CN114974875B - Preparation method of environment-friendly high-performance bonded permanent magnetic ferrite magnetic powder - Google Patents
Preparation method of environment-friendly high-performance bonded permanent magnetic ferrite magnetic powder Download PDFInfo
- Publication number
- CN114974875B CN114974875B CN202210763660.XA CN202210763660A CN114974875B CN 114974875 B CN114974875 B CN 114974875B CN 202210763660 A CN202210763660 A CN 202210763660A CN 114974875 B CN114974875 B CN 114974875B
- Authority
- CN
- China
- Prior art keywords
- performance
- mixture
- permanent magnetic
- bonded permanent
- powder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 229910000859 α-Fe Inorganic materials 0.000 title claims abstract description 35
- 238000002360 preparation method Methods 0.000 title claims abstract description 31
- 239000006247 magnetic powder Substances 0.000 title claims abstract description 30
- 239000002245 particle Substances 0.000 claims abstract description 115
- 239000000463 material Substances 0.000 claims abstract description 56
- 238000000034 method Methods 0.000 claims abstract description 44
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical compound [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 claims abstract description 43
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 37
- 230000007613 environmental effect Effects 0.000 claims abstract description 16
- 230000007935 neutral effect Effects 0.000 claims abstract description 12
- 239000000203 mixture Substances 0.000 claims description 76
- 239000000843 powder Substances 0.000 claims description 56
- 229910001631 strontium chloride Inorganic materials 0.000 claims description 45
- AHBGXTDRMVNFER-UHFFFAOYSA-L strontium dichloride Chemical compound [Cl-].[Cl-].[Sr+2] AHBGXTDRMVNFER-UHFFFAOYSA-L 0.000 claims description 45
- 238000005496 tempering Methods 0.000 claims description 40
- 238000011282 treatment Methods 0.000 claims description 40
- 238000000227 grinding Methods 0.000 claims description 29
- 238000002156 mixing Methods 0.000 claims description 29
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 28
- 239000007788 liquid Substances 0.000 claims description 27
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 claims description 24
- 239000011734 sodium Substances 0.000 claims description 23
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 22
- 238000007792 addition Methods 0.000 claims description 21
- 239000007864 aqueous solution Substances 0.000 claims description 20
- 230000008569 process Effects 0.000 claims description 20
- HRZFUMHJMZEROT-UHFFFAOYSA-L sodium disulfite Chemical compound [Na+].[Na+].[O-]S(=O)S([O-])(=O)=O HRZFUMHJMZEROT-UHFFFAOYSA-L 0.000 claims description 20
- BDAGIHXWWSANSR-NJFSPNSNSA-N hydroxyformaldehyde Chemical compound O[14CH]=O BDAGIHXWWSANSR-NJFSPNSNSA-N 0.000 claims description 19
- 229910000018 strontium carbonate Inorganic materials 0.000 claims description 19
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 18
- 238000000498 ball milling Methods 0.000 claims description 18
- 229910021538 borax Inorganic materials 0.000 claims description 18
- 239000004328 sodium tetraborate Substances 0.000 claims description 18
- 235000010339 sodium tetraborate Nutrition 0.000 claims description 18
- 238000001035 drying Methods 0.000 claims description 17
- 238000005187 foaming Methods 0.000 claims description 16
- 239000012535 impurity Substances 0.000 claims description 16
- 238000005453 pelletization Methods 0.000 claims description 16
- 229940001584 sodium metabisulfite Drugs 0.000 claims description 16
- 235000010262 sodium metabisulphite Nutrition 0.000 claims description 16
- 238000005406 washing Methods 0.000 claims description 16
- 238000003801 milling Methods 0.000 claims description 14
- 238000012545 processing Methods 0.000 claims description 13
- 238000005245 sintering Methods 0.000 claims description 13
- 229910000030 sodium bicarbonate Inorganic materials 0.000 claims description 12
- 235000017557 sodium bicarbonate Nutrition 0.000 claims description 12
- 239000002253 acid Substances 0.000 claims description 11
- 239000011651 chromium Substances 0.000 claims description 10
- 238000003756 stirring Methods 0.000 claims description 9
- 239000006185 dispersion Substances 0.000 claims description 8
- 230000000694 effects Effects 0.000 claims description 8
- 239000011343 solid material Substances 0.000 claims description 8
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 7
- 229910052804 chromium Inorganic materials 0.000 claims description 7
- 239000002994 raw material Substances 0.000 claims description 7
- 238000007873 sieving Methods 0.000 claims description 6
- 239000000243 solution Substances 0.000 claims description 6
- UIIMBOGNXHQVGW-DEQYMQKBSA-M Sodium bicarbonate-14C Chemical compound [Na+].O[14C]([O-])=O UIIMBOGNXHQVGW-DEQYMQKBSA-M 0.000 claims description 4
- 238000011049 filling Methods 0.000 claims description 4
- 238000000926 separation method Methods 0.000 claims description 3
- 239000004088 foaming agent Substances 0.000 claims description 2
- 230000001105 regulatory effect Effects 0.000 abstract description 3
- 238000010304 firing Methods 0.000 description 43
- 230000007246 mechanism Effects 0.000 description 11
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 6
- 230000007547 defect Effects 0.000 description 6
- 239000008188 pellet Substances 0.000 description 6
- 230000000630 rising effect Effects 0.000 description 6
- 230000002378 acidificating effect Effects 0.000 description 5
- 230000008859 change Effects 0.000 description 5
- 230000005389 magnetism Effects 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 239000000654 additive Substances 0.000 description 4
- 230000000996 additive effect Effects 0.000 description 4
- 238000003490 calendering Methods 0.000 description 4
- 238000009837 dry grinding Methods 0.000 description 4
- 238000001914 filtration Methods 0.000 description 4
- 238000001746 injection moulding Methods 0.000 description 4
- 238000003825 pressing Methods 0.000 description 4
- 238000001238 wet grinding Methods 0.000 description 4
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- 239000000853 adhesive Substances 0.000 description 3
- 230000001070 adhesive effect Effects 0.000 description 3
- 239000003513 alkali Substances 0.000 description 3
- 230000001276 controlling effect Effects 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 230000002829 reductive effect Effects 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- DWAQJAXMDSEUJJ-UHFFFAOYSA-M Sodium bisulfite Chemical compound [Na+].OS([O-])=O DWAQJAXMDSEUJJ-UHFFFAOYSA-M 0.000 description 2
- 238000005054 agglomeration Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 239000012752 auxiliary agent Substances 0.000 description 2
- 229910000416 bismuth oxide Inorganic materials 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- TYIXMATWDRGMPF-UHFFFAOYSA-N dibismuth;oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Bi+3].[Bi+3] TYIXMATWDRGMPF-UHFFFAOYSA-N 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 230000005415 magnetization Effects 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 238000005554 pickling Methods 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 235000010267 sodium hydrogen sulphite Nutrition 0.000 description 2
- 239000004289 sodium hydrogen sulphite Substances 0.000 description 2
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 1
- GSEJCLTVZPLZKY-UHFFFAOYSA-N Triethanolamine Chemical compound OCCN(CCO)CCO GSEJCLTVZPLZKY-UHFFFAOYSA-N 0.000 description 1
- 235000019013 Viburnum opulus Nutrition 0.000 description 1
- 244000071378 Viburnum opulus Species 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 229910002056 binary alloy Inorganic materials 0.000 description 1
- GRWVQDDAKZFPFI-UHFFFAOYSA-H chromium(III) sulfate Chemical compound [Cr+3].[Cr+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O GRWVQDDAKZFPFI-UHFFFAOYSA-H 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000001139 pH measurement Methods 0.000 description 1
- 229910001404 rare earth metal oxide Inorganic materials 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/0302—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity characterised by unspecified or heterogeneous hardness or specially adapted for magnetic hardness transitions
- H01F1/0311—Compounds
- H01F1/0313—Oxidic compounds
- H01F1/0315—Ferrites
Abstract
The application belongs to the technical field of bonded permanent magnetic ferrite materials, and discloses a preparation method of environment-friendly high-performance bonded permanent magnetic ferrite magnetic powder. The bonded permanent magnetic ferrite magnetic powder prepared by the method comprises Fe 2 O 3 ‑SrCO 3 ‑Na 2 B 4 O 7 Macroparticles of ternary system and Fe 2 O 3 ‑SrCO 3 The small particles of the binary material system have hexavalent chromium content not higher than 10ppm, water content not higher than 0.2%, pH being neutral, can completely pass through a 150-mesh screen, have excellent performance, can be mixed and regulated according to different bonding applications by different proportions of the large and small particles, and have the characteristics of environmental friendliness, low hexavalent chromium content, high magnetic performance, high cost performance, wide application range and the like.
