A method for preparing high coercivity SrFe 12 O 19 permanent magnet ferrite

Abstract

A method for preparing SrFe with high coercivity using iron oxide red, belonging to the technical field of the preparation of permanent magnet ferrite. The present invention uses iron oxide red as a raw material and prepares SrFe permanent magnet ferrite powder material with high coercivity by the method of "chemical activation - inorganic ion induction". The method is as follows: 1. Heat and keep iron oxide red, strontium carbonate and potassium hydroxide at a certain temperature for a period of time and then cool to room temperature; 2. Dispersedly wash the cooled material to obtain a solid product and then disperse it in water, and add inorganic salts for inorganic ion induction treatment; 3. Wash the above reaction material, dry it, keep it warm and then calcine it, and finally cool it to room temperature with the furnace to obtain SrFe permanent magnet ferrite powder. The SrFe permanent magnet ferrite prepared by the present invention solves the disadvantages of low coercivity and high sintering temperature of the ferrite pre-sintered material in the prior art, and realizes the re-value utilization of low-value iron oxide red. 12 O 19 permanent magnet ferrite, and belongs to the technical field of the preparation of permanent magnet ferrite. The present invention uses iron oxide red as a raw material and prepares SrFe permanent magnet ferrite powder material with high coercivity by the method of "chemical activation - inorganic ion induction". The method is as follows: 1. Heat and keep iron oxide red, strontium carbonate and potassium hydroxide at a certain temperature for a period of time and then cool to room temperature; 2. Dispersedly wash the cooled material to obtain a solid product and then disperse it in water, and add inorganic salts for inorganic ion induction treatment; 3. Wash the above reaction material, dry it, keep it warm and then calcine it, and finally cool it to room temperature with the furnace to obtain SrFe permanent magnet ferrite powder. The SrFe permanent magnet ferrite prepared by the present invention solves the disadvantages of low coercivity and high sintering temperature of the ferrite pre-sintered material in the prior art, and realizes the re-value utilization of low-value iron oxide red. 12 O 19 permanent magnet ferrite powder material, and the method is as follows: 1. Heat and keep iron oxide red, strontium carbonate and potassium hydroxide at a certain temperature for a period of time and then cool to room temperature; 2. Dispersedly wash the cooled material to obtain a solid product and then disperse it in water, and add inorganic salts for inorganic ion induction treatment; 3. Wash the above reaction material, dry it, keep it warm and then calcine it, and finally cool it to room temperature with the furnace to obtain SrFe permanent magnet ferrite powder. The SrFe permanent magnet ferrite prepared by the present invention solves the disadvantages of low coercivity and high sintering temperature of the ferrite pre-sintered material in the prior art, and realizes the re-value utilization of low-value iron oxide red. 12 O 19 permanent magnet ferrite powder. The SrFe permanent magnet ferrite prepared by the present invention solves the disadvantages of low coercivity and high sintering temperature of the ferrite pre-sintered material in the prior art, and realizes the re-value utilization of low-value iron oxide red. 12 O 19 permanent magnet ferrite solves the disadvantages of low coercivity and high sintering temperature of the ferrite pre-sintered material in the prior art, and realizes the re-value utilization of low-value iron oxide red.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of permanent magnet ferrite, and particularly relates to a method for preparing SrFe with high coercivity by using iron oxide red by-produced from steel mills. 12 O 19 permanent magnet ferrite. Background Art

[0002] SrFe 12 O 19 Permanent magnet ferrite has the advantages of rich raw materials, low manufacturing cost, high coercivity, good chemical stability, corrosion resistance, etc., and has been widely used in various fields, such as the rotor of brushless DC motors in the electronic field, the aircraft stealth technology in the microwave field, and the high-density magnetic recording materials in the data storage and recording field, etc. From the development trend in recent years, China has become the world's largest producer of permanent magnet ferrite materials, but the technical content and performance of most products are relatively low, and can only occupy the market of medium and low-grade products, and has not yet formed competitiveness in the market of high-grade products.

