A method for solid-state steel slag recycling treatment based on a hierarchical system

Abstract

The present application belongs to the technical field of iron and steel metallurgy, and specifically relates to a solid-state steel slag recycling method based on a grading system. The parameters of the solid-state steel slag are detected to establish a solid-state steel slag quality dataset; a solid-state steel slag grading index is selected to formulate a solid-state steel slag grading system; different grades of solid-state steel slag are designed to match the processing mode; the parameters of the solid-state steel slag to be processed are obtained to select the corresponding processing mode for processing. The method is simple and reliable, and has high processing efficiency. The solid-state steel slag is graded before processing, and the same grade of steel slag is controlled by the same processing mode, so that stable operation of the solid-state steel slag processing process can be realized, resource waste caused by large fluctuations in the composition of the solid-state steel slag can be avoided, the consumption of slag processing raw materials can be reduced, the processing time can be shortened, industrial solid waste emissions and environmental pollution can be reduced, the economic benefits of steel enterprises can be increased, and the present application has important reference and guiding significance for efficient recycling of metallurgical industrial waste slag.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of iron and steel metallurgy, and particularly relates to a solid-state steel slag recycling method based on a grading system. BACKGROUND

[0002] The steel slag contains valuable components such as iron, phosphorus and manganese, and has great recycling value. The common steel slag treatment methods currently used include magnetic separation, hot stewing and hot splashing, which all have the characteristics of low one-time treatment efficiency, complex equipment and high cost. After iron separation, some steel enterprises sell the tailings, resulting in a large amount of resource waste. The steel slag treatment process mainly relies on human experience control, and different steel slags are uniformly treated, which is difficult to achieve the effect of stable dephosphorization and iron separation. The solid-state steel slag has complex components and large particle size difference, which are all factors leading to unstable control of solid-state steel slag treatment. There is no effective method for treating solid-state steel slag in the prior art. SUMMARY

[0003] To solve the problems in the prior art, the main purpose of the present application is to provide a solid-state steel slag recycling method based on a grading system, which classifies solid-state steel slags with large component fluctuations, regards solid-state steel slags in the same category as stable, and controls them by using the same treatment method, so as to realize stable treatment of waste solid-state steel slags, finally realize efficient recycling of solid-state steel slags, reduce industrial solid waste accumulation and environmental pollution, increase economic benefits of steel enterprises, and have important reference and guiding significance for recycling of metallurgical waste solid-state steel slags.

[0004] To solve the above technical problems, according to one aspect of the present application, the present application provides the following technical scheme:

[0005] A solid-state steel slag recycling method based on a grading system, comprising the following steps:

[0006] S1. Detecting solid-state steel slag parameters to establish a solid-state steel slag quality data set;

[0007] S2. Selecting a solid-state steel slag grading index to develop a solid-state steel slag grading system;

[0008] S3. Designing a treatment mode matched with different grades of solid-state steel slags;

[0009] S4. Obtaining parameters of solid-state steel slags to be treated, and selecting a corresponding treatment mode for treatment.

[0010] As a preferred scheme of the solid-state steel slag recycling method based on a grading system, in the step S1, the solid-state steel slag quality data set includes density, particle size, main components and production batch.

[0011] As a preferred scheme of the method for solid-state steel slag recycling treatment based on a grading system, in the step S2, the solid-state steel slag grading index comprises main components of the solid-state steel slag and contents thereof.

[0012] As a preferred scheme of the method for solid-state steel slag recycling treatment based on a grading system, in the step S2, the grading system of the main components of the solid-state steel slag and the contents thereof is based on the detected phosphorus content, wherein the solid-state steel slag with a phosphorus content less than 1 wt% is defined as low-phosphorus solid-state steel slag, the solid-state steel slag with a phosphorus content of 1-3 wt% is defined as medium-phosphorus solid-state steel slag, and the solid-state steel slag with a phosphorus content greater than 3 wt% is defined as high-phosphorus solid-state steel slag.

