A method for comprehensive metallurgy of powder metallurgy + high-phosphorus oolitic hematite

Abstract

The present invention discloses a method of powder metallurgy + high-phosphorus oolitic hematite comprehensive metallurgy, adopts a short-process steelmaking process route of powder metallurgy + high-phosphorus oolitic hematite comprehensive metallurgy, and uses a production process of reducing iron powder solid carbon / H2 to reduce iron oxides by powder metallurgy to produce high-purity pure iron molten steel, forming a set of new, complete and systematic green low-C, low-S, low-P, low-impurity, high-purity molten steel with high quality short-process metallurgy. This patent can be used to simply and large-scale use high-phosphorus oolitic hematite to produce high-purity steel base materials with low C, low S, low P, and low impurities, which can significantly and fundamentally improve the quality of steel.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for comprehensive metallurgy of powder metallurgy + high-phosphorus oolitic hematite. Background Art

[0002] The western Hubei region is rich in iron ore resources, mainly high-phosphorus oolitic hematite (also known as Ningxiang-type oolitic hematite, one of the nine types of iron ore in my country, with a national reserve of more than 10 billion tons). The proven reserves of high-phosphorus oolitic hematite in western Hubei are about 4 billion tons, and its potential economic value is as high as 100 billion US dollars. In order to develop and utilize high-phosphorus oolitic hematite in western Hubei (Fe 45%, P about 0.8-1.5%), it is difficult to produce high-iron and low-phosphorus products using the traditional sintering-ironmaking-steelmaking long process. Therefore, although a lot of research has been done on this ore at home and abroad, according to current understanding, no major breakthrough has been made in industrial application and it has not been widely used.

[0003] The research on the effective utilization of oolitic hematite ore is of great significance in my country and the world. It is well known that phosphorus has a great influence on the performance of steel. Phosphorus is a harmful element in most steel grades, which increases the brittleness of steel, especially at low temperatures (commonly known as cold brittleness). For steel with high carbon content, the harmful effect of phosphorus is more significant. Therefore, in the traditional blast furnace steelmaking process, the phosphorus in iron ore should be reduced as much as possible to ensure the reduction of phosphorus in molten steel. At present, the methods of reducing phosphorus in high-phosphorus iron ore in various countries around the world mainly include mineral processing methods, chemical methods, smelting methods, and microbial dephosphorization methods, but none of them have reached industrial application. How to effectively reduce the phosphorus in high-phosphorus iron ore so that it can be widely used in the steel industry is still a world problem.

[0004] The technological progress of the steel industry and the improvement of steel quality depend on the optimization, innovation and development of production processes and equipment. Clean steel production requires overcoming the shortcomings of traditional smelting process flows. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the above-mentioned background technology and provide a method for comprehensive metallurgy of powder metallurgy + high-phosphorus oolitic hematite. The method of the present invention adopts a proprietary short-process metallurgical technology of direct reduction by powder metallurgy solid carbon / H2 reduction method and smelting by electric furnace (medium frequency / electric arc furnace) / oxygen-enriched natural gas heating furnace, focusing on exploratory research on high-phosphorus oolitic hematite in Guandian, Jianshi County, Enshi, to produce high-iron, low-sulfur, low-phosphorus and low-impurity high-quality steel (Fe content ≥ 99.0%, P content 0.006-0.020%, C content 0.005-0.02%, S content 0.007-0.020%) clean steel base material. The process technology method for comprehensive utilization of high-phosphorus oolitic hematite has been found, and the proprietary process technology method and equipment have been established.

[0006] The original composition of high-phosphorus oolitic hematite in Guandian, Jianshi, western Hubei is: Fe 40-45%, P 0.5-1.2%, SiO211-15%, Ai2O35.6%, CaO 2.6%, MgO 0.67%, CaF21.33%, S 0.03-0.13%, and the total amount of gangue is 15-21%. Obviously, this kind of ore contains high levels of S, P, and gangue, and it is difficult to use it directly, and special processing must be carried out.

[0007] The technical solution adopted by the present invention is:

[0008] A method for comprehensive metallurgy of powder metallurgy + high-phosphorus oolitic hematite, comprising the following steps:

[0009] Step 1: Desulfurization to remove non-iron gangue and crystal water: crush the high-phosphorus oolitic hematite ore into 3-20 mm, add 5-10% lime powder accounting for the weight of the high-phosphorus oolitic hematite and mix evenly, add the mixture into a furnace and roast at 950-1000℃ for 1 hour, and perform magnetic separation at 2000-3000GS;

[0010] The innovative features of this process: This type of ore contains a relatively high amount of sulfur, at 0.03-0.13%. Lime powder is added to the surface of the iron ore during roasting in advance to remove part of the P, S and crystal water during roasting. A small amount of lime is added to the reducing agent during reduction to deeply remove sulfur, creating low-S conditions for refining and removing sulfur.

