molten steel slag discharged from the 30-ton converter into a slag stewing pond, wherein the main chemical components are shown in a table 3, and the mass percent of the main chemical components is shown in the table.

TABLE 3 ratio of main chemical components of molten steel slag (%)

S3, spraying 9.12 tons of mixed ore pulp on the surface of the molten steel slag, and generating reducing gases such as H ₂, CO and the like by carbon powder and water in a high-temperature environment provided by the molten steel slag, wherein the reducing gases reduce the weakly magnetic hematite in the iron tailings into the strongly magnetic magnetite in the high-temperature environment.

S4, crushing and turning slag by using an excavator after the water in the mixed ore pulp is evaporated, and mixing the dried and reduced iron tailings into the slag by turning slag to form a slag mixture.

And S5, repeating the steps for three times to enable the steel slag mixture in the slag disintegrating pool to reach rated capacity, and sealing by covering the slag disintegrating pool cover.

S6, injecting water into the slag stewing pond through a water pipe at the bottom of the slag stewing pond, so that the water is soaked in the steel slag mixture for 2 hours, and then opening a water valve at the bottom to drain water, so that the steel slag mixture is thermally stewed in saturated steam for 6 hours.

S7, after slag stewing, digging out the steel slag mixture in the slag stewing pool, crushing the steel slag mixture to below 5mm by adopting a jaw crusher for primary crushing and a rod mill for secondary crushing, and extracting 9.87 tons of metal iron particles from the steel slag mixture by using an iron remover. The yield of the metallic iron particles was 9.66% and the TFe grade was 93.27%.

And S8, performing wet ball milling on the residual steel slag mixture after removing the metal iron particles to be less than 0.075mm, and performing magnetic separation by a semi-countercurrent electromagnetic drum type weak magnetic separator with the magnetic field strength of 87.56 kA/m to extract 32.85 tons of iron concentrate. The yield of the fine iron powder is 32.16%, and the TFe grade is 44.62%.

S9, drying the tailings after the iron extraction of the steel slag mixture, wherein the mass of the residual tailings is 59.43 tons, the yield is 58.18%, and the TFe grade is 13.57%. The activity of tailings is tested by referring to the national standard GB/T12957-2005, the 28-day activity index is found to be as high as 73.6%, and the requirement (more than or equal to 65%) of the 28-day activity index of the second-class steel slag in the national standard GB/T51003-2014 is met.

In S9, preparing a solid waste-based cementing material according to the mass ratio of tailings to blast furnace slag to P.O42.5 cement to desulfurized gypsum=30:40:25:5, preparing a sand gel test piece by referring to national standard GB/T17671-2021, curing and testing the compressive strength for 28 days, and finding that the compressive strength for 28 days reaches 38.9MPa.

Example 2

s1, uniformly mixing 0.11 ton of carbon powder with 7.5 tons of red mud pulp to form mixed pulp, wherein the concentration of the red mud pulp is 50%, the main chemical components of the red mud are shown in Table 4, and the main components of the carbon powder are shown in Table 2.

TABLE 4 main chemical composition of red mud (%)

S2, pouring the molten steel slag discharged from the 30-ton converter into a slag stewing pond, wherein the main chemical compositions are shown in the table 3.

S3, spraying 7.61 tons of mixed ore pulp on the surface of the molten steel slag, and generating reducing gases such as H ₂, CO and the like by carbon powder and water in a high-temperature environment provided by the molten steel slag, wherein the reducing gases reduce weakly magnetic hematite in the red mud into ferromagnetic magnetite in the high-temperature environment.

S4, crushing and turning slag by using an excavator after the water in the mixed ore pulp is evaporated, and mixing the dried and reduced red mud into the slag by turning slag to form a slag mixture.

S7, after slag stewing, digging out the steel slag mixture in the slag stewing pool, crushing the steel slag mixture to below 5mm by adopting a jaw crusher for primary crushing and a rod mill for secondary crushing, and extracting 9.91 tons of metal iron particles from the steel slag mixture by using an iron remover. The yield of the metallic iron particles is 9.79%, and the TFe grade is 92.84%.

And S8, performing wet ball milling on the residual steel slag mixture after removing the metal iron particles to be less than 0.075mm, and performing magnetic separation by a semi-countercurrent electromagnetic drum type weak magnetic separator with the magnetic field strength of 87.56 kA/m to extract 32.97 tons of iron concentrate. The yield of the fine iron powder is 32.56%, and the TFe grade is 46.19%.

