A method for treating tailings after reduction dephosphorization

Abstract

The present application discloses a method for treating tailings after reduction dephosphorization, comprising: adding the reduction dephosphorization slag and surplus steel into a ladle containing another furnace of primary molten steel, entering the VOD furnace for oxygen blowing decarburization, adding lime, fluorite and other slag materials for oxygen blowing dephosphorization treatment, so that Ca3P2 and CaC2 contained in the reduction dephosphorization tailings are oxidized to generate non-toxic Ca3(PO4)2, CaO and CO2 through oxygen blowing smelting at high temperature in the VOD furnace, thereby solving the problem of harmful gas pollution caused by tailings after dephosphorization of stainless steel or high-temperature alloy, and preventing the tailings after dephosphorization of stainless steel or high-temperature alloy from generating harmful gas pollution.

Description

Technical Field

[0001] The present application relates to the field of stainless steel dephosphorization tailings treatment, and in particular to a method for treating tailings after reduction dephosphorization. Background Art

[0002] Dephosphorization of stainless steel or high temperature alloy is a major issue in special steel smelting. Stainless steel dephosphorization technology can be divided into oxidation dephosphorization and reduction dephosphorization. Reduction dephosphorization is an important development direction due to its advantages such as high dephosphorization rate, no alloy burning loss, and wide adaptability of raw materials. Reduction dephosphorization refers to the method of adding dephosphorization solvent to steel (iron) liquid in an inert or reducing atmosphere to reduce phosphorus in steel to negative trivalent phosphide and remove it.

[0003] The reduction dephosphorization method does not need to worry about excessive alloy element burnout, and the dephosphorization efficiency is high, but there is a "rephosphorization" phenomenon, and harmful gases will be produced during the smelting process to pollute the environment. There are problems such as the dephosphorization products are difficult to handle and pollute the environment. The tailings generated by reduction dephosphorization contain Ca3P2 and CaC2, which will generate PH3 and C2H2 toxic and harmful gases when exposed to water or moisture, and must be treated harmlessly.

[0004] Therefore, we need a method for treating tailings after reduction dephosphorization to solve the problem that tailings after dephosphorization of stainless steel or high-temperature alloys produce harmful gases to pollute the environment, so that the tailings after dephosphorization of stainless steel or high-temperature alloys will not produce harmful gases to pollute the environment. Summary of the invention

[0005] The purpose of this application is to solve the problem that the tailings after dephosphorization of stainless steel or high-temperature alloys produce harmful gases to pollute the environment. In order to solve the above problem, this application provides a method for treating the tailings after reduction dephosphorization, which can prevent the tailings after dephosphorization of stainless steel or high-temperature alloys from producing harmful gases to pollute the environment.

[0006] To achieve the above objectives, the present application embodiment adopts the following technical solutions:

[0007] A method for treating tailings after reduction dephosphorization, comprising: S100: adding the tailings of reduction dephosphorization and surplus steel together into a ladle of another furnace of primary steelmaking molten steel; S200: blowing oxygen for smelting for 30 to 60 minutes at a temperature of 1580 to 1630°C and a vacuum degree of 1.5 to 2KPa, wherein the oxygen flow rate is 1000 to 1200Nm 3 / h, oxygen pressure is 0.8~1.0MPa, bottom blowing argon flow rate is 15~20Nm 3 / h, pressure of 0.5-0.7MPa, oxidize Ca3P2 in the reduction dephosphorization tailings to generate CaO and P2O5, oxidize CaC2 to generate CaO and CO2, and remove carbon in the molten steel to generate CO2 to below 0.30%; S300: add slag-making materials such as lime and fluorite; S400: at a temperature of 1580-1640℃ and a vacuum of 30-50KPa, blow oxygen for dephosphorization for 60-90 minutes, with an oxygen flow rate of 800-1000Nm 3 / h, oxygen pressure 0.8~1.0MPa, bottom blowing argon flow 20~30Nm 3 / h, pressure 0.6 ~ 1.0MPa, promote the oxidation of phosphorus in steel, and generate calcium phosphate with lime, which enters the reduction dephosphorization tailings for removal; S500: discharge the molten steel from the lower water inlet of the ladle into another ladle for subsequent refining links; the reduction dephosphorization tailings are poured into the slag basin from the ladle mouth and circulated like ordinary dephosphorization slag.