[0011] Step 2 Solid Carbon / H2 Reduction:

[0012] Process route 1:

[0013] Step 2.1 Grind the high-phosphorus oolitic hematite ore after magnetic separation in step 1 into powder ore with a mesh size of 80 meshes, add 3% mixed salt and 0.3-3% pellet binder accounting for the weight of the high-phosphorus oolitic hematite, mix and press to form high-phosphorus iron ore powder pellets, the mass of the mixed salt is calculated by percentage, and is a mixture of 80% Na2B4O7.XH2O and 20% Na2CO3, and the pellet binder is humic acid, lignin, kaolin or cellulose;

[0014] Step 2.2 Reduction with external solid C reducing agent: 30-50% reducing agent accounting for the weight of high-phosphorus iron ore powder pellets, 10-20% CaO or CaCO3 powder accounting for the weight of the reducing agent, and 2-5% Na2CO3 accounting for the weight of the high-phosphorus iron ore powder pellets are mixed with the high-phosphorus iron ore powder pellets, and directly reduced at 950-1150°C for 2-4h in a powder metallurgy high-temperature mesh belt furnace or a push boat furnace, or at 1100-1150°C for 6-8h in a coal-based vertical furnace to obtain direct reduced iron DRI with an Fe content of 70-80%; the reducing agent is blue carbon powder, coke powder, anthracite powder or biomass carbon powder;

[0015] Or H2 reduction: The high-phosphorus iron ore powder pellets are reduced with H2 or ammonia decomposition gas at 950-1050℃ in a powder metallurgy high-temperature mesh belt furnace, push boat furnace or gas-based vertical furnace for 2-3 hours to obtain direct reduced iron DRI with an Fe content of 70-80%;

[0016] Process route 2:

[0017] Step 2.1: grinding the high-phosphorus oolitic hematite ore after magnetic separation in step 1 into powder ore, mixing a carbon powder reducing agent, a pelletizing binder accounting for 0.3-3% of the weight of the high-phosphorus iron ore powder, and the high-phosphorus iron ore powder, pressing balls, and drying to obtain high-phosphorus iron ore powder C-containing pellets; wherein the (C / O) ratio of fixed carbon in the carbon powder reducing agent to oxygen in iron oxides in the high-phosphorus oolitic hematite powder is in the range of 1 to 1.5, S in the carbon powder reducing agent is ≤0.02%, fixed carbon is ≥80%, ash is ≤5%, and the pelletizing binder is humic acid, lignin, kaolin or cellulose;

[0018] Step 2.2 reduction with an external solid C reducing agent: 10-20% of the weight of the high-phosphorus iron ore powder containing C pellets by weight of the reducing agent, 10-20% of the weight of the CaO or CaCO3 powder by weight of the reducing agent, and 2-5% of the weight of the high-phosphorus iron ore powder containing C pellets by weight of Na2CO3 are mixed with the high-phosphorus iron ore powder containing C pellets, and directly reduced at 950-1050°C for 2-3h in a powder metallurgy high-temperature mesh belt furnace or a push boat furnace, or at 1000-1050°C for 6-8h in a coal-based vertical furnace to obtain direct reduced iron DRI with an Fe content of 70-80%; the reducing agent is blue carbon powder, coke powder, anthracite powder or biomass carbon powder;

[0019] Or H2 reduction: High phosphorus iron ore powder containing C pellets are reduced with H2 or ammonia decomposition gas at 950-1050℃ in a powder metallurgy high-temperature mesh belt furnace, push boat furnace or gas-based vertical furnace for 2-3 hours to obtain direct reduced iron DRI with an Fe content of 70-80%;

[0020] Process route three:

[0021] The high-phosphorus oolitic hematite ore after magnetic separation in step 1, a reducing agent accounting for 30-50% of the weight of the high-phosphorus oolitic hematite ore, CaO or CaCO3 powder accounting for 10-20% of the weight of the reducing agent, and Na2CO3 accounting for 2-5% of the weight of the high-phosphorus oolitic hematite ore are uniformly mixed, and directly reduced in a powder metallurgy high-temperature mesh belt furnace or a push boat furnace at 1050-1150° C. for 2-4 hours, or in a coal-based vertical furnace at 1100-1150° C. for 6-8 hours to obtain direct reduced iron DRI with an Fe content of 70-80%; the reducing agent is blue carbon powder, coke powder, anthracite powder or biomass carbon powder;

[0022] Step 3: Melting: Direct reduced iron DRI is obtained, and the Fe content is 70-80%.

[0023] The DRI containing 1-4% C and pure C powder accounting for 2-4% of the weight of DRI are continuously melted in a medium frequency furnace at 1250-1400° C. to obtain high C, high P and low S / high S and low impurity molten iron;

[0024] The innovative features of this process: Under high C (high C refers to C content of 1-4%), melting at low temperature of 1250-1400℃ can effectively remove non-iron impurities: x O y Elements such as Si, Mn, Ca, Mg, Al, Ti, Cr, V, and B that exist in the reduced iron are not reduced, thereby improving the cleanliness of the molten iron and reducing the traditional molten iron purification process.

[0025] Or the DRI containing C < 1.0% is continuously melted in a medium frequency furnace or an electric furnace at 1500-1650°C to obtain low C, high P, low S / high S, low impurity molten iron;

[0026] The innovative features of this process: Under low C conditions, melting at a high temperature of 1500-1650℃ can effectively remove non-ferrous impurities: x O y Elements such as Si, Mn, Ca, Mg, Al, Ti, Cr, V, and B that exist in the reduced iron are not reduced by C, which also improves the cleanliness of the molten iron and reduces the traditional molten iron purification process.