And S9, drying the tailings after the iron extraction of the steel slag mixture, wherein the mass of the residual tailings is 58.37 tons, the yield is 57.65%, and the TFe grade is 13.36%. The activity of tailings is tested by referring to the national standard GB/T12957-2005, the 28-day activity index is found to be as high as 83.4%, and the requirement of the national standard GB/T51003-2014 on the 28-day activity index (more than or equal to 80%) of one type of steel slag is met.

In S9, preparing a solid waste-based cementing material by using the mass ratio of tailings to blast furnace slag to P.O42.5 cement to desulfurized gypsum=30:40:25:5, preparing a sand gel test piece by referring to national standard GB/T17671-2021, curing and testing the compressive strength for 28 days, and finding that the strength reaches 44.6MPa.

Comparative example 1

A heat stewing treatment method of steel slag comprises the following steps:

s1, pouring 30 tons of molten steel slag discharged from a converter into a slag stewing pond, wherein the main chemical compositions are shown in table 3.

S2, cooling the surface of the molten steel slag by water, and crushing and turning the steel slag by an excavator after the water on the surface of the steel slag is evaporated.

And S3, repeating the steps for three times to ensure that the steel slag in the slag disintegrating pool reaches 90 tons, and covering a cover of the heat stewing device for sealing.

S4, injecting water into the slag stewing pond through a water pipe at the bottom of the slag stewing pond, so that the water is soaked in the steel slag, and then, opening a water valve at the bottom to drain water, so that the steel slag mixture is thermally stewed in saturated steam for 6 hours.

S5, after slag stewing, digging out the pulverized steel slag in the slag stewing pool, crushing the pulverized steel slag to below 5mm by adopting a jaw crusher for primary crushing and a rod mill for secondary crushing, and extracting metal iron particles in the pulverized steel slag by using an iron remover to obtain 9.77 tons. The yield of the metallic iron particles is 10.86%, and the TFe grade is 94.26%.

S6, performing wet ball milling on the residual steel slag after removing the metal iron to be less than 0.075mm, and performing magnetic separation by a semi-countercurrent electromagnetic drum type weak magnetic separator with the magnetic field strength of 87.56 kA/m to extract 30.35 tons of iron concentrate. The yield of the fine iron powder is 33.72%, and the TFe grade is 45.83%.

And S7, drying the tailings after the iron extraction of the steel slag, wherein the mass of the residual tailings is 49.88 tons, the yield is 55.42%, and the TFe grade is 13.09%. The activity of the dried tailings is tested by referring to the national standard GB/T12957-2005, and the 28-day activity index is found to be as high as 76.7 percent, so that the requirement of the national standard GB/T51003-2014 on the 28-day activity index (more than or equal to 65 percent) of the second-class steel slag is met.

In S7, preparing a solid waste-based cementing material by using the mass ratio of tailings to blast furnace slag to P.O42.5 cement to desulfurized gypsum=30:40:25:5, preparing a sand gel test piece by referring to national standard GB/T17671-2021, curing and testing the compressive strength for 28 days, and finding that the strength reaches 40.2MPa.

Comparative example 2

A method for building iron tailings comprises the following steps:

The iron tailings are dried and screened to be less than 0.075mm, and the activity of the treated iron tailings is tested by referring to the national standard GB/T12957-2005, and the 28-day activity index is found to be 58.4%. The solid waste-based cementing material is prepared by the mass ratio of the treated iron tailings to the blast furnace slag to the P.O42.5 cement to the desulfurized gypsum=30:40:25:5, and the cement sand test piece is prepared by referring to the national standard GB/T17671-2021, is subjected to health maintenance and is tested for 28 days of compressive strength, and the strength is found to reach 25.6MPa.

Comparative example 3

A method for building materials from red mud comprises the following steps:

The red mud is dried and screened to be less than 0.075mm, and the activity of the treated red mud is tested by referring to the national standard GB/T12957-2005, and the activity index is found to be 60.2% in 28 days. The solid waste-based cementing material is prepared by the mass ratio of treated red mud to blast furnace slag to P.O 42.5 cement to desulfurized gypsum=30:40:25:5, and the cement sand test piece is prepared by referring to the national standard GB/T17671-2021, is subjected to health maintenance and is tested for 28 days of compressive strength, and the strength is found to reach 28.4MPa.

Comparative examples 1, 2 and 1 the iron component recovery results are shown in table 5, and the solid waste activity and 28-day compressive strength test results of the solid waste-based cement are shown in table 6.

Table 5 comparison of iron component recovery test results

Table 6 comparison of tailings Activity and 28 day compression Strength test results for solid waste based cementitious materials

According to table 5, when the quality of the molten steel slag is the same as that of the conventional steel slag heat-stewing treatment method, compared with the conventional steel slag heat-stewing treatment method, the TFe grade of the metal iron particles extracted by the waste heat reduction high-water-content iron-containing solid waste steel slag heat-stewing iron extraction and building material method is slightly reduced, and the yield is slightly increased, which is obviously obtained by comparing the embodiment 1 and the embodiment 2 with the comparative embodiment 1.