[0008] In the above technical scheme, the embodiment of the present application first performs oxygen blowing smelting decarburization under vacuum state, then breaks the vacuum state to add lime and fluorite, then blows oxygen to dephosphorize under vacuum state, and finally separates steel and slag.

[0009] Further, according to an embodiment of the present application, a method for treating tailings after reduction dephosphorization is operated in a VOD furnace.

[0010] Further, according to an embodiment of the present application, during the operation of a method for treating tailings after reduction dephosphorization, the VOD furnace is in a closed state.

[0011] Further, according to an embodiment of the present application, in step S100, the primary molten steel added to another furnace of primary molten steel is a low-alloy steel grade.

[0012] Further, according to an embodiment of the present application, the oxygen blowing in step S200 is performed under vacuum conditions.

[0013] Further, according to an embodiment of the present application, the oxygen blowing smelting in step S200 is carried out at a high temperature.

[0014] Further, according to an embodiment of the present application, in step S300, adding slag-forming materials such as lime and fluorite is carried out under a state of breaking the vacuum.

[0015] Further, according to an embodiment of the present application, the slag-forming material in step S300 also includes synthetic slag.

[0016] Further, according to an embodiment of the present application, the oxygen blowing operation in step S400 is performed under a vacuum state. Further, according to an embodiment of the present application, a method for treating tailings after reduction dephosphorization utilizes the reaction comprising:

[0017] Ca3P2+4O2=3CaO+P2O5

[0018] 3CaO+P2O5=Ca3(PO4)2

[0019] 2CaC2+5O2=2CaO+4CO2.

[0020] Compared with the prior art, the present application adds the reducing dephosphorization slag and surplus steel into a ladle containing another furnace of primary molten steel, enters the VOD furnace for oxygen blowing decarburization, adds lime, fluorite and other slag materials for oxygen blowing dephosphorization treatment, so that the Ca3P2 and CaC2 contained in the reducing dephosphorization tailings are oxidized to generate non-toxic Ca3(PO4)2, CaO and CO2 through oxygen blowing smelting at high temperature in the VOD furnace, thereby solving the problem of harmful gas pollution generated by the tailings after dephosphorization of stainless steel or high-temperature alloys, and preventing the tailings after dephosphorization of stainless steel or high-temperature alloys from generating harmful gases to pollute the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present application is further described below in conjunction with the accompanying drawings and embodiments.

[0022] Figure 1 A flow chart of a method for treating tailings after reduction dephosphorization DETAILED DESCRIPTION

[0023] In order to make the purpose and technical solution of the present invention clearly and completely described, and the advantages more clearly understood, the embodiments of the present invention are further described in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are part of the embodiments of the present invention, rather than all of the embodiments, and are only used to explain the embodiments of the present invention, and are not used to limit the embodiments of the present invention. All other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the description of the present invention, it should be noted that the terms "center", "middle", "upper", "lower", "left", "right", "inner", "outer", "top", "bottom", "side", "vertical", "horizontal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "one", "first", "second", "third", "fourth", "fifth", "sixth" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] For the purpose of simplicity and illustration, the principles of the embodiments are mainly described by reference to examples. In the following description, many specific details are proposed to provide a thorough understanding of the embodiments. However, it is obvious that for those of ordinary skill in the art, these embodiments may not be limited to these specific details in practice. In some instances, known methods and structures are not described in detail to avoid making these embodiments unnecessarily difficult to understand. In addition, all embodiments can be used in combination with each other.

[0027] The present application provides a method for treating tailings after reduction dephosphorization, comprising:

[0028] S100: Add the reduction dephosphorization tailings and the remaining steel into the ladle of another furnace of primary steelmaking molten steel.

[0029] Specifically, the reduction dephosphorization tailings and the remaining steel are added together into the ladle of another furnace of primary molten steel, which is a low-alloy steel grade, and placed in a VOD furnace for operation. The VOD furnace is in a closed state during the entire operation.

[0030] S200: Oxygen blowing smelting for 30 to 60 minutes at a temperature of 1580 to 1630°C and a vacuum of 1.5 to 2KPa, with an oxygen flow rate of 1000 to 1200Nm 3 / h, oxygen pressure is 0.8~1.0MPa, bottom blowing argon flow rate is 15~20Nm 3 / h, with a pressure of 0.5-0.7MPa, the Ca3P2 in the reduction dephosphorization tailings is oxidized to form CaO and P2O5, and the CaC2 is oxidized to form CaO and CO2. At the same time, the carbon in the molten steel is oxidized to form CO2, which is removed to below 0.30%.

[0031] Specifically, decarburization is carried out in a VOD furnace, and oxygen blowing is performed on the primary molten steel in which the reduction dephosphorization tailings and surplus steel are added in the VOD furnace for 30 to 60 minutes at a temperature of 1580 to 1630°C and a vacuum degree of 1.5 to 2KPa, wherein the oxygen flow rate is 1000 to 1200Nm 3 / h, oxygen pressure is 0.8~1.0MPa, bottom blowing argon flow rate is 15~20Nm 3 / h, the pressure is 0.5~0.7MPa, after oxygen blowing smelting, Ca3P2 in the dephosphorization tailings is reduced and oxidized to generate CaO and P2O5, CaC2 is oxidized to generate CaO and CO2, and the carbon in the molten steel is oxidized to generate CO2, and the carbon in the molten steel will be removed to below 0.30%. The above reaction applies the following reaction:

[0032] Ca3P2+4O2=3CaO+P2O5

[0033] 3CaO+P2O5=Ca3(PO4)2

[0034] 2CaC2+5O2=2CaO+4CO2.

[0035] S300: Add lime, fluorite and other slag-forming materials.

[0036] Specifically, after the carbon in the molten steel is removed to below 0.30%, the vacuum state of the VOD furnace is broken, and slag-forming materials such as lime and fluorite are added.

[0037] Furthermore, in this embodiment S300 also includes:

[0038] S310: Synthetic slag may also be added.

[0039] Specifically, when adding slag-forming materials such as lime and fluorite, synthetic slag can be added according to the situation to increase the refining effect and improve the purity of the molten steel.

[0040] S400: At a temperature of 1580-1640°C and a vacuum of 30-50KPa, oxygen dephosphorization is carried out for 60-90 minutes, with an oxygen flow rate of 800-1000Nm 3 / h, oxygen pressure 0.8~1.0MPa, bottom blowing argon flow 20~30Nm 3 / h, pressure 0.6 ~ 1.0MPa, promote the oxidation of phosphorus in steel, and generate calcium phosphate with lime, which enters the reduction dephosphorization tailings for removal.

[0041] Specifically, after adding lime, fluorite and other slag-making materials, VOD furnace dephosphorization is carried out, and oxygen is blown for dephosphorization for 60 to 90 minutes at a temperature of 1580 to 1640°C and a vacuum degree of 30 to 50 KPa, with an oxygen flow rate of 800 to 1000 Nm 3 / h, oxygen pressure 0.8~1.0MPa, bottom blowing argon flow 20~30Nm 3 / h, pressure 0.6 ~ 1.0MPa, promotes the oxidation of phosphorus in steel, reacts with lime to form calcium phosphate, and oxidizes to form non-toxic Ca3(PO4)2, CaO and CO2.

[0042] S500: The molten steel is discharged from the lower water outlet of the ladle into another ladle for subsequent refining steps; the reduction dephosphorization tailings are poured into the slag basin from the ladle outlet and circulated in the same way as ordinary dephosphorization slag.

[0043] Specifically, the molten steel after the reaction in the VOD furnace is completed is discharged from the water inlet at the bottom of the ladle into another ladle for subsequent refining, and the reduction dephosphorization tailings in the VOD furnace are poured into the slag basin from the ladle outlet and treated together with the ordinary dephosphorization slag.

[0044] Furthermore, step S500 further includes:

[0045] S510: The excess steel can be recycled during the reaction. In the molten steel with low alloy content, the recovery rate of chromium is 50-80%, and the recovery rate of nickel is more than 90%.

