Low-aluminum and low-oxygen industrial pure iron, and preparation method and application thereof

Abstract

The present application relates to the field of metallurgical preparation, in particular to a kind of low-aluminum low-oxygen industrial pure iron and preparation method and application, including, industrial pure iron is melted in oxygen atmosphere, refining, after deoxidation, low-aluminum industrial pure iron can be obtained by pouring;The low-aluminum industrial pure iron prepared is mixed with carbon particles, once melted in vacuum environment, carbon particles are injected again, secondary melting is carried out, and low-aluminum low-oxygen industrial pure iron is obtained by pouring, wherein, the injection amount of carbon particles in primary melting is 0.005-0.01wt.% of the mass of low-aluminum industrial pure iron, and the injection amount of carbon particles in secondary melting is 0.02-0.03wt.% of the mass of low-aluminum industrial pure iron.The present application adopts double-furnace melting process, aluminum is removed in the first furnace with oxygen as oxygenating agent, and in the second furnace, deoxygenation is carried out in vacuum environment using carbon particles as raw material, and low-aluminum low-oxygen industrial pure iron is prepared, with aluminum content not higher than 20ppm, and oxygen content not higher than 10ppm.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metallurgy, in particular to a low-aluminum and low-oxygen industrial pure iron and a preparation method and application thereof. BACKGROUND

[0002] The diamond wire saw cutting technology has replaced the mortar multi-wire cutting technology in the cutting of silicon wafers due to its high cutting efficiency, low processing cost, and small environmental pollution. With the scarcity of silicon wafer resources, the requirement for the refinement of diamond wire is becoming higher and higher. The diamond wire core wire is made of high-carbon steel wire rod through a series of processes such as heat treatment, drawing, and electroplating. The wire breaking phenomenon occurs during the drawing process, which reduces the yield. Pure iron is the main component of high-carbon steel, which is the raw material for preparing diamond wire. The content of aluminum oxide in pure iron is the main factor affecting the wire breaking rate of diamond wire. At present, the aluminum content of pure iron for preparing high-carbon steel is 55 ppm, and the oxygen content is 40 ppm, which cannot meet the use requirements. It is necessary to purify the pure iron to reduce the content of aluminum and oxygen elements in high-carbon steel, and thus to reduce the wire breaking rate of diamond wire.

[0003] At present, the method of refining is mostly used to remove aluminum and oxygen from industrial pure iron. The existing technology discloses a pure iron refining method, which includes the following steps: after the raw materials are heated and melted, oxygen is introduced to oxidize the silicon, manganese, chromium, titanium, vanadium, and phosphorus elements in the raw materials, and then the carbon, manganese, copper, tin, sulfur, and other elements in the molten steel are removed by refining to obtain pure iron liquid. The technical scheme disclosed in the prior art mainly focuses on removing the aluminum element in industrial pure iron, but does not propose a technical scheme for significantly reducing the oxygen element in industrial pure iron. Therefore, the pure iron prepared by the prior art cannot be used as a raw material for high-carbon steel to solve the problem of high wire breaking rate of diamond wire. SUMMARY

[0004] Therefore, the technical problem to be solved by the present application is to reduce the content of aluminum and oxygen elements in industrial pure iron, and to overcome the defects of the existing technology that the process of purifying pure iron is easy to cause aluminum return and oxygen dissolution, resulting in high content of aluminum and oxygen elements. Thus, a low-aluminum and low-oxygen industrial pure iron and a preparation method and application thereof are provided.

[0005] To this end, the present application provides the following technical scheme:

[0006] The application discloses a preparation method of low-aluminum and low-oxygen industrial pure iron, and belongs to the technical field of metallurgy.

[0007] The oxygen atmosphere of the step S1 is filled after power supply, the power supply power is 140-145 kW; the pressure of the oxygen atmosphere is 15000 Pa-17000 Pa, the refining temperature is 1580 DEG C.-1600 DEG C., the pouring temperature is 1580 DEG C.-1600 DEG C.; the melting time is 40-70 min, the refining time is 10-15 min, and the deoxidation time is 20-25 min.

[0008] The application further provides the low-aluminum and low-oxygen industrial pure iron, which comprises the following components: aluminum with a content of not more than 20 ppm; and / or oxygen with a content of not more than 10 ppm.