From table 5, it is apparent from comparison of example 1, example 2 and comparative example 1 that the TFe grade of the extracted fine iron powder of the present invention is very little different from that of the conventional steel slag heat-stewing process, the yield is significantly increased, the fine iron powder yield of example 1 is increased by 2.5 tons, and the fine iron powder yield of example 2 is increased by 2.62 tons when the quality of the molten steel slag is the same.

As apparent from table 5 by comparing example 1, example 2 and comparative example 1, when the quality of the molten steel slag is the same, compared with the conventional steel slag heat-stewing treatment method, the TFe grade of the tailings produced by the waste heat reduction high-water-content iron-containing solid waste steel slag heat-stewing iron extraction and building material method of the invention has little difference, the yield is remarkably increased, the yield of the tailings of example 1 is increased by 9.55 ten thousand tons, and the yield of the tailings of example 2 is increased by 8.49 ten thousand tons.

According to Table 6, when the quality of the molten steel slag is the same, compared with the traditional steel slag heat braising treatment method, the activity of tailings generated by pouring iron tailing pulp on the surface of the molten steel slag is reduced by 3.1%, but the requirement of 28 days activity index (more than or equal to 65%) of the second-class steel slag in the national standard GB/T51003-2014 can still be met, the activity of tailings generated by pouring red mud pulp is obviously increased by 6.7% when the molten steel slag is compared with the comparative example 1, comparative example 2 and comparative example 3, and the requirement of 28 days activity index (more than or equal to 80%) of the first-class steel slag in the national standard GB/T51003-2014 can be met.

According to Table 6, it is obvious that by comparing the example 1 with the comparative example 2, compared with the iron tailings which are only dried and screened, the activity of tailings generated by pouring iron tailings pulp on the surface of the molten steel slag is obviously increased by 15.2%, because the waste heat of the molten steel slag plays a role in thermal activation on the iron tailings, clay minerals in the iron tailings are decomposed into active SiO ₂ and Al ₂O₃, dissolution of components such as active silicon and aluminum is promoted, and the ball milling of the residual materials plays a role in mechanically activating the iron tailings, the passivation mucous membrane on the surfaces of iron tailings particles is destroyed, dissolution of the components such as active silicon and aluminum is promoted, the specific surface area of the iron tailings particles is increased by ball milling, and the contact area of the iron tailings particles participating in hydration reaction is increased.

According to Table 6, it is obvious that by comparing example 2 with comparative example 3, compared with the red mud which is only dried and screened, the activity of tailings generated by dumping red mud pulp on the surface of molten steel slag is obviously increased by 23.2%, because the waste heat of the molten steel slag plays a role in thermally activating the red mud, clay minerals in the red mud are decomposed into active SiO ₂ and Al ₂O₃, dissolution of active silicon, aluminum and other components is promoted, and the ball milling of the residual materials plays a role in mechanically activating the red mud.

According to the table 6, when the quality of the molten steel slag is the same as that of the comparative example 1, it is obvious that the strength of the solid waste-based cementing material prepared by pouring the tailings generated by the iron tailing pulp on the surface of the molten steel slag is slightly reduced by 3.2% compared with the traditional steel slag heat stewing treatment method, the strength of the solid waste-based cementing material prepared by pouring the tailings generated by the red mud pulp on the surface of the molten steel slag is obviously increased by 10.9%, and the strength requirement of 45.2# cement can be met, because the red mud supplements Al ₂O₃ in the solid waste-based cementing material, and OH ^- in the red mud provides an alkaline environment, the solid waste-based cementing material in the example 2 undergoes an alkali excitation reaction, more hydrated aluminosilicate gel and hydrated aluminate gel are generated, and the strength of the solid waste-based cementing material is improved.

As apparent from table 6, by comparing example 1 with comparative example 2, the strength of the solid waste-based cementitious material prepared by pouring tailings generated from the iron tailing pulp on the surface of molten steel slag is remarkably increased compared with the iron tailings subjected to drying and screening only, because the tailings generated by pouring the iron tailing pulp on the surface of molten steel slag of the present invention have higher activity after thermal activation and mechanical activation, and react with blast furnace slag, p.o 42.5 cement, and desulfurized gypsum to generate more cementitious materials.