Description
Technical Field
The application relates to the technical field of bonded permanent magnetic ferrite materials, in particular to a preparation method of environment-friendly high-performance bonded permanent magnetic ferrite magnetic powder.
Background
The bonded permanent magnetic ferrite magnetic powder is used for being combined with resin and is formed into a bonded magnet through extrusion, calendaring, injection molding and the like. The bonded permanent magnet has better magnetic performance than the sintered magnet, but has the defects of higher cost, high brittleness, easy cracking, low molding precision, secondary machining and the like because secondary sintering molding is needed; the bonded permanent magnetic ferrite magnetic powder can be combined with a plurality of different resins to prepare different types of bonded magnets, so that the defects of the sintered magnets can be effectively avoided, and the rapid development has been achieved in the 21 st century.
However, the bonded permanent magnetic ferrite has the defects of low magnetic performance and the like, and many improvements are made for the defects: as disclosed in chinese patent application CN202111271373.9, "a bonded ferrite magnetic powder for injection molding and a preparation method and application thereof", the bonded ferrite magnetic powder for injection molding is prepared by proportionally adding fine powder with an average particle size of 0.5-1.2 microns and coarse powder with an average particle size of 3.0-6.0 microns into ball milling, adding ball milling auxiliary agent with a water ratio of 0.5:0.5:10 and triethanolamine, ethylene glycol, wherein the magnetic powder contains bismuth oxide with a weight ratio of 0.2% -0.4%, and can be molded into flexible magnets; CN201610167551.6 (bonded ferrite magnetic powder and bonded magnet and preparation method thereof) discloses bonded ferrite magnetic powder with a main phase molecular formula of (Sr 1-xBax) O. nFe 2 O 3 Wherein, the molar ratio n=6.11-6.30,0.10 is less than or equal to x and less than or equal to 0.20, strontium chloride accounting for 0.5-4.0 percent of the weight of the iron oxide red raw material is added in the mixing process, the manufacturing steps comprise presintering, coarse crushing, grinding, drying and annealing, and the obtained bonded ferrite magnetic powder has higher compression density, better fluidity and magnet Br exceeding 310mT after injection.
In order to improve the performance of the bonded ferrite magnetic powder, the prior art often needs to undergo procedures such as secondary grinding, tempering treatment and the like, so that the problems of higher hexavalent chromium content, no environmental protection and the like are caused, or expensive materials such as rare earth oxide, bismuth oxide and the like are added for modification, so that the cost is higher, namely the prior art has the problems of cost control, environmental protection (hexavalent chromium is less than 15 ppm) and high magnetic performance which are difficult to consider.
Disclosure of Invention
The application aims to overcome the defects of the background art and provides a preparation method of environment-friendly high-performance bonded permanent magnetic ferrite magnetic powder, wherein the bonded permanent magnetic ferrite magnetic powder prepared by the method comprises Fe 2 O 3 -SrCO 3 -Na 2 B 4 O 7 Macroparticles of ternary system and Fe 2 O 3 -SrCO 3 Small particles of binary material system, the hexavalent chromium content of which is not higher than 10ppm, and the water content of which is not higher than0.2 percent of pH is neutral, can completely pass through a 150-mesh screen, has excellent performance, can be mixed and regulated according to different bonding applications by different proportions of particles, and has the characteristics of environmental friendliness, low hexavalent chromium content, high magnetic performance, high cost performance, wide application range and the like.
In order to achieve the purpose of the application, the preparation method of the environment-friendly high-performance bonded permanent magnetic ferrite magnetic powder comprises the following steps:
step 1, fe 2 O 3 -SrCO 3 -Na 2 B 4 O 7 Preparation of ternary material system large particles:
1-1 preparation of a mixture: iron oxide red (Fe) 2 O 3 ) Strontium carbonate (SrCO) 3 ) In terms of mole ratio Fe 2 O 3 : mixing SrO with the concentration of 5.5-6.2;
1-2 pelletizing: using a pelletizer to pelletize the mixture into pellets with the diameter of 6-12 mm, and adding hot borax (Na) in the pelletizing process 2 B 4 O 7 ) Aqueous solution and strontium chloride (SrCl) 2 ) An aqueous solution;
pelletizing is the process of forming pellets as the powder rolls snowballs in a rotating disk, and liquid is generally added to stabilize the pellets and have certain hardness. The traditional technology is only adding water, and the pelletizing process of the application adds borax (Na 2 B 4 O 7 ) Aqueous solution and strontium chloride (SrCl) 2 ) An aqueous solution.
1-3 sintering the ball material: the firing of the large particles is controlled in the section of deep firing degree: i.e. after iHc, the green compact density inflection point (highest point); in this step, large particles are granulated and hot borax (Na 2 B 4 O 7 ) The aqueous solution has a deep firing degree (the magnetic property only decreases after grinding treatment) so that the particles are nearly spherical, and the performance of a 30MPa compact is that the density is 3.0g/cm 3 -3.2g/cm 3 The iHc is between 1500Oe and 1200Oe, the Br is high, and the fluidity is good.
1-4, grinding the sintered ball material into coarse powder with the average particle diameter of 2.5-4.5 mu m; the coarse powder is further processed into fine powder with average particle size of 1.2-1.6 μm.
1-5 tempering: to achieve the best effectIf the fine powder is required to be subjected to 150-mesh dispersing treatment before treatment, the tempering temperature is adjusted between 650 ℃ and 900 ℃ to achieve the compact performance of 30MPa, namely the density of 3.2g/cm 3 -3.5g/cm 3 The iHc is between 3000Oe and 2700Oe, and Br is not lower than 1650Gs;
tempering control mechanism: the iHc and the tempering temperature form a positive correlation, and Br is firstly positive correlation and then is converted into a negative correlation after reaching a certain degree; the tempering temperature is controlled in the rising section of Br.
Step 2, fe 2 O 3 -SrCO 3 Preparation of binary material system small particles:
2-1 preparation of a mixture: iron oxide red (Fe) 2 O 3 ) Strontium carbonate (SrCO) 3 ) In terms of mole ratio Fe 2 O 3 ：SrCO 3 Mixing 5.3-6.0;
2-2 pelletizing: using a balling machine to make the mixture into balls with the diameter of 6mm-12mm, and adding normal-temperature strontium chloride (SrCl) in the balling process 2 ) An aqueous solution.
2-3 sintering the ball material: the firing of the small particles is controlled before the point of inflection (highest point) of the density of the compact in the section of shallow firing degree, i.e. the raised state of iHc. The firing control degree refers to the firing control mechanism (figure 1) "
The small particles are added with strontium chloride in the pelletizing process, the firing degree is shallow (the magnetism rises a little after grinding treatment), so that the particles are slender, the compact performance of 30MPa is that the density is 2.7g/cm 3 -2.9g/cm 3 The iHc is high and is not lower than 1800Oe, and the filling property is good.
2-4, grinding the sintered ball material into coarse powder with the average particle diameter of 1.5-2.5 mu m; the coarse powder is further processed into fine powder with average particle size of 0.6-1.0 μm.
2-5 tempering: in order to achieve the best effect, the fine powder needs to be subjected to 200-mesh dispersing treatment before treatment, and the tempering temperature is adjusted between 750 ℃ and 1000 ℃ so that the performance of the 30MPa pressed compact is that the density is 2.8g/cm 3 -3.0g/cm 3 The iHc reaches 3900Oe-3600Oe, and Br is 1500Gs-1600Gs.