[0003] In the process of steel rolling, acid is generally used to pickling hot-rolled steel plates to remove the oxide layer and then cold rolling is carried out. The pickling process will produce pickling waste liquid containing iron. After a certain treatment of the pickling waste liquid, iron oxide red with extremely high Fe2O3 content can be obtained, and the iron oxide red produced by using the pickling waste liquid is mostly used for inorganic pigments and the production of permanent magnet ferrite. Among them, using iron oxide red to prepare SrFe 12 O 19 permanent magnet ferrite is one of the important ways to realize the value-added utilization of low-value iron oxide red at present.

[0004] At present, many large steel enterprises in China use iron oxide red by-produced from steel mills to produce SrFe 12 O 19 permanent magnet ferrite pre-sintered materials, but the magnetic properties of the ferrite pre-sintered materials produced are all relatively low, especially the coercivity, and there is also the disadvantage of high sintering temperature. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a method for preparing SrFe with high coercivity by using iron oxide red 12 O 19 permanent magnet ferrite. The purpose is to solve the problem of low coercivity of ferrite pre-sintered materials in the prior art, and prepare SrFe 12 O 19 permanent magnet ferrite powder materials with high coercivity by the method of "chemical activation - inorganic ion induction", and realize the value-added utilization of iron oxide red.

[0006] In order to achieve the above invention purpose, the technical scheme adopted by the present invention is as follows:

[0007] A method for preparing SrFe 12 O 19 permanent magnet ferrite using iron oxide red, comprising the following steps:

[0008] Step 1:

[0009] Using iron oxide red, strontium carbonate (SrCO3) and potassium hydroxide (KOH) as reaction raw materials, mixing and heating the above materials, then keeping warm and constant temperature, and after the heat preservation is completed, cooling with the furnace to room temperature;

[0010] Among them, the iron oxide red and SrCO3 are proportioned according to the molar ratio of Fe to Sr of (10 - 12):1, and the mass of KOH is 1 - 6 times the sum of the masses of iron oxide red and SrCO3;

[0011] Step 2:

[0012] Disperse the material cooled in Step 1 in deionized water, and wash with deionized water to obtain a solid product. Disperse the obtained solid product in deionized water, and then add an inorganic salt for inorganic ion induction treatment;

[0013] Step 3:

[0014] Wash the reaction material in Step 2 with deionized water, then place it in a drying oven for drying and heat preservation. Calcinate the dried reactant again, and finally cool with the furnace to room temperature to obtain SrFe 12 O 19 permanent magnet ferrite powder.

[0015] Furthermore, in Step 1, after the raw materials are mixed, place them in a corundum crucible and react in a muffle furnace. After the reaction materials are mixed, heat them to 400 - 700°C at a rate of 5 - 20°C / min, and keep warm and constant temperature for 3 - 7 h.

[0016] Furthermore, in Step 2, after dispersing the material cooled in Step 1, wash it with deionized water 2 - 5 times to obtain a solid product, and then disperse the obtained solid product in deionized water.

[0017] Furthermore, in Step 2, the inorganic salt is one or more of KBr, K2SO4, KNO3, KCl, KF. The molar ratio of the anion added in the inorganic salt to the molar amount of Fe in the iron oxide red is (0.2 - 9):1. When adding multiple inorganic salts, the multiple inorganic salts are in any ratio.

[0018] Further, the specific process of the inorganic ion induction treatment in step 2 is as follows: after adding inorganic salts, place it in a rotor and carry out the treatment in a thermostatic heating magnetic stirrer with heat collection. The constant temperature is 20-80°C, and the stirring time is 2-24 h. Its function is to adsorb inorganic ions on the surface of the iron oxide red and strontium carbonate solids treated with KOH to control the growth of their crystal structures.

[0019] Further, in step 3, the reaction materials in step 2 are washed 3-5 times with deionized water and then dried. The drying temperature is 40-80°C, and the heat preservation time is 6-24 h.

[0020] Further, in step 3, the reactants obtained after drying are calcined at 900-1150°C for 1-4 h, and the heating rate is 5-20°C / min.