[0013] As a preferred scheme of the method for solid-state steel slag recycling treatment based on a grading system, in the step S2, the grading system of the main components of the solid-state steel slag and the contents thereof is based on the detected total iron content, wherein the total iron content of the solid-state steel slag is divided by 20 wt% as a line, wherein the solid-state steel slag with a total iron content less than or equal to 20 wt% is defined as low-iron solid-state steel slag, and the solid-state steel slag with a total iron content greater than 20 wt% is defined as high-iron solid-state steel slag.

[0014] As a preferred scheme of the method for solid-state steel slag recycling treatment based on a grading system, in the step S2, the solid-state steel slag is divided into six grades, i.e., low-phosphorus low-iron, low-phosphorus high-iron, medium-phosphorus low-iron, medium-phosphorus high-iron, high-phosphorus low-iron, and high-phosphorus high-iron, according to the phosphorus content and the total iron content of the solid-state steel slag.

[0015] As a preferred scheme of the method for solid-state steel slag recycling treatment based on a grading system, in the step S3, a treatment mode matched with the solid-state steel slag of different grades is designed, and the treatment mode is specifically as follows:

[0016] The low-phosphorus low-iron solid-state steel slag treatment mode: the low-phosphorus low-iron solid-state steel slag has low phosphorus content, and has strong dephosphorization capacity when used for converter slagging, and the iron content in the slag is low, so that iron selection treatment is not needed; therefore, the low-phosphorus low-iron solid-state steel slag does not need to be treated.

[0017] The low-phosphorus high-iron solid-state steel slag treatment mode: the low-phosphorus high-iron solid-state steel slag needs to be subjected to iron selection treatment, and the temperature is kept at 1300-1500 ℃ during the melting treatment in the induction heating furnace, and the melting is kept for 10-20 min, and the argon gas is blown at the bottom to uniformly stir the molten pool while the temperature is kept, the argon gas flow is 100-300 Nm 3 / (h·t 渣 ), the temperature of the argon gas is 1200-1400 ℃, and the molten slag and the metal liquid are stratified after the temperature keeping is finished, and the metal liquid flows out through the tapping hole to be recycled.

[0018] Medium phosphorus low iron solid steel slag treatment mode: medium phosphorus low iron solid steel slag needs to be dephosphorized, the treatment process is: Fe2O3 is added to the induction heating furnace, the mass of Fe2O3 is 5-15% of the total mass of the solid steel slag; then the medium phosphorus low iron solid steel slag is added, and the carbonaceous reducing agent is added along with the slag flow, the amount of the carbonaceous reducing agent is 1-1.5 times of the amount of the carbonaceous reducing agent required for the reduction of FeO and P2O5 in the slag; then the steel slag is heated to 1300-1500 DEG C and melted, after melting, the temperature is kept for 10-20 min, while the argon gas is blown at the bottom to stir the molten pool uniformly, the argon gas flow is 100-300 Nm 3 / (h·t 渣 ), the temperature of the argon gas is 1200-1400 DEG C; after the temperature keeping is finished, the molten slag and the metal liquid are stratified by standing for 0.5-1 h; the phosphorus vapor is collected by the phosphorus recovery device on the upper part of the furnace body, and the metal liquid is recovered by flowing out of the tapping hole;

[0019] Medium phosphorus high iron solid steel slag treatment mode: medium phosphorus high iron solid steel slag needs to be dephosphorized and iron selected, the treatment process is: the medium phosphorus high iron solid steel slag is added, and the carbonaceous reducing agent is added along with the slag flow, the amount of the carbonaceous reducing agent is 1-2 times of the amount of the carbonaceous reducing agent required for the reduction of FeO and P2O5 in the slag; then the steel slag is heated to 1300-1500 DEG C and melted, after melting, the temperature is kept for 10-20 min, while the argon gas is blown at the bottom to stir the molten pool uniformly, the argon gas flow is 100-300 Nm 3 / (h·t 渣 ), the temperature of the argon gas is 1200-1400 DEG C; after the temperature keeping is finished, the molten slag and the metal liquid are stratified by standing for 0.5-1 h; the phosphorus vapor is collected by the phosphorus recovery device on the upper part of the furnace body, and the metal liquid is recovered by flowing out of the tapping hole;