[0027] Step 4 Refine:

[0028] 1). Preparation of auxiliary materials:

[0029] S-removing agent or P-removing agent: composed of CaO / CaCO3, CaF2, Na2CO3, CaCl2, CaO or CaCO3: CaF2: Na2CO3:CaCl2= 6:2:2.5:0.5, CaO / CaCO3, CaF2, Na2CO3, CaCl2 powders are mixed and briquette into a diameter of 30-50mm according to the above ratio;

[0030] The innovative features of this process: a comprehensive desulfurization or phosphorus removal agent with CaO or CaCO3, CaF2 as the main component, because a large amount of non-iron slag has been removed in the process of reducing iron smelting, and only the S and P in the molten iron need to be removed during refining. Experiments have proved that the cheap and easy-to-use Ca-based slag agent can completely achieve the purpose of reducing S or P. Of course, using more and better desulfurization or phosphorus removal slag agents in the steelmaking profession will definitely achieve better results.

[0031] 2). C removal agent: Fe≥68%Fe2O3 low-S iron concentrate and Fe≥65%Fe3O4 powder are pressed into blocks with a diameter of 30-50mm;

[0032] The innovative features of this process: Blowing O2 into C-containing molten iron is a traditional and classic method, and pressing Fe2O3 low-S iron concentrate and Fe≥65% / Fe3O4 (Fe2O3 low-S iron concentrate Fe≥68%) into blocks with a diameter of 30-50mm is another feature of this process, because after the molten iron is clear and at high temperature (≥1500℃), the addition of iron oxide powder will produce a violent reaction and a blowout. For safety and to control the reaction speed and control the degree of decarbonization. Experiments have shown that pressing Fe2O3 low-S iron concentrate and Fe≥65% / Fe3O4 (Fe2O3 low-S iron concentrate Fe≥68%) into blocks with a diameter of 30-50mm is a very effective method.

[0033] (I) Refining of high C, high S, high P and low impurity molten iron: after the molten iron is molten, the molten iron temperature is ≥1450℃, C≥1%, S≥0.02%, P≥0.1%:

[0034] a. Desulfurization: Add 3-5% desulfurization agent block by weight of molten iron for 3-10 minutes to complete the desulfurization process; or add it in batches depending on the S content in the molten iron;

[0035] b. Carbon removal: Blow O2 or add 1-2% of carbon removal agent block to the weight of molten iron. Carbon removal by blowing O2: When the sampled carbon content is less than 0.2%, carbon removal is completed. Carbon removal by carbon removal agent: Observe the furnace condition. There is a strong spark spray at the beginning. As the sparks gradually decrease, there are very few sparks and a few unreacted carbon removal agent blocks floating on the surface of the molten iron, indicating that carbon removal is completed.

[0036] c. P removal: Add 5-20% P removal agent block by weight of molten iron for 3-10 minutes to complete the P removal process, or add it in batches depending on the P content in the molten iron to complete the P removal process;

[0037] d. Deoxidation: Al or a commonly used deoxidation agent for steelmaking is then added to remove O. The deoxidation is completed when the O content is <0.1%, and a high-purity molten steel with low C, low S, low P, and low impurities is obtained. It is only necessary to add alloys according to the required steel grade and transfer to the conventional steelmaking process.

[0038] (II) Refining of high C, low S, high P and low impurity molten iron, where the molten iron temperature is ≥1500℃: C≥1%, S<0.02%, P≥0.1%:

[0039] a. Desulfurization: For ultra-low S steel, add 1-3% desulfurization agent block by weight of molten iron for 3-10 minutes to complete the desulfurization process, or add it in batches depending on the S content in the molten steel;

[0040] b. Carbon removal: Blow O2 or add carbon removal agent blocks accounting for 1-2% of the weight of molten iron. Carbon removal by blowing O2: When the sampled carbon content is less than 0.2%, carbon removal is completed; Carbon removal by carbon removal agent: Observe the furnace condition. In the early stage, there is a strong spark spray. As the sparks gradually decrease, there are very few sparks and a few unreacted carbon removal agent blocks floating on the surface of the molten steel, indicating that carbon removal is completed;

[0041] c. P removal: Add 5-20% P removal agent block by weight of molten iron for 3-10 minutes to complete the P removal process, or add it in batches depending on the P content in the molten iron to complete the P removal process;

[0042] d. Deoxidation: Al or commonly used deoxidation agent in metallurgy is then added to remove O. When the O content is detected to be less than 0.1%, the deoxidation is completed and low C, low S, low P, low impurity and high-purity molten steel is obtained. It only needs to add alloy according to the required steel grade and then transfer to the conventional steelmaking process.

[0043] (III) Refining of low C, low S, high P and low impurity molten iron, where the molten iron temperature is ≥1550℃, C<0.02%, S<0.02%, P≥0.1%:

[0044] a. Desulfurization: For ultra-low S molten iron, add 1-3% of the weight of the molten iron to desulfurize the molten iron for 3-10 minutes to complete the desulfurization process, or add it in batches depending on the S content in the molten steel. In order to further desulfurize, add 1-3% of the weight of the molten iron to the molten iron C powder;

[0045] b. Carbon removal: Blow O2 or add 1-2% of carbon removal agent block to remove carbon in depth. Blow O2 to remove carbon: When the sample detects the carbon content <0.2%, the carbon removal is completed. Carbon removal with carbon removal agent: Observe the sparks of the furnace. As the sparks gradually decrease, there are very few sparks and a few unreacted carbon removal agent blocks floating on the surface of the molten steel, indicating that the carbon removal is completed.