Tempering control mechanism: the iHc and tempering temperature form a positive correlation, br is positive correlation, and after reaching a certain degree, the relationship is converted into a negative correlation; the tempering temperature is controlled in the rising section of Br.
Step 3, mixing: mixing the large particles prepared in the step 1 with the small particles prepared in the step 2 in proportion, wherein the mass ratio of the small particles is 10% -100%;
step 4, environmental protection treatment: and (3) processing the mixture obtained in the step (3) according to the following flow:
4-1 foaming, mixing the mixture and sodium metabisulfite (Na 2 S 2 O 5 ) Sodium bicarbonate (NaHCO) 3 ) Respectively adding into hot water with a weight of more than 3 times of the total weight of the mixture, and stirring and foaming at a water temperature of not less than 50deg.C (sodium bicarbonate is decomposed more rapidly at a temperature of more than 50deg.C);
sodium metabisulfite produces sodium bisulphite in water, and sodium bisulphite reacts with hexavalent chromium in an acidic medium to produce chromium sulfate: the reductive nature of sulfite and the strong oxidative nature of hexavalent chromium produce harmless trivalent chromium. Wherein sodium metabisulfite (Na) 2 S 2 O 5 ) The determination method of the adding amount is that the content of hexavalent chromium in the mixture is firstly determined, according to the reaction principle of sodium metabisulfite and hexavalent chromium,
4Cr 6+ +3Na 2 S 2 O 5 +6HCl→2Cr 2 (SO 4 ) 3 +6NaCl+H 2 O
the theoretical dosage of the sodium metabisulfite is 2.74 times of the mass of hexavalent chromium in the mixture [ sodium metabisulfite molecular weight 190 x 3/(chromium atomic weight 52 x 4) ], and the actual dosage is determined to be not less than 2.8 times of the mass of hexavalent chromium in the mixture by proper allowance consideration;
sodium bicarbonate (NaHCO) 3 ) The additive mainly plays roles of foaming, dispersing the mixture, promoting the dissolution of hexavalent chromium and the like, and the addition amount of the additive is 30-60% of the mass of the sodium metabisulfite.
4-2 acid washing, namely continuously and slowly adding hydrochloric acid (the reaction is required to be carried out under an acidic condition) into the foamed mixed feed liquid in a stirring state, so that harmful hexavalent chromium is converted into harmless trivalent chromium, simultaneously removing unreacted complete or excessive raw materials and sodium bicarbonate, adding the hydrochloric acid until the pH value of the mixed feed liquid is 2-3, finishing acid washing when the hexavalent chromium in the mixed feed liquid is completely converted or cannot be detected, and separating the feed liquid (adopting methods such as water washing, filter pressing or filtering) to reach the neutral pH value.
Wherein the separated waste liquid is based on Cr 2 (SO 4 ) 3 +6NaOH＝2Cr(OH) 3 <Precipitation>+3Na 2 SO 4 And the principle is that the liquid alkali is added for treatment and then is discharged in compliance, and the separated solid material enters the next flow.
4-3, drying and dispersing: drying the separated solid material, wherein the drying temperature is not higher than 600 ℃ (preventing the change of particle state and preventing the re-entrainment of hexavalent chromium), the water content is not higher than 0.2%, and dispersing the dried powder into powder which passes through 150 meshes (preventing agglomeration, improving fluidity and dispersibility) by using a dispersing machine;
step 5, removing impurities: physical separation methods, such as 120 mesh cyclone screen, are adopted to remove impurities and large particles, so as to ensure magnetic performance and magnetic field alignment.
In the technical scheme, the acid washing is used for removing excessive chloride ions or other impurities, preventing the bonded magnet from foaming and rotting during application, and the acid washing can be repeatedly performed.
Further, in some embodiments of the present application, the 1-2 hot borax (Na 2 B 4 O 7 ) The temperature of the aqueous solution is 80-95 ℃, and the addition amount of borax is 0.5-2.0% of the mass of the mixture.
Further, in some embodiments of the present application, the 1-2 strontium chloride (SrCl) 2 ) The water solution is at normal temperature, and the addition amount of the strontium chloride is 2-5% of the mass of the mixture.
Further, in some embodiments of the present application, the coarse grinding means in 1-4 is ball milling or Raymond or vibration milling; the further processing mode is one or more of ball milling (wet milling or dry milling), vibration milling, grinding and sieving.
Further, in some embodiments of the present application, the strontium chloride in 2-2 (SrCl) 2 ) The addition amount of the aqueous solution is 4-6% of the mass of the mixture.
Further, in some embodiments of the present application, the coarse grinding mode in 2-4 is ball milling or Raymond or vibration milling; the further processing mode is one or more of ball milling (wet milling or dry milling), vibration milling, grinding and sieving.
Further, in some embodiments of the present application, the specific mixing ratio in the step 3 may be adjusted according to the actual bonding application and performance requirement, and the mass ratio of the large particles to the small particles is as follows:
| macroparticle content | Small particle content | Characteristics of | Applicable purpose |
| 90％-50％ | 10％-50％ | Good compressibility, fluidity and comprehensive magnetic properties | Injection, injection molding |
| 70％-20％ | 30％-80％ | Good fluidity and extrudability, and comprehensive magnetic properties | Extrusion and calendaring |
| 30％-0％ | 70％-100％ | Good orientation and calendaring performance, and high iHc | Calendaring and extrudingOut of |
Compared with the prior art, the application has the following advantages:
(1) The specific purpose is achieved in the present application by controlling the specific composition and state of the particles.
The magnetic properties (Br, iHc) of the permanent magnetic ferrite magnetic powder mainly depend on the composition and microstructure, namely the processes of component system, firing control, powder control and the like.
Br=4pi×ls (saturation magnetization Jm) ×r/s (alignment degree) ×density, wherein:
pi ls (saturation magnetization Jm) is the intrinsic magnetic force of the material, and is constant;
the r/s alignment degree is related to the shape, the size and the distribution of magnetic powder particles, and the application is realized by introducing a sintering auxiliary agent (SrCl) 2 ) And control the firing of large particles of a deep ternary system and firing of small particles of a shallow ternary system, and achieve good orientation and high iHc.
The density is related to the firing degree, shape, size and distribution of the magnetic powder particles; the application achieves the compact density of 30MPa and high Br by controlling the large particle composition, the thickness-diameter ratio and the large particle collocation.
The higher the presence rate of the magnetic powder particle single domain particles is, the better the iHc, and the particle size is 0.6-1.5 mu m. The small particles of the application are produced by adopting Fe 2 O 3 -SrCO 3 Binary system and strontium chloride (SrCl) addition 2 ) The firing degree is controlled to be shallow and the length-diameter ratio is controlled, and the obtained ferrite magnetic powder particles are high-performance single domain particles with the main body of 0.6-1.0 um.
(2) The microstructure of the permanent magnetic ferrite magnetic powder is hexahedron, the length is obviously larger than the diameter, the long diameter and the similar size are called as the material with the same property, generally, the material with the different property has higher magnetic property due to good orientation, and the material with the same property has better mobility due to nearly spherical shape. The large particles of the application adopt Fe 2 O 3 -SrCO 3 -Na 2 B 4 O 7 Ternary system, hot borax (Na) is added in the pelletizing process 2 B 4 O 7 ) Particle-controllable aqueous solutionsSize and thickness, strontium chloride (SrCl) is added 2 ) The length of the particles can be controlled by the aqueous solution, and the firing degree can reach the length-diameter ratio and thickness of the particles, so that the particles have the orientation of the foreign materials and the fluidity of the like materials, and simultaneously have higher compression density, and the 30MPa pressed compact performance of the large particles is that the density is 3.2g/cm 3 -3.5g/cm 3 The iHc is between 3000Oe and 2700Oe, and Br is not lower than 1650Gs;
(3) The application adopts dispersion treatment before tempering, acid washing neutralization after tempering, water washing, low-temperature drying, physical screening treatment and a mode of mixing large and small particles; the magnetic material has the advantages of few impurities, adjustable grain composition, neutral pH value, no free chloride ions, no foaming and rotting during bonding use, and realization of both magnetic performance and processability.