[0020] High phosphorus low iron solid steel slag treatment mode: high phosphorus low iron solid steel slag needs to be dephosphorized, the treatment process is: Fe2O3 is added to the induction heating furnace, the mass of Fe2O3 is 5-15% of the total mass of the solid steel slag; then the high phosphorus low iron solid steel slag is added, and the carbonaceous reducing agent and the catalyst are added along with the slag flow, the catalyst is heavy metal industrial waste residue including red mud, copper slag and nickel slag, which can accelerate the dephosphorization reaction of the slag, shorten the reaction time and improve the dephosphorization efficiency; the amount of the carbonaceous reducing agent is 1-1.5 times of the amount of the carbonaceous reducing agent required for the reduction of FeO and P2O5 in the slag, and the amount of the catalyst is 0.2-0.5 times of the amount of the high phosphorus low iron solid steel slag; then the steel slag is heated to 1300-1500 DEG C and melted, after melting, the temperature is kept for 10-20 min, while the argon gas is blown at the bottom to stir the molten pool uniformly, the argon gas flow is 100-300 Nm 3 / (h·t 渣), the temperature of the argon is 1200-1400 DEG C; after the heat preservation ends, the molten slag and the metal liquid are layered by standing for 0.5-1 h; the phosphorus vapor is collected by a phosphorus recovery device on the upper part of the furnace body, and the metal liquid flows out through a tapping hole for recovery.

[0021] The high-phosphorus high-iron solid steel slag is treated by dephosphorization and iron selection, and the treatment process is as follows: the high-phosphorus high-iron solid steel slag is added, and carbonaceous reducing agent and catalyst are added along with the slag flow; the catalyst is heavy metal industrial waste residue including red mud, copper slag and nickel slag; the amount of the carbonaceous reducing agent is 1-1.5 times the amount required for reducing FeO and P2O5 in the slag; the amount of the catalyst is 0.2-0.5 times the amount of the high-phosphorus high-iron solid steel slag; then the steel slag is melted by heating to 1300-1500 DEG C, and after melting, heat preservation is performed for 10-20 min; while heat preservation is performed, argon is blown at the bottom to uniformly stir the molten pool; the flow rate of the argon is 100-300 Nm 3 / (h·t 渣 ; the temperature of the argon is 1200-1400 DEG C; after the heat preservation ends, the molten slag and the metal liquid are layered by standing for 0.5-1 h; the phosphorus vapor is collected by a phosphorus recovery device on the upper part of the furnace body, and the metal liquid flows out through a tapping hole for recovery.

[0022] As a preferred scheme of the method for treating and recycling solid steel slag based on a grading system, the treated steel slag is directly added to a converter steelmaking process as a converter slagging agent, and the addition amount is 5-8 kg / t 钢 .

[0023] The beneficial effects of the present application are as follows:

[0024] The present application provides a method for treating and recycling solid steel slag based on a grading system. The parameters of the solid steel slag are detected to establish a solid steel slag quality data set; a solid steel slag grading index is selected to develop a solid steel slag grading system; different grades of solid steel slag are matched with corresponding treatment modes; the parameters of the solid steel slag to be treated are obtained, and the corresponding treatment mode is selected for treatment. The method is simple and reliable, and has high treatment efficiency. The solid steel slag is graded before treatment, the same grade of steel slag is controlled by the same treatment mode, the stable operation of the solid steel slag treatment process can be realized, the resource waste caused by large fluctuations in the composition of the solid steel slag is avoided, the consumption of slag treatment raw materials is reduced, the treatment time is shortened, the industrial solid waste emission and environmental pollution are reduced, and the economic benefits of the steel enterprise are increased. The present application has important reference and guiding significance for efficient recycling of metallurgical industrial waste residue. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0026] The technical solutions of the present application will be further described below in combination with specific embodiments.