As apparent from table 6, by comparing example 2 with comparative example 3, the strength of the solid waste-based cementitious material prepared by pouring the tailings generated by pouring the red mud slurry on the surface of the molten steel slag is remarkably increased compared with the red mud subjected to drying and screening only, because the tailings generated by pouring the red mud slurry on the surface of the molten steel slag has higher activity after thermal activation and mechanical activation, and reacts with blast furnace slag, p.o42.5 cement and desulfurized gypsum to generate more cementitious materials.

In conclusion, the invention utilizes the waste heat of the molten steel slag to realize the drying, the reduction magnetization roasting and the thermal activation of the iron tailings or the red mud, increases the yield of the metal iron particles and the iron concentrate, and effectively recovers the iron components in the iron tailings or the red mud. The red mud containing a large amount of A1 ₂O₃ and OH ^- supplements the aluminum component of the slag mixture tailings, provides an alkali excitation environment, enables the slag mixture tailings to have higher activity, slightly reduces the activity of the iron tailings and the slag mixture tailings, has little influence, can be used as building materials, and has higher activity compared with the iron tailings/red mud subjected to drying and screening, the tailings generated by pouring the iron tailings/red mud pulp on the surface of the molten steel slag are subjected to thermal activation and mechanical activation, and the solid waste-based cementing material prepared from the slag mixture tailings has higher strength. The invention realizes the cooperative treatment of multi-source solid waste, realizes the secondary utilization of the waste heat of the molten steel slag and the pulp waste water, and has remarkable economic and environmental benefits.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for hot-stewing and iron-extraction of steel slag and building materials using waste heat to reduce high-water and iron-containing solid waste, characterized in that it comprises the following steps:

S1: mixing iron tailings slurry or/and red mud slurry with carbon powder in a mass ratio of 100:1-5 to obtain a mixed slurry;

S2: pouring the molten slag into the slag stewing pool;

S3: spraying the mixed slurry on the surface of the molten slag;

S4: After the water in the mixed slurry is evaporated, the steel slag is crushed and turned over, so that the dried and reduced iron tailings and/or red mud and the remaining carbon powder are mixed into the steel slag to form a steel slag mixture;

S5: Repeat S2 to S4 until the steel slag mixture reaches the rated capacity of the slag tank, and then cover the slag tank;

S6: injecting water into the slag stewing pool to stew the slag;

S7: crushing the slag mixture after smelting to extract metallic iron particles;

S8: After ball milling the remaining material, extracting iron concentrate;

S9: The remaining tailings are used as raw materials for building materials.

2. The method for hot-stewing and iron-extraction of steel slag and building materials by waste heat reduction of high-water-containing iron-containing solid waste according to claim 1, characterized in that the moisture content in the iron tailings slurry is 10%-60%, where % is mass percentage;

The water content in the red mud slurry is 20%-75%, where % is the mass percentage.

3. The method for hot stewing of steel slag to extract iron and make building materials by waste heat reduction of high-water and iron-containing solid waste according to claim 2 is characterized in that the moisture content in the iron tailings slurry is 40%-60%, where % is the mass percentage.

4. The method for hot stewing of steel slag to extract iron and make building materials by waste heat reduction of high-water and iron-containing solid waste according to claim 1 is characterized in that the moisture content in the red mud slurry is 40%-60%, where % is the mass percentage.

5. The method for hot stewing and iron extraction from steel slag and converting it into building materials by waste heat reduction of high-water and high-iron-containing solid waste according to claim 1 is characterized in that the mixed slurry accounts for 20%-40% of the mass of the molten steel slag.

6. The method for hot stewing of steel slag to extract iron and make building materials from high-water and high-iron-content solid waste using waste heat reduction as claimed in claim 1 is characterized in that the stewing time is 4-8 hours; the particle size of the powdered steel slag after stewing is less than 5 mm after crushing.

7. The method for hot stewing and iron extraction from steel slag and its construction material production by waste heat reduction of high-water- and iron-containing solid waste according to claim 1 is characterized in that an iron remover is used to extract the metallic iron particles therein.

8. The method for hot stewing and iron extraction from steel slag and building materials using waste heat reduction of high-water and high-iron-content solid waste according to claim 1 is characterized in that the particle size of the remaining material after wet ball milling is less than 0.075 mm.

9. The method for hot stewing of steel slag to extract iron and convert it into building materials by waste heat reduction of high-water- and iron-containing solid waste according to claim 1, characterized in that a weak magnetic separation device is used to extract the iron concentrate.

10. The method for hot stewing and iron extraction from steel slag and building materials by waste heat reduction of high-water and high-iron-content solid waste according to claim 1 is characterized in that the remaining tailings are used as raw materials for cement mixtures, concrete admixtures or solid waste-based cementitious materials.