[0046] c. P removal: Add 5-20% of the weight of the molten iron to remove the P agent block for 3-10 minutes to complete the P removal process, or add it in batches depending on the P content in the molten steel to complete the P removal process;

[0047] d. Deoxidation: Al or commonly used deoxidation agent in metallurgy is then added to remove O. When the O content is detected to be less than 0.1%, the deoxidation is completed and low C, low S, low P, low impurity and high-purity molten steel is obtained. It only needs to add alloy according to the required steel grade and then transfer to the conventional steelmaking process.

[0048] The method of the present invention adopts the solid carbon / H2 reduction iron oxide basic process of powder metallurgy to produce reduced iron powder + steelmaking production process to form a complete and systematic green high-quality short-process metallurgical process. The method of the present invention can simply and large-scale use high-phosphorus oolitic hematite to produce high-purity steel base materials with low C, low S, low P and low impurities, greatly improving the quality of steel.

[0049] In addition to the above innovative features, the present invention has the following comprehensive innovative features:

[0050] (1) The process route is short, the equipment is reliable, industrial production can be implemented, the investment and production costs are low, the amount of additives used is small, and it is environmentally friendly (no need for wet mineral processing, fully protecting the beautiful environment of green waters and clear mountains deep in the mountains); the progress of the steel industry and the improvement of steel performance mainly depend on the innovation and development of production technology. Clean steel production must also overcome the shortcomings of traditional process flows and further optimize and innovate.

[0051] (2) The comprehensive S / P removal agent with CaO / CaCO3 and CaF2 as main components in the method of the present invention has already eliminated a large amount of non-iron slag in the process of reducing iron smelting, and only needs to remove S and P in refining. Experiments have proved that the cheap and easy-to-use Ca-based slag agent can completely achieve the purpose of reducing S / P, making the metallurgical process simple. The corresponding research on vanadium-titanium magnetite using the above process shows that the process scheme of the present invention can be used not only for high-phosphorus oolitic hematite, but also for the comprehensive utilization of vanadium-titanium magnetite and other difficult-to-select iron ores.

[0052] (3) The main innovation of the process of the present invention is that it adopts a short-process steelmaking process route of powder metallurgy + high-phosphorus oolitic hematite comprehensive metallurgy, and combines the original high-phosphorus oolitic hematite powder metallurgy reduction iron powder solid carbon / H2 reduction iron oxide production process with a special continuous melting + refining short-process steelmaking process to produce high-purity pure iron molten steel, forming a new, complete and systematic green low-C, low-S, low-P, low-impurity and high-purity molten steel high-quality short-process metallurgical process.

[0053] By utilizing the present invention, high-phosphorus oolitic hematite can be simply and massively applied to prepare high-purity steel base material with low C, low S, low P and low impurities, thereby substantially improving the quality of steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0055] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments to facilitate a clear understanding of the present invention, but they do not constitute a limitation on the present invention.

[0056] The original composition of the high-phosphorus oolitic hematite ore in Guandian, Jianshi, western Hubei is: Fe 40-45%, P 0.5-1.2%, SiO211-15%, Ai2O35.6%, CaO 2.6%, MgO 0.67%, CaF21.33%, S 0.03-0.13%, and the total amount of gangue is 15-21%.

[0057] like Figure 1As shown, high phosphorus oolitic hematite lump ore -- crushed (3-20mm) -- + lime powder 5-10% mixed -- roasted (950-1000℃) 1h -- magnetic separation (2000-3000GS):

[0058] The main components after magnetic separation are: Fe45-47%, P 0.5-0.65%, S 0.018-0.035%;

[0059] The main components of high P block ore reduction DRI comprehensive sample are: Fe74-78%, P 0.55-0.86%, S 0.022-0.045%;

[0060] Or the main components of high P powder ore reduction DRI comprehensive sample: Fe75-80%, P0.45-0.94%, S 0.019-0.035%;

[0061] The present invention discloses a method for comprehensive metallurgy of powder metallurgy + high-phosphorus oolitic hematite, comprising the following steps:

[0062] Step 1: Desulfurization to remove non-iron gangue and crystal water: crush the high-phosphorus oolitic hematite ore from Guandian, Jianshi, western Hubei into 3-20 mm, add 10% lime powder accounting for the weight of the high-phosphorus oolitic hematite and mix evenly, add the mixture into a furnace and roast at 950-1000℃ for 1 hour, and perform magnetic separation at 2000-3000GS;

[0063] Step 2 Reduction: The high P block ore DRI melting fraction 1 in Table 1 is carried out according to process route 1 H2 reduction, the high P block ore DRI melting fraction 2 in Table 1 is carried out according to process route 2 H2 reduction, and the high P block ore DRI melting fraction 3 in Table 1 is carried out according to process route 3.

[0064] Step 3 Melting: The high-P lump ore DRI melting 1-3 in Table 1 is melted by selecting the corresponding method according to the C content in the key process of this process;

[0065] Step 4 refining: 1. According to the corresponding C, S, and P contents in the high-P lump ore DRI melts 1-3 in Table 1, select the corresponding method for refining to obtain the corresponding high-P lump ore DRI refined 1-3 as shown in Table 2.

[0066] According to the respective C, S and P contents in the high-P powder ore DRI melt fraction 1-2 in Table 3, the corresponding method is selected for refining, and the corresponding high-P powder ore DRI refined fraction 1-2 is obtained as shown in Table 4.