[0027] Embodiment 1

[0028] The solid-state steel slag generated in the converter steelmaking process of a certain plant is treated by using the method. The specific implementation process is as follows: 100 g of slag sample is taken, and the composition of the solid-state steel slag is detected to obtain the phosphorus content of 2.15wt% in the slag and the total iron content of 24.31wt%, which belongs to medium-phosphorus high-iron solid-state steel slag. 30 g of pulverized coal is added as a reducing agent, and the pulverized coal is added into the induction furnace along with the slag flow. The reaction temperature is controlled at 1450℃, and the holding time is 15 min. Argon gas is blown at the bottom for stirring during the holding, the argon gas flow is 200 Nm 3 / (h·t 渣 ), and the temperature of the argon gas is 1300℃. After the holding is completed, the slag is left to stand for 0.5 h.

[0029] The composition of the solid-state steel slag before and after the treatment of the present embodiment is shown in Table 1. As shown in Table 1, after the treatment by using the method of the present application, the P2O5 content in the steel slag is reduced from 2.15wt% to 0.17wt%, and the total iron content is reduced from 24.31wt% to 10.01wt%, which shows a remarkable effect of dephosphorization and iron selection. The treated steel slag can be directly added to the converter steelmaking process as a slagging agent, so as to realize the efficient utilization of the solid-state steel slag generated in the converter steelmaking process.

[0030] Table 1 Composition of solid-state steel slag before and after treatment (wt%)

[0031]

[0032] Embodiment 2

[0033] The solid-state steel slag generated in the converter steelmaking process of a certain plant is treated by using the method. The specific implementation process is as follows: 100 g of slag sample is taken, and the composition of the solid-state steel slag is detected to obtain the phosphorus content of 2.15wt% in the slag and the total iron content of 24.31wt%, which belongs to medium-phosphorus high-iron solid-state steel slag. 30 g of pulverized coal is added as a reducing agent, and the pulverized coal is added into the induction furnace along with the slag flow. The reaction temperature is controlled at 1450℃, and the holding time is 15 min. Argon gas is blown at the bottom for stirring during the holding, the argon gas flow is 200 Nm 3 / (h·t 渣), the temperature of the argon gas is 1300℃. After the holding, the sample is left for 0.5h.

[0034] The composition of the steel slag before and after the treatment of the solid steel slag in the converter steelmaking according to the present embodiment is shown in Table 2. As shown in Table 2, after the treatment according to the present embodiment, the content of P2O5 in the steel slag is reduced from 5.43wt% to 0.33wt%, and the content of total iron is reduced from 16.26wt% to 11.31wt%. The dephosphorization and iron selection effects are remarkable. The treated steel slag can be directly added to the converter steelmaking process as a slagging agent, and the solid steel slag in the converter steelmaking is efficiently utilized.

[0035] Table 2 Composition of the solid steel slag before and after the treatment (wt%)

[0036]

[0037] Comparative Example 1

[0038] The difference from Example 2 is that no catalyst is added during the treatment.

[0039] The composition of the steel slag before and after the treatment of the solid steel slag in the converter steelmaking according to the present embodiment is shown in Table 2. As shown in Table 2, after the treatment according to the present embodiment, the content of P2O5 in the steel slag is reduced from 5.43wt% to 0.33wt%, and the content of total iron is reduced from 16.26wt% to 11.31wt%. The dephosphorization and iron selection effects are remarkable. The treated steel slag can be directly added to the converter steelmaking process as a slagging agent, and the solid steel slag in the converter steelmaking is efficiently utilized.

[0040] Table 2 Composition of the solid steel slag before and after the treatment (wt%)

[0041]

[0042]

[0043] Comparative Example 2

[0044] The difference from Example 2 is that no Fe2O3 is added during the treatment.

[0045] The composition of the steel slag before and after the treatment of the solid steel slag in the converter steelmaking according to the present embodiment is shown in Table 2. As shown in Table 2, after the treatment according to the present embodiment, the content of P2O5 in the steel slag is reduced from 5.43wt% to 0.33wt%, and the content of total iron is reduced from 16.26wt% to 11.31wt%. The dephosphorization and iron selection effects are remarkable. The treated steel slag can be directly added to the converter steelmaking process as a slagging agent, and the solid steel slag in the converter steelmaking is efficiently utilized.