[0009] The application further provides application of the low-aluminum and low-oxygen industrial pure iron prepared by the preparation method of the low-aluminum and low-oxygen industrial pure iron to smelting high-carbon steel.

[0010] The application has the following advantages:

[0011] 1. The preparation method of the low-aluminum and low-oxygen industrial pure iron provided by the application comprises the following steps: melting industrial pure iron in an oxygen atmosphere, refining, deoxidizing, and pouring to obtain low-aluminum industrial pure iron; and mixing the prepared low-aluminum industrial pure iron with carbon particles, once melting in a vacuum environment, injecting carbon particles again, twice melting, and pouring to obtain low-aluminum and low-oxygen industrial pure iron. After the first furnace is de-aluminized through the oxygen-aluminum reaction, the generated aluminum oxide is dispersed in the melt, the aluminum oxide in the melt and the furnace lining will react with carbon, causing aluminum return, therefore, the double-furnace smelting process is adopted, the aluminum oxide generated in the first furnace is purified and poured into low-aluminum pure iron, which can significantly remove the aluminum element in the pure iron, and also avoids the reaction between the aluminum oxide dispersed in the melt and the carbon particles used for deoxidization to increase the aluminum content in the furnace, and then, the low-aluminum pure iron after de-aluminization is deoxidized through the carbon-oxygen reaction in the second furnace in a vacuum environment, thereby solving the problem that the oxygen content in the low-aluminum pure iron liquid cannot be reduced to within 10 ppm in the first furnace.

[0012] Meanwhile, the dual-furnace smelting process employed in this invention involves injecting carbon particles into the furnace in stages during the second furnace process. This reduces the oxygen content in the prepared pure iron. By adding a small amount of carbon during the first melting, initial deoxidation is achieved during the melting of low-alumina pure iron. This avoids the situation where adding a large amount of carbon particles at once would cause the carbon to react with the alumina in the furnace lining and release aluminum elements from the lining during the pure iron melting process. By adding carbon during the second melting after the low-alumina pure iron has been melted, it is ensured that the carbon particles added during the second melting undergo deep deoxidation within the molten pure iron. This shortens the reaction time of the carbon particles added during the second melting in the furnace and avoids the situation where the carbon particles react with the aluminum elements in the furnace and revert to aluminum. By adding carbon in stages, the oxygen content in the pure iron is significantly reduced while the amount of aluminum reversion is also reduced. The final pure iron produced has an aluminum content of less than 20 ppm and an oxygen content of less than 10 ppm.

[0013] 2. The method for preparing low-aluminum, low-oxygen industrial pure iron provided by this invention addresses the issue that the aluminum and oxygen elements in the molten iron mainly originate from the aluminum and oxygen elements contained in the raw materials and oxides, as well as the aluminum and oxygen elements generated by the decomposition of the crucible refractory material. During the molten iron smelting process, when carbon is absent, the alumina refractory material in the crucible is stable, and the decomposition reaction is weak. In this case, the main sources of aluminum and oxygen in the molten iron are the aluminum and oxygen elements contained in the raw materials and oxides. However, when carbon is present in the molten iron, the carbon reacts with the alumina. Therefore, in this invention, to shorten the reaction time of carbon particles in the furnace during the deoxidation reaction of low-aluminum pure iron, the timing of injecting carbon particles for deep deoxygenation of the low-aluminum pure iron molten iron is controlled after the molten iron smelting process, maintaining a certain reaction time before casting to obtain low-aluminum, low-oxygen pure iron.

[0014] 3. The method for preparing low-aluminum, low-oxygen industrial pure iron provided by this invention uses oxygen as an oxygenating agent in the first furnace smelting process. Insufficient oxygen affects the oxygen-aluminum reaction, resulting in incomplete dealuminization; excessive oxygen results in a less significant decrease in aluminum content, increasing the difficulty of deoxidation in the second furnace. Therefore, limiting the furnace pressure after oxygen introduction ensures sufficient dealuminization in the molten iron without increasing the oxygen content and causing deoxidation difficulties, thus achieving a balance between aluminum and oxygen content in the final pure iron. Simultaneously, the contact area between the molten iron surface and oxygen in the furnace during industrial pure iron melting is much larger than after the iron raw material is fully melted. Therefore, the rate at which oxygen dissolves in the molten iron during melting is much higher than after full melting. The longer the melting time, the higher the dissolved oxygen content in the molten iron, and the more complete the oxygen-dealuminization reaction, resulting in a lower aluminum content in the pure iron. This invention limits the melting time of the first furnace, reducing the aluminum content in the pure iron while conserving energy (as excessive melting time prevents further changes in aluminum content).

[0015] 4. The pure iron prepared by the low-aluminum and low-oxygen industrial pure iron preparation method of the present invention has an oxygen content as low as 10ppm and an aluminum content as low as 20ppm. When applied to high carbon steel, it can reduce the alumina content in high carbon steel, which can meet the requirement of diamond wire prepared from high carbon steel to maintain a continuous wire length of 120km. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a graph showing the carbon-aluminum equilibrium relationship at 1600℃ under different furnace pressures;

[0018] Figure 2 This is the aluminum stripping process curve of Embodiment 1 of the present invention;

[0019] Figure 3 This is the deoxidation process curve of Embodiment 1 of the present invention;

[0020] Figure 4 A schematic diagram showing the relationship between the amount of carbon particles injected during secondary melting and the carbon, oxygen, and aluminum content in low-oxygen, low-aluminum pure iron liquid. Detailed Implementation

[0021] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0022] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products. The vacuum induction furnaces used in Examples 1-5 and Comparative Examples 1-4 are model VIM150, with a maximum pressure of 30-50 Pa, a maximum capacity of 165 kg, and a maximum power of 160 kW.

[0023] The aluminum and oxygen in molten iron mainly come from two sources: firstly, aluminum and oxygen contained in the raw materials and introduced by oxide inclusions; and secondly, aluminum and oxygen introduced by the decomposition reaction of the crucible refractory material. This invention uses an alumina crucible with an alumina content of over 90%.

[0024] When there is no carbon in the molten iron, the alumina in the crucible decomposes, supplying aluminum and oxygen to the molten iron. The relevant reaction equation is as follows:

[0025] Al2O 3(s) = 2[Al] + 3[O]

[0026] ΔG o =1202000-386.3T

[0027]

[0028] As can be seen from the above formula, the decomposition reaction of alumina is independent of the furnace pressure. Therefore, when there is no carbon in the pure iron liquid, the alumina refractory is very stable and the decomposition reaction is very weak. At this time, the aluminum and oxygen in the pure iron liquid come from the aluminum and oxygen contained in the raw materials and the aluminum and oxygen brought in by the oxide mixture.

[0029] When carbon is present in molten iron, the relevant reaction between carbon and alumina at 1600℃ is as follows:

[0030] Al2O 3(s) +3[C]=2[Al]+3CO (g)

[0031] ΔG o =311440-143.27T

[0032]

[0033] K = 9.55 × 10 -6

[0034]

[0035] Choosing a pure substance as the standard state, At this time, let f [c] and f [Al] Both are 1. Combining the above relationships, we get:

[0036] w[C]=0.47×10 -3 P CO w[Al] 2 / 3

[0037] See also Figure 1The graph shows the carbon-aluminum equilibrium relationship at 1600℃ under different furnace pressures. It reveals that the higher the carbon content in the molten iron, the higher the temperature of the molten iron, and the lower the furnace pressure, the greater the tendency for alumina to react with carbon. Therefore, while vacuum carbon deoxidation of low-alumina pure iron using an alumina crucible will increase the aluminum content in the molten iron to some extent, it is still possible to control the furnace pressure, molten iron temperature, and carbon addition during the melting of the cast low-alumina pure iron, while maintaining a high level of deoxidation, the aluminum content can still be kept at an extremely low level.

[0038] Example 1

[0039] This embodiment provides a method for preparing low-aluminum, low-oxygen industrial pure iron, including the following steps:

[0040] 155 kg of industrial pure iron was loaded into the crucible of a vacuum induction furnace. Air was extracted from the furnace until the pressure reached the equipment limit of the vacuum induction furnace. Figure 2 The dealumination process curve shown indicates that when the power in the furnace reaches 140kW, oxygen is introduced to raise the furnace pressure to 15000Pa. Melting continues for 60 minutes until all the pure iron is melted. This process is maintained until the pure iron melt is clear. Then, the oxygen is extracted until the furnace pressure reaches the equipment limit. The pure iron is heated to 1580℃ and refined for 10 minutes. Power is then cut off until a film forms on the surface of the pure iron, and the process continues according to... Figure 2 The dealuminization process curve is followed by power supply, and simultaneously, low-temperature vacuum deoxidation in the furnace is performed for 20 minutes. The molten pure iron is then poured at a pouring temperature of 1580℃ to produce low-aluminum pure iron. Figure 2 The power supply process of the dealuminization process curve includes: 0-15 min of melting time, with power maintained at 60 kW; 15-30 min of melting time, with power increased to 80 kW; 30-45 min of melting time, with power increased to 100 kW; starting at 45 min, power is increased to 140 kW while a certain amount of oxygen is introduced into the furnace until the furnace pressure reaches 15000 Pa; power is maintained at 140 kW until the initial charge melts and the temperature rises to the refining temperature of 1580℃; at 130 min of melting time, the furnace is evacuated and the power supply is reduced to a holding power of 60 kW for refining and holding; after refining, power is cut off until a film forms on the surface of the melt; after film formation, at 60 kW, the melt is degassed at low temperature for a certain period of time, and then the power is increased to 140 kW to rapidly heat the melt to the casting temperature and complete the casting.

[0041] 120 kg of low-aluminum pure iron and 0.005 wt.% carbon particles were loaded into the crucible of the vacuum induction furnace. Air was evacuated from the furnace until the pressure reached the equipment limit of the vacuum induction furnace. Then, according to… Figure 3The deoxidation process curve shown indicates that electricity is supplied to the furnace, and melting takes 65 minutes. After melting, once the low-aluminum pure iron melt is clear and the temperature of the mixture in the vacuum induction furnace reaches 1600℃, 0.03 wt.% carbon particles are added to the vacuum induction furnace and held at 1580℃ for 20 minutes. Once the carbon particles are completely melted, the temperature is maintained for another 20 minutes, and then cast to obtain low-aluminum, low-oxygen pure iron. Figure 3 The deoxidation process curve includes the following steps: For the melting time of 0-15 minutes, the power is maintained at 60kW. At this time, the low-aluminum pure iron in the vacuum induction furnace is not completely melted. For the melting time of 15-30 minutes, the power is increased to 80kW. At this time, the low-aluminum pure iron in the vacuum induction furnace becomes molten. The carbon particles injected in the first melting begin to react with oxygen. For the melting time of 30-45 minutes, the power is increased to 100kW. After 45 minutes, the power is increased to 140kW and maintained until the initial charge melts and the temperature reaches the required temperature. Then, the power is reduced to 60kW and the temperature is maintained at 1580℃. Carbon is added a second time. After the carbon particles melted a second time react with oxygen, the power is maintained at 60kW. After holding at this temperature for 20 minutes, the casting is completed.

[0042] Example 2

[0043] This embodiment provides a method for preparing low-aluminum, low-oxygen industrial pure iron, including the following steps:

[0044] 155 kg of industrial pure iron was loaded into the crucible of a vacuum induction furnace. The air inside the furnace was evacuated until the pressure inside the furnace reached the equipment limit of the vacuum induction furnace. Power was supplied to the furnace until the power inside the furnace reached 140 kW. Oxygen was then introduced into the furnace to make the pressure inside the furnace reach 16000 Pa. Melting continued for 65 minutes until all the pure iron was melted. After the pure iron melted, the oxygen inside the furnace was evacuated until the pressure inside the furnace reached the equipment limit. The pure iron melt was heated to 1600℃ and refined for 15 minutes. Then the power was cut off until a film formed on the surface of the pure iron melt. Power was then supplied to the furnace. At the same time, the furnace was deoxidized under low temperature vacuum for 25 minutes. The pure iron melt was then poured at a pouring temperature of 1580℃ to obtain low-aluminum pure iron.

[0045] 120 kg of low-aluminum pure iron and 0.01 wt.% carbon particles were loaded into the crucible of a vacuum induction furnace. The air inside the furnace was evacuated until the pressure inside the furnace reached the equipment limit of the vacuum induction furnace. Electricity was supplied to the furnace until the power inside the furnace reached 142 kW. Melting was carried out for 50 minutes. After melting, the low-aluminum pure iron melt was cleared and the temperature of the mixture inside the vacuum induction furnace reached 1600℃. Then, 0.02 wt.% carbon particles were added to the vacuum induction furnace and the temperature was maintained at 1600℃ for 30 minutes. The mixture was then cast to obtain low-aluminum, low-oxygen pure iron.

[0046] Example 3

[0047] This embodiment provides a method for preparing low-aluminum, low-oxygen industrial pure iron, including the following steps:

[0048] 155 kg of industrial pure iron was loaded into the crucible of a vacuum induction furnace. The air inside the furnace was evacuated until the pressure inside the furnace reached the equipment limit of the vacuum induction furnace. Power was supplied to the furnace until the power inside the furnace was 145 W. Oxygen was then introduced into the furnace to make the pressure inside the furnace reach 17000 Pa. Melting continued for 40 minutes until all the pure iron was melted. After the pure iron melted, the oxygen inside the furnace was evacuated until the pressure inside the furnace reached the equipment limit. The pure iron melt was heated to 1600 °C and refined for 15 minutes. Then the power was cut off until a film formed on the surface of the pure iron melt. Power was then supplied to the furnace. At the same time, the furnace was deoxidized under low temperature vacuum for 20 minutes. The pure iron melt was then poured at a pouring temperature of 1600 °C to obtain low-aluminum pure iron.

[0049] 120 kg of low-aluminum pure iron and 0.005 wt.% carbon particles were loaded into the crucible of a vacuum induction furnace. The air inside the furnace was evacuated until the pressure inside the furnace reached the equipment limit of the vacuum induction furnace. Electricity was supplied to the furnace until the power inside the furnace reached 145 kW. Melting was carried out for 70 minutes. After melting, the low-aluminum pure iron melt was clear and the temperature of the mixture inside the vacuum induction furnace reached 1580℃. Then, 0.025 wt.% carbon particles were added to the vacuum induction furnace and the temperature was maintained at 1580℃ for 25 minutes. The mixture was then cast to obtain low-aluminum, low-oxygen pure iron.

[0050] Example 4

[0051] This embodiment provides a method for preparing low-aluminum, low-oxygen industrial pure iron, including the following steps:

[0052] 160 kg of industrial pure iron was loaded into the crucible of a vacuum induction furnace. The air inside the furnace was evacuated until the pressure inside the furnace reached the equipment limit of the vacuum induction furnace. Power was supplied to the furnace until the power inside the furnace reached 140 kW. Oxygen was then introduced into the furnace to make the pressure inside the furnace reach 17000 Pa. Melting continued for 40 minutes until all the pure iron was melted. After the pure iron melted, the oxygen inside the furnace was evacuated until the pressure inside the furnace reached the equipment limit. The pure iron melt was heated to 1600 ℃ and refined for 14 minutes. Power was then cut off until a film formed on the surface of the pure iron melt. Power was then supplied to the furnace. At the same time, the furnace was deoxidized under low temperature vacuum for 23 minutes. The pure iron melt was then poured at a pouring temperature of 1580 ℃ to obtain low-aluminum pure iron.

[0053] 135 kg of low-aluminum pure iron and 0.009 wt.% carbon particles were loaded into the crucible of a vacuum induction furnace. The air inside the furnace was evacuated until the pressure inside the furnace reached the equipment limit of the vacuum induction furnace. Electricity was supplied to the furnace until the power inside the furnace reached 140 kW. Melting was carried out for 60 minutes. After melting, when the low-aluminum pure iron melt was clear and the temperature of the mixture inside the vacuum induction furnace reached 1600℃, 0.028 wt.% carbon particles were added to the vacuum induction furnace and the temperature was maintained at 1590℃ for 27 minutes. Low-aluminum and low-oxygen pure iron was then cast to obtain the product.

[0054] Example 5

[0055] This embodiment provides a method for preparing low-aluminum, low-oxygen industrial pure iron, including the following steps:

[0056] 150 kg of industrial pure iron is loaded into the crucible of a vacuum induction furnace. The air inside the furnace is extracted until the pressure inside the furnace reaches the equipment limit of the vacuum induction furnace. Power is supplied to the furnace until the power inside the furnace reaches 143 kW. Oxygen is then introduced into the furnace to make the pressure inside the furnace reach 16000 Pa. Melting continues for 70 minutes until all the pure iron is melted. After the pure iron melts completely, the oxygen inside the furnace is extracted until the pressure inside the furnace reaches the equipment limit. The pure iron melt is heated to 1590℃ and refined for 13 minutes. Then the power is cut off until a film forms on the surface of the pure iron melt. Power is then supplied to the furnace, and at the same time, the furnace is deoxidized under low temperature vacuum for 24 minutes. The pure iron melt is then poured at a pouring temperature of 1590℃ to obtain low-aluminum pure iron.

[0057] 125 kg of low-aluminum pure iron and 0.007 wt.% carbon particles were loaded into the crucible of a vacuum induction furnace. The air inside the furnace was evacuated until the pressure inside the furnace reached the equipment limit of the vacuum induction furnace. Electricity was supplied to the furnace until the power inside the furnace reached 140 kW. Melting was carried out for 65 minutes. After melting, when the low-aluminum pure iron melt was clear and the temperature of the mixture inside the vacuum induction furnace reached 1590℃, 0.026 wt.% carbon particles were added to the vacuum induction furnace and the temperature was maintained at 1590℃ for 23 minutes. Low-aluminum and low-oxygen pure iron was then cast to obtain the product.

[0058] Comparative Example 1

[0059] This comparative example provides a method for preparing industrial pure iron with low aluminum and low oxygen, including the following steps:

[0060] 155 kg of industrial pure iron was loaded into the crucible of a vacuum induction furnace. The air inside the furnace was evacuated until the pressure reached the equipment limit of the vacuum induction furnace. Power was supplied to the furnace until the power inside the furnace reached 140 kW. Oxygen was then introduced into the furnace to bring the pressure inside the furnace to 15000 Pa. Melting continued for 60 minutes until all the pure iron was melted. The oxygen inside the furnace was then evacuated until the pressure inside the furnace reached the equipment limit. The pure iron was heated to 1580 °C and refined for 10 minutes. Power was then cut off until a film formed on the surface of the pure iron. Power was then supplied to the furnace, and at the same time, the furnace was deoxidized under low-temperature vacuum for 20 minutes. The power supply was then increased until the temperature of the melt inside the vacuum induction furnace reached 1580 °C. 0.03 wt.% carbon particles were added to the vacuum induction furnace and the temperature was maintained at 1580 °C for 20 minutes. Low-aluminum, low-oxygen pure iron was then cast.

[0061] Comparative Example 2

[0062] This comparative example provides a method for preparing industrial pure iron with low aluminum and low oxygen, including the following steps:

[0063] The method for preparing low-aluminum pure iron is the same as that in Example 1 of this invention;

[0064] 120 kg of low-aluminum pure iron is loaded into the crucible of a vacuum induction furnace. The air inside the furnace is evacuated and removed. After complete melting, the temperature of the pure iron liquid is raised to 1580℃ and held for 10-15 minutes. Argon gas of 5000 Pa-8000 Pa is introduced into the furnace, and 0.03 wt.% carbon particles are injected into the furnace. The temperature of the pure iron liquid is raised to 1600℃ and held for 8 minutes. Low-aluminum and low-oxygen pure iron is then cast.

[0065] Comparative Example 3

[0066] This comparative example provides a method for preparing industrial pure iron with low aluminum and low oxygen, including the following steps:

[0067] The method for preparing low-aluminum pure iron is the same as that in Example 1 of this invention;

[0068] 120 kg of low-aluminum pure iron and 0.03 wt.% carbon particles were loaded into the crucible of a vacuum induction furnace. The air inside the furnace was evacuated until the pressure inside the furnace reached the equipment limit of the vacuum induction furnace. Electricity was supplied to the furnace until the power inside the furnace reached 140 kW. After melting for 60 minutes and the temperature of the mixture inside the vacuum induction furnace reached 1600℃, 0.04 wt.% carbon particles were added to the vacuum induction furnace and the temperature was maintained at 1580℃ for 20 minutes. Low-aluminum and low-oxygen pure iron was then cast.

[0069] Comparative Example 4

[0070] This comparative example provides a method for preparing industrial pure iron with low aluminum and low oxygen, including the following steps:

[0071] The method for preparing low-aluminum pure iron is the same as that in Example 1 of this invention;

[0072] 120 kg of low-aluminum pure iron is placed in the crucible of a vacuum induction furnace. The air inside the furnace is extracted until the pressure inside the furnace reaches the equipment limit of the vacuum induction furnace. Electricity is supplied to the furnace until the power inside the furnace reaches 140 kW. After melting for 60 minutes and the temperature of the mixture inside the vacuum induction furnace reaches 1600℃, 0.03 wt.% carbon particles are added to the vacuum induction furnace and the temperature is maintained at 1580℃ for 20 minutes. Low-aluminum and low-oxygen pure iron is then cast.

[0073] Experimental Example 1

[0074] The content of each component in the pure iron prepared in Examples 1-5 and Comparative Examples 1-4 was determined. The methods included: taking 20g of the pure iron scraps prepared in Examples 1-5 and Comparative Examples 1-4, cleaning them with alcohol, and drying them with cold air; taking the pure iron rods prepared in Examples 1-5 and Comparative Examples 1-4, machining them into Φ4mm rods, polishing the surface of the rods with fine sandpaper, cleaning them with alcohol, and drying them with cold air; using an ON analyzer to determine the oxygen content of the rods; and using ICP to determine the aluminum content of the scraps. The aluminum and oxygen content in the pure iron prepared in Examples 1-5 and Comparative Examples 1-4 is shown in Table 1.

[0075] Experiment Example 2

[0076] The low-aluminum, low-oxygen pure iron obtained in Example 1 was used to prepare high-carbon steel. The smelting steps for high-carbon steel included...

[0077] Melting period: All low-aluminum, low-oxygen pure iron and metallic chromium are loaded into the crucible, with metallic chromium at the bottom and purified iron on top of metallic chromium. The furnace is closed and vacuumed to bring the pressure inside the furnace to within 100 Pa. Then, the low-aluminum, low-oxygen pure iron and metallic chromium are melted according to the normal smelting process.

[0078] Refining period: After the initial charge is fully melted, adjust the temperature of the molten steel to 1600℃, maintain the furnace temperature at 30-50Pa, and hold for 8-10 minutes.

[0079] Alloying period: After refining, power is turned off to form a film and 50,000 Pa argon gas is introduced into the furnace. At the same time, all metallic manganese, polycrystalline silicon and carbon particles are added. After complete melting, the furnace is stirred at 80% rated power for 5 minutes, and samples are taken to analyze the chemical composition.

[0080] Pouring: After the molten steel composition meets the requirements, adjust the molten steel temperature to 1550℃ and then pour it under power. During pouring, the molten steel level in the tundish should reach 4 / 5 of the tundish height within 1 second, and the subsequent pouring speed should be maintained at 3 kg / s until the pouring is completed.

[0081] The preparation steps of high-carbon steel wire rod include:

[0082] The raw materials are high-purity materials such as metallic chromium, carbon particles, polycrystalline silicon, metallic manganese, and low-aluminum, low-oxygen pure iron. Vacuum ingots with a diameter of 360mm are produced using a vacuum induction furnace. The 360mm diameter vacuum ingots are then produced into 480mm diameter consumable ingots using a vacuum arc furnace. The 480mm diameter consumable ingots are forged into 140mm square billets and rolled into 5.5mm wire rods using Shagang's high-speed wire rod mill.

[0083] The high-carbon steel prepared from low-aluminum, low-oxygen pure iron obtained in Example 1 of this invention can meet the requirement of maintaining the continuity of diamond wire prepared from high-carbon steel for 120km.

[0084] SeeFigure 4 As shown, this diagram illustrates the relationship between the amount of secondary carbon particles injected and the carbon, oxygen, and aluminum content in low-oxygen, low-aluminum pure iron liquid. It can be seen that when the amount of secondary carbon particles injected reaches 400 ppm, which is the amount of secondary carbon particles injected in Comparative Example 3, the carbon particles not only participate in the reaction but also react with the alumina in the furnace lining, resulting in an increase in the aluminum content. However, when the amount of secondary carbon particles injected is below 300 ppm, the aluminum content does not increase, proving that the carbon particles at this time only participate in the carbon-oxygen reaction and the aluminum content does not increase due to the increase in the amount of carbon particles injected.

[0085] Table 1. Aluminum and oxygen content in pure iron prepared in Examples 1-5 and Comparative Examples 1-4

[0086] Al (ppm) Oxygen (ppm) Example 1 15 7 Example 2 18 9 Example 3 13 8 Example 4 18 8 Example 5 16 7 Comparative Example 1 51 29 Comparative Example 2 10 35 Comparative Example 3 44 23 Comparative Example 4 11 21

[0087] It is known that the pure iron prepared by the low-aluminum, low-oxygen pure iron preparation method described in Examples 1-5 of this invention has a low oxygen and aluminum content. Specifically, this invention employs a two-furnace smelting process. After the oxygen-aluminum reaction, the iron is cast to produce low-aluminum pure iron for deoxidation treatment to ensure that the second furnace process does not result in aluminum reversion and an increase in aluminum content. Furthermore, in the first furnace, dealuminization is achieved through an oxygen-aluminum reaction, using oxygen as an oxygenating agent. After charging, the furnace pressure reaches 15000-17000 Pa, and the melting time is 60-70 minutes, reducing the aluminum content of the low-aluminum pure iron to below 10 ppm. In the second furnace... Vacuum carbon-oxygen reaction deoxidation is performed entirely under vacuum conditions. Initial deoxidation occurs during the initial melting of low-aluminum pure iron in a vacuum, through a single melting and carbon addition process. This prevents carbon from reacting with the alumina in the furnace lining and releasing aluminum elements during the pure iron melting process. After the low-aluminum pure iron melts, a second melting and carbon addition process is performed to ensure that the carbon particles react within the molten pure iron, shortening the reaction time of the carbon particles in the furnace and preventing them from reacting with the alumina in the furnace lining. This significantly reduces the oxygen content in the pure iron. Through the double-furnace melting process, the final product is low-aluminum, low-oxygen pure iron with an aluminum content of less than 20 ppm and an oxygen content of less than 10 ppm.

[0088] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing low-aluminum, low-oxygen industrial pure iron, characterized in that, Includes the following steps: S1, low-aluminum industrial pure iron can be obtained by melting, refining and deoxidizing industrial pure iron in an oxygen atmosphere and then casting it. S2, mix the low-aluminum industrial pure iron obtained in step S1 with carbon particles, melt it once in a vacuum environment, inject carbon particles again, melt it a second time, and cast it to obtain low-aluminum and low-oxygen industrial pure iron. The amount of carbon particles injected in the first melting is 0.005-0.01 wt.% of the mass of the low-aluminum industrial pure iron, and the amount of carbon particles injected in the second melting is 0.02-0.03 wt.% of the mass of the low-aluminum industrial pure iron. The first melting time in step S2 is 60-70 minutes, and the second melting time is 20-30 minutes.

2. The method for preparing low-aluminum, low-oxygen industrial pure iron according to claim 1, characterized in that, The temperature for the first and second melting processes in step S2 is 1580-1600℃.

3. The method for preparing low-aluminum, low-oxygen industrial pure iron according to claim 1, characterized in that, The oxygen atmosphere in step S1 is introduced after power is applied, with a power of 140-145kW.

4. The method for preparing low-aluminum, low-oxygen industrial pure iron according to claim 3, characterized in that, The pressure of the oxygen atmosphere in step S1 is 15000Pa-17000Pa.

5. The method for preparing low-aluminum, low-oxygen industrial pure iron according to claim 4, characterized in that, In step S1, the refining temperature is 1580℃-1600℃, and the casting temperature is 1580℃-1600℃.

6. The method for preparing low-aluminum, low-oxygen industrial pure iron according to claim 5, characterized in that, The melting time in step S1 is 40-70 min, the refining time is 10-15 min, and the deoxidation time is 20-25 min.

7. A low-aluminum, low-oxygen industrial pure iron prepared by the preparation method according to any one of claims 1-6.

8. The low-aluminum, low-oxygen industrial pure iron according to claim 7, characterized in that, The low-aluminum, low-oxygen industrial pure iron. This includes aluminum with a content not exceeding 20 ppm; and / or oxygen with a content not exceeding 10 ppm.

9. The application of the low-aluminum, low-oxygen industrial pure iron prepared by the preparation method according to any one of claims 1-6 or the low-aluminum, low-oxygen industrial pure iron according to claims 7-8 in the smelting of high-carbon steel.

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