[0067] Since the quality of high-phosphorus oolitic hematite ore source is fluctuating, in this process, high-phosphorus oolitic hematite lump ore accounts for 80% and ore powder 20%, so three reduction processes for lump ore and powder ore are adopted. The main Fe, P, and S contents after reduction are also fluctuating. Comprehensive smelting is the key process of this process, so it is only necessary to carry out comprehensive smelting and refining according to the lump ore and powder ore respectively, to achieve the same standard clean steel base material of low C, low S, low P, low impurity and high purity iron.

[0068] Table 1: Results of melting and fractionation of high P lump ore reduction DRI comprehensive sample (three times)

[0069]

[0070] Table 2: Comprehensive sample refining after DRI melting after high P lump ore reduction (three times)

[0071]

[0072] Table 3: Results of melting and fractionation of high P powder ore reduction DRI comprehensive sample (secondary)

[0073]

[0074] Table 4: Comprehensive refining of high P powder ore after DRI melting (secondary)

[0075]

[0076] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. A method for comprehensive metallurgy of powder metallurgy + high-phosphorus oolitic hematite, characterized in that The following steps are involved: Step 1: Desulfurization to remove non-iron gangue and crystal water: crush the high-phosphorus oolitic hematite ore into 3-20 mm, add 5-10% lime powder accounting for the weight of the high-phosphorus oolitic hematite and mix evenly, add the mixture into a furnace and roast at 950-1000℃ for 1 hour, and perform magnetic separation at 2000-3000GS; Step 2 Restore: Step 2.1 Grind the high-phosphorus oolitic hematite ore after magnetic separation in step 1 into powder ore, add 3% mixed salt and 0.3-3% pellet binder accounting for the weight of the high-phosphorus oolitic hematite, and press them into high-phosphorus iron ore powder pellets, wherein the mixed salt is a mixture of Na2B4O7.XH2O80% + Na2CO3 20%; Step 2.2 Reduction with external solid C reducing agent: 30-50% reducing agent accounting for the weight of high-phosphorus iron ore powder pellets, 10-20% CaO or CaCO3 powder accounting for the weight of the reducing agent, and 2-5% Na2CO3 accounting for the weight of the high-phosphorus iron ore powder pellets are mixed with the high-phosphorus iron ore powder pellets, and directly reduced at 950-1150°C in a powder metallurgy high-temperature mesh belt furnace or push boat furnace for 2-4 hours, or at 1100-1150°C in a coal-based vertical furnace for 6-8 hours to obtain direct reduced iron DRI with an Fe content of 70-80%; Or H2 reduction: The high-phosphorus iron ore powder pellets are reduced with H2 or ammonia decomposition gas at 950-1050℃ in a powder metallurgy high-temperature mesh belt furnace, push boat furnace or gas-based vertical furnace for 2-3 hours to obtain direct reduced iron DRI with an Fe content of 70-80%; Step 3 Melting: The DRI containing 1-4% C and pure C powder accounting for 2-4% of the weight of DRI are continuously melted in a medium frequency furnace at 1250-1400° C. to obtain high C, high P and low S / high S and low impurity molten iron; Or the above DRI containing C < 1.0% is continuously melted in a medium frequency furnace or an electric furnace at 1500-1650°C to obtain low C, high P, low S / high S, low impurity molten iron; Step 4 Refining: (I) Refining of high C, high S, high P and low impurity molten iron: after the molten iron is molten, the molten iron temperature is ≥1450℃, C≥1%, S≥0.02%, P≥0.1%: a. Desulfurization: Add 3-5% desulfurization agent block by weight of molten iron for 3-10 minutes to complete the desulfurization process; or add it in batches depending on the S content in the molten iron; b. Carbon removal: Blow O2 or add 1-2% of carbon removal agent block to the weight of molten iron. Carbon removal by blowing O2: When the sampled carbon content is less than 0.2%, carbon removal is completed. Carbon removal by carbon removal agent: Observe the furnace condition. There is a strong spark spray at the beginning. As the sparks gradually decrease, there are very few sparks and a few unreacted carbon removal agent blocks floating on the surface of the molten iron, indicating that carbon removal is completed. c. P removal: Add 5-20% P removal agent block by weight of molten iron for 3-10 minutes to complete the P removal process, or add it in batches depending on the P content in the molten iron to complete the P removal process; d. Deoxidation: Al wire or commonly used deoxidation agent for steelmaking is then added to remove O. When the O content is detected to be less than 0.1%, deoxidation is completed to obtain low C, low S, low P, low impurity and high purity molten steel. It only needs to add alloys according to the required steel type and transfer to the conventional steelmaking process; (II) Refining of high C, low S, high P and low impurity molten iron, where the molten iron temperature is ≥1500℃, C≥1%, S<0.02%, P≥0.1%: a. Desulfurization: For ultra-low S steel, add 1-3% desulfurization agent block by weight of molten iron for 3-10 minutes to complete the desulfurization process, or add it in batches depending on the S content in the molten steel; b. Carbon removal: Blow O2 or add carbon removal agent blocks accounting for 1-2% of the weight of molten iron. Carbon removal by blowing O2: When the sampled carbon content is less than 0.2%, carbon removal is completed; Carbon removal by carbon removal agent: Observe the furnace condition. In the early stage, there is a strong spark spray. As the sparks gradually decrease, there are very few sparks and a few unreacted carbon removal agent blocks floating on the surface of the molten steel, indicating that carbon removal is completed; c. P removal: Add 5-20% P removal agent block by weight of molten iron for 3-10 minutes to complete the P removal process, or add it in batches depending on the P content in the molten iron to complete the P removal process; d. Deoxidation: Al wire or commonly used deoxidation agent in metallurgy is then added to remove O. When the O content is detected to be less than 0.1%, deoxidation is completed to obtain low C, low S, low P, low impurity and high purity molten steel. It only needs to add alloy according to the required steel grade and transfer to the conventional steelmaking process; (III) Refining of low C, low S, high P and low impurity molten iron, where the molten iron temperature is ≥1550℃, C<1%, S<0.02%, P≥0.1%: a. Desulfurization: For ultra-low S molten iron, add 1-3% of the weight of the molten iron to desulfurize the molten iron for 3-10 minutes to complete the desulfurization process, or add it in batches depending on the S content in the molten steel. In order to further desulfurize, add 1-3% of the weight of the molten iron to the molten iron C powder; b. Carbon removal: Blow O2 or add 1-2% of carbon removal agent block to remove carbon in depth. Blow O2 to remove carbon: When the sample detects the carbon content <0.2%, the carbon removal is completed. Carbon removal with carbon removal agent: Observe the sparks of the furnace. As the sparks gradually decrease, there are very few sparks and a few unreacted carbon removal agent blocks floating on the surface of the molten steel, indicating that the carbon removal is completed. c. P removal: Add 5-20% of the weight of the molten iron to remove the P agent block for 3-10 minutes to complete the P removal process, or add it in batches depending on the P content in the molten steel to complete the P removal process; d. Deoxidation: Then add Al wire or commonly used deoxidation agent in metallurgy to deoxidize. When the O content is detected to be less than 0.1%, the deoxidation is completed and low C, low S, low P, low impurity and high-purity molten steel is obtained. It only needs to add alloy according to the required steel grade and transfer to the conventional steelmaking process.