[0046] Table 2 Composition of the solid steel slag before and after the treatment (wt%)

[0047]

[0048] The present application is based on the steel slag grading system for dephosphorization and iron separation treatment of solid steel slag, and a higher dephosphorization and iron separation efficiency can be obtained. The phosphorus content in the dephosphorized slag is low, which can be directly reused in the converter steelmaking process, and finally reaches the purpose of efficient utilization of the converter solid steel slag. The method is simple and reliable, and has high dephosphorization efficiency. It can not only solve the problem of large solid steel slag stock and environmental pollution, but also reduce the consumption of slagging materials in converter steelmaking, shorten the pretreatment time, reduce the slagging heat loss, and increase the economic benefit of steel enterprises. It has important reference and guiding significance for efficient recycling of metallurgical slag.

[0049] The above only describes the preferred embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation, direct / indirect application in other related technical fields, or direct / indirect application in other related technical fields made by using the content of the present application are included in the patent protection scope of the present application.

Claims

1. A method for solid-state steel slag recycling treatment based on a hierarchical system, characterized by, The method comprises the following steps: S1. Detecting parameters of solid steel slag, and establishing a solid steel slag quality dataset; S2. Selecting a solid steel slag grading index, and formulating a solid steel slag grading system; In the step S2, the grading system of the main components and contents of the solid steel slag is determined according to the detected phosphorus content: the solid steel slag with a phosphorus content less than 1wt% is defined as low-phosphorus solid steel slag, the solid steel slag with a phosphorus content of 1-3wt% is defined as medium-phosphorus solid steel slag, and the solid steel slag with a phosphorus content greater than 3wt% is defined as high-phosphorus solid steel slag; the grading system of the main components and contents of the solid steel slag is determined according to the detected total iron content: the total iron content of the solid steel slag is divided by 20wt% as a line, wherein the solid steel slag with a total iron content less than or equal to 20wt% is defined as low-iron solid steel slag, and the solid steel slag with a total iron content greater than 20wt% is defined as high-iron solid steel slag; the solid steel slag is divided into six grades of low-phosphorus low-iron, low-phosphorus high-iron, medium-phosphorus low-iron, medium-phosphorus high-iron, high-phosphorus low-iron and high-phosphorus high-iron according to the phosphorus content and total iron content of the solid steel slag; S3. Designing a processing mode matched with the solid steel slag of different grades; In the step S3, a processing mode matched with the solid steel slag of different grades is designed, specifically as follows: Low-phosphorus low-iron solid steel slag processing mode: the low-phosphorus low-iron solid steel slag does not need to be processed; Low phosphorus high iron solid steel slag treatment mode: low phosphorus high iron solid steel slag needs to be treated by iron selection, and the temperature is kept at 1300-1500℃ during melting treatment in an induction heating furnace. After melting, the temperature is kept for 10-20 min. The argon gas is blown at the bottom to stir the molten pool uniformly. The argon gas flow is 100-300 Nm 3 / (h·t 渣 ), and the temperature of the argon gas is 1200-1400℃. After the temperature keeping is finished, the molten slag and the metal liquid are layered for 0.5-1 h, and the metal liquid is discharged through the tapping hole for recovery. The medium-phosphorus low-iron solid steel slag treatment mode: the medium-phosphorus low-iron solid steel slag needs to be dephosphorized, and the treatment process is as follows: Fe2O3 is added into an induction heating furnace, and the mass of Fe2O3 is 5-15% of the total mass of the solid steel slag; then the medium-phosphorus low-iron solid steel slag is added, and a carbonaceous reducing agent is added along with the slag flow, and the addition amount of the carbonaceous reducing agent is 1-1.5 times of the amount of the carbonaceous reducing agent required for the reduction of FeO and P2O5 in the slag; then the steel slag is heated to 1300-1500 DEG C to be melted, and after melting, the molten pool is uniformly