(4) The application can be suitable for different application fields and performance requirements by controlling the powder characteristics, the magnetic characteristics and different proportions of large and small particles of the particles.
(5) The application has the advantages of low hexavalent chromium content, environmental friendliness, greatly improved processing characteristics (no foaming and rotting sheet) during bonding, especially the use of foaming agent, improved hexavalent chromium removal efficiency, reduced sodium metabisulfite consumption, and simplified subsequent water treatment. The hexavalent chromium content of the obtained product is not higher than 10ppm, the water content is not higher than 0.2%,100% of the product passes through 150 meshes, the pH is neutral, the performance is excellent, and the product can be mixed and adjusted according to different binding applications by different proportions of particles with different sizes.
Drawings
FIG. 1 is a specific firing control mechanism of the present application.
Detailed Description
The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application. It is to be understood that the following description is intended to be illustrative of the application and not restrictive.
The terms "comprising," "including," "having," "containing," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, step, method, article, or apparatus.
The conjunction "consisting of …" excludes any unspecified element, step or component. If used in a claim, such phrase will cause the claim to be closed, such that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of …" appears in a clause of the claim body, rather than immediately following the subject, it is limited to only the elements described in that clause; other elements are not excluded from the stated claims as a whole.
When an equivalent, concentration, or other value or parameter is expressed as a range, preferred range, or a range bounded by a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, when ranges of "1 to 5" are disclosed, the described ranges should be construed to include ranges of "1 to 4", "1 to 3", "1 to 2 and 4 to 5", "1 to 3 and 5", and the like. When a numerical range is described herein, unless otherwise indicated, the range is intended to include its endpoints and all integers and fractions within the range.
The singular forms include plural referents unless the context clearly dictates otherwise. "optional" or "any" means that the subsequently described event or event may or may not occur, and that the description includes both cases where the event occurs and cases where the event does not.
Approximating language, in the specification and claims, may be applied to modify an amount that would not limit the application to the specific amount, but would include an acceptable portion that would be close to the amount without resulting in a change in the basic function involved. Accordingly, the modification of a numerical value with "about", "about" or the like means that the present application is not limited to the precise numerical value. In some examples, the approximating language may correspond to the precision of an instrument for measuring the value. In the description and claims of the application, the range limitations may be combined and/or interchanged, if not otherwise specified, including all the sub-ranges subsumed therein.
The indefinite articles "a" and "an" preceding an element or component of the application are not limited to the requirement (i.e. the number of occurrences) of the element or component. Thus, the use of "a" or "an" should be interpreted as including one or at least one, and the singular reference of an element or component includes the plural reference unless the amount clearly dictates otherwise.
Furthermore, the descriptions of the terms "one embodiment," "some embodiments," "examples," "particular examples," or "some examples," etc., described below mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms are not necessarily for the same embodiment or example. The technical features of the respective embodiments of the present application may be combined with each other as long as they do not collide with each other.
The environment-friendly high-performance bonded permanent magnetic ferrite magnetic powder comprises Fe 2 O 3 -SrCO 3 -Na 2 B 4 O 7 Macroparticles of ternary system and Fe 2 O 3 -SrCO 3 Small particles of binary material system.
The hexavalent chromium content is not higher than 10ppm, the water content is not higher than 0.2%, the pH value is neutral, and the hexavalent chromium can completely pass through a 150-mesh screen.
The adhesive has excellent performance and can be mixed and adjusted according to different bonding applications by different proportions of the particles with different sizes.
The manufacturing method comprises the following steps:
step 1, fe 2 O 3 -SrCO 3 -Na 2 B 4 O 7 Preparation of ternary material system large particles:
(1) Preparing a mixture: iron oxide red (Fe) 2 O 3 ) Strontium carbonate (SrCO) 3 ) In terms of mole ratio Fe 2 O 3 : mixing SrO with the content of 5.5-6.2.
(2) Pelletizing: the mixture was formed into pellets of 6mm-12mm diameter using a pelletizer with B, S additions, wherein:
the B path is hot borax (Na) 2 B 4 O 7 ) The temperature of the aqueous solution is 80-95 ℃, and the addition amount of borax is 0.5-2.0% of the mass of the mixture;
s path is strontium chloride (SrCl) 2 ) The addition amount of the aqueous solution and the strontium chloride is 2 to 5 percent of the mass of the mixture.
(3) Firing the ball material: the firing of the large particles is controlled in the section of deep firing degree: i.e. after iHc, the green compact density inflection point (highest point);
borax is added in the sintering process of the large particles, the sintering degree is deep (the magnetism only decreases after grinding treatment), so that the particles are nearly spherical, and the performance of the pressed compact with the pressure of 30MPa is that the density is 3.0g/cm 3 -3.2g/cm 3 The iHc is between 1200Oe and 1500Oe, the Br is high, and the fluidity is good;
(4) Grinding the sintered ball material into coarse powder with the average grain diameter of 2.5-4.5 mu m by adopting ball milling, raymond or vibration milling and other modes; the coarse powder is further processed into fine powder with average particle size of 1.2-1.6 μm.
Further processing can be one or more of ball milling (wet milling or dry milling), vibration milling, grinding and sieving.
(5) Tempering: in order to achieve the best effect, 150 mesh dispersing treatment is needed to be carried out on the fine powder before the treatment, and the tempering temperature is adjusted between 650 ℃ and 900 ℃ so as to achieve that the performance iHc of the 30MPa pressed compact is between 3000Oe and 2700Oe, and Br is not lower than 1650Gs.
Tempering control mechanism: the iHc and tempering temperature form a positive correlation, br is positive correlation, and after reaching a certain degree, the relationship is converted into a negative correlation; the tempering temperature is controlled in the rising section of Br.
Step 2, fe 2 O 3 -SrCO 3 Preparation of binary material system small particles:
(1) preparing a mixture: iron oxide red (Fe) 2 O 3 ) Strontium carbonate (SrCO) 3 ) In terms of mole ratio Fe 2 O 3 : mixing SrO with the content of 5.3-6.0.
(2) Pelletizing: the mixture is formed into balls with the diameter of 6mm-12mm by using a balling machine, and S is added in the balling process, and the mixture is strontium chloride (SrCl) at normal temperature 2 ) The adding amount of the aqueous solution and the strontium chloride is 4-6% of the mass of the mixture.
(3) Firing the ball material: the firing of the small particles is controlled before the point of inflection (highest point) of the density of the compact in the section of shallow firing degree, i.e. the raised state of iHc. The firing control degree is according to a firing control mechanism (figure 1) "
The small particles are regulated by strontium, the firing degree is shallow (the magnetism will rise a little after grinding treatment) so that the particles are slender-30 MPa pressed compact performance is that the density is 2.7g/cm 3 -2.9g/cm 3 The iHc is not lower than 1800Oe, and the filling property is high.
(4) Grinding the sintered ball material into coarse powder with average grain size of 1.5-2.5 μm by ball milling, raymond or vibration milling; the coarse powder is further processed into fine powder with average particle size of 0.6-1.0 μm.
Further processing can be one or more of ball milling (wet milling or dry milling), vibration milling, grinding and sieving.
(5) Tempering: in order to achieve the best effect, 200 meshes of dispersion treatment is needed to be carried out on the fine powder before the treatment, the tempering temperature is adjusted between 750 ℃ and 1000 ℃ so as to achieve that the compact performance iHc of 30MPa reaches 3600Oe-3900Oe, and Br is 1500Gs-1600Gs.
Tempering control mechanism: the iHc and tempering temperature form a positive correlation, br is positive correlation, and after reaching a certain degree, the relationship is converted into a negative correlation; the tempering temperature is controlled in the rising section of Br.