[0046] The reducing dephosphorization slag and surplus steel are added into a ladle containing another furnace of primary molten steel, and then enter into a VOD furnace for oxygen decarburization. Lime, fluorite and other slag materials are added for oxygen dephosphorization. Ca3P2 and CaC2 contained in the reducing dephosphorization slag are oxidized to generate non-toxic Ca3(PO4)2, CaO and CO2 through oxygen blowing smelting at high temperature in the VOD furnace. The problem of harmful gas pollution caused by the dephosphorization slag of stainless steel or high-temperature alloy is solved. The dephosphorization slag of stainless steel or high-temperature alloy will not generate harmful gas to pollute the environment.

[0047] The technical solution of the present application is further described below by listing embodiments and comparative examples, but the present application is not limited to these embodiments.

[0048] [Example 1]

[0049] The reduction dephosphorization tailings and excess steel are added to the primary steelmaking molten steel, and decarburization is carried out in a VOD furnace. The primary steelmaking molten steel added with the reduction dephosphorization tailings and excess steel in the VOD furnace is subjected to oxygen blowing smelting for 30 minutes at a temperature of 1580°C and a vacuum degree of 1.5KPa, wherein the oxygen flow rate is 1000Nm 3 / h, oxygen pressure is 0.8MPa, bottom blowing argon flow rate is 15Nm3 / h, the pressure is 0.5MPa, after 30 minutes, the vacuum state is broken and 800KG of lime and 300KG of fluorite are added, and then the VOD furnace is used for oxygen dephosphorization at a temperature of 1580℃ and a vacuum degree of 30KPa for 60 minutes, with an oxygen flow rate of 800Nm 3 / h, oxygen pressure 0.8MPa, bottom blowing argon flow 20Nm 3 / h, pressure 0.6MPa, and finally slag separation.

[0050] [Example 2]

[0051] The reduction dephosphorization tailings and excess steel are added to the primary steelmaking molten steel, and decarburization is carried out in a VOD furnace. The primary steelmaking molten steel added with the reduction dephosphorization tailings and excess steel in the VOD furnace is subjected to oxygen blowing smelting for 45 minutes at a temperature of 1605°C and a vacuum degree of 1.7KPa, wherein the oxygen flow rate is 1100Nm 3 / h, oxygen pressure is 0.9MPa, bottom blowing argon flow rate is 17Nm 3 / h, the pressure is 0.6MPa, after 30 minutes, the vacuum state is broken and 800KG of lime and 300KG of fluorite are added, and then the VOD furnace is used for oxygen dephosphorization for 75 minutes at a temperature of 1610℃ and a vacuum degree of 40KPa, with an oxygen flow rate of 900Nm 3 / h, oxygen pressure 0.9MPa, bottom blowing argon flow 25Nm 3 / h, pressure 0.8MPa, and finally slag separation.

[0052] [Example 3]

[0053] The reduction dephosphorization tailings and excess steel are added to the primary steelmaking molten steel, and decarburization is carried out in a VOD furnace. The primary steelmaking molten steel added with the reduction dephosphorization tailings and excess steel in the VOD furnace is subjected to oxygen blowing smelting for 30 minutes at a temperature of 1580°C and a vacuum degree of 1.5KPa, wherein the oxygen flow rate is 1000Nm 3 / h, oxygen pressure is 0.8MPa, bottom blowing argon flow rate is 15Nm 3 / h, the pressure is 0.5MPa, after 30 minutes, the vacuum state is broken and 1000KG of lime and 400KG of fluorite are added, and then the VOD furnace is used for oxygen dephosphorization at a temperature of 1580℃ and a vacuum degree of 30KPa for 60 minutes, with an oxygen flow rate of 800Nm 3 / h, oxygen pressure 0.8MPa, bottom blowing argon flow 20Nm 3 / h, pressure 0.6MPa, and finally slag separation.

[0054] [Example 4]

[0055] The reduction dephosphorization tailings and excess steel are added to the primary steelmaking molten steel, and decarburization is carried out in a VOD furnace. The primary steelmaking molten steel added with the reduction dephosphorization tailings and excess steel in the VOD furnace is subjected to oxygen blowing smelting for 30 minutes at a temperature of 1605°C and a vacuum degree of 1.7KPa, wherein the oxygen flow rate is 1100Nm 3 / h, oxygen pressure is 0.9MPa, bottom blowing argon flow rate is 17Nm 3 / h, the pressure is 0.6MPa, after 30 minutes, the vacuum state is broken and 1200KG of lime and 500KG of fluorite are added, and then the VOD furnace is used for oxygen dephosphorization at a temperature of 1610℃ and a vacuum degree of 40KPa for 60 minutes, with an oxygen flow rate of 900Nm 3 / h, oxygen pressure 0.9MPa, bottom blowing argon flow 25Nm 3 / h, pressure 0.8MPa, and finally slag separation.