stirred by argon blowing at the bottom for 10-20 min, the argon flow rate is 100-300 Nm 3 / (h·t 渣 ), the temperature of the argon is 1200-1400 DEG C; after the heat preservation is completed, the molten slag and the metal liquid are stratified by standing for 0.5-1 h; the phosphorus vapor is collected by a phosphorus recovery device on the upper part of the furnace body, and the metal liquid flows out through a tapping hole for recovery; The medium-phosphorus high-iron solid steel slag treatment mode: the medium-phosphorus high-iron solid steel slag needs to be treated by dephosphorization and iron selection, and the treatment process is as follows: the medium-phosphorus high-iron solid steel slag is added, the carbonaceous reducing agent is added along with the slag flow, the amount of the carbonaceous reducing agent is 1-2 times of the amount of the carbonaceous reducing agent required for reducing FeO and P2O5 in the slag; then the steel slag is heated to 1300-1500 DEG C to be melted, and after melting, the temperature is kept for 10-20 min, and while keeping the temperature, argon gas is blown at the bottom to stir the molten pool uniformly, the argon gas flow is 100-300 Nm 3 / (h·t 渣 ), the temperature of the argon gas is 1200-1400 DEG C; after the temperature keeping is finished, the molten slag and the metal liquid are stratified by being kept still for 0.5-1 h; the phosphorus vapor is collected by a phosphorus recovery device on the upper part of the furnace body, and the metal liquid flows out through a tapping hole to be recovered; High-phosphorus low-iron solid steel slag treatment mode: high-phosphorus low-iron solid steel slag needs to be dephosphorized, and the treatment process is: Fe2O3 is added to the induction heating furnace, and the mass is 5-15% of the total mass of the solid steel slag; then high-phosphorus low-iron solid steel slag is added, and carbonaceous reducing agent and catalyst are added along with the slag flow, the catalyst is heavy metal industrial waste residue including red mud, copper slag and nickel slag, the amount of carbonaceous reducing agent is 1-1.5 times the amount required for the reduction of FeO and P2O5 in the slag, and the amount of catalyst is 0.2-0.5 times the amount of high-phosphorus low-iron solid steel slag; then heat to 1300-1500℃ to melt the steel slag, and after melting, keep warm for 10-20min, while stirring the molten pool with argon blowing at the bottom, the argon flow is 100-300Nm 3 / (h·t 渣 ), the temperature of argon is 1200-1400℃; after keeping warm, stand for 0.5-1h to make the molten slag and the metal liquid stratify; phosphorus vapor is collected by the phosphorus recovery device on the upper part of the furnace, and the metal liquid flows out through the tapping hole for recovery; The high-phosphorus high-iron solid steel slag treatment mode: the high-phosphorus high-iron solid steel slag needs to be treated by dephosphorization and iron selection, and the treatment process is: adding high-phosphorus high-iron solid steel slag, adding carbonaceous reducing agent and catalyst along with the slag flow, the catalyst is heavy metal industrial waste residue including red mud, copper slag and nickel slag, the adding amount of the carbonaceous reducing agent is 1-1.5 times of the amount required for reducing FeO and P2O5 in the slag, and the adding amount of the catalyst is 0.2-0.5 times of the amount of the high-phosphorus high-iron solid steel slag; then heating to 1300-1500 DEG C to melt the steel slag, after melting, keeping warm for 10-20 min, while stirring the molten pool by blowing argon gas at the bottom, the argon gas flow is 100-300 Nm 3 / (h·t 渣 ), the temperature of the argon gas is 1200-1400 DEG C; after keeping warm, standing for 0.5-1 h to make the molten slag and the metal liquid stratify; Phosphorus vapor is collected by a phosphorus recovery device on the upper part of the furnace body, and the molten metal flows out through the tapping hole for recovery; S4. Obtaining parameters of the solid steel slag to be processed, and selecting a processing mode corresponding thereto for processing.

2. The method for solid-state steel slag recycling treatment based on a hierarchical system according to claim 1, characterized by, In the step S1, the solid steel slag quality dataset comprises density, particle size, main components and production batch.

3. The method for solid-state steel slag recycling treatment based on a hierarchical system according to claim 1, characterized by, The processed steel slag is directly added to the converter steelmaking process as a converter slag agent, and the addition amount is 5-8 kg / t 钢 .

Images