2. A method for comprehensive metallurgy of powder metallurgy + high-phosphorus oolitic hematite, characterized in that The following steps are involved: Step 1: Desulfurization to remove non-iron gangue and crystal water: crush the high-phosphorus oolitic hematite ore into 3-20 mm, add 5-10% lime powder accounting for the weight of the high-phosphorus oolitic hematite and mix evenly, add the mixture into a furnace and roast at 950-1000℃ for 1 hour, and perform magnetic separation at 2000-3000GS; Step 2 Restore: Step 2.1: grinding the high-phosphorus oolitic hematite ore after magnetic separation in step 1 into powder ore, mixing a carbon powder reducing agent, a pelletizing binder accounting for 0.3-3% of the weight of the high-phosphorus iron ore powder, and the high-phosphorus iron ore powder, pressing balls, and drying to obtain high-phosphorus iron ore powder C-containing pellets; wherein the (C / O) ratio of fixed carbon in the carbon powder reducing agent to oxygen in iron oxides in the high-phosphorus oolitic hematite powder is in the range of 1 to 1.5, S in the carbon powder reducing agent is ≤0.02%, fixed carbon is ≥80%, and ash is ≤5%; Step 2.2 Reduction with external solid C reducing agent: 10-20% of the weight of the high-phosphorus iron ore powder containing C pellets by reducing agent, 10-20% of the weight of CaO or CaCO3 powder by reducing agent, and 2-5% of the weight of the high-phosphorus iron ore powder containing C pellets by Na2CO3 are mixed with the high-phosphorus iron ore powder containing C pellets, and directly reduced in a powder metallurgy high-temperature mesh belt furnace or push boat furnace at 950-1050°C for 2-3h, or in a coal-based vertical furnace at 1000-1050°C for 6-8h to obtain direct reduced iron DRI with an Fe content of 70-80%; Or H2 reduction: High phosphorus iron ore powder containing C pellets are reduced with H2 or ammonia decomposition gas at 950-1050℃ in a powder metallurgy high-temperature mesh belt furnace, push boat furnace or gas-based vertical furnace for 2-3 hours to obtain direct reduced iron DRI with an Fe content of 70-80%; Step 3 Melting: The DRI containing 1-4% C and pure C powder accounting for 2-4% of the weight of DRI are continuously melted in a medium frequency furnace at 1250-1400° C. to obtain high C, high P and low S / high S and low impurity molten iron; Or the above DRI containing C < 1.0% is continuously melted in a medium frequency furnace or an electric furnace at 1500-1650°C to obtain low C, high P, low S / high S, low impurity molten iron; Step 4 Refining: (I) Refining of high C, high S, high P and low impurity molten iron: after the molten iron is molten, the molten iron temperature is ≥1450℃, C≥1%, S≥0.02%, P≥0.1%: a. Desulfurization: Add 3-5% desulfurization agent block by weight of molten iron for 3-10 minutes to complete the desulfurization process; or add it in batches depending on the S content in the molten iron; b. Carbon removal: Blow O2 or add 1-2% of carbon removal agent blocks to the weight of molten iron. Carbon removal by blowing O2: When the sampled carbon content is less than 0.2%, carbon removal is completed. Carbon removal by carbon removal agent: Observe the furnace condition. There will be strong spark spraying at the beginning. As the sparks gradually decrease, there will be very few sparks and a few unreacted carbon removal agent blocks floating on the surface of the molten iron, indicating that carbon removal is completed. c. P removal: Add 5-20% P removal agent block by weight of molten iron for 3-10 minutes to complete the P removal process, or add it in batches depending on the P content in the molten iron to complete the P removal process; d. Deoxidation: Al wire or deoxidation agent commonly used in steelmaking is then added to remove O. When the O content is detected to be less than 0.1%, deoxidation is completed to obtain low C, low S, low P, low impurity and high purity molten steel. It only needs to add alloys according to the required steel grade and transfer to the conventional steelmaking process; (II) Refining of high C, low S, high P and low impurity molten iron, where the molten iron temperature is ≥1500℃, C≥1%, S<0.02%, P≥0.1%: a. Desulfurization: For ultra-low S steel, add 1-3% desulfurization agent block by weight of molten iron for 3-10 minutes to complete the desulfurization process, or add it in batches depending on the S content in the molten steel; b. Carbon removal: Blow O2 or add carbon removal agent blocks accounting for 1-2% of the weight of molten iron. Carbon removal by blowing O2: When the sampled carbon content is less than 0.2%, carbon removal is completed; Carbon removal by carbon removal agent: Observe the furnace condition. In the early stage, there is a strong spark spray. As the sparks gradually decrease, there are very few sparks and a few unreacted carbon removal agent blocks floating on the surface of the molten steel, indicating that carbon removal is completed; c. P removal: Add 5-20% P removal agent block by weight of molten iron for 3-10 minutes to complete the P removal process, or add it in batches depending on the P content in the molten iron to complete the P removal process; d. Deoxidation: Al wire or commonly used deoxidation agent in metallurgy is then added to remove O. When the O content is detected to be less than 0.1%, deoxidation is completed to obtain low C, low S, low P, low impurity and high purity molten steel. It only needs to add alloy according to the required steel grade and transfer to the conventional steelmaking process; (III) Refining of low C, low S, high P and low impurity molten iron, where the molten iron temperature is ≥1550℃, C<1%, S<0.02%, P≥0.1%: a. Desulfurization: For ultra-low S molten iron, add 1-3% of the weight of the molten iron to desulfurize the molten iron for 3-10 minutes to complete the desulfurization process, or add it in batches depending on the S content in the molten steel. In order to further desulfurize, add 1-3% of the weight of the molten iron to the molten iron C powder; b. Carbon removal: Blow O2 or add 1-2% of carbon removal agent block to remove carbon in depth. Blow O2 to remove carbon: When the sample detects the carbon content <0.2%, the carbon removal is completed. Carbon removal with carbon removal agent: Observe the sparks of the furnace. As the sparks gradually decrease, there are very few sparks and a few unreacted carbon removal agent blocks floating on the surface of the molten steel, indicating that the carbon removal is completed. c. P removal: Add 5-20% of the weight of the molten iron to remove the P agent block for 3-10 minutes to complete the P removal process, or add it in batches depending on the P content in the molten steel to complete the P removal process; d. Deoxidation: Then add Al wire or commonly used deoxidation agent in metallurgy to deoxidize. When the O content is detected to be less than 0.1%, the deoxidation is completed and low C, low S, low P, low impurity and high-purity molten steel is obtained. It only needs to add alloy according to the required steel grade and transfer to the conventional steelmaking process.