[0056] [Example 5]

[0057] The reduction dephosphorization tailings and excess steel are added to the primary steelmaking molten steel, and decarburization is carried out in a VOD furnace. The primary steelmaking molten steel added with the reduction dephosphorization tailings and excess steel in the VOD furnace is subjected to oxygen blowing smelting for 60 minutes at a temperature of 1630°C and a vacuum degree of 2KPa, wherein the oxygen flow rate is 1200Nm 3 / h, oxygen pressure is 1.0MPa, bottom blowing argon flow rate is 20Nm 3 / h, the pressure is 0.7MPa, after 30 minutes, the vacuum state is broken and 800KG of lime and 300KG of fluorite are added, and then the VOD furnace is used for oxygen dephosphorization at a temperature of 1640℃ and a vacuum degree of 50KPa for 90 minutes, with an oxygen flow rate of 1000Nm 3 / h, oxygen pressure 1.0MPa, bottom blowing argon flow 30Nm 3 / h, pressure 1.0MPa, and finally slag separation.

[0058] [Example 6]

[0059] The reduction dephosphorization tailings and excess steel are added to the primary steelmaking molten steel, and decarburization is carried out in a VOD furnace. The primary steelmaking molten steel added with the reduction dephosphorization tailings and excess steel in the VOD furnace is subjected to oxygen blowing smelting for 30 minutes at a temperature of 1580°C and a vacuum degree of 1.5KPa, wherein the oxygen flow rate is 1000Nm 3 / h, oxygen pressure is 0.8MPa, bottom blowing argon flow rate is 15Nm 3 / h, the pressure is 0.5MPa, after 30 minutes, the vacuum state is broken and 800KG of lime, 300KG of fluorite and 150KG of synthetic slag are added, and then the VOD furnace is blown with oxygen for dephosphorization for 60 minutes at a temperature of 1580℃ and a vacuum degree of 30KPa, with an oxygen flow rate of 800Nm 3 / h, oxygen pressure 0.8MPa, bottom blowing argon flow 20Nm3 / h, pressure 0.6MPa, and finally slag separation.

[0060] [Comparative Example 1]

[0061] The reduction dephosphorization tailings were not subjected to decarburization and dephosphorization treatment.

[0062] [Comparative Example 2]

[0063] The reduction dephosphorization tailings and excess steel are added to the primary steelmaking molten steel, and decarburization is carried out in a VOD furnace. The primary steelmaking molten steel added with the reduction dephosphorization tailings and excess steel in the VOD furnace is subjected to oxygen blowing smelting for 20 minutes at a temperature of 1580°C and a vacuum degree of 1.5KPa, wherein the oxygen flow rate is 1000Nm 3 / h, oxygen pressure is 0.8MPa, bottom blowing argon flow rate is 15Nm 3 / h, the pressure is 0.5MPa, after 30 minutes, the vacuum state is broken and 800KG of lime and 300KG of fluorite are added, and then the VOD furnace is used for oxygen dephosphorization at a temperature of 1580℃ and a vacuum degree of 30KPa for 45 minutes, with an oxygen flow rate of 800Nm 3 / h, oxygen pressure 0.8MPa, bottom blowing argon flow 20Nm 3 / h, pressure 0.6MPa, and finally slag separation.

[0064] [Comparative Example 3]

[0065] The reduction dephosphorization tailings and excess steel are added to the primary steelmaking molten steel, and decarburization is carried out in a VOD furnace. The primary steelmaking molten steel added with the reduction dephosphorization tailings and excess steel in the VOD furnace is subjected to oxygen blowing smelting for 30 minutes at a temperature of 1630°C and a vacuum degree of 2KPa, wherein the oxygen flow rate is 1200Nm 3 / h, oxygen pressure is 1.0MPa, bottom blowing argon flow rate is 20Nm 3 / h, the pressure is 0.7MPa, after 30 minutes, the vacuum state is broken and 600KG of lime and 200KG of fluorite are added, and then the VOD furnace is used for oxygen dephosphorization at a temperature of 1640℃ and a vacuum degree of 50KPa for 60 minutes, with an oxygen flow rate of 1000Nm 3 / h, oxygen pressure 1.0MPa, bottom blowing argon flow 30Nm 3 / h, pressure 1.0MPa, and finally slag separation.