[0021] Further, in step 3, the average particle size of the obtained SrFe 12 O 19 permanent magnet ferrite powder is 0.5-3 μm, and the coercivity is greater than 4800 Oe.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The inorganic ion induction treatment method adopted in the present invention can effectively improve the coercivity of the obtained SrFe 12 O 19 permanent magnet ferrite powder;

[0024] 2. The raw materials used in the present invention are the by-product iron oxide red from steel mills, realizing the value-added utilization of secondary resources, with strong operability, which is an effective way to obtain high-performance permanent magnet ferrites;

[0025] 3. The preparation method of the present invention has the characteristic of low temperature compared with the traditional solid-phase sintering to produce permanent magnet ferrites, which can save energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the room temperature hysteresis loop diagram of SrFe 12 O 19 obtained in Example 1 of the present invention;

[0027] Figure 2 It is the room temperature hysteresis loop diagram of SrFe 12 O 19 obtained in Example 2 of the present invention;

[0028] Figure 3 It is the room temperature hysteresis loop diagram of SrFe 12 O 19 obtained in Example 3 of the present invention;

[0029] Figure 4 For the room-temperature hysteresis loop diagram of SrFe obtained in Example 4 of the present invention 12 O 19 ;

[0030] Figure 5 For the room-temperature hysteresis loop diagram of SrFe obtained in Example 5 of the present invention 12 O 19 ;

[0031] Figure 6 For the room-temperature hysteresis loop diagram of SrFe obtained in Example 6 of the present invention 12 O 19 ;

[0032] Figure 7 For the room-temperature hysteresis loop diagram of SrFe obtained in Example 7 of the present invention 12 O 19 ;

[0033] Figure 8 For the room-temperature hysteresis loop diagram of SrFe obtained in Example 8 of the present invention 12 O 19 ;

[0034] Figure 9 For the room-temperature hysteresis loop diagram of SrFe obtained in Comparative Example 1 of the present invention 12 O 19 . Detailed implementation manners

[0035] A method for preparing high-coercivity SrFe 12 O 19 permanent ferrite by using by-product iron oxide red from a certain steel plant according to the present invention comprises the following steps:

[0036] The composition of the by-product iron oxide red from the certain steel plant is shown in Table 1:

[0037] Table 1 Composition of iron oxide red (mass fraction / %)

[0038]

[0039] When adding the iron oxide red, strontium carbonate, potassium hydroxide and inorganic salts in the examples, they are all in solid state.

[0040] Example 1

[0041] Step 1:

[0042] Using iron oxide red, SrCO3, and KOH as reaction raw materials, where the iron oxide red and SrCO3 are proportioned according to a molar ratio of Fe to Sr of 11:1, and the mass of KOH is 6 times the sum of the masses of iron oxide red and SrCO3. After mixing the above materials, place them in a corundum crucible and, in a muffle furnace, raise the temperature to 400 °C at a rate of 20 °C / min, and keep it at a constant temperature for 7 h. After the heat preservation is completed, cool it to room temperature with the furnace;

[0043] Step 2:

[0044] Disperse the material cooled in Step 1 in deionized water and wash it 3 times with deionized water to obtain a solid product. Disperse the obtained solid product in 100 mL of deionized water, then add KBr and K2SO, with an anion molar ratio of 1:3, to the beaker. The molar amount of anions added in the inorganic salt is in a ratio of 0.2:1 to the molar amount of Fe. Place a rotor and perform inorganic ion induction treatment on a heating magnetic stirrer with a constant temperature. The constant temperature is 20 °C and the stirring time is 24 h;

[0045] Step 3:

[0046] Wash the reaction material after the induction treatment in Step 2 5 times with deionized water and then place it in a drying oven for drying. The drying temperature is 40 °C and the heat preservation time is 24 h. Calcinate the dried reactant at 1150 °C for 4 h, with a heating rate of 20 °C / min, and finally cool it to room temperature with the furnace to obtain SrFe 12 O 19 permanent magnet ferrite powder. The SrFe 12 O 19 room temperature hysteresis loop diagram is as Figure 1 shown. The average particle size of the finally obtained SrFe 12 O 19 powder is 1.5 μm and the coercivity is 5504 Oe.

[0047] Example 2

[0048] Step 1:

[0049] Using iron oxide red, SrCO3, and KOH as reaction raw materials, where the iron oxide red and SrCO3 are proportioned according to a molar ratio of Fe to Sr of 10.5:1, and the mass of KOH is 1 times the sum of the masses of iron oxide red and SrCO3. After mixing the above materials, place them in a corundum crucible and, in a muffle furnace, raise the temperature to 500 °C at a rate of 10 °C / min, and keep it at a constant temperature for 3 h. After the heat preservation is completed, cool it to room temperature with the furnace;

[0050] Step 2:

[0051] Disperse the material cooled in Step 1 in deionized water and wash it 5 times with deionized water to obtain a solid product. Disperse the obtained solid product in 100 mL of deionized water, then add KCl and KNO3 with a molar ratio of anions of 1:1 to the beaker. The molar amount of anions added in the inorganic salt is in a ratio of 0.2:1 to the Fe molar amount. Place a rotor and conduct inorganic ion induction treatment on a thermostatic heating magnetic stirrer with a heating mantle. The constant temperature is 20°C, and the stirring time is 24 h;

[0052] Step 3:

[0053] Wash the reaction material aged in Step 2 5 times with deionized water and then place it in a drying oven for drying. The drying temperature is 40°C, and the heat preservation time is 24 h. Calcinate the dried reactant at 1000°C for 2 h with a heating rate of 10°C / min, and finally cool it to room temperature in the furnace to obtain SrFe 12 O 19 permanent magnet ferrite powder. The room temperature hysteresis loop of SrFe 12 O 19 is as shown in Figure 2 and finally the average particle size of the obtained SrFe 12 O 19 powder is 1.8 μm, and the coercivity is 5058 Oe.

[0054] Example 3

[0055] Step 1:

[0056] Use iron oxide red, SrCO3, and KOH as reaction raw materials, where iron oxide red and SrCO3 are proportioned according to a molar ratio of Fe to Sr of 10:1, and the mass of KOH is 2 times the sum of the masses of iron oxide red and SrCO3. Mix the above materials and place them in a corundum crucible. In a muffle furnace, heat it to 400°C at a rate of 10°C / min and keep it at a constant temperature for 6 h. After the heat preservation ends, cool it to room temperature in the furnace;

[0057] Step 2:

[0058] Disperse the material cooled in Step 1 in deionized water and wash it 5 times with deionized water to obtain a solid product. Disperse the obtained solid product in 100 mL of deionized water, then add KF to the beaker. The molar amount of anions added in the inorganic salt is in a ratio of 1:1 to the Fe molar amount. Place a rotor and conduct inorganic ion induction treatment on a thermostatic heating magnetic stirrer with a heating mantle. The constant temperature is 40°C, and the stirring time is 6 h;

[0059] Step 3:

[0060] The reaction materials after the induction treatment in Step 2 were washed 5 times with deionized water and then placed in a drying oven for drying. The drying temperature was 60 °C and the heat preservation time was 12 h. The dried reactants were calcined at 900 °C for 4 h with a heating rate of 5 °C / min, and finally cooled to room temperature in the furnace to obtain SrFe 12 O 19 permanent magnet ferrite powder. The room temperature hysteresis loop diagram of SrFe 12 O 19 is as shown in Figure 3 The finally obtained SrFe 12 O 19 powder has an average particle size of 3.0 μm and a coercivity of 4860 Oe.

[0061] Example 4

[0062] Step 1:

[0063] Take iron oxide red, SrCO3 and KOH as reaction raw materials. Among them, iron oxide red and SrCO3 are proportioned according to the molar ratio of Fe to Sr of 11.5:1, and the mass of KOH is 6 times the sum of the masses of iron oxide red and SrCO3. After mixing the above materials, place them in a corundum crucible, and in a muffle furnace, raise the temperature to 400 °C at a speed of 5 °C / min and keep it at a constant temperature for 7 h. After the heat preservation is over, cool it to room temperature in the furnace;

[0064] Step 2:

[0065] Disperse the materials cooled in Step 1 in deionized water and wash them 5 times with deionized water to obtain a solid product. Disperse the obtained solid product in deionized water, then add KCl to the beaker. The molar amount of the added anion in the inorganic salt is in a ratio of 9:1 to the molar amount of Fe. Put in a rotor and place it on a thermostatic heating magnetic stirrer for inorganic ion induction treatment. The constant temperature is 50 °C and the stirring time is 24 h;

[0066] Step 3:

[0067] The reaction materials after the induction treatment in Step 2 were washed 5 times with deionized water and then placed in a drying oven for drying. The drying temperature was 50 °C and the heat preservation time was 24 h. The dried reactants were calcined at 1150 °C for 3 h with a heating rate of 20 °C / min, and finally cooled to room temperature in the furnace to obtain SrFe 12 O 19 permanent magnet ferrite powder. The room temperature hysteresis loop diagram of SrFe 12 O 19 is as shown in Figure 4 The finally obtained SrFe 12 O 19 powder has an average particle size of 1.2 μm and a coercivity of 5420 Oe.

[0068] Example 5

[0069] Step 1:

[0070] Take iron oxide red, SrCO3 and KOH as reaction raw materials. Among them, iron oxide red and SrCO3 are proportioned according to the molar ratio of Fe to Sr of 11.2:1. The mass of KOH is 5.5 times the sum of the masses of iron oxide red and SrCO3. After mixing the above materials, place them in a corundum crucible. In a muffle furnace, heat up to 500 °C at a speed of 15 °C / min, and keep warm and constant temperature for 6 h. After the heat preservation is over, cool to room temperature with the furnace;

[0071] Step 2:

[0072] Disperse the material cooled in Step 1 in deionized water, and wash it 5 times with deionized water to obtain a solid product. Disperse the obtained solid product in deionized water, then add K2SO4 to the beaker. The molar amount of the anion added in the inorganic salt is in a ratio of 4.5:1 to the molar amount of Fe. Put in a rotor, and place it on a thermostatic heating magnetic stirrer with a collector for inorganic ion induction treatment. The constant temperature is 70 °C, and the stirring time is 18 h;

[0073] Step 3:

[0074] Wash the reaction material after the induction treatment in Step 2 5 times with deionized water, then place it in a drying oven for drying. The drying temperature is 80 °C, and the heat preservation time is 10 h. Calcinate the dried reactant at 1100 °C for 1.5 h, and the heating rate is 12 °C / min. Finally, cool to room temperature with the furnace to obtain SrFe 12 O 19 permanent magnet ferrite powder. The room temperature hysteresis loop diagram of SrFe 12 O 19 is as shown in Figure 5 shown. The average particle size of the finally obtained SrFe 12 O 19 powder is 2.2 μm, and the coercivity is 5276 Oe.

[0075] Example 6

[0076] Step 1:

[0077] Take iron oxide red, SrCO3 and KOH as reaction raw materials. Among them, iron oxide red and SrCO3 are proportioned according to the molar ratio of Fe to Sr of 10:1. The mass of KOH is 2.5 times the sum of the masses of iron oxide red and SrCO3. After mixing the above materials, place them in a corundum crucible. In a muffle furnace, heat up to 550 °C at a speed of 5 °C / min, and keep warm and constant temperature for 3.5 h. After the heat preservation is over, cool to room temperature with the furnace;

[0078] Step 2:

[0079] Disperse the material cooled in Step 1 in deionized water, and wash it 5 times with deionized water to obtain a solid product. Disperse the obtained solid product in deionized water, then add K2SO4 and KF with an anion molar ratio of 1:4 to the beaker. The molar amount of anions added in the inorganic salt is 8.5:1 compared to the Fe molar amount. Place a rotor and conduct inorganic ion induction treatment on a thermostatic heating magnetic stirrer with a heating mantle. The constant temperature is 75 °C, and the stirring time is 5 h;

[0080] Step 3:

[0081] Wash the reaction material after the induction treatment in Step 2 5 times with deionized water, then place it in a drying oven for drying. The drying temperature is 80 °C, and the heat preservation time is 14 h. Calcinate the dried reactant at 1025 °C for 2.2 h with a heating rate of 12.5 °C / min, and finally cool it to room temperature in the furnace to obtain SrFe 12 O 19 permanent magnet ferrite powder. The normal temperature hysteresis loop diagram of SrFe 12 O 19 is as shown in Figure 6 and the average particle size of the finally obtained SrFe 12 O 19 powder is 0.9 μm, and the coercivity is 5202 Oe.

[0082] Example 7

[0083] Step 1:

[0084] Use iron oxide red, SrCO3 and KOH as reaction raw materials. Among them, iron oxide red and SrCO3 are proportioned according to the molar ratio of Fe to Sr of 11.2:1, and the mass of KOH is 6 times the sum of the masses of iron oxide red and SrCO3. Mix the above materials and place them in a corundum crucible. In a muffle furnace, raise the temperature to 620 °C at a speed of 13 °C / min and keep it at a constant temperature for 3.6 h. After the heat preservation is over, cool it to room temperature in the furnace;

[0085] Step 2:

[0086] Disperse the material cooled in Step 1 in deionized water, and wash it 5 times with deionized water to obtain a solid product. Disperse the obtained solid product in deionized water, then add KNO3 and KF with an anion molar ratio of 3:1 to the beaker. The molar amount of anions added in the inorganic salt is 6:1 compared to the Fe molar amount. Place a rotor and conduct inorganic ion induction treatment on a thermostatic heating magnetic stirrer with a heating mantle. The constant temperature is 75 °C, and the stirring time is 16 h;

[0087] Step 3:

[0088] The reaction materials after the induction treatment in Step 2 were washed 5 times with deionized water and then placed in a drying oven for drying. The drying temperature was 45 °C and the heat preservation time was 24 h. The reactants obtained after drying were calcined at 975 °C for 4 h with a heating rate of 12.5 °C / min, and finally cooled to room temperature in the furnace to obtain SrFe 12 O 19 permanent magnet ferrite powder. The room-temperature hysteresis loop diagram of SrFe 12 O 19 is as shown in Figure 7 The SrFe 12 O 19 powder finally obtained has an average particle size of 0.7 μm and a coercivity of 5105 Oe.

[0089] Example 8

[0090] Step 1:

[0091] Take iron oxide red, SrCO3 and KOH as reaction raw materials. Among them, iron oxide red and SrCO3 are proportioned according to the molar ratio of Fe to Sr of 10.3:1, and the mass of KOH is 2 times the sum of the masses of iron oxide red and SrCO3. After mixing the above materials, place them in a corundum crucible and heat them to 700 °C at a rate of 5 °C / min in a muffle furnace, and keep the temperature constant for 3 h. After the heat preservation is over, cool it to room temperature in the furnace;

[0092] Step 2:

[0093] Disperse the materials cooled in Step 1 in deionized water and wash them 5 times with deionized water to obtain a solid product. Disperse the obtained solid product in deionized water, then add KBr and KF with a molar ratio of anions of 1:2 to the beaker. The molar amount of anions added in the inorganic salt is in a ratio of 2:1 to the molar amount of Fe. Put in a rotor and place it on a thermostatic heating magnetic stirrer for inorganic ion induction treatment. The constant temperature is 40 °C and the stirring time is 24 h;

[0094] Step 3:

[0095] The reaction materials after the induction treatment in Step 2 were washed 5 times with deionized water and then placed in a drying oven for drying. The drying temperature was 60 °C and the heat preservation time was 12 h. The reactants obtained after drying were calcined at 1150 °C for 2.5 h with a heating rate of 16 °C / min, and finally cooled to room temperature in the furnace to obtain SrFe 12 O 19 permanent magnet ferrite powder. The room-temperature hysteresis loop diagram of SrFe 12 O 19 is as shown in Figure 8 The SrFe 12 O 19The average particle size of the powder is 0.5 μm, and the coercivity is 4974 Oe.

[0096] Comparative Example 1

[0097] Step 1:

[0098] Take iron oxide red, SrCO3 and KOH as reaction raw materials. Among them, the iron oxide red and SrCO3 are proportioned according to the molar ratio of Fe to Sr of 10:1, and the mass of KOH is 3 times the sum of the masses of iron oxide red and SrCO3. After mixing the above materials, place them in a corundum crucible. In a muffle furnace, heat up to 600 °C at a rate of 7.5 °C / min and keep it at a constant temperature for 5 h. After the heat preservation is completed, cool it to room temperature with the furnace.

[0099] Step 2:

[0100] Disperse the material cooled in Step 1 in deionized water and wash it 5 times with deionized water to obtain a solid product. Disperse the obtained solid product in 100 mL of deionized water. Do not add any inorganic ions in this step. Put in a rotor and place it on a thermostatic heating magnetic stirrer for stirring. The constant temperature is 60 °C and the stirring time is 4 h.

[0101] Step 3:

[0102] Wash the reaction material after stirring in Step 2 5 times with deionized water and then place it in a drying oven for drying. The drying temperature is 70 °C and the heat preservation time is 10 h. Calcinate the dried reactant at 1100 °C for 1 h, and the heating rate is 5 °C / min. Finally, cool it to room temperature with the furnace to obtain SrFe 12 O 19 permanent magnet ferrite powder. The room temperature hysteresis loop diagram of SrFe 12 O 19 is as shown in Figure 9 shown. The average particle size of the finally obtained SrFe 12 O 19 powder is 3.0 μm, and the coercivity is 4478 Oe.

Claims

1. A method for preparing SrFe 12 O 19 permanent magnet ferrite using iron oxide red, characterized in that It includes the following steps: Step 1: Using iron oxide red, strontium carbonate, and potassium hydroxide as reaction raw materials, mix them and heat up, then keep warm and at a constant temperature. After the heat preservation ends, cool down to room temperature with the furnace; Step 2: Disperse the material cooled in Step 1 in deionized water, and wash it with deionized water to obtain a solid product. Disperse the obtained solid product in deionized water, and then add inorganic salts to the system for inorganic ion induction treatment; The molar ratio of the added amount of anions in the inorganic salt to the molar amount of Fe is (0.2~9):1; The inorganic salt is one or more of KBr, K2SO4, KNO3, KCl, KF. When adding multiple inorganic salts, the multiple inorganic salts are in any ratio; Step 3: The reaction materials from Step 2 are washed with deionized water, then placed in a drying oven for drying and heat preservation. The reactants obtained after drying are calcined again and cooled to room temperature in the furnace to obtain SrFe 12 O 19 permanent magnet ferrite powder.

2. A method for preparing high coercivity SrFe 12 O 19 permanent magnet ferrite using iron oxide red, characterized in that, In Step 1, the iron oxide red and strontium carbonate are proportioned according to the molar ratio of Fe to Sr of (10~12):1, and the mass of potassium hydroxide is 1~6 times the sum of the masses of iron oxide red and strontium carbonate.

3. A method for preparing high coercivity SrFe 12 O 19 permanent ferrite using iron oxide red, characterized in that, In Step 1, the raw materials are mixed and placed in a corundum crucible for reaction. After the reaction materials are mixed, they are heated to 400~700℃ at a rate of 5~20℃ / min, and kept warm and at a constant temperature for 3~7 h.

4. A method for preparing high coercivity SrFe 12 O 19 permanent ferrite using iron oxide red, characterized in that, In Step 2, after dispersing the material cooled in Step 1, wash it with deionized water 2~5 times to obtain a solid product.

5. A method for preparing high coercivity SrFe 12 O 19 permanent ferrite using iron oxide red, characterized in that, In Step 2, the constant temperature for the inorganic ion induction treatment is 20~80℃, and the stirring time is 2~24 h.

6. A method for preparing high coercivity SrFe 12 O 19 permanent magnet ferrite using iron oxide red, characterized in that In Step 3, wash the reaction materials in Step 2 with deionized water 3~5 times and then dry them. The drying temperature is 40~80℃, and the heat preservation time is 6~24 h.

7. A method for preparing SrFe 12 O 19 permanent magnet ferrite with high coercivity using iron oxide red, characterized in that In Step 3, the reactant obtained after drying is calcined at 900~1150℃ for 1~4 h, and the heating rate is 5~20℃ / min.

8. A method for preparing high coercivity SrFe 12 O 19 permanent magnet ferrite using iron oxide red, characterized in that, The obtained SrFe 12 O 19 powder has an average particle size of 0.5 - 3 μm and a coercive force greater than 4800 Oe.

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