3. A method for comprehensive metallurgy of powder metallurgy + high-phosphorus oolitic hematite, characterized in that The following steps are involved: Step 1: Desulfurization to remove non-iron gangue and crystal water: crush the high-phosphorus oolitic hematite ore into 3-20 mm, add 5-10% lime powder accounting for the weight of the high-phosphorus oolitic hematite and mix evenly, add the mixture into a furnace and roast at 950-1000℃ for 1 hour, and perform magnetic separation at 2000-3000GS; Step 2: Reduction: the high-phosphorus oolitic hematite ore after magnetic separation in step 1, a reducing agent accounting for 30-50% of the weight of the high-phosphorus oolitic hematite ore, CaO or CaCO3 powder accounting for 10-20% of the weight of the reducing agent, and Na2CO3 accounting for 2-5% of the weight of the high-phosphorus oolitic hematite ore are uniformly mixed, and directly reduced in a powder metallurgy high-temperature mesh belt furnace or a push boat furnace at 1050-1150° C. for 2-4 hours, or in a coal-based vertical furnace at 1100-1150° C. for 6-8 hours to obtain direct reduced iron DRI with an Fe content of 70-80%; Step 3 Melting: The DRI containing 1-4% C and pure C powder accounting for 2-4% of the weight of DRI are continuously melted in a medium frequency furnace at 1250-1400° C. to obtain high C, high P and low S / high S and low impurity molten iron; Or the DRI containing C < 1.0% is continuously melted in a medium frequency furnace or an electric furnace at 1500-1650°C to obtain low C, high P, low S / high S, low impurity molten iron; Step 4 Refining: (I) Refining of high C, high S, high P and low impurity molten iron: after the molten iron is molten, the molten iron temperature is ≥1450℃, C≥1%, S≥0.02%, P≥0.1%: a. Desulfurization: Add 3-5% desulfurization agent block by weight of molten iron for 3-10 minutes to complete the desulfurization process; or add it in batches depending on the S content in the molten iron; b. Carbon removal: Blow O2 or add 1-2% of carbon removal agent block to the weight of molten iron. Carbon removal by blowing O2: When the sampled carbon content is less than 0.2%, carbon removal is completed. Carbon removal by carbon removal agent: Observe the furnace condition. There is a strong spark spray at the beginning. As the sparks gradually decrease, there are very few sparks and a few unreacted carbon removal agent blocks floating on the surface of the molten iron, indicating that carbon removal is completed. c. P removal: Add 5-20% P removal agent block by weight of molten iron for 3-10 minutes to complete the P removal process, or add it in batches depending on the P content in the molten iron to complete the P removal process; d. Deoxidation: Al or a commonly used deoxidation agent for steelmaking is then added to remove O. When the O content is less than 0.1%, deoxidation is completed to obtain a low C, low S, low P, low impurity, high-purity molten steel. It is only necessary to add alloys according to the required steel type and transfer to the conventional steelmaking process; (II) Refining of high C, low S, high P and low impurity molten iron, molten iron temperature ≥1500℃: C≥1%, S<0.02%, P≥0.1%: a. Desulfurization: For ultra-low S steel, add 1-3% desulfurization agent block by weight of molten iron for 3-10 minutes to complete the desulfurization process, or add it in batches depending on the S content in the molten steel; b. Carbon removal: Blow O2 or add carbon removal agent blocks accounting for 1-2% of the weight of molten iron. Carbon removal by blowing O2: When the sampled carbon content is less than 0.2%, carbon removal is completed; Carbon removal by carbon removal agent: Observe the furnace condition. In the early stage, there is a strong spark spray. As the sparks gradually decrease, there are very few sparks and a few unreacted carbon removal agent blocks floating on the surface of the molten steel, indicating that carbon removal is completed; c. P removal: Add 5-20% P removal agent block by weight of molten iron for 3-10 minutes to complete the P removal process, or add it in batches depending on the P content in the molten iron to complete the P removal process; d. Deoxidation: Al or a commonly used deoxidation agent in metallurgy is then added to remove O. When the O content is less than 0.1%, deoxidation is completed to obtain low C, low S, low P, low impurity and high purity molten steel. It is only necessary to add alloys according to the required steel grade and transfer to the conventional steelmaking process; (III) Refining of low C, low S, high P and low impurity molten iron, molten iron temperature ≥1550℃: C<0.02%, S<0.02%, P≥0.1%: a. Desulfurization: For ultra-low S molten iron, add 1-3% of the weight of the molten iron to desulfurize the molten iron for 3-10 minutes to complete the desulfurization process, or add it in batches depending on the S content in the molten steel. In order to further desulfurize, add 1-3% of the weight of the molten iron to the molten iron C powder; b. Carbon removal: Blow O2 or add 1-2% of carbon removal agent block to remove carbon in depth. Blow O2 to remove carbon: When the sample detects the carbon content <0.2%, the carbon removal is completed. Carbon removal with carbon removal agent: Observe the sparks of the furnace. As the sparks gradually decrease, there are very few sparks and a few unreacted carbon removal agent blocks floating on the surface of the molten steel, indicating that the carbon removal is completed. c. P removal: Add 5-20% of the weight of the molten iron to remove the P agent block for 3-10 minutes to complete the P removal process, or add it in batches depending on the P content in the molten steel to complete the P removal process; d. Deoxidation: Al or commonly used deoxidation agent in metallurgy is then added to remove O. When the O content is detected to be less than 0.1%, the deoxidation is completed and low C, low S, low P, low impurity and high-purity molten steel is obtained. It only needs to add alloy according to the required steel grade and then transfer to the conventional steelmaking process.