[0066] The steps of the above-mentioned Examples 1-6 and Comparative Examples 1-3 were applied to 50 tons of primary molten steel and the reduction dephosphorization tailings and surplus steel therein, and the experimental data obtained are as shown in Table 1 below:

[0067] Table 1

[0068]

[0069] As described in Table 1, after using a method for treating tailings after reduction dephosphorization of the present application, Ca3P2 and CaC2 contained in the reduction dephosphorization tailings can be significantly removed, so that they will not generate PH3 and C2H2 toxic and harmful gases after contacting water or moisture, thereby improving the recovery rate of chromium and nickel, and preventing the tailings after dephosphorization of stainless steel or high-temperature alloys from generating harmful gases to pollute the environment.

[0070] Although the above describes the illustrative specific implementation methods of the present application so that technicians in this technical field can understand the present application, the present application is not limited to the scope of the specific implementation methods. For ordinary technicians in this technical field, as long as various changes are within the spirit and scope of the present application defined and determined by the attached claims, all application creations using the concept of the present application are protected.

Claims

1. A method for treating tailings after reduction dephosphorization, characterized in that: include: S100: adding the reduction dephosphorization tailings and the remaining steel into a ladle of another furnace of primary steelmaking molten steel, wherein the primary steelmaking molten steel is a steel grade with a low alloy content; S200: Enter the VOD furnace for oxygen blowing and decarburization. At a temperature of 1580-1630℃ and a vacuum degree of 1.5-2KPa, oxygen blowing and smelting are carried out for 30-60 minutes, with an oxygen flow rate of 1000-1200Nm 3 / h, oxygen pressure is 0.8~1.0MPa, bottom blowing argon flow rate is 15~20Nm 3 / h, the pressure is 0.5-0.7MPa, Ca3P2 in the reduction dephosphorization tailings is oxidized to generate CaO and P2O5, CaC2 is oxidized to generate CaO and CO2, and at the same time, carbon in the molten steel is oxidized to generate CO2 and removed to below 0.30%; S300: adding slag-making materials lime and fluorite; S400: At a temperature of 1580-1640°C and a vacuum of 30-50KPa, oxygen dephosphorization is carried out for 60-90 minutes, with an oxygen flow rate of 800-1000Nm 3 / h, oxygen pressure 0.8~1.0MPa, bottom blowing argon flow 20~30Nm 3 / h, pressure 0.6-1.0MPa, promotes the oxidation of phosphorus in steel, and generates calcium phosphate with lime, which enters the reduction dephosphorization tailings for removal; S500: Discharge the molten steel from the lower water inlet of the ladle into another ladle for subsequent refining steps; pour the reduction dephosphorization tailings from the ladle opening into a slag basin and circulate in the same way as ordinary dephosphorization slag.

2. The method for treating tailings after reduction dephosphorization according to claim 1, characterized in that: During the operation of the method for treating tailings after reduction dephosphorization, the VOD furnace is in a closed state.

3. The method for treating tailings after reduction dephosphorization according to claim 1, characterized in that: The oxygen blowing in step S200 is performed under vacuum conditions.

4. The method for treating tailings after reduction dephosphorization according to claim 1, characterized in that: In the step S300, the slag-making materials lime and fluorite are added under the condition of breaking the vacuum.

5. The method for treating tailings after reduction dephosphorization according to claim 1, characterized in that: The slag-making material in step S300 also includes synthetic slag.

6. The method for treating tailings after reduction dephosphorization according to claim 1, characterized in that: The oxygen blowing operation in step S400 is performed under a vacuum state.

7. The method for treating tailings after reduction dephosphorization according to claim 1, characterized in that: The method for treating tailings after reduction dephosphorization utilizes the following reactions: Ca3P2+4O2=3CaO+P2O5, 3CaO+P2O5=Ca3(PO4)2, 2CaC2+5O2=2CaO+4CO2.

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