Low-manganese iron powder and production method and application thereof
Through the two demanurizing process and the method of adding ice crystals, the manganese content in the iron powder was successfully reduced, and the problem of difficulty in reducing the manganese content in the prior art was solved, ensuring the high-quality preparation of the cathode material of lithium iron phosphate battery.
Patent Information
- Application Number
- CN202411619187.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-13
- Publication Date
- 2024-12-27
AI Technical Summary
The manganese content in iron powder in the existing production process is difficult to reduce to ≤0.03 wt%, which cannot meet the market's strict requirements for the positive electrode materials of lithium iron phosphate batteries.
The second demanurization process is adopted. During smelting, the first demanurization agent is mainly iron oxide and potassium feldspar as the auxiliary. During refining, the second demanurization agent is mainly potassium feldspar as the auxiliary and iron oxide is the auxiliary. During refining, the second demanurization agent is mainly potassium feldspar as the auxiliary and iron oxide is the auxiliary. Ice crystals are added during the process, and low ferromanganese powder is obtained through water atomization treatment and magnetic separation screening.
Effectively reduce the manganese content in iron powder to <0.03 wt%, ensure high-quality preparation of the positive electrode material of lithium iron phosphate battery, and by reasonably adjusting the components and process parameters of manganese demanittor, avoiding manganese recovery, and improving the oxidation and removal efficiency of manganese .
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of metal powders, and in particular to low-manganese iron powder and a production method and application thereof. Background Art
[0002] With the vigorous development of the new energy vehicle industry, the market demand for lithium iron phosphate battery positive electrode materials is gradually increasing. Among them, iron phosphate, as the key main raw material in the preparation process of lithium iron phosphate positive electrode materials, is usually prepared by reacting iron powder and phosphoric acid. However, the current market has strict requirements for iron powder used to prepare iron phosphate, that is, the manganese content must be ≤0.03wt%. However, under the existing production process, the manganese content in iron powder can only be reduced to 0.08wt%. In view of this, it is urgent to develop a production method for low-manganese iron powder to ensure that the manganese content in the iron powder can meet the stringent requirements of the market, thereby providing a solid guarantee for the high-quality preparation of lithium iron phosphate battery positive electrode materials. Summary of the invention
[0003] The invention provides a low-manganese iron powder and a production method and application thereof, which solves the problem of high manganese content in iron powder in the related art.
[0004] The technical solution of the present invention is as follows: The present invention provides a method for producing low manganese iron powder, comprising the following steps: S1. Smelting: Smelting the scrap steel, adding a slag-making agent and a first demanganeseizing agent, tapping the steel, and obtaining molten iron; S2, refining: refining the smelting molten iron, adding a second demanganizing agent, and soft blowing argon to obtain refined molten iron; S3: water atomization treatment: the refined molten iron is subjected to water atomization treatment and then dried to obtain raw powder; S4: Screening: The raw powder is screened by magnetic separation to obtain low manganese iron powder; The first demanganizing agent comprises the following components in parts by weight: 60-80 parts of iron oxide, 20-40 parts of potassium feldspar, and 10-20 parts of dolomite; The second demanganeseizing agent comprises the following components in parts by weight: 60-80 parts of potassium feldspar, 20-40 parts of iron oxide scale, and 10-20 parts of dolomite.
[0005] As a further technical solution, the slag-forming agent includes the following components in parts by weight: 15 to 25 parts of fluorite and 60 to 90 parts of quicklime.
[0006] In the present invention, the slag-making agent includes fluorite and quicklime, which can ensure a good slag-steel reaction interface and fluidity and accelerate the formation of slag, and can dephosphorize and desulfurize.
[0007] As a further technical solution, the amount of the slag-forming agent added is 50-75 kg / t based on the amount of scrap steel added; and / or The amount of the first demanganizing agent added is 8-10 kg / t; and / or The addition amount of the second demanganizing agent is 8-10 kg / t.
[0008] As a further technical solution, the scrap steel is composed of the following components in weight percentage: C 0.113%~0.143%, Si 0.052%~0.074%, Mn 0.219%~0.246%, P≤0.03%, S≤0.035%, Cr 0.031%~0.041%, Mo 0.002%~0.006%, Ni 0.016%~0.02%, Cu 0.014%~0.023%, and the rest is Fe and other inevitable impurities.
[0009] In the present invention, the influence of elemental components on the demanganese effect is reduced by strictly controlling the component content of scrap steel, especially the carbon content.
[0010] As a further technical solution, the second demanganizing agent further includes 10 to 30 parts of cryolite.
[0011] In the present invention, the inventors found that when the second demanganizing agent also includes cryolite, the manganese content in the iron powder can be further reduced. It is speculated that the addition of cryolite can promote the formation of more stable compounds of manganese oxide, thereby reducing the content of free manganese oxide in the slag, further avoiding the phenomenon of manganese back, and further reducing the manganese content in the iron powder.
[0012] As a further technical solution, in the second demanganizing agent, the weight ratio of potassium feldspar to cryolite is 4-5:1.
[0013] In the present invention, when the weight ratio of potassium feldspar to cryolite in the second demanganeseizing agent is 4-5:1, it is helpful to further reduce the manganese content in the iron powder.
[0014] As a further technical solution, the Fe content in the iron oxide scale is ≥95wt%.
[0015] As a further technical solution, the K in the potassium feldspar 2 O content is ≥11%.
[0016] As a further technical solution, the sum of the contents of CaO and MgO in the dolomite is ≥90wt%.
[0017] As a further technical solution, the CaF 2 The content is ≥98wt%.
[0018] As a further technical solution, the CaO content in the quicklime is ≥99.6wt%.
[0019] As a further technical solution, the F content in the cryolite is ≥53wt%, the Al content is ≥13wt%, and the Na content is ≥32wt%.
[0020] As a further technical solution, in step S1, the temperature during steel tapping is 1700-1800°C.
[0021] As a further technical solution, in step S2, the soft argon blowing treatment is carried out for 10 to 20 minutes.
[0022] As a further technical solution, in step S3, during the water atomization treatment, the atomization water pressure is 12-14.5 MPa and the water flow rate is 140-160 L / min.
[0023] The present invention also provides a low manganese iron powder produced by the production method.
[0024] The present invention also proposes the use of the low-manganese iron powder produced by the production method or the low-manganese iron powder in new energy batteries.
[0025] The working principle and beneficial effects of the present invention are: In the present invention, the manganese content in the iron powder is reduced to less than 0.03wt% by performing two demanganizations during the smelting and refining processes. During the smelting process, a demanganization agent mainly composed of iron oxide scale and supplemented by potassium feldspar is added; during the refining process, a demanganization agent mainly composed of potassium feldspar and supplemented by iron oxide scale is added. By rationally regulating the main and auxiliary materials of the demanganization agent during the two demanganization processes, the oxidation removal of manganese is improved, and the phenomenon of manganese return caused by the reduction of manganese oxide in the slag is prevented, thereby significantly reducing the manganese content in the iron powder. DETAILED DESCRIPTION
[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on 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.
[0027] In the following examples and comparative examples, unless otherwise specified, the Fe content in the iron oxide scale is 95wt%; the K content in the potassium feldspar is 2 O content is 11wt%; the total content of CaO and MgO in dolomite is 90wt%; CaF 2The content is 98wt%; the CaO content in quicklime is 99.6wt%; the F content in cryolite is 53wt%, the Al content is 13wt%, and the Na content is 32wt%.
[0028] Example 1 A method for producing low manganese iron powder comprises the following steps: S1. Smelting: 1 t of scrap steel is smelted, slag-making agent and first demanganese agent are added, steel is tapped at 1700°C to obtain molten iron; Wherein, based on the amount of scrap steel added, the amount of slag-forming agent added is 50kg / t, and the amount of the first demanganizing agent added is 8kg / t; The slag-making agent includes the following components in parts by weight: 15 parts of fluorite and 60 parts of quicklime; The first demanganizing agent comprises the following components in parts by weight: 60 parts of iron oxide, 20 parts of potassium feldspar, and 10 parts of dolomite; The scrap steel consists of the following components in weight percentage: C 0.113%, Si 0.052%, Mn 0.219%, P 0.03%, S0.035%, Cr 0.031%, Mo 0.002%, Ni 0.016%, Cu 0.014%, and the rest is Fe and other inevitable impurities; S2, refining: refining the smelting molten iron, adding the second demanganese agent, and soft blowing argon for 10 minutes to obtain refined molten iron; Wherein, based on the amount of scrap steel added, the amount of the second demanganeseizing agent added is 8kg / t; The second demanganizing agent comprises the following components in parts by weight: 60 parts of potassium feldspar, 20 parts of iron oxide scale, and 10 parts of dolomite; S3, water atomization treatment: After the refined molten iron is treated with water atomization, it is dried to obtain raw powder; Among them, during water atomization treatment, the atomization water pressure is 12MPa and the water flow rate is 140L / min; S4. Screening: The raw powder is screened by magnetic separation to obtain low manganese iron powder.
[0029] Example 2 A method for producing low manganese iron powder comprises the following steps: S1. Smelting: 1 t of scrap steel is smelted, slag-making agent and first demanganese agent are added, steel is tapped at 1800°C, and molten iron is obtained; Wherein, based on the amount of scrap steel added, the amount of slag-forming agent added is 75kg / t, and the amount of the first demanganizing agent added is 10kg / t; The slag-making agent includes the following components in parts by weight: 25 parts of fluorite and 90 parts of quicklime; The first demanganizing agent comprises the following components in parts by weight: 80 parts of iron oxide, 40 parts of potassium feldspar, and 20 parts of dolomite; The scrap steel consists of the following components in weight percentage: C 0.143%, Si 0.074%, Mn 0.246%, P 0.027%, S 0.030%, Cr 0.041%, Mo 0.006%, Ni 0.02%, Cu 0.023%, and the remainder is Fe and other inevitable impurities; S2, refining: refining the smelting molten iron, adding the second demanganizing agent, and soft blowing argon for 20 minutes to obtain refined molten iron; Wherein, the addition amount of the second demanganeseizing agent is 10kg / t based on the amount of scrap steel added; The second demanganizing agent comprises the following components in parts by weight: 80 parts of potassium feldspar, 40 parts of iron oxide scale, and 20 parts of dolomite; S3, water atomization treatment: After the refined molten iron is treated with water atomization, it is dried to obtain raw powder; Among them, during water atomization treatment, the atomization water pressure is 14.5MPa and the water flow rate is 160L / min; S4. Screening: The raw powder is screened by magnetic separation to obtain low manganese iron powder.
[0030] Example 3 The only difference between this embodiment and embodiment 2 is that, in this embodiment, the first demanganizing agent further includes 10 parts of cryolite.
[0031] Example 4 The only difference between this embodiment and embodiment 2 is that in this embodiment, the second demanganizing agent further includes 10 parts of cryolite.
[0032] Example 5 The only difference between this embodiment and embodiment 2 is that in this embodiment, the second demanganizing agent further includes 30 parts of cryolite.
[0033] Example 6 The only difference between this embodiment and embodiment 2 is that in this embodiment, the second demanganizing agent further includes 20 parts of cryolite.
[0034] Example 7 The only difference between this embodiment and embodiment 2 is that in this embodiment, the second demanganizing agent further includes 16 parts of cryolite.
[0035] Comparative Example 1 The only difference between this comparative example and Example 1 is that in this comparative example, the first demanganizing agent comprises the following components in parts by weight: 60 parts of potassium feldspar, 20 parts of iron oxide scale, and 10 parts of dolomite.
[0036] Comparative Example 2 The difference between this comparative example and Example 1 is that in this comparative example, the second demanganizing agent comprises the following components in parts by weight: 60 parts of iron oxide scale, 20 parts of potassium feldspar, and 10 parts of dolomite.
[0037] Comparative Example 3 The difference between this comparative example and Example 1 is that, in this comparative example, the first demanganizing agent comprises the following components in parts by weight: 60 parts of potassium feldspar, 20 parts of iron oxide, and 10 parts of dolomite; the second demanganizing agent comprises the following components in parts by weight: 60 parts of iron oxide, 20 parts of potassium feldspar, and 10 parts of dolomite.
[0038] Comparative Example 4 The difference between this comparative example and Example 1 is that, in this comparative example, smelting and refining include the following steps: S1. Smelting: 1 t of scrap steel is smelted, slag-making agent and the first demanganese agent are added, and steel is tapped at 1700°C. When tapping steel, the second demanganese agent is added to obtain molten iron; Wherein, based on the amount of scrap steel added, the amount of slag forming agent added is 50kg / t, the amount of the first demanganese agent added is 8kg / t, and the amount of the second demanganese agent added is 8kg / t; The slag-making agent includes the following components in parts by weight: 15 parts of fluorite and 60 parts of quicklime; The first demanganizing agent comprises the following components in parts by weight: 60 parts of iron oxide, 20 parts of potassium feldspar, and 10 parts of dolomite; The second demanganizing agent comprises the following components in parts by weight: 60 parts of potassium feldspar, 20 parts of iron oxide scale, and 10 parts of dolomite; The scrap steel consists of the following components in weight percentage: C 0.113%, Si 0.052%, Mn 0.219%, P 0.03%, S0.035%, Cr 0.031%, Mo 0.002%, Ni 0.016%, Cu 0.014%, and the rest is Fe and other inevitable impurities; S2. Refining: Refining the molten iron, and soft blowing argon for 10 minutes to obtain refined molten iron.
[0039] Comparative Example 5 The difference between this comparative example and Example 1 is that, in this comparative example, smelting and refining include the following steps: S1. Smelting: 1 t of scrap steel is smelted, slag-making agent and first demanganese agent are added, steel is tapped at 1700°C to obtain molten iron; Wherein, based on the amount of scrap steel added, the amount of slag-forming agent added is 50kg / t, and the amount of the first demanganizing agent added is 8kg / t; The slag-making agent includes the following components in parts by weight: 15 parts of fluorite and 60 parts of quicklime; The first demanganizing agent comprises the following components in parts by weight: 60 parts of iron oxide, 20 parts of potassium feldspar, and 10 parts of dolomite; The scrap steel consists of the following components in weight percentage: C 0.113%, Si 0.052%, Mn 0.219%, P 0.03%, S0.035%, Cr 0.031%, Mo 0.002%, Ni 0.016%, Cu 0.014%, and the rest is Fe and other inevitable impurities; S2. Refining: Refining the molten iron, and soft blowing argon for 10 minutes to obtain refined molten iron.
[0040] The manganese content of the iron powders produced in Examples 1 to 7 and Comparative Examples 1 to 5 was tested using a full-spectrum spark direct-reading spectrometer (model: SparkCCD 6500). The test results are shown in Table 1 below.
[0041] Table 1 Manganese content test results
[0042] The comparison between Example 1 and Comparative Examples 1 to 5 shows that the manganese content in the iron powder can be significantly reduced to less than 0.03wt% by adding a demanganese agent mainly composed of iron oxide scale and supplemented by potassium feldspar during smelting and a demanganese agent mainly composed of potassium feldspar and supplemented by iron oxide scale during refining.
[0043] Comparison between Examples 2-3 and 4 shows that when the second demanganizing agent further includes cryolite, the manganese content in the iron powder can be further reduced. Comparison between Examples 4-5 and 6-7 shows that when the weight ratio of potassium feldspar to cryolite in the second demanganizing agent is 4-5:1, it helps to further reduce the manganese content in the iron powder.
[0044] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for producing low manganese iron powder, characterized in that: The following steps are involved: S1. Smelting: Smelting the scrap steel, adding a slag-making agent and a first demanganeseizing agent, tapping the steel, and obtaining molten iron; S2, refining: refining the smelting molten iron, adding a second demanganizing agent, and soft blowing argon to obtain refined molten iron; S3: water atomization treatment: the refined molten iron is subjected to water atomization treatment and then dried to obtain raw powder; S4: Screening: The raw powder is screened by magnetic separation to obtain low manganese iron powder; The first demanganizing agent comprises the following components in parts by weight: 60-80 parts of iron oxide, 20-40 parts of potassium feldspar, and 10-20 parts of dolomite; The second demanganeseizing agent comprises the following components in parts by weight: 60-80 parts of potassium feldspar, 20-40 parts of iron oxide scale, and 10-20 parts of dolomite.
2. The method for producing low manganese iron powder according to claim 1, characterized in that: The slag-making agent comprises the following components in parts by weight: 15-25 parts of fluorite and 60-90 parts of quicklime.
3. The method for producing low manganese iron powder according to claim 1, characterized in that: The amount of the slag-forming agent added is 50-75 kg / t based on the amount of scrap steel added; and / or The amount of the first demanganizing agent added is 8-10 kg / t; and / or The addition amount of the second demanganizing agent is 8-10 kg / t.
4. The method for producing low manganese iron powder according to claim 1, characterized in that: The scrap steel consists of the following components in weight percentage: C 0.113%~0.143%, Si 0.052%~0.074%, Mn 0.219%~0.246%, P≤0.03%, S≤0.035%, Cr 0.031%~0.041%, Mo 0.002%~0.006%, Ni 0.016%~0.02%, Cu 0.014%~0.023%, and the rest is Fe and other inevitable impurities.
5. The method for producing low manganese iron powder according to claim 1, characterized in that: The second demanganizing agent further comprises 10 to 30 parts of cryolite.
6. The method for producing low manganese iron powder according to claim 5, characterized in that: The weight ratio of potassium feldspar to cryolite is 4-5:
1.
7. The method for producing low manganese iron powder according to claim 1, characterized in that: In step S1, when the steel is tapped, the temperature is 1700-1800°C.
8. The method for producing low manganese iron powder according to claim 1, characterized in that: In step S3, during the water atomization treatment, the atomization water pressure is 12-14.5 MPa and the water flow rate is 140-160 L / min.
9. A low manganese iron powder, characterized in that: Produced by the production method according to any one of claims 1 to 8.
10. Use of the low manganese iron powder produced by the production method of low manganese iron powder according to any one of claims 1 to 8 or the low manganese iron powder according to claim 9 in new energy batteries.