4. The method of powder metallurgy + high-phosphorus oolitic hematite comprehensive metallurgy according to claim 1, characterized in that: Step 2.1: Grind the medium-high phosphorus oolitic hematite ore into powder ore with a mesh size of 80 mesh.

5. The method of powder metallurgy + high-phosphorus oolitic hematite comprehensive metallurgy according to claim 1 or 2, characterized in that: The pellet binder described in step 2.1 is humic acid, lignin, kaolin or cellulose.

6. The method of powder metallurgy + high-phosphorus oolitic hematite comprehensive metallurgy according to claim 1 or 2, characterized in that: The reducing agent described in step 2.2 is blue carbon powder, coke powder, anthracite powder or biomass carbon powder.

7. The method of powder metallurgy + high-phosphorus oolitic hematite comprehensive metallurgy according to claim 3, characterized in that: The reducing agent described in step 2 is blue carbon powder, coke powder, anthracite powder or biomass carbon powder.

8. The method of powder metallurgy + high-phosphorus oolitic hematite comprehensive metallurgy according to claim 1, 2 or 3, characterized in that: The desulfurization agent or desulfurization agent in the refining of step 4 is composed of CaO / CaCO3, CaF2, Na2CO3, and CaCl2, with CaO or CaCO3: CaF2: Na2CO3: CaCl2 = 6:2:2.5:0.

5. The powders of CaO / CaCO3, CaF2, Na2CO3, and CaCl2 are mixed and briquette-pressed into a diameter of 30-50 mm according to the above ratio.

9. The method of powder metallurgy + high-phosphorus oolitic hematite comprehensive metallurgy according to claim 1, 2 or 3, characterized in that: The decarbonizing agent in step 4 refining is Fe≥68%Fe2O3 low-S iron concentrate and Fe≥65%Fe3O4 powder pressed into a briquette with a diameter of 30-50mm.

Images