Step 3, mixing: mixing the large particles prepared in the step 1 with the small particles prepared in the step 2 according to a certain proportion, wherein the mass ratio of the small particles is 10% -100%, and the specific proportion can be adjusted according to the actual bonding application and performance requirements.
Step 4, environmental protection treatment: the mixture is processed according to the following procedures:
procedure 1-foaming, mixing the mixture, sodium metabisulfite (Na 2 S 2 O 5 ) Sodium bicarbonate (NaHCO) 3 ) Respectively adding into hot water with a total weight of more than 3 times of the total weight of the mixture, and stirring thoroughly for foaming for about 30min at a water temperature of not less than 50deg.C (sodium bicarbonate rapidly decomposes at a temperature of more than 50deg.C);
wherein sodium metabisulfite (Na) 2 S 2 O 5 ) The determination method of the adding amount is that the content of hexavalent chromium in the mixture is firstly determined, according to the reaction principle of sodium metabisulfite and hexavalent chromium,
4Cr 6+ +3Na 2 S 2 O 5 +6HCl→2Cr 2 (SO 4 ) 3 +6NaCl+H 2 O，
the theoretical dosage of the sodium metabisulfite is 2.74 times of the mass of hexavalent chromium in the mixture [ sodium metabisulfite molecular weight 190 x 3/(chromium atomic weight 52 x 4) ], and the actual dosage is determined to be not less than 2.8 times of the mass of hexavalent chromium in the mixture by proper allowance consideration;
sodium bicarbonate (NaHCO) 3 ) The additive mainly plays roles of foaming, dispersing the mixture, promoting the dissolution of hexavalent chromium and the like, and the addition amount of the additive is 30-60% of the mass of the sodium metabisulfite.
And 2-pickling, namely continuously and slowly adding hydrochloric acid (the reaction is required to be carried out under an acidic condition) into the foamed mixed feed liquid in a stirring state, so that harmful hexavalent chromium is converted into harmless trivalent chromium, simultaneously removing unreacted complete or excessive raw materials and sodium bicarbonate, adding the hydrochloric acid until the pH value of the mixed feed liquid is 2-3, finishing pickling when the hexavalent chromium in the mixed feed liquid is completely converted or cannot be detected, and separating the feed liquid by adopting methods such as water washing, filter pressing or filtering to achieve neutral pH value.
Wherein the separated waste liquid is based on Cr 2 (SO 4 ) 3 +6NaOH＝2Cr(OH) 3 <Precipitation>+3Na 2 SO 4 Principle, liquid alkali and other treatments are added and then the mixture is discharged in compliance. The separated solid material enters the next flow.
Flow 3-drying and dispersing: and (3) drying the separated solid material, wherein the drying temperature is not higher than 600 ℃ (preventing the change of the particle state and preventing the re-entrainment of hexavalent chromium), and the water content is not higher than 0.2%. The dried powder was subjected to dispersion treatment by a disperser to pass through 150 mesh. Prevent agglomeration and improve fluidity and dispersibility.
Step 5, removing impurities: physical separation methods, such as 120 mesh cyclone screen, are adopted to remove impurities and large particles, so as to ensure magnetic performance and magnetic field alignment.
In the above technical scheme, preferably, the pH of the product is neutral, and the pH measurement method is as follows: 20g of powder and 50g of water, adding water to make up to 70ml after boiling for 5-10 min, boiling, and colorimetrically measuring the pH value to 6-8 by using pH test paper.
In the above technical scheme, preferably, hexavalent chromium of the product is not more than 10ppm.
In the above-described technical scheme, firing is controlled according to a specific "firing control mechanism (fig. 1)":
the large particles are subjected to joint adjustment of B-path borax and S-path strontium chloride, the firing is controlled in a 'deep firing degree' section, namely, after iHc and a compact density inflection point (highest point), the magnetism of the milled particles is monotonously reduced; process property, 30MPa compact property is density of 3.0g/cm 3 -3.2g/cm 3 The iHc is between 1200Oe and 1500Oe, the Br is high, and the fluidity is good;
the small particles are adjusted by S paths of strontium chloride, the firing is controlled in a section with shallow firing degree, namely, the iHc rising situation is controlled, and the magnetism rises a little before the density inflection point (highest point) of the pressed compact after grinding treatment; process property, 30MPa compact property is density of 2.7g/cm 3 -2.9g/cm 3 The iHc is not lower than 1800Oe, and the filling property is high.
The B path in the preparation method means that hot borax (Na) 2 B 4 O 7 ) The method comprises the steps of carrying out a first treatment on the surface of the The S path means adding strontium chloride (SrCl) during the pelletizing process 2 )。
Example 1
An environment-friendly high-performance bonded permanent magnetic ferrite magnetic powder comprises Fe 2 O 3 -SrCO 3 -Na 2 B 4 O 7 Macroparticles of ternary system and Fe 2 O 3 -SrCO 3 Small particles, large and small particles of the binary material system have the following technical characteristics:
the manufacturing method comprises the following steps:
step 1, fe 2 O 3 -SrCO 3 -Na 2 B 4 O 7 Preparation of ternary material system large particles:
1-1 preparation of a mixture: iron oxide red (Fe) 2 O 3 ) Strontium carbonate (SrCO) 3 ) In terms of mole ratio Fe 2 O 3 : mixing SrO with the concentration of 5.5;
1-2 pelletizing: the mixture was formed into pellets of 6mm diameter using a pelletizer with B, S additions, wherein:
the B path is hot borax (Na) 2 B 4 O 7 ) The water solution is at 80 ℃, and the borax addition amount is 0.5% of the mass of the mixture;
s path is strontium chloride (SrCl) 2 ) The addition amount of the aqueous solution and the strontium chloride is 2% of the mass of the mixture;
1-3 sintering the ball material: the firing of the large particles is controlled in the section of deep firing degree: i.e. after iHc, the green compact density inflection point (highest point);
1-4, grinding the sintered ball material into coarse powder with the average grain diameter of 2.5 mu m by adopting ball milling, raymond or vibration milling and other modes; the coarse powder was further processed into fine powder having an average particle diameter of 1.2. Mu.m.
1-5 tempering: in order to achieve the best effect, 150 mesh dispersing treatment is required to be carried out on the fine powder before treatment; tempering control mechanism: the iHc and the tempering temperature are in positive correlation, br is first in positive correlation to a certain extentThen converting into a negative correlation; the tempering temperature is controlled at the rising section of Br; the tempering temperature is adjusted between 650 ℃ and 900 ℃ so that the performance of the 30MPa pressed compact is as follows: density 3.2g/cm 3 iHc is not lower than 1650Gs at 3000Oe and Br;
step 2, fe 2 O 3 -SrCO 3 Preparation of binary material system small particles:
2-1 preparation of a mixture: iron oxide red (Fe) 2 O 3 ) Strontium carbonate (SrCO) 3 ) In terms of mole ratio Fe 2 O 3 : mixing SrO with the concentration of 5.3;
2-2 pelletizing: the mixture is formed into balls with the diameter of 6mm by using a balling machine, and S is added in the balling process, and the mixture is strontium chloride (SrCl) at normal temperature 2 ) The adding amount of the aqueous solution and the strontium chloride is 4% of the mass of the mixture;
2-3 sintering the ball material: the firing of the small particles is controlled before the point of inflection (highest point) of the density of the compact in the section of shallow firing degree, i.e. the raised state of iHc. The firing control degree refers to the firing control mechanism (figure 1) "
2-4, grinding the sintered ball material into coarse powder with the average grain diameter of 1.5 mu m by adopting ball milling, raymond or vibration milling and other modes; the coarse powder was further processed into fine powder having an average particle diameter of 0.6. Mu.m.
2-5 tempering: in order to achieve the best effect, 200 meshes of dispersion treatment is needed to be carried out on the fine powder before the treatment, and the tempering temperature is adjusted between 750 ℃ and 1000 ℃ so that the performance of the 30MPa pressed compact is as follows: density 2.8/cm 3 、iHc3900Oe、Br1500Gs。
Step 3, mixing: mixing the large particles prepared in the step 1 with the small particles prepared in the step 2 according to a certain proportion, wherein the mass ratio of the small particles is 10% -100%, and the specific proportion can be adjusted according to the actual bonding application and performance requirements.
Step 4, environmental protection treatment: the mixture is processed according to the following procedures:
4-1 foaming, mixing the mixture and sodium metabisulfite (Na 2 S 2 O 5 ) Sodium bicarbonate (NaHCO) 3 ) Respectively adding into hot water with a water temperature of not lower than 50deg.C and 3 times of total weight of the mixtureStirring thoroughly, foaming for about 30min;
wherein the input amount of the mixture is 1000kg, and the hexavalent chromium content is 200ppm; sodium metabisulfite (Na) 2 S 2 O 5 ) The actual dosage of (2) is 0.56kg (1000 x 200/1000000 x 2.8); sodium bicarbonate (NaHCO) 3 ) The addition amount of (C) was 0.17kg.
4-2 acid washing, namely continuously and slowly adding hydrochloric acid (the reaction is required to be carried out under an acidic condition) into the foamed mixed feed liquid in a stirring state, so that harmful hexavalent chromium is converted into harmless trivalent chromium, simultaneously removing unreacted complete or excessive raw materials and sodium bicarbonate, adding the hydrochloric acid until the pH value of the mixed feed liquid is 2-3, finishing acid washing when the hexavalent chromium in the mixed feed liquid is completely converted or cannot be detected, and separating the feed liquid by adopting methods such as water washing, filter pressing or filtering to achieve neutral pH value.
Wherein the separated waste liquid is based on Cr 2 (SO 4 ) 3 +6NaOH＝2Cr(OH) 3 <Precipitation>+3Na 2 SO 4 Principle, liquid alkali and other treatments are added and then the mixture is discharged in compliance. The separated solid material enters the next flow.
4-3, drying and dispersing: and (3) drying the separated solid material, wherein the drying temperature is not higher than 600 ℃ (preventing the change of the particle state and preventing the re-entrainment of hexavalent chromium), and the water content is not higher than 0.2%. The dried powder was subjected to dispersion treatment by a disperser to pass through 150 mesh.
Step 5, removing impurities: the product performance obtained by removing impurities and large particles through a 120-mesh cyclone sieve is as follows.
The grain composition, fluidity and magnetic property of the material are adjustable, the hexavalent chromium content is 0-10ppm, the water content is 0.1%, the pH is 7 (free chloride ions are not contained), and the material can completely pass through a 150-mesh screen (less impurities). When in subsequent bonding use, the adhesive is easy to disperse and not agglomerate; the bonded magnet has no bubbles and no sheet rot; the environmental protection performance, the magnetic performance and the processing performance are realized.
Example 2
An environment-friendly high-performance bonded permanent magnetic ferrite magnetic powder comprises Fe 2 O 3 -SrCO 3 -Na 2 B 4 O 7 Macroparticles of ternary system and Fe 2 O 3 -SrCO 3 Small particles, large and small particles of the binary material system have the following technical characteristics:
the manufacturing method comprises the following steps:
step 1, fe 2 O 3 -SrCO 3 -Na 2 B 4 O 7 Preparation of ternary material system large particles:
1-1 preparation of a mixture: iron oxide red (Fe) 2 O 3 ) Strontium carbonate (SrCO) 3 ) In terms of mole ratio Fe 2 O 3 : mixing SrO with the concentration of 6.2;
1-2 pelletizing: the mixture was formed into pellets of 12mm diameter using a pelletizer with B, S additions, wherein:
the B path is hot borax (Na) 2 B 4 O 7 ) The water solution is at 95 ℃, and the borax addition amount is 2.0% of the mass of the mixture;
s path is strontium chloride (SrCl) 2 ) The addition amount of the aqueous solution and the strontium chloride is 5% of the mass of the mixture;
1-3 sintering the ball material: the firing of the large particles is controlled in the section of deep firing degree: i.e. after iHc, the green compact density inflection point (highest point);
1-4, grinding the sintered ball material into coarse powder with the average grain diameter of 4.5 mu m by adopting ball milling, raymond or vibration milling and other modes; the coarse powder was further processed into fine powder having an average particle diameter of 1.6. Mu.m.
1-5 tempering: tempering temperature of 650 °cAdjusting the temperature between 900 ℃ to ensure that the performance of the 30MPa pressed compact is as follows: density 3.5g/cm 3 iHc at 2700Oe, br no less than 1850Gs;
step 2, fe 2 O 3 -SrCO 3 Preparation of binary material system small particles:
2-1 preparation of a mixture: iron oxide red (Fe) 2 O 3 ) Strontium carbonate (SrCO) 3 ) In terms of mole ratio Fe 2 O 3 : mixing SrO with the concentration of 6.0;
2-2 pelletizing: the mixture is formed into balls with the diameter of 12mm by using a balling machine, and S is added in the balling process, and the mixture is strontium chloride (SrCl) at normal temperature 2 ) The adding amount of the aqueous solution and the strontium chloride is 6% of the mass of the mixture;
2-3 sintering the ball material: the firing of the small particles is controlled to be "shallow in firing degree", that is, before the point of inflection (highest point) of the density of the compact in the state where iHc rises. The firing control degree refers to the firing control mechanism (figure 1) "
2-4, grinding the sintered ball material into coarse powder with the average grain diameter of 2.5 mu m by adopting ball milling, raymond or vibration milling and other modes; the coarse powder was further processed into fine powder having an average particle diameter of 1.0. Mu.m.
2-5 tempering: the tempering temperature is adjusted between 750 ℃ and 1000 ℃ so that the performance of the 30MPa pressed compact is as follows: density 3.0/cm 3 、iHc3600Oe、Br1600Gs。
Step 3, mixing: mixing the large particles prepared in the step 1 with the small particles prepared in the step 2 according to a certain proportion, wherein the mass ratio of the small particles is 10% -100%, and the specific proportion can be adjusted according to the actual bonding application and performance requirements.
Step 4, environmental protection treatment: the mixture is processed according to the following procedures:
4-1 foaming, mixing the mixture and sodium metabisulfite (Na 2 S 2 O 5 ) Sodium bicarbonate (NaHCO) 3 ) Respectively putting the materials into hot water with the weight being 3.6 times of the total weight of the mixture, and fully stirring and foaming for about 30min at the water temperature of 55 ℃;
wherein the input amount of the mixture is 2000kg, and the hexavalent chromium content of the mixture is 150ppm; sodium metabisulfite (Na) 2 S 2 O 5 ) The actual dosage of (1.50 kg) (2000 x 150/1000000 x 5 times); sodium bicarbonate (NaHCO) 3 ) The addition amount of (C) was 0.9kg.
4-2 acid washing, namely continuously and slowly adding hydrochloric acid (the reaction is required to be carried out under an acidic condition) into the foamed mixed material liquid in a stirring state until the pH value of the mixed material liquid is 2-3, finishing acid washing when hexavalent chromium in the mixed material liquid is completely converted or cannot be detected, and separating the material liquid by adopting methods such as water washing, filter pressing or filtering to achieve neutral pH value.
4-3, drying and dispersing: and (3) drying the separated solid material, wherein the drying temperature is not higher than 600 ℃ (preventing the change of the particle state and preventing the re-entrainment of hexavalent chromium), and the water content is not higher than 0.2%. The dried powder was subjected to dispersion treatment by a disperser to pass through 150 mesh.
Step 5, removing impurities: the product performance obtained by removing impurities and large particles through a 120-mesh cyclone sieve is as follows.
The grain composition, fluidity and magnetic property of the material are adjustable, the hexavalent chromium content is 0-7ppm, the water content is 0.1%, the pH is 7 (free chloride ions are not contained), and the material can completely pass through a 150-mesh screen (less impurities). When in subsequent bonding use, the adhesive is easy to disperse and not agglomerate; the bonded magnet has no bubbles and no sheet rot; the environmental protection performance, the magnetic performance and the processing performance are realized.
Example 3
The environment-protecting high-performance bonded permanent magnetic ferrite magnetic powder is prepared with the following large and small particles, which are obtained through specific composition and sintering control, and through the processes of environment protection and the like.
The manufacturing steps comprise: preparation of large particles, preparation of small particles, mixing of large particles and small particles, environmental protection treatment and impurity removal (except for the parameters shown in the above table, other specific preparation methods are the same as in example 2).
The hexavalent chromium content is 1ppm (meeting the international environmental protection requirement), the pH is neutral (free chloride ion is not present), and the density is 3.7g/cm 3 Average particle size 1.26. Mu.m; the density is high, the fluidity is good, and the bonding magnet can be well filled in resin during bonding, the Br of the obtained bonding magnet can reach above 3100Gs, the iHc can reach 3000Oe, the foaming and rotting of the bonding magnet can be avoided, and the environment-friendly effect, the magnetic performance and the processability are realized.
Comparative example 1
The large particles are added without B paths, and the other processes are the same as in the embodiment 3, and the environment-friendly high-performance bonded permanent magnetic ferrite magnetic powder is prepared by mixing the following large particles and small particles obtained through specific composition and firing control, and then performing environment-friendly treatment and the like.
The properties of the obtained product were as follows.
Comparative example 2
The environmental protection treatment of step 4 is not carried out, and other processes are the same as those of the embodiment 3.
The defects are as follows: hexavalent chromium content of 150ppm can not meet the field with environmental protection requirements; at pH 5, there may be free chloride ions or unreacted excess material, and 30% of the magnet flakes will foam and 10% will rot during bonding applications.
It will be readily appreciated by those skilled in the art that the foregoing is merely illustrative of the present application and is not intended to limit the application, but any modifications, equivalents, improvements or the like which fall within the spirit and principles of the present application are intended to be included within the scope of the present application.
Claims (8)
1. The preparation method of the environment-friendly high-performance bonded permanent magnetic ferrite powder is characterized by comprising the following steps of:
step 1, fe 2 O 3 -SrCO 3 - Na 2 B 4 O 7 Preparation of ternary material system large particles:
1-1 preparation of a mixture: iron oxide red and strontium carbonate as raw materials are mixed according to mol ratio of Fe 2 O 3 : mixing SrO with the concentration of 5.5-6.2;
1-2 pelletizing: using a balling machine to make the mixture into balls with the diameter of 6mm-12mm, and adding hot borax water solution and strontium chloride water solution in the balling process;
1-3 sintering the ball material: the particles are nearly spherical, the performance of the pressed compact of 30MPa is that the density is 3.0g/cm 3 -3.2 g/cm 3 The iHc is between 1500Oe and 1200Oe, the Br is high, and the fluidity is good;
1-4, grinding the sintered ball material into coarse powder with the average particle diameter of 2.5-4.5 mu m; further processing the coarse powder into fine powder with average particle diameter of 1.2-1.6 μm;
tempering 1-5;
step 2, fe 2 O 3 -SrCO 3 Preparation of binary material system small particles:
2-1 preparation of a mixture: iron oxide red and strontium carbonate as raw materials are mixed according to mol ratio of Fe 2 O 3 ：SrCO 3 Mixing 5.3-6.0;
2-2 pelletizing: using a balling machine to make the mixture into balls with the diameter of 6mm-12mm, and adding normal-temperature strontium chloride aqueous solution in the balling process;
2-3 sintering the ball material: so that the particle is in a slender shape, the compact performance of 30MPa is that the density is 2.7g/cm 3 -2.9 g/cm 3 The iHc is high and is not lower than 1800Oe, and the filling property is good;
2-4, grinding the sintered ball material into coarse powder with the average particle diameter of 1.5-2.5 mu m; further processing the coarse powder into fine powder with average particle diameter of 0.6-1.0 μm;
tempering 2-5;
step 3, mixing: mixing the large particles prepared in the step 1 with the small particles prepared in the step 2 in proportion, wherein the mass ratio of the small particles is 10% -100%;
step 4, environmental protection treatment: and (3) processing the mixture obtained in the step (3) according to the following flow:
4-1 foaming, namely respectively adding the mixture, sodium metabisulfite and sodium bicarbonate into hot water with the weight being more than 3 times of the total weight of the mixture, and fully stirring and foaming the mixture at the water temperature of not lower than 50 ℃;
4-2 acid washing, namely continuously and slowly adding hydrochloric acid into the foamed mixed feed liquid in a stirring state to convert harmful hexavalent chromium into harmless trivalent chromium, simultaneously removing unreacted complete or excessive raw materials and sodium bicarbonate, adding the hydrochloric acid until the pH value of the mixed feed liquid is 2-3, finishing acid washing when the hexavalent chromium in the mixed feed liquid is completely converted or cannot be detected, and separating the feed liquid until the pH value is neutral;
4-3, drying and dispersing: drying the separated solid material;
step 5, removing impurities;
in the step 1-5, tempering is carried out to achieve the best effect, 150 mesh dispersion treatment is carried out on the fine powder before treatment, and the tempering temperature is adjusted between 650 ℃ and 900 ℃ so as to achieve the compact performance iHc of 30MPa in 3000Oe-2700Oe and Br not lower than 1650Gs;
in the step 2-5, tempering is carried out to achieve the best effect, 200 mesh dispersion treatment is carried out on the fine powder before treatment, and the tempering temperature is adjusted between 750 ℃ and 1000 ℃ so that the performance iHc of the 30MPa pressed compact reaches 3900Oe-3600Oe and the Br reaches 1500Gs-1600 Gs;
the iHc is referred to as intrinsic coercivity.
2. The method for preparing environment-friendly high-performance bonded permanent magnetic ferrite powder according to claim 1, wherein sodium bicarbonate in the 4-1 is used as a foaming agent, and the dosage of the sodium metabisulfite is 30% -60% of the addition amount.
3. The method for preparing environment-friendly high-performance bonded permanent magnetic ferrite powder according to claim 1, wherein the drying temperature in 4-3 is not higher than 600 ℃, the water content is not higher than 0.2%, and the dried powder is dispersed and treated by a dispersing machine to pass through 150 meshes; the step 5 of impurity removal adopts a physical separation method, and large particles are removed through a 120-mesh cyclone sieve to ensure magnetic performance and magnetic field alignment degree.
4. The method for preparing environment-friendly high-performance bonded permanent magnetic ferrite powder according to claim 1, wherein the temperature of the hot borax aqueous solution in 1-2 is 80-95 ℃, and the borax addition amount is 0.5% -2.0% of the mass of the mixture.
5. The method for preparing environment-friendly high-performance bonded permanent magnetic ferrite powder according to claim 1, wherein the aqueous solution of strontium chloride in 1-2 is at normal temperature, and the addition amount of the strontium chloride is 2% -5% of the mass of the mixture.
6. The method for preparing environment-friendly high-performance bonded permanent magnetic ferrite magnetic powder according to claim 1, wherein the coarse grinding mode in 1-4 is ball milling, raymond or vibration grinding; the further processing mode is one or more of ball milling, vibration milling, grinding and sieving.
7. The method for preparing environment-friendly high-performance bonded permanent magnetic ferrite powder according to claim 1, wherein the addition amount of the strontium chloride aqueous solution in the 2-2 is 4% -6% of the mass of the mixture.
8. The method for preparing environment-friendly high-performance bonded permanent magnetic ferrite magnetic powder according to claim 1, wherein the coarse grinding mode in 2-4 is ball milling, raymond or vibration grinding; the further processing mode is one or more of ball milling, vibration milling, grinding and sieving.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210763660.XA CN114974875B (en) | 2022-06-30 | 2022-06-30 | Preparation method of environment-friendly high-performance bonded permanent magnetic ferrite magnetic powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210763660.XA CN114974875B (en) | 2022-06-30 | 2022-06-30 | Preparation method of environment-friendly high-performance bonded permanent magnetic ferrite magnetic powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114974875A CN114974875A (en) | 2022-08-30 |
| CN114974875B true CN114974875B (en) | 2023-11-14 |
Family
ID=82967086
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210763660.XA Active CN114974875B (en) | 2022-06-30 | 2022-06-30 | Preparation method of environment-friendly high-performance bonded permanent magnetic ferrite magnetic powder |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114974875B (en) |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4786430A (en) * | 1987-01-24 | 1988-11-22 | Basf Aktiengesellschaft | Method for producing hexagonal ferrites |
| WO2004018716A1 (en) * | 2002-08-21 | 2004-03-04 | Nippon Steel Corporation | Method of granulating sintering material for iron manufacturing |
| EP2244269A1 (en) * | 2006-03-10 | 2010-10-27 | Hitachi Metals, Ltd. | Method for producing sintered ferrite magnet |
| CN102351525A (en) * | 2011-07-19 | 2012-02-15 | 吕佳佳 | Manufacture method of permanent magnet ferrite material powder for injection molding |
| CN102424583A (en) * | 2011-09-05 | 2012-04-25 | 吕佳佳 | Magnetic powder for bonding hard ferrite |
| CN102992744A (en) * | 2011-09-13 | 2013-03-27 | 张连墩 | M-type strontium ferrite powder for injection molding bonded permanent magnet and preparation process of M-type strontium ferrite powder |
| WO2014017637A2 (en) * | 2012-07-27 | 2014-01-30 | Tdk株式会社 | MANUFACTURING METHOD FOR Sr FERRITE PARTICLES FOR SINTERED MAGNET, AND MANUFACTURING METHOD FOR Sr FERRITE SINTERED MAGNET |
| JP2014159541A (en) * | 2013-01-22 | 2014-09-04 | Sekisui Chem Co Ltd | Thermally expandable fire-resistant resin composition |
| WO2016155909A1 (en) * | 2015-03-31 | 2016-10-06 | Consejo Superior De Investigaciones Cientificas (Csic) | Albite and/or anorthite glass ceramic material exhibing thermal warmth |
| CN108341687A (en) * | 2018-04-27 | 2018-07-31 | 太原理工大学 | A kind of preparation method of high-performance level cloth water-permeable brick |
| CN109748579A (en) * | 2019-02-26 | 2019-05-14 | 南通华兴磁性材料有限公司 | The preparation method of high impedance high magnetic characteristics nickel-manganese Zinc ferrite material |
| JP6614371B1 (en) * | 2019-01-28 | 2019-12-04 | 哲男 原田 | A high-chromium cast iron cast-in method for cermet TiC chips and a plate liner manufacturing method for a bellless raw material charging apparatus using this method. |
-
2022
- 2022-06-30 CN CN202210763660.XA patent/CN114974875B/en active Active
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4786430A (en) * | 1987-01-24 | 1988-11-22 | Basf Aktiengesellschaft | Method for producing hexagonal ferrites |
| WO2004018716A1 (en) * | 2002-08-21 | 2004-03-04 | Nippon Steel Corporation | Method of granulating sintering material for iron manufacturing |
| EP2244269A1 (en) * | 2006-03-10 | 2010-10-27 | Hitachi Metals, Ltd. | Method for producing sintered ferrite magnet |
| CN102351525A (en) * | 2011-07-19 | 2012-02-15 | 吕佳佳 | Manufacture method of permanent magnet ferrite material powder for injection molding |
| CN102424583A (en) * | 2011-09-05 | 2012-04-25 | 吕佳佳 | Magnetic powder for bonding hard ferrite |
| CN102992744A (en) * | 2011-09-13 | 2013-03-27 | 张连墩 | M-type strontium ferrite powder for injection molding bonded permanent magnet and preparation process of M-type strontium ferrite powder |
| WO2014017637A2 (en) * | 2012-07-27 | 2014-01-30 | Tdk株式会社 | MANUFACTURING METHOD FOR Sr FERRITE PARTICLES FOR SINTERED MAGNET, AND MANUFACTURING METHOD FOR Sr FERRITE SINTERED MAGNET |
| JP2014159541A (en) * | 2013-01-22 | 2014-09-04 | Sekisui Chem Co Ltd | Thermally expandable fire-resistant resin composition |
| WO2016155909A1 (en) * | 2015-03-31 | 2016-10-06 | Consejo Superior De Investigaciones Cientificas (Csic) | Albite and/or anorthite glass ceramic material exhibing thermal warmth |
| CN108341687A (en) * | 2018-04-27 | 2018-07-31 | 太原理工大学 | A kind of preparation method of high-performance level cloth water-permeable brick |
| JP6614371B1 (en) * | 2019-01-28 | 2019-12-04 | 哲男 原田 | A high-chromium cast iron cast-in method for cermet TiC chips and a plate liner manufacturing method for a bellless raw material charging apparatus using this method. |
| CN109748579A (en) * | 2019-02-26 | 2019-05-14 | 南通华兴磁性材料有限公司 | The preparation method of high impedance high magnetic characteristics nickel-manganese Zinc ferrite material |
Non-Patent Citations (2)
| Title |
|---|
| SrFe12O19改性的半导电屏蔽材料电荷注入特性研究;刘明月;中国优秀硕士学位论文全文数据库 (基础科学辑);B020-352 * |
| 室温离子液体修饰无机纳米微粒的制备与表征;孟祥丽;中国优秀硕士学位论文全文数据库 (基础科学辑);B020-63 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114974875A (en) | 2022-08-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101844914B (en) | Magnetoplumbate-type permanent magnetic ferrite and manufacturing method thereof | |
| CN101899281B (en) | Rare earth polishing powder and production method thereof | |
| CN104609859B (en) | Introduce from climing combustion the method that sintering of nano-material auxiliary agent low-temperature sintering is prepared 0-3 magnetoelectric ceramic | |
| EP3248942B1 (en) | Resin composition containing a hexagonal plate shaped ferrite powder, manufacturing method thereof, and molded product formed from the resin composition | |
| CN110156452B (en) | M-type strontium ferrite and preparation method thereof | |
| CN110577400A (en) | Preparation method of manganese zinc ferrite with high magnetic conductivity | |
| CN115312283B (en) | High-compaction-density injection magnetic powder and preparation method thereof | |
| CN114974875B (en) | Preparation method of environment-friendly high-performance bonded permanent magnetic ferrite magnetic powder | |
| KR101156806B1 (en) | Ferrite magnetic powder for bonded magnets, process for production thereof, and bonded magnets | |
| GB2051772A (en) | Dry process for the production of hexagonal-system ferrite | |
| CN109102977A (en) | A kind of high density dry-pressing opposite sex ferrimagnet and its manufacturing method | |
| CN110204326A (en) | A kind of ferrite permanent-magnet materials and preparation method thereof with core-shell structure | |
| CN110963794A (en) | Preparation method of economical permanent magnetic ferrite material | |
| CN108164174A (en) | A kind of preparation method of cement grinding aid | |
| GB1586783A (en) | Process for the production of a hexagonalsystem ferrite powder a plastic-ferrite composite magnet containing the ferrite powder so produced and a process for producing the composite magnet | |
| CN110564953B (en) | Method for improving quality of vanadium-titanium magnetite concentrate sinter | |
| CN105967672A (en) | High-performance calcium strontium zinc barium ferrite and preparation method thereof | |
| CN106083023B (en) | A kind of preparation method and product of high mechanical properties strontium ferrite magnet | |
| CN106006695A (en) | Preparation method of high-strength composite gypsum micropowder | |
| JP7405648B2 (en) | Ferrite powder for bonded magnets and its manufacturing method | |
| CN101409122A (en) | High-performance permanent ferrite and dyadic manufacturing method thereof | |
| TWI693206B (en) | Method of fabricating modified ferrite magnetic powder and method of fabricating ferrite magnet | |
| CN109133711A (en) | A kind of preparation method of cement grinding aid | |
| CN114031386B (en) | Green and environment-friendly resource recycling method | |
| CN117383923A (en) | Calcium barium strontium permanent magnetic